Archive for the ‘Gene Therapy Research’ Category

In brief

In fewer than five years, a gene-editing technology known as CRISPR has revolutionized research. Now, many are wondering if it can do the same for medicine. Several companies are hoping to commercialize CRISPR-based therapies that could potentially offer a permanent fix for a vast array of genetic diseases. But theres a catch: Getting CRISPR into the body, across cell membranes, and into human DNA is no simple feat. Read on to learn how chemists and bioengineers are joining the CRISPR craze to solve gene editings delivery dilemma.

In fewer than five years, an important new gene-editing tool called CRISPR has radically changed the face and pace of biological research. The ability to quickly and cleanly remove and replace stretches of DNA has already inspired thousands of publications featuring the technique and led to the creation of a slew of biotech businesses hoping to capitalize on CRISPR.

CRISPRs power to effortlessly target and tweak any piece of DNA seems limitless. Thomas Barnes is the chief scientific officer of the CRISPR-centered Intellia Therapeutics, whose founders include one of the inventors of CRISPR, Jennifer Doudna. He says there is an ever-growing backlog of well-understood rare genetic conditions with little that people can do about them. Barnes hopes CRISPR will change that.

By tackling genetic disease at its rootsmutations in the DNACRISPR could end thousands of ailments, Barnes and others believe. Multiple research groups and companies are hot on the tracks of unleashing CRISPR on sickle cell disease, hemophilia, cystic fibrosis, Duchenne muscular dystrophy, genetic forms of blindness, and, of course, cancer.

The hype is partly about CRISPRs broad applicability, but CRISPRs true promise is its potential for a one-and-done cure. Changing your DNA is a permanent fix. CRISPRshort for the clustered regularly interspaced short palindromic repeats in the bacterial immune system from which the technology was derivedis a two-part system: a customizable guide RNA and a protein called Cas9. The guide RNA directs Cas9 to any desired segment of DNA for editing. The Cas9 enzyme then cuts the DNA at that precise location, allowing for genes to be turned on or off or for the removal or insertion of DNA.

But editing the DNA of cells in a petri dishor even curing a mouse of a diseaseis one thing; making the hot new technology work in humans is a whole other challenge. Sneaking the gene-editing complex into human cells is no easy task.

It will take some fancy molecular maneuvering to get the bulky Cas9 protein and the negatively charged guide RNA into humans. To work its magic, the unwieldy gene-editing system first needs to get into the body, skirt past the immune system, and infiltrate its target tissue. From there, it must sneak across cell membranes, escape the acidic environment of the cells endosomes to find the nucleus, and then home in on the correct location on the DNA. In other words, CRISPR has a drug delivery problem.

The Cas9 enzyme and the guide RNA composing the CRISPR complex cannot be swallowed in pill form or simply injected into the bloodstream. And a one-size-fits-all package is unlikely to work for every condition, so researchers are eagerly testing old strategies and creating new ones to achieve a CRISPR cure.

David Liu of Harvard University says this delivery dilemma isnt unusual for a new gene-editing technology, but researchers now feel this incredible urgency and excitement because of the promise of using CRISPR for therapeutic applications. Since its inception as a gene-editing tool in 2012, nearly 5,000 papers mentioning CRISPR have been published in PubMed. The CRISPR craze is reeling in polymer chemists, drug delivery designers, and bioengineers all helping move CRISPR from the lab bench to the doctors office.

Ive just never seen any field that progresses at this pace, says Niren Murthy of the University of California, Berkeley, who cofounded a start-up called GenEdit, dedicated to CRISPR delivery, in February 2016. There is nothing comparable to the competitiveness of the CRISPR field, he says.

From a delivery perspective, I am sure there will be all sorts of surprises, says Kathryn Whitehead of Carnegie Mellon University. C&EN spoke with more than 30 academic and industry researchers about CRISPRs delivery dilemma. Some expect success soon. Others are trying to temper expectations, pointing to the historically long time horizon for turning new technologies into treatments. But as Whitehead says, If this is possible, everything changes.

CRISPR gene editing is derived from a primordial immune system in bacteria called clustered regularly interspaced short palindromic repeats. A guide RNA, which is complementary to a target DNA sequence, directs the Cas9 enzyme (light blue) to a specified location for DNA cutting. Some applications require an additional DNA template (not shown) to fill in the cut. Source: Adapted from OriGene Technologies

CRISPR isnt the first gene-editing technology promising to cure thousands of diseases. In fact, multiple studies of treatments developed using older technologies are now under way. Drug delivery guru Daniel Anderson of Massachusetts Institute of Technology points out that one of the most advanced programs is Sangamo Biosciences ongoing clinical trial to remove T cells from patients, edit their DNA to make them resistant to HIV, and reinject the modified cells. So presumably, there are some genome-edited people walking around in California that they helped create, Anderson says.

Sangamo is using an older gene-editing tool called zinc finger nucleases, a complex protein structure designed to bind and cleave a specific region of DNA. And doctors at the Great Ormond Street Hospital in London recently reported using a similar gene-editing technique called TALENs, which also recognizes and cuts precise DNA sequences, to engineer immune cells for a therapy that may have cured two infants of leukemia.

Both technologies have been around for longer than CRISPR has, with zinc-finger-based editing being in the works for more than two decades. They also both suffer from a limitation that has inhibited their widespread adoption: Each is a cumbersome protein complex that needs to be individually engineered for every new DNA target.

CRISPR, meanwhile, is easily adaptable. The Cas9 cutting protein remains the same for all applications, and to make a new edit, researchers need only to switch out the guide RNA. If the DNA sequence that needs editing is known, securing the complementary guide RNA is as easy as clicking Order from a supplier.

When CRISPR came along, everyone knew what to do with it, Intellias Barnes says. People had been going around in a go-kart and you gave them a Ferrari, so away they go.

Jacob Corn of UC Berkeley says cheap and easily customizable guide RNA empowers the democratization of gene editing. Corns lab is one of several using CRISPR to cureat least in isolated cells and micesickle cell disease, where a single-letter DNA mutation stymies the oxygen-ferrying capacity of red blood cells.

Corn envisions a world where patient DNA testing is coupled to CRISPRs customizability, and scientists can easily whip up a fix for problematic genetic mutations. I think that, in the future, well be able to tackle genetic diseases with the same speed we can diagnose them, he says.

Corns dream might not be far off, at least for blood disorders such as sickle cell disease. In that condition, stem cells collected from the blood or bone marrow could be removed from a patient, edited in the lab to correct the DNA typoa process called ex vivo gene editingand then reinjected to proliferate and make a patient healthy.

Editing cells harvested from a patient is relatively straightforward. Researchers commonly use electroporation, a technique that uses an electric pulse to momentarily create pores that allow the Cas9 protein and guide RNA complex to slip inside cells in a dish. This technique has the potential to address hematological disorders and is also being used to beef up immune cells to fight cancers such as leukemia.

Lloyd Klickstein, head of translational medicine for the new indications discovery unit at the Novartis Institutes for BioMedical Research, says, Thus far, the ex vivo technologies are whats been done, and thats what most of the companies are looking to do first, Novartis included.

The concept looks promising on paper, but no one knows how well it will work in humans. Chinese researchers at Sichuan University claimed to be the first to do ex vivo therapy with a handful of people with cancer last year, and University of Pennsylvania researchers are gearing up for a similar clinical trial in Philadelphia, San Francisco, and Houston this year.

Although researchers are excited about the potential to use CRISPR to create therapies from peoples own blood, immune, and stem cells, thousands more genetic conditions affect everything else. For those disorders, CRISPR needs to be delivered like more traditional medicines so it can work its wonders editing DNA inside the body. But the challenge of shuttling CRISPR directly to the diseased tissue, or in vivo gene editing, is so daunting it could stall CRISPRs otherwise rapid advancement.

The first in vivo CRISPR therapy to be tested in humans will likely borrow its delivery vehicle from the world of gene therapy, where hollowed shells of viruses are used to transport genes inside cells and then, in theory, permanently produce a therapeutic protein. Decades of gene therapy research has yielded a reasonably good carrier for genetic material, the adeno-associated virus (AAV). Compared with other viral vehicles, the immune system tends to ignore AAV, and the carrier is able to target specific cell types in the body.

Editas Medicines founding scientific adviser is one of CRISPRs inventors, Feng Zhang of the Broad Institute. Editas is using AAV to deliver CRISPR in monkeys. In this study, CRISPR targets the genetic mutation that causes Leber congenital amaurosis 10, a rare form of progressive childhood blindness. The biotech firm plans to ask FDA for permission to start human studies of the treatment, which must be directly injected into the eye, by the end of this year. We chose that disease because we felt that we could deliver our machinery there, says Charles Albright, chief scientific officer of Editas.

Seokjoong Kim, research director at the South Korea-based gene-editing company ToolGen, is also conducting CRISPR experiments in mice for eye disorders, including age-related macular degeneration and diabetic retinopathy. ToolGen will also deliver CRISPR with AAV because it is the most validated delivery tool clinically, Kim says. He notes that AAV is already being used in gene therapy clinical trials for Parkinsons disease, hemophilia, and vision disorders.

We are building on decades of work in gene therapy, Albright says. We believe that patients and regulators and physicians will feel more comfortable using this method. Using CRISPR in humans is enough of an unknown for Editas and ToolGen, and they believe the chances of success and drug approval are higher with an established delivery system such as AAV.

But AAVs strength for gene therapyperpetual production of a proteinis its drawback for gene editing. One of the potential issues with AAV is that there is no good way to control the expression of Cas9, says Mark Kay, director of the Program in Human Gene Therapy at Stanford University. Once inside cells, the DNA plasmid will continue producing the Cas9 enzyme indefinitely. Since CRISPR needs to make its edit only once, the longer Cas9 hangs out inside the cell, the greater the chance the enzyme will make unwanted cuts in a patients DNA, Kay says.

Those off-target cuts are frequent topics of concern among CRISPR scientists. Even though the tool is precise, there is no guarantee it will perform to perfection. That liability has driven many researchers to look for other ways of delivering CRISPR.

The challenge of commercializing CRISPR has an even closer cousin than gene therapy. Work by scientists in 1998 unexpectedly showed that double-stranded RNA molecules could suppress the translation of messenger RNA (mRNA) into protein. Known as RNA interference, or RNAi, the research garnered a Nobel Prize in 2006 and spurred the creation of start-ups aimed at turning this powerful method of silencing genes into therapies.

But RNA cannot be directly injected into the bloodstream, where it gets degraded and triggers an immune reaction. So scientists have spent the past decade figuring out how to get their molecules inside cells. Now, CRISPR researchers are hoping to borrow their most common delivery vehicle, the lipid nanoparticle.

To reuse lipid nanoparticles for CRISPR, the gene-editing system has to be packaged in a way that recapitulates the negatively charged RNA molecules used in RNAi. Instead of delivering Cas9 as a functional protein, many researchers are sticking the mRNA instructions to make Cas9 inside their nanoparticles and letting the cell produce the protein.

Andersons lab at MIT has been a center of thought for this research. Hao Yin, a postdoctoral researcher in Andersons lab, packaged Cas9 mRNA in lipid nanoparticles previously developed in the Anderson lab for shipping RNAi molecules across a cells lipid membrane. Yin then delivered that alongside guide RNAs packaged separately in AAV to fix broken genes in mice with liver disease. The upside of the method is minimal off-target cutting by Cas9. The downside is that the efficiency is very low, Yin says. Only about 6% of hepatocytes, or liver cells, were edited by CRISPR (Nat. Biotechnol. 2016, DOI: 10.1038/nbt.3471).

New and improved lipid nanoparticles are popping up that can deliver both Cas9 mRNA and the guide RNA in the same particle. Although that dual packaging would in theory improve editing efficiency, it also poses some logistical problems. The molecules used in RNAi are only about 20 nucleotides long. Guide RNAs used in CRISPR, on the other hand, are about 100 nucleotides long, and the mRNA encoding Cas9 is an unwieldy beast of 4,500 nucleotides. So if you take the off-the-shelf lipid nanoparticle formulation and instead encapsulate the CRISPR system, its just not very good, says Daniel J. Siegwart of the University of Texas Southwestern Medical Center.

Siegwart, who was previously a postdoctoral researcher in Andersons lab, became the first to successfully deliver that kind of dual packaging to mice in December. Lipid nanoparticles require several ingredients for ferrying RNA into cells, including positively charged lipids for binding the negatively charged RNA. Siegwarts group synthesized zwitterionic amino lipids, ones containing both positive and negative charges, which help bind, stabilize, and release the mRNA as the particles cross into cells (Angew. Chem. Int. Ed. 2016, DOI: 10.1002/anie.201610209).

Lipid nanoparticles enter cells through a pinched-off cell membrane envelope called the endosome, and getting Cas9 mRNA out of that structure can be another limiting step. In January, Paul A. Wender and Robert M. Waymouth of Stanford University unveiled a polymer nanoparticle system to overcome this problem. Their particle acts like a physical property chameleon, Wender says, changing its form as it crosses the cell membrane and enters the endosome.

Wender and Waymouths system, called charge-altering releasable transporters, are made of initially positively charged oligo(-amino ester) polymers that bind the negatively charged mRNA. Upon entering the endosome, where the pH becomes more acidic, positively charged amine molecules in the polymer become neutrally charged amides, which releases the mRNA into the cell (Proc. Natl. Acad. Sci. USA 2017, DOI: 10.1073/pnas.1614193114). Although their paper didnt explicitly test the concept on Cas9 mRNA, thats on the to-do list.

Lipid nanoparticle innovation may be blossoming, and CRISPR developers are confident they can reach the clinic more quickly and safely than with RNAi, but that delivery vessel is by no means foolproof.

Rodger Novak, chief executive officer of CRISPR Therapeutics, whose founders include another of CRISPRs co-inventors, Emmanuelle Charpentier, points out that CRISPR has an advantage over RNAi, which turns down protein production only temporarily and needs to be readministered periodically. Those repeat injections can cause liver toxicity, a side effect that has slowed down the initially rapid progress of RNAi companies. Although the technology is maturing, there are no approved RNAi drugs.

The whole lipid nanoparticle field is a little bit weird, Ross Wilson of UC Berkeley says. The literature is full of success stories that are never followed up on; they just fizzle.

Wilson is one of several researchers working on delivering Cas9 as a protein rather than as mRNA in a lipid nanoparticle or as DNA in a virus. Researchers call this form of CRISPR a ribonucleoprotein, which is the active form of the guide RNA hooked up to the Cas9 enzyme in a single, ready-to-go complex.

David Liu of Harvard University says delivering CRISPR in a virus gives the least amount of control because it manufactures the Cas9 protein indefinitely. If there are too many Cas9 enzymes in a cell, there is a greater chance that one of them may accidentally cut DNA in the wrong place. Directly delivering the protein gives the most control because lower levels of Cas9 in each cell means a lower risk of potentially dangerous off-target cutting, Liu says. His group developed cationic lipid nanoparticles for CRISPR ribonucleoprotein delivery (Nat. Biotechnol. 2015, DOI: 10.1038/nbt.3081).

Liu, along with Qiaobing Xu of Tufts University, also created lipid nanoparticles that are biodegradable inside cells. The system binds negatively charged CRISPR ribonucleoproteins initially, but releases them upon entering the chemically reducing environment of the cell (Proc. Natl. Acad. Sci. USA 2016, DOI: 10.1073/pnas.1520244113).

Wilson is looking to find a way to deliver CRISPR ribonucleoproteins without the hassle of lipid nanoparticles. To do that, he needs to make the ribonucleoprotein complex stable in the bloodstream, able to escape the cells endosome, and even able to home in on a particular tissue type. But there is a downside. The immunogenicity of Cas9 could be a real issue, Wilson says.

Other scientists are crafting even more exotic delivery systems for CRISPR, including a yarn ball-like structure called a DNA nanoclew developed by Chase Beisel and Zhen Gu of North Carolina State University. Their nanoclew uses repeated stretches of DNA complementary to the guide RNA wrapped up in a ball to deliver Cas9 protein to cells. (Angew. Chem. Int. Ed. 2015, DOI: 10.1002/anie.201506030).

Even as the field works out the delivery kinks, therapies are expected to soon reach people. Clinical trials using ex vivo gene editing in humans with CRISPR is anticipated to start in the U.S. this year, with in vivo gene editing likely in 2018 and 2019.

Casebia Therapeutics, a joint venture between Novartis and CRISPR Therapeutics, is making its commitment to the delivery challenge clear, with plans to hire a head of delivery. James Burns, CEO and president of Casebia, says, There are some approaches that we can take now, but to really harness or achieve CRISPRs full potential, we are going to have to invest in new delivery technologies. Currently, most CRISPR-based companies are taking an agnostic, whatever works approach, testing both AAV and lipid nanoparticles for their first rounds of treatment.

Berkeleys Corn points out another problem with CRISPR that many people conveniently gloss over. We are really good at breaking sequences and not really good at fixing them, he says. Some conditions can be cured using Cas9 to cut out a mutation or turn a gene off. But there are many more conditions where faulty DNA needs actual correcting. That requires a third component: a DNA template strand to tell the cells repair machinery how to fill in a cut made by Cas9.

Delivering all three has been really challenging and it has not been demonstrated in in vivo systems with any lipid nanoparticles yet, says Kunwoo Lee, who is now CEO of the start-up GenEdit that he founded in February 2016 shortly before finishing his Ph.D. in Murthys lab at Berkeley. GenEdit focuses on applications of CRISPR that will require a DNA template for repair.

Lee and his colleagues at GenEdit already have a few scientific studies under review, including one that uses gold nanoparticles as a core material to load the three components of the CRISPR system. They are also working on lipid and polymer nanoparticle systems, all designed to deliver CRISPR ribonucleoproteins. Although that strategy is promising for minimizing off-target cutting, it may also be the furthest away from being an injectable treatment in the clinic.

There is simply no way that any particular delivery modality is going to provide the means to address all of those targets, so it really needs to be an all-of-the-above approach, says Erik Sontheimer of the RNA Therapeutics Institute at the University of Massachusetts Medical School. And from the looks of it, the CRISPR companies are approaching it as such.

Ive heard many people say buckle up because there will be a trough of disillusionment that has to be traversed before it can become a clinical reality, Sontheimer says. But the potential payoff is so clear, that there will be enough staying power if and when that comes.

Read more from the original source:
CRISPR's breakthrough problem | February 13, 2017 Issue - Vol. 95 ... - The Biological SCENE

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Medical schools steadily improve clinical care with research Crain's Detroit Business ... study on whether intravenous delivery of nutrients into the first part of the intestine or stomach will reduce eating and improve weight-related conditions to Wayne State's novel gene therapy research for blinding eye disease, which affects 100,000 ...

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Gene therapy utilizes the delivery of DNA into cells, which can be accomplished by several methods, summarized below. The two major classes of methods are those that use recombinant viruses (sometimes called biological nanoparticles or viral vectors) and those that use naked DNA or DNA complexes (non-viral methods).

All viruses bind to their hosts and introduce their genetic material into the host cell as part of their replication cycle. This genetic material contains basic 'instructions' of how to produce more copies of these viruses, hacking the body's normal production machinery to serve the needs of the virus. The host cell will carry out these instructions and produce additional copies of the virus, leading to more and more cells becoming infected. Some types of viruses insert their genome into the host's cytoplasm, but do not actually enter the cell. Others penetrate the cell membrane disguised as protein molecules and enter the cell.

There are two main types of virus infection: lytic and lysogenic. Shortly after inserting its DNA, viruses of the lytic cycle quickly produce more viruses, burst from the cell and infect more cells. Lysogenic viruses integrate their DNA into the DNA of the host cell and may live in the body for many years before responding to a trigger. The virus reproduces as the cell does and does not inflict bodily harm until it is triggered. The trigger releases the DNA from that of the host and employs it to create new viruses.

The genetic material in retroviruses is in the form of RNA molecules, while the genetic material of their hosts is in the form of DNA. When a retrovirus infects a host cell, it will introduce its RNA together with some enzymes, namely reverse transcriptase and integrase, into the cell. This RNA molecule from the retrovirus must produce a DNA copy from its RNA molecule before it can be integrated into the genetic material of the host cell. The process of producing a DNA copy from an RNA molecule is termed reverse transcription. It is carried out by one of the enzymes carried in the virus, called reverse transcriptase. After this DNA copy is produced and is free in the nucleus of the host cell, it must be incorporated into the genome of the host cell. That is, it must be inserted into the large DNA molecules in the cell (the chromosomes). This process is done by another enzyme carried in the virus called integrase.

Now that the genetic material of the virus has been inserted, it can be said that the host cell has been modified to contain new genes. If this host cell divides later, its descendants will all contain the new genes. Sometimes the genes of the retrovirus do not express their information immediately.

One of the problems of gene therapy using retroviruses is that the integrase enzyme can insert the genetic material of the virus into any arbitrary position in the genome of the host; it randomly inserts the genetic material into a chromosome. If genetic material happens to be inserted in the middle of one of the original genes of the host cell, this gene will be disrupted (insertional mutagenesis). If the gene happens to be one regulating cell division, uncontrolled cell division (i.e., cancer) can occur. This problem has recently begun to be addressed by utilizing zinc finger nucleases[1] or by including certain sequences such as the beta-globin locus control region to direct the site of integration to specific chromosomal sites.

Gene therapy trials using retroviral vectors to treat X-linked severe combined immunodeficiency (X-SCID) represent the most successful application of gene therapy to date. More than twenty patients have been treated in France and Britain, with a high rate of immune system reconstitution observed. Similar trials were restricted or halted in the USA when leukemia was reported in patients treated in the French X-SCID gene therapy trial.[citation needed] To date, four children in the French trial and one in the British trial have developed leukemia as a result of insertional mutagenesis by the retroviral vector. All but one of these children responded well to conventional anti-leukemia treatment. Gene therapy trials to treat SCID due to deficiency of the Adenosine Deaminase (ADA) enzyme (one form of SCID)[2] continue with relative success in the USA, Britain, Ireland, Italy and Japan.

Adenoviruses are viruses that carry their genetic material in the form of double-stranded DNA. They cause respiratory, intestinal, and eye infections in humans (especially the common cold). When these viruses infect a host cell, they introduce their DNA molecule into the host. The genetic material of the adenoviruses is not incorporated (transient) into the host cell's genetic material. The DNA molecule is left free in the nucleus of the host cell, and the instructions in this extra DNA molecule are transcribed just like any other gene. The only difference is that these extra genes are not replicated when the cell is about to undergo cell division so the descendants of that cell will not have the extra gene. As a result, treatment with the adenovirus will require readministration in a growing cell population although the absence of integration into the host cell's genome should prevent the type of cancer seen in the SCID trials. This vector system has been promoted for treating cancer and indeed the first gene therapy product to be licensed to treat cancer, Gendicine, is an adenovirus. Gendicine, an adenoviral p53-based gene therapy was approved by the Chinese food and drug regulators in 2003 for treatment of head and neck cancer. Advexin, a similar gene therapy approach from Introgen, was turned down by the US Food and Drug Administration (FDA) in 2008.

Concerns about the safety of adenovirus vectors were raised after the 1999 death of Jesse Gelsinger while participating in a gene therapy trial. Since then, work using adenovirus vectors has focused on genetically crippled versions of the virus.

The viral vectors described above have natural host cell populations that they infect most efficiently. Retroviruses have limited natural host cell ranges, and although adenovirus and adeno-associated virus are able to infect a relatively broader range of cells efficiently, some cell types are refractory to infection by these viruses as well. Attachment to and entry into a susceptible cell is mediated by the protein envelope on the surface of a virus. Retroviruses and adeno-associated viruses have a single protein coating their membrane, while adenoviruses are coated with both an envelope protein and fibers that extend away from the surface of the virus. The envelope proteins on each of these viruses bind to cell-surface molecules such as heparin sulfate, which localizes them upon the surface of the potential host, as well as with the specific protein receptor that either induces entry-promoting structural changes in the viral protein, or localizes the virus in endosomes wherein acidification of the lumen induces this refolding of the viral coat. In either case, entry into potential host cells requires a favorable interaction between a protein on the surface of the virus and a protein on the surface of the cell. For the purposes of gene therapy, one might either want to limit or expand the range of cells susceptible to transduction by a gene therapy vector. To this end, many vectors have been developed in which the endogenous viral envelope proteins have been replaced by either envelope proteins from other viruses, or by chimeric proteins. Such chimera would consist of those parts of the viral protein necessary for incorporation into the virion as well as sequences meant to interact with specific host cell proteins. Viruses in which the envelope proteins have been replaced as described are referred to as pseudotyped viruses. For example, the most popular retroviral vector for use in gene therapy trials has been the lentivirus Simian immunodeficiency virus coated with the envelope proteins, G-protein, from Vesicular stomatitis virus. This vector is referred to as VSV G-pseudotyped lentivirus, and infects an almost universal set of cells. This tropism is characteristic of the VSV G-protein with which this vector is coated. Many attempts have been made to limit the tropism of viral vectors to one or a few host cell populations. This advance would allow for the systemic administration of a relatively small amount of vector. The potential for off-target cell modification would be limited, and many concerns from the medical community would be alleviated. Most attempts to limit tropism have used chimeric envelope proteins bearing antibody fragments. These vectors show great promise for the development of "magic bullet" gene therapies.

A replication-competent vector called ONYX-015 is used in replicating tumor cells. It was found that in the absence of the E1B-55Kd viral protein, adenovirus caused very rapid apoptosis of infected, p53(+) cells, and this results in dramatically reduced virus progeny and no subsequent spread. Apoptosis was mainly the result of the ability of EIA to inactivate p300. In p53(-) cells, deletion of E1B 55kd has no consequence in terms of apoptosis, and viral replication is similar to that of wild-type virus, resulting in massive killing of cells.

A replication-defective vector deletes some essential genes. These deleted genes are still necessary in the body so they are replaced with either a helper virus or a DNA molecule.

[3]

Replication-defective vectors always contain a transfer construct. The transfer construct carries the gene to be transduced or transgene. The transfer construct also carries the sequences which are necessary for the general functioning of the viral genome: packaging sequence, repeats for replication and, when needed, priming of reverse transcription. These are denominated cis-acting elements, because they need to be on the same piece of DNA as the viral genome and the gene of interest. Trans-acting elements are viral elements, which can be encoded on a different DNA molecule. For example, the viral structural proteins can be expressed from a different genetic element than the viral genome.

[3]

The Herpes simplex virus is a human neurotropic virus. This is mostly examined for gene transfer in the nervous system. The wild type HSV-1 virus is able to infect neurons and evade the host immune response, but may still become reactivated and produce a lytic cycle of viral replication. Therefore, it is typical to use mutant strains of HSV-1 that are deficient in their ability to replicate. Though the latent virus is not transcriptionally apparent, it does possess neuron specific promoters that can continue to function normally[further explanation needed]. Antibodies to HSV-1 are common in humans, however complications due to herpes infection are somewhat rare.[4] Caution for rare cases of encephalitis must be taken and this provides some rationale to using HSV-2 as a viral vector as it generally has tropism for neuronal cells innervating the urogenital area of the body and could then spare the host of severe pathology in the brain.

Non-viral methods present certain advantages over viral methods, with simple large scale production and low host immunogenicity being just two. Previously, low levels of transfection and expression of the gene held non-viral methods at a disadvantage; however, recent advances in vector technology have yielded molecules and techniques with transfection efficiencies similar to those of viruses.[5]

This is the simplest method of non-viral transfection. Clinical trials carried out of intramuscular injection of a naked DNA plasmid have occurred with some success; however, the expression has been very low in comparison to other methods of transfection. In addition to trials with plasmids, there have been trials with naked PCR product, which have had similar or greater success. Cellular uptake of naked DNA is generally inefficient. Research efforts focusing on improving the efficiency of naked DNA uptake have yielded several novel methods, such as electroporation, sonoporation, and the use of a "gene gun", which shoots DNA coated gold particles into the cell using high pressure gas.[6]

Electroporation is a method that uses short pulses of high voltage to carry DNA across the cell membrane. This shock is thought to cause temporary formation of pores in the cell membrane, allowing DNA molecules to pass through. Electroporation is generally efficient and works across a broad range of cell types. However, a high rate of cell death following electroporation has limited its use, including clinical applications.

More recently a newer method of electroporation, termed electron-avalanche transfection, has been used in gene therapy experiments. By using a high-voltage plasma discharge, DNA was efficiently delivered following very short (microsecond) pulses. Compared to electroporation, the technique resulted in greatly increased efficiency and less cellular damage.

The use of particle bombardment, or the gene gun, is another physical method of DNA transfection. In this technique, DNA is coated onto gold particles and loaded into a device which generates a force to achieve penetration of the DNA into the cells, leaving the gold behind on a "stopping" disk.

Sonoporation uses ultrasonic frequencies to deliver DNA into cells. The process of acoustic cavitation is thought to disrupt the cell membrane and allow DNA to move into cells.

In a method termed magnetofection, DNA is complexed to magnetic particles, and a magnet is placed underneath the tissue culture dish to bring DNA complexes into contact with a cell monolayer.

Hydrodynamic delivery involves rapid injection of a high volume of a solution into vasculature (such as into the inferior vena cava, bile duct, or tail vein). The solution contains molecules that are to be inserted into cells, such as DNA plasmids or siRNA, and transfer of these molecules into cells is assisted by the elevated hydrostatic pressure caused by the high volume of injected solution.[7][8][9]d

The use of synthetic oligonucleotides in gene therapy is to deactivate the genes involved in the disease process. There are several methods by which this is achieved. One strategy uses antisense specific to the target gene to disrupt the transcription of the faulty gene. Another uses small molecules of RNA called siRNA to signal the cell to cleave specific unique sequences in the mRNA transcript of the faulty gene, disrupting translation of the faulty mRNA, and therefore expression of the gene. A further strategy uses double stranded oligodeoxynucleotides as a decoy for the transcription factors that are required to activate the transcription of the target gene. The transcription factors bind to the decoys instead of the promoter of the faulty gene, which reduces the transcription of the target gene, lowering expression. Additionally, single stranded DNA oligonucleotides have been used to direct a single base change within a mutant gene. The oligonucleotide is designed to anneal with complementarity to the target gene with the exception of a central base, the target base, which serves as the template base for repair. This technique is referred to as oligonucleotide mediated gene repair, targeted gene repair, or targeted nucleotide alteration.

To improve the delivery of the new DNA into the cell, the DNA must be protected from damage and (positively charged). Initially, anionic and neutral lipids were used for the construction of lipoplexes for synthetic vectors. However, in spite of the facts that there is little toxicity associated with them, that they are compatible with body fluids and that there was a possibility of adapting them to be tissue specific; they are complicated and time consuming to produce so attention was turned to the cationic versions.

Cationic lipids, due to their positive charge, were first used to condense negatively charged DNA molecules so as to facilitate the encapsulation of DNA into liposomes. Later it was found that the use of cationic lipids significantly enhanced the stability of lipoplexes. Also as a result of their charge, cationic liposomes interact with the cell membrane, endocytosis was widely believed as the major route by which cells uptake lipoplexes. Endosomes are formed as the results of endocytosis, however, if genes can not be released into cytoplasm by breaking the membrane of endosome, they will be sent to lysosomes where all DNA will be destroyed before they could achieve their functions. It was also found that although cationic lipids themselves could condense and encapsulate DNA into liposomes, the transfection efficiency is very low due to the lack of ability in terms of endosomal escaping. However, when helper lipids (usually electroneutral lipids, such as DOPE) were added to form lipoplexes, much higher transfection efficiency was observed. Later on, it was figured out that certain lipids have the ability to destabilize endosomal membranes so as to facilitate the escape of DNA from endosome, therefore those lipids are called fusogenic lipids. Although cationic liposomes have been widely used as an alternative for gene delivery vectors, a dose dependent toxicity of cationic lipids were also observed which could limit their therapeutic usages.

The most common use of lipoplexes has been in gene transfer into cancer cells, where the supplied genes have activated tumor suppressor control genes in the cell and decrease the activity of oncogenes. Recent studies have shown lipoplexes to be useful in transfecting respiratory epithelial cells.

Polymersomes are synthetic versions of liposomes (vesicles with a lipid bilayer), made of amphiphilic block copolymers. They can encapsulate either hydrophilic or hydrophobic contents and can be used to deliver cargo such as DNA, proteins, or drugs to cells. Advantages of polymersomes over liposomes include greater stability, mechanical strength, blood circulation time, and storage capacity.[10][11][12]

Complexes of polymers with DNA are called polyplexes. Most polyplexes consist of cationic polymers and their fabrication is based on self-assembly by ionic interactions. One important difference between the methods of action of polyplexes and lipoplexes is that polyplexes cannot directly release their DNA load into the cytoplasm. As a result, co-transfection with endosome-lytic agents such as inactivated adenovirus was required to facilitate nanoparticle escape from the endocytic vesicle made during particle uptake. However, a better understanding of the mechanisms by which DNA can escape from endolysosomal pathway, i.e. proton sponge effect,[13] has triggered new polymer synthesis strategies such as incorporation of protonable residues in polymer backbone and has revitalized research on polycation-based systems.[14]

Due to their low toxicity, high loading capacity, and ease of fabrication, polycationic nanocarriers demonstrate great promise compared to their rivals such as viral vectors which show high immunogenicity and potential carcinogenicity, and lipid-based vectors which cause dose dependence toxicity. Polyethyleneimine[15] and chitosan are among the polymeric carriers that have been extensively studies for development of gene delivery therapeutics. Other polycationic carriers such as poly(beta-amino esters)[16] and polyphosphoramidate[17] are being added to the library of potential gene carriers. In addition to the variety of polymers and copolymers, the ease of controlling the size, shape, surface chemistry of these polymeric nano-carriers gives them an edge in targeting capability and taking advantage of enhanced permeability and retention effect.[18]

A dendrimer is a highly branched macromolecule with a spherical shape. The surface of the particle may be functionalized in many ways and many of the properties of the resulting construct are determined by its surface.

In particular it is possible to construct a cationic dendrimer, i.e. one with a positive surface charge. When in the presence of genetic material such as DNA or RNA, charge complimentarity leads to a temporary association of the nucleic acid with the cationic dendrimer. On reaching its destination the dendrimer-nucleic acid complex is then taken into the cell via endocytosis.

In recent years the benchmark for transfection agents has been cationic lipids. Limitations of these competing reagents have been reported to include: the lack of ability to transfect some cell types, the lack of robust active targeting capabilities, incompatibility with animal models, and toxicity. Dendrimers offer robust covalent construction and extreme control over molecule structure, and therefore size. Together these give compelling advantages compared to existing approaches.

Producing dendrimers has historically been a slow and expensive process consisting of numerous slow reactions, an obstacle that severely curtailed their commercial development. The Michigan-based company Dendritic Nanotechnologies discovered a method to produce dendrimers using kinetically driven chemistry, a process that not only reduced cost by a magnitude of three, but also cut reaction time from over a month to several days. These new "Priostar" dendrimers can be specifically constructed to carry a DNA or RNA payload that transfects cells at a high efficiency with little or no toxicity.[citation needed]

Inorganic nanoparticles, such as gold, silica, iron oxide (ex. magnetofection) and calcium phosphates have been shown to be capable of gene delivery.[19] Some of the benefits of inorganic vectors is in their storage stability, low manufacturing cost and often time, low immunogenicity, and resistance to microbial attack. Nanosized materials less than 100nm have been shown to efficiently trap the DNA or RNA and allows its escape from the endosome without degradation. Inorganics have also been shown to exhibit improved in vitro transfection for attached cell lines due to their increased density and preferential location on the base of the culture dish. Quantum dots have also been used successfully and permits the coupling of gene therapy with a stable fluorescence marker.

Cell-penetrating peptides (CPPs), also known as peptide transduction domains (PTDs), are short peptides (< 40 amino acids) that efficiently pass through cell membranes while being covalently or non-covalently bound to various molecules, thus facilitating these molecules entry into cells. Cell entry occurs primarily by endocytosis but other entry mechanisms also exist. Examples of cargo molecules of CPPs include nucleic acids, liposomes, and drugs of low molecular weight.[20][21]

CPP cargo can be directed into specific cell organelles by incorporating localization sequences into CPP sequences. For example, nuclear localization sequences are commonly used to guide CPP cargo into the nucleus.[22] For guidance into mitochondria, a mitochondrial targeting sequence can be used; this method is used in protofection (a technique that allows for foreign mitochondrial DNA to be inserted into cells' mitochondria).[23][24]

Due to every method of gene transfer having shortcomings, there have been some hybrid methods developed that combine two or more techniques. Virosomes are one example; they combine liposomes with an inactivated HIV or influenza virus. This has been shown to have more efficient gene transfer in respiratory epithelial cells than either viral or liposomal methods alone. Other methods involve mixing other viral vectors with cationic lipids or hybridising viruses.

Read the original here:
Vectors in gene therapy - Wikipedia

What happened

After updating investors on its wide-ranging gene therapy research program at a key industry conference early in the month,shares ofbluebird bio(NASDAQ:BLUE) surged 20.7% higher in January,according toS&P Global Market Intelligence.

At the J.P. Morgan Healthcare Conference in early January, Bluebird Bio's management outlined how it hopes to transform treating rare disease, including cerebral ALD (CALD), transfusion dependent beta thalassemia (TDT), and sickle cell disease.

Image source: Getty Images.

The company provided an outlook for 2022 that includes a goal of having two gene therapies on the market, two other therapies near commercialization, and four or more research programs in clinical studies.

In 2017, Bluebird Bio's plans include prepping a filing of its TDT therapy, LentiGlobin, for approval in Europe, and developing a pathway to regulatory approval of its CALD therapy, Lenti-D.

The company is also going to continue early stage research into its CAR-T program, including its work on bb2121, a BCMA-targeting therapy that's being developed with Celgene (NASDAQ:CELG) for multiple myeloma.

The potential to significantly reduce, or eliminate, the need for blood transfusions in TDT patients has industry watchers estimating that LentiGlobin could reshape patient treatment. If so, this gene therapy could be a nine-figure (or higher) top-seller. A similar opportunity exists for Lenti-D.

Perhaps most compelling, however, is the potential market opportunity for bb2121. Although a number of new multiple myeloma treatments have been launched over the past few years, the need for new treatment options remains high. Roughly 30,000 people are newly diagnosed with myeloma in the U.S. each year, and sadly, the five-year survival rate is just 48.5%, according to the National Cancer Institute.Clinical trials for bb2121 are early stage studies, so a lot could go wrong from here. But successfully targeting BCMA and improved outcomes without a lot of safety risks could significantly change how doctors treat their patients. If that happens, bb2121 could become a billion-dollar blockbuster someday.

Todd Campbell owns shares of Celgene.His clients may have positions in the companies mentioned.The Motley Fool owns shares of and recommends Celgene. The Motley Fool recommends Bluebird Bio. The Motley Fool has a disclosure policy.

Originally posted here:
Why bluebird bio Stock Surged 20.7% Higher in January - Motley Fool

MedicalResearch.com Interview with:

Dr. Gwenaelle Geleoc

Gwenaelle Geleoc, PhD Assistant Professor Department of Otolaryngology F.M. Kirby Neurobiology Center Childrens Hospital and Harvard Medical School Boston, MA

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: We seek to develop gene therapy to restore auditory and balance function in a mouse model of Usher syndrome. Usher syndrome is a rare genetic disorder which causes deafness, progressive blindness and in some cases balance deficits. We used a novel viral vector developed by Luk Vandenberghe and package gene sequences encoding for Ush1c and applied it to young mice suffering from Usher syndrome. These mice mimic a mutation found in patients of Acadian descent. We assessed recovery of hearing and balance function in young adult mice which had received the treatment. Otherwise deaf and dizzy, we found that the treated mice had recovered hearing down to soft sounds equivalent to a whisper and normal balance function.

MedicalResearch.com: What should readers take away from your report? Response: This work demonstrates that gene therapy treatments can efficiently restore auditory and balance function. The level of recovery that we have obtained has never been seen before. Having identified a potent vehicle and applying the treatment at the right time was crucial in our study.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: We need to extend this work to other deafness genes that lead to congenital or progressive deafness. The difficulty will arise when looking at genes that extend beyond the capacity of the vector we used for this study. Any gene over 5kb will not fit in our vector. Other strategies will therefore be required.

MedicalResearch.com: Is there anything else you would like to add? Response: Our goal is to advance research to develop new treatments for deafness and balance disorders. I welcome collaborations and material sharing with anyone who wish to work with us for this purpose.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.

Citation:

Gwenalle S Gloc et al. Gene therapy restores auditory and vestibular function in a mouse model of Usher syndrome type 1c. Nature Biotechnology, February 2017 DOI: 10.1038/nbt.3801

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

More Medical Research Interviews on MedicalResearch.com

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Read the original here:
Gene Therapy Restores Hearing Down To A Whisper, in Mice - MedicalResearch.com (blog)

What happened

After updating investors on its wide-ranging gene therapy research program at a key industry conference early in the month,shares ofbluebird bio(NASDAQ: BLUE) surged 20.7% higher in January,according toS&P Global Market Intelligence.

At the J.P. Morgan Healthcare Conference in early January, Bluebird Bio's management outlined how it hopes to transform treating rare disease, including cerebral ALD (CALD), transfusion dependent beta thalassemia (TDT), and sickle cell disease.

Image source: Getty Images.

The company provided an outlook for 2022 that includes a goal of having two gene therapies on the market, two other therapies near commercialization, and four or more research programs in clinical studies.

Continue Reading Below

ADVERTISEMENT

In 2017, Bluebird Bio's plans include prepping a filing of its TDT therapy, LentiGlobin, for approval in Europe, and developing a pathway to regulatory approval of its CALD therapy, Lenti-D.

The company is also going to continue early stage research into its CAR-T program, including its work on bb2121, a BCMA-targeting therapy that's being developed with Celgene (NASDAQ: CELG) for multiple myeloma.

The potential to significantly reduce, or eliminate, the need for blood transfusions in TDT patients has industry watchers estimating that LentiGlobin could reshape patient treatment. If so, this gene therapy could be a nine-figure (or higher) top-seller. A similar opportunity exists for Lenti-D.

Perhaps most compelling, however, is the potential market opportunity for bb2121. Although a number of new multiple myeloma treatments have been launched over the past few years, the need for new treatment options remains high. Roughly 30,000 people are newly diagnosed with myeloma in the U.S. each year, and sadly, the five-year survival rate is just 48.5%, according to the National Cancer Institute.Clinical trials for bb2121 are early stage studies, so a lot could go wrong from here. But successfully targeting BCMA and improved outcomes without a lot of safety risks could significantly change how doctors treat their patients. If that happens, bb2121 could become a billion-dollar blockbuster someday.

10 stocks we like better than Bluebird Bio When investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.*

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Todd Campbell owns shares of Celgene.His clients may have positions in the companies mentioned.The Motley Fool owns shares of and recommends Celgene. The Motley Fool recommends Bluebird Bio. The Motley Fool has a disclosure policy.

Read more from the original source:
Why bluebird bio Stock Surged 20.7% Higher in January - Fox Business

Using stem cells and gene therapy to treat orcure disease may still sound like science fiction, but a scientific meeting here last week emphasizedall the fronts onwhich it is moving closer and closer to fact.

Were entering a new era in medicine, said Lloyd Minor, MD, dean of the School of Medicine, in his opening remarks at the first annual symposium of the schools new Center for Definitive and Curative Medicine. Stanford researchersare poised to use stem cells and gene therapy to amelioratea wide swath of diseases, from common diagnoses such as diabetes and cancerto rare diseases ofthe brain, blood, skin, immune system and other organs. Ultimately, the goal is to create one-time treatments that can provide lifetime cures; hence the definitive and curative part of the centers name. Stanford is a leader in this branch of medical research, Minor said, addingThis is a vital component of our vision for precision health.

Stanford has a long history of leading basic-science discoveries in stem cell biology, andis now engaged in studyingmany different ways those discoveries couldbenefit patients, saidMaria Grazia Roncarolo, MD, who leads the new center.Our job is to produce clinical data so compelling that industry will pick up the product and take it to the next stage, Roncaraolo told the audience.

Among otherevent highlights:

More coverage of the days events is available in a story from the San Jose Mercury News that describeshowAnthonyOro, MD, PhD, and his colleagues are fighting epidermolysis bullosa, a devastating genetic disease of the skin. Oro closed his talk with a slightly goofy photo of a man getting a spray tan. It got a laugh, but his point was serious: Our goal for the cell therapy of the future is spray-on skin to correct a horrible genetic disease.

Ambitious? Yes. Science fiction? In the future, maybe not.

Previously: One of the most promising minds of his generation: Joseph Wu takes stem cells to heart,Life with epidermolysis bullosa: Pain is my reality, pain is my normaland Rat-grown mouse pancreases reverse diabetes in mice, say researchers Photo of Matthew Porteus courtesy of Stanford Childrens

Link:
Stanford scientists describe stem-cell and gene-therapy advances in scientific symposium - Scope (blog)

Posted on Feb. 8, 2017, 6 a.m. in Gene Therapy Sensory

Harvard Medical School scientists have perfected a form of gene therapy that has enabled genetically deaf mice to hear sounds as quiet as a whisper.

Harvard Medical School scientists have perfected gene therapy to the point that it can restore hearing. Their research and experiments have shown that the hearing of genetically deaf mice can be restored to the point that they hear noises at 25 decibels. This decibel level is equivalent to that of a soft whisper.

The Nuances of Gene Therapy for Improved Hearing

Harvard's gene therapy researchers state the most important aspect of their gene therapy breakthrough is a vector they created known as "Anc80". This vector brings a therapeutic gene to the cells within the cochlea's outer ear that are quite difficult to access. These outer hair cells boost sound, empowering inner hair cells to transmit a much more powerful communication to the brain. Gwenalle Gloc of Boston Children's Hospital's Department of Otolaryngology and F.M. Kirby Neurobiology Center, states the new system functions quite well by rescuing vestibular and auditory function to a degree that was not previously achieved in medical history. Research Details

Harvard's research team includes scientists employed by Massachusetts Eye and Ear. The group tested its gene therapy technique on mice with Usher Syndrome. This is a genetic disease that harms hearing as well as vision. Humans who are saddled with this disease are afflicted with a gene mutation that makes the protein harmonin ineffective. As a result, the hair cells responsible for accepting auditory signals and transmitting them to the brain are rendered useless.

The research team tapped into the power of its new vector to transmit an improved version of the gene, referred to as Ush1c, directly into the ear. It didn't take long for the ear's outer and inner hair cells to generate effective harmonin. Subsequent hearing tests conducted on mice proved that animals born deaf could hear. Some of these mice could even pick up on uber-soft auditory signals just like their normal peers.

The Magic of Gene Therapy

The scientific community is abuzz over gene therapy. Some believe gene therapy will ultimately prove to be the cure for deafness. It was only two years ago when scientists and investigators from Harvard and the University of Michigan's Hearing Research Institute found that the hearing-associated protein, NT3, can be stimulated through gene therapy. Additional approaches are geared toward stimulating the regeneration of hair cells within the ear. As an example, Harvard researchers have found that drugs referred to as Notch inhibitors can spur existing ear cells to transition into hair cells that improve hearing in mice.

The Harvard team reports its latest success with gene therapy made use of a similar technique that heightened hearing in 2015. However, these researchers now believe their newly generated vector will restore an even higher level of auditory ability. They also noted that the Ush1c gene applied to deaf mice served to heighten their balance. Mice with Usher Syndrome typically suffer from such poor balance. The Future of Gene Therapy

The future looks quite bright for those who suffer from hearing deficiencies. The research described above is fantastic news for those who suffer from hearing loss. It is possible that gene therapy will eventually supplant cochlear implants that are currently used to improve hearing in young patients. Though Cochlear implants have served patients quite well, there is still room for improvement.

Patients would like to hear an extended range of frequencies and the direction of a sound's source. They would also like to be able to differentiate between the auditory nuances of background noise, voices, music etc. The added benefit of heightened physical balance will serve to enhance Usher Syndrome patients' balance and mobility.

More:
Gene Therapy to Restore Hearing | Worldhealth.net Anti-Aging News - Anti Aging News

A physician at the Parkinsons Institute and Clinical Center in Sunnyvale has been awarded $1.9 million from the California Institute for Regenerative Medicine to advance potential therapies for Parkinsons disease.

Birgitt Schuele MD, director of gene discovery and stem cell modeling at the center, will use the funding to study the effects of lowering levels of a key protein linked to Parkinsons disease as a possible gene therapy approach to haltthe degeneration of nerve cells in patients brains.

Other researchers to receive similar funding are from Stanford University, UC-San Francisco, and UCLA.

We are proud to be recognized by the CIRM among 11 projects from leading centers such as Stanford and UCs for our work, Schuele said. Although we are a small organization, we are at the forefront of scientific developments toward novel and innovative treatments for Parkinsons disease.

Parkinsons disease is a progressive, chronic disorder of the central nervous system that affects the motor system and can impair movement, balance and coordination. Common symptoms include tremors and difficulty moving. While the causes are unknown, genetics and environmental exposures are thought to be contributing factors.

According to the institute, more than 1.5 million Americans are living with the disease, and although most patients diagnosed are over 50, some experience onset much earlier. The Sunnyvale institute does research as well as provides patient care.

According to Schuele, characteristic features in a Parkinsons brain are clumps containing a protein called alpha-synuclein. She says studies have shown that too much of the protein can kill nerve cells. In addition, genetic research has discovered families with early and aggressive Parkinsons have the genetic makeup that causes overproduction of alpha-synuclein.

The funding will be used in additional research to see if the gene that creates the protein can be removed, inhibiting production of it in the brain and possibly stopping the progression of the disease.

In order to study this gene therapy, Schuele says she and institute researchers are transforming skin cells donated from Parkinsons patients into pluripotent cells, which then become neurons that can be used to make an artificial brain model. Using the model, Schuele says she will be able to manipulate the gene producing the potentially harmful protein.

We hypothesize that lowering alpha-synuclein to normal physiological levels should shield the nerve cells and slow down the neurodegenerative disease process, Schuele says.

The project is being done in collaboration with the University of Lund in Sweden and Dr. Deniz Kirik, who will test the gene therapy in pre-clinical models in rodents with the hope of preparing for clinical trials within three years.

Originally posted here:
Sunnyvale: Parkinson's institute awarded $1.9 million for research - Milpitas Post

Medical News Today

Gene therapy: Deaf to hearing a whisper BBC News Deaf mice have been able to hear a tiny whisper after being given a "landmark" gene therapy by US scientists. They say restoring ... The researchers developed a synthetic virus that was able to "infect" the ear with the correct instructions for ... Groundbreaking gene therapy restores hearing, balanceMedical News Today Gene therapy helps deaf mice hear sounds as soft as whispersFierceBiotech Gene therapy restores hearing in deaf mice: Experts say the technique could be used in humans in THREE YEARSDaily Mail ResearchGate (blog) -Wired.co.uk -BioNews all 19 news articles »

Read more from the original source:
Gene therapy: Deaf to hearing a whisper - BBC News

Gene Therapy for Heart Disease Wins Fast-Track Status | P&T ... P&T Community The FDA has granted a fast-track designation for a phase 3 study of Generx (Ad5FGF-4, Angionetics Inc.) cardiovascular angiogenic gene therapy as a one-time ... and more »

Read the rest here:
Gene Therapy for Heart Disease Wins Fast-Track Status | P&T ... - P&T Community

Small sheets of healthy skin are being grown from scratch at a Stanford University lab, proof that gene therapy can help heal a rare disease that causes great human suffering.

The precious skin represents growing hope for patients who suffer from the incurable blistering disease epidermolysis bullosa and acceleration of the once-beleaguered field of gene therapy, which strives to cure disease by inserting missing genes into sick cells.

It is pink and healthy. Its tougher. It doesnt blister, said patient and research volunteer Monique Roeder, 33, of Cedar City, Utah, who has received grafts of corrected skin cells, each about the size of an iPhone 5, to cover wounds on her arms.

More than 10,000 human diseases are caused by a single gene defect, and epidermolysis bullosa is among the most devastating. Patients lack a critical protein that binds the layers of skin together. Without this protein, the skin tears apart, causing severe pain, infection, disfigurement and in many cases, early death from an aggressive form of skin cancer.

The corrected skin is part of a pipeline of potential gene therapies at Stanfords new Center for Definitive and Curative Medicine, announced last week.

The center, a new joint initiative of Stanford Healthcare, Stanford Childrens Health and the Stanford School of Medicine, is designed to accelerate cellular therapies at the universitys state-of-the-art manufacturing facility on Palo Altos California Avenue. Simultaneously, it is aiming to bring cures to patients faster than before and boost the financial value of Stanfords discoveries before theyre licensed out to biotech companies.

With trials such as these, we are entering a new era in medicine, said Dr. Lloyd B. Minor, dean of the Stanford University School of Medicine.

Gene therapy was dealt a major setback in 1999 when Jesse Gelsinger, an Arizona teenager with a genetic liver disease, had a fatal reaction to the virus that scientists had used to insert a corrective gene.

But current trials are safer, more precise and build on better basic understanding. Stanford is also using gene therapy to target other diseases, such as sickle cell anemia and beta thalassemia, a blood disorder that reduces the production of hemoglobin.

There are several diseases that are miserable and worthy of gene therapy approaches, said associate professor of dermatology Dr. Jean Tang, who co-led the trial with Dr. Peter Marinkovich. But epidermolysis bullosa, she said, is one of the worst of the worst.

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It took nearly 20 years for Stanford researchers to bring this gene therapy to Roeder and her fellow patients.

It is very satisfying to be able to finally give patients something that can help them, said Marinkovich. In some cases, wounds that had not healed for five years were successfully healed with the gene therapy.

View post:
Gene therapy's latest benefit: New skin - Daily Democrat

An improved gene therapy vector restores hearing and balance in genetically deaf mice, according to Boston's Children's Hospital researchers. Using therapy developed by Massachusetts Eye and Ear, the mice's levels of hearing are reported to be able to detect sounds as soft as 25 decibels, which is comparable to a whisper.

The idea of gene therapy is to deliver a corrected version of therapeutic DNA into the genomes of cells, which corrects genetic diseases.

Viruses can be altered in a laboratory to provide a "vector" that can carry the corrected therapeutic DNA into the cells. The abnormal gene expression is then altered, and the genetic disease corrected.

Previous studies have used vectors to attempt the restoration of hearing among deaf mice. However, the vectors have only managed to penetrate the inner hair cells of the cochlea.

The cochlea is a spiral-shaped tube that changes sounds to nerve messages and sends the information to the brain. Tiny hairs in the cochlea vibrate to carry information about sound to the brain.

Two new studies, published in Nature Biotechnology, have further explored vectors in mice to determine whether other hair cells of the cochlea, which are harder to reach, could be penetrated and corrected.

The first study was led by Harvard Medical School senior investigators Jeffrey R. Holt, Ph.D., of Boston's Children's Hospital in Massachusetts, Konstantina Stankovic, Ph.D., of Massachusetts Eye and Ear, and Luk H. Vandenberghe, Ph.D. The trio developed a new synthetic vector called Anc80 in 2015 at Massachusetts Eye and Ear's Grousbeck Gene Therapy Center.

The new study found that Anc80 could successfully transfer genes to the harder-to-reach areas of the outer hair cells when introduced into the cochlea. "We have shown that Anc80 works remarkably well in terms of infecting cells of interest in the inner ear," says Stankovic. "With more than 100 genes already known to cause deafness in humans, there are many patients who may eventually benefit from this technology."

Gwenalle Gloc, Ph.D., of the department of otolaryngology and F.M. Kirby Neurobiology Center at Boston's Children's Hospital, led the second study. The study tested Anc80 in a mouse model of Usher syndrome. Usher syndrome is a genetic condition caused by abnormalities of the inner ear. The condition causes partial or total hearing and vision loss that becomes worse over time, eventually impairing balance.

Gloc and colleagues aimed to find out whether delivering a corrected gene using a vector in a mouse model of Usher syndrome would enhance hearing and balance.

"This strategy is the most effective one we've tested," says Gloc. "Outer hair cells amplify sound, allowing inner hair cells to send a stronger signal to the brain. We now have a system that works well and rescues auditory and vestibular function to a level that's never been achieved before," she adds.

Gloc and the Boston's Children's Hospital team studied mice with an Ush1c gene mutation - the mutation that causes Usher type 1c among humans. The gene mutation stops a protein called harmonin from functioning, which causes the hair cells that receive sound and communicate with the brain to deteriorate, leading to hearing loss.

Introducing a corrected version of Ush1c to the inner ear of the mice shortly after birth resulted in the inner and outer hair cells in the cochlea producing normal harmonin. Furthermore, the hair cells responded to sound waves and communicated with the brain, thus enabling hearing.

The team found that 19 out of 25 mice heard sounds below 80 decibels and that some of the mice could hear sounds as quiet as 25-30 decibels. "Now, you can whisper, and they can hear you," says Gloc. The researchers also discovered that the gene therapy restored balance in the mice and eliminated erratic movements.

Hearing and balanced improved in the mice that were treated soon after birth. However, hearing and balance were not restored in the mice that were treated 10-12 days after birth.

"Anything that could stabilize or improve native hearing at an early age would give a huge boost to a child's ability to learn and use spoken language," notes Margaret Kenna, a specialist in genetic hearing loss at Boston's Children's Hospital who conducts research into Usher syndrome.

"This is a landmark study. Here we show, for the first time, that by delivering the correct gene sequence to a large number of sensory cells in the ear, we can restore both hearing and balance to near-normal levels."

Jeffrey R. Holt

Future work for the researchers will involve examining why mice treated 10-12 days after birth did not improve. They also aim to test gene therapy in larger animals and plan to develop treatments for other types of genetic hearing loss. With further work, this research may one day lead to treatments that can benefit patients.

Learn whether there is a link between anemia and hearing loss.

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Groundbreaking gene therapy restores hearing, balance - Medical News Today

By delivering a benign virus to the ear of mice, scientists have enabled deaf lab mice to hear for the first time.

GENE therapy delivered by a benign virus enabled deaf lab mice to hear for the first time, researchers revealed this week, offering hope for people suffering with genetic hearing impairments.

The breakthrough could pave the way for gene-based treatments, they reported in two studies, published in Nature Biotechnology.

With more than 100 genes already known to cause deafness in humans, there are many patients who may eventually benefit from this technology, said Konstantina Stankovic, a professor at Harvard Medical School.

Genetic hearing disorders affect some 125 million people worldwide, according to the World Health Organisation.

An expert not involved in the research welcomed the findings as very encouraging, but cautioned the technique has yet to be proven safe, and that human trials are likely years away.

In the first study, Stankovic and colleagues used a harmless virus to transport deep into the mouse ear a gene that can fix a specific form of hereditary deafness.

Previous attempts had failed, but this time the viral package was delivered to the right address: the so-called outer hair cells that tune the inner ear to sound waves.

Outer hair cells amplify sound, allowing inner hair cells to send a stronger signal to the brain, explained Gwenaelle Geleoc, a researcher at the F.M. Kirby Neurobiology Center at Boston Childrens Hospital.

The technique bestowed hearing and balance to a level thats never been achieved before, she said in a statement.

Now you can whisper, and the mice can hear you. In the second study, a team led by Geleoc used the same viral courier to treat mice with a mutated gene responsible for Usher syndrome, a rare childhood genetic disease that causes deafness, loss of balance, and in some cases blindness.

The virus carried a normal version of the same gene to damaged ear hair cells soon after the mice were born.

NARROW TIME WINDOW

The results far exceeded anything to date: 19 of 25 treated mice heard sounds quieter than 80 decibels. Normal human conversation is about 70 decibels.

A few of the mice could hear sounds as soft as 25 to 30 decibels roughly equivalent to whispering.

According to Margaret Kenna, a specialist in genetic hearing loss at Boston Childrens Hospital not involved in the studies, cochlear implants are great, but your own hearing is better. Electronic implants work by bypassing damaged hair cells in the ear to send sound signals directly to the brain.

Anything that could stabilise or improve native hearing at an early age would give a huge boost to a childs ability to learn and use spoken language, she said.

The need for early intervention, however, could be a problem in itself, other experts pointed out.

In humans, such an intervention would ideally have to happen before a child is born, said Jonathan Ashmore, a professor at University College Londons Ear Institute.

Alan Boyd, president of Britains Faculty of Pharmaceutical Medicine hailed a very encouraging result.

But it is only a mouse model, he cautioned, noting that it is still unknown how the human immune system might react.

Any gene deafness treatment is at least three years away, if not more, Boyd conjectured.

Follow three people who hope the mapping of the human genome will transform their lives. Will the Human Genome Project change our relationship with ourselves forever?

Visit link:
Hearing impairment cure? Gene therapy allows deaf mice to hear - NEWS.com.au

Good News at Fred Hutch Fred Hutch News Service A multi-institutional research team in Seattle recently was awarded more than $3.7 million in federal grant funding to develop a novel gene therapy approach for dangerous genetic disorders that affect hemoglobin, the blood's oxygen-carrying molecules.

Link:
Good News at Fred Hutch - Fred Hutch News Service

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Small sheets of healthy skin are being grown from scratch at a Stanford University lab, proof that gene therapy can help heal a rare disease that causes great human suffering.

The precious skin represents growing hope for patients who suffer from the incurable blistering disease epidermolysis bullosa and acceleration of the once-beleaguered field of gene therapy, which strives to cure disease by inserting missing genes into sick cells.

It is pink and healthy. Its tougher. It doesnt blister, said patient and research volunteer Monique Roeder, 33, of Cedar City, Utah, who has received grafts of corrected skin cells, each about the size of an iPhone 5, to cover wounds on her arms.

More than 10,000 human diseases are caused by a single gene defect, and epidermolysis bullosa is among the most devastating. Patients lack a critical protein that binds the layers of skin together. Without this protein, the skin tears apart, causing severe pain, infection, disfigurement and in many cases, early death from an aggressive form of skin cancer.

The corrected skin is part of a pipeline of potential gene therapies at Stanfords new Center for Definitive and Curative Medicine, announced last week.

The center, a new joint initiative of Stanford Healthcare, Stanford Childrens Health, and the Stanford School of Medicine, is designed to accelerate cellular therapies at the universitys state-of-the-art manufacturing facility on Palo Altos California Avenue. Simultaneously, itisaiming to bring cures to patients faster than before and boost the financial value of Stanfords discoveries before theyre licensed out to biotech companies.

With trials such as these, we are entering a new era in medicine, said Dr. Lloyd B. Minor, dean of the Stanford University School of Medicine.

Gene therapy was dealt a major setback in 1999 when Jesse Gelsinger, an Arizona teenager with a genetic liver disease, had a fatal reaction to the virus that scientists had used to insert a corrective gene.

But current trials are safer, more precise and build on better basic understanding. Stanford is also using gene therapy to target other diseases, such as sickle cell anemia and beta thalassemia,a blood disorder that reduces the production of hemoglobin.

There are several diseases that are miserable and worthy of gene therapy approaches, said associate professor of dermatology Dr. Jean Tang, who co-led the trial with Dr. Peter Marinkovich. But epidermolysis bullosa, she said, is one of the worst of the worst.

It took nearly 20 years for Stanford researchers to bring this gene therapy to Roeder and her fellow patients.

It is very satisfying to be able to finally give patients something that can help them, said Marinkovich.In some cases, wounds that had not healed for five years were successfully healed with the gene therapy.

Before, he noted, there was only limited amounts of what you can do for them. We can treat their wounds and give them sophisticated Band-Aids. But after you give them all that stuff, you still see the skin falling apart, Marinkovich said. This makes you feel like youre making a difference in the world.

Roeder seemed healthy at birth. But when her family celebrated her arrival by imprinting her tiny feet on a keepsake birth certificate, she blistered. They encouraged her to lead a normal childhood, riding bicycles and gentle horses. Shes happily married. But shes grown cautious, focusing on photography, writing a blog and enjoying her pets.

Scarring has caused her hands and feet digits to become mittened or webbed. Due to pain and risk of injury, she uses a wheelchair rather than walking long distances.

Every movement has to be planned out in my head so I dont upset my skin somehow, she said. Wound care can take three to six hours a day.

She heard about the Stanford research shortly after losing her best friend, who also had epidermolysis bullosa, to skin cancer, a common consequence of the disease. Roeder thought: Why dont you try? She didnt get the chance.

The team of Stanford experts harvested a small sample of skin cells, about the size of a pencil eraser, from her back. They put her cells in warm broth in a petri dish, where they thrived.

To this broth they added a special virus, carrying the missing gene. Once infected, the cells began producing normal collagen.

They coaxed these genetically corrected cells to form sheets of skin. The sheets were then surgically grafted onto a patients chronic or new wounds in six locations. The team reported their initial results in Novembers Journal of the American Medical Association.

Historically, medical treatment has had limited options: excising a sick organ or giving medicine, said Dr. Anthony E. Oro of Stanfords Institute for Stem Cell Biology and Regenerative Medicine. When those two arent possible, theres only symptom relief.

But the deciphering of the human genome, and new tools in gene repair, have changed the therapeutic landscape.

Now that we know the genetic basis of disease, we can use the confluence of stem cell biology, genome editing and tissue engineering to develop therapies, Oro said.

Its not practical to wrap the entire body of a patient with epidermolysis bullosa in vast sheets of new skin, like a mummy, Oro said.

But now that the team has proved that gene therapy works, they can try related approaches, such as using gene-editing tools directly on the patients skin, or applying corrected cells like a spray-on tan.

A cure doesnt take one step, said Tang. It takes many steps towards disease modification, and this is the first big one. Were always looking for something better.

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Stanford team is growing healthy skin for ill patients - The Mercury News

Science Daily

Gene therapy restores hearing in deaf mice, down to a whisper ... Science Daily In the summer of 2015, a team of scientists eported restoring rudimentary hearing in genetically deaf mice using gene therapy. Now the research team reports ... and more »

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Gene therapy restores hearing in deaf mice, down to a whisper ... - Science Daily

February 07, 2017 07:45 ET | Source: Abeona Therapeutics Inc

Multiple Oral Platform Presentations and Poster Sessions Highlighting Gene Therapy Programs, Tuesday, February 14th through Thursday, February 16th

NEW YORK and CLEVELAND, Feb. 07, 2017 (GLOBE NEWSWIRE) -- Abeona Therapeutics Inc. (NASDAQ:ABEO), a leading clinical-stage biopharmaceutical company focused on developing therapies for life-threatening rare genetic diseases, today announced that data on gene therapy programs for Sanfilippo syndrome Type A (MPS IIIA), Infantile Batten Disease (CLN1) and Juvenile Batten Disease will be highlighted at the upcoming 13th Annual WORLDSymposium 2017 lysosomal storage disorders conference, February 13-17, San Diego, CA. Details for the two oral presentations and three poster sessions are listed below.

Platform Presentations:

ABO-102 Phase 1/2 Clinical trial update - Sanfilippo syndrome Type A (MPS IIIA):

ABO-202 CLN1, Infantile Batten Disease (INCL):

Poster Sessions:

ABO-102 Phase 1/2 Clinical trial update - Sanfilippo syndrome Type A:

ABO-202 CLN1, Infantile Batten Disease (INCL):

ABO-201 CLN3, Juvenile Batten Disease (JNCL):

Abeona Recent ABO-102 Program Highlights:

About WORLDSymposium: The goal of WORLDSymposium is to provide an interdisciplinary forum to explore and discuss specific areas of interest, research and clinical applicability related to lysosomal diseases. Each year, WORLDSymposiumhosts a scientific meeting presenting the latest information from basic science, translational research, and clinical trials for lysosomal diseases. This symposium is designed to help researchers and clinicians to better manage and understand diagnostic options for patients with lysosomal diseases, identify areas requiring additional basic and clinical research, public policy and regulatory attention, and identify the latest findings in the natural history of lysosomal diseases. For more information, visit http://www.worldsymposia.org/

About Abeona: Abeona Therapeutics Inc. is a clinical-stage biopharmaceutical company developing gene therapies for life-threatening rare genetic diseases. Abeona's lead programs include ABO-102 (AAV-SGSH) and ABO-101 (AAV-NAGLU), adeno-associated virus (AAV) based gene therapies for Sanfilippo syndrome (MPS IIIA and IIIB, respectively). Abeona is also developing EB-101 (gene-corrected skin grafts) for recessive dystrophic epidermolysis bullosa (RDEB), EB-201 for epidermolysis bullosa (EB), ABO-201 (AAV-CLN3) gene therapy for juvenile Batten disease (JNCL), ABO-202 (AAV-CLN1) gene therapy for treatment of infantile Batten disease (INCL), and ABO-301 (AAV-FANCC) for Fanconi anemia (FA) disorder and ABO-302 using a novel CRISPR/Cas9-based gene editing approach to gene therapy for rare blood diseases. In addition, Abeona has a plasma-based protein therapy pipeline, including SDF Alpha (alpha-1 protease inhibitor) for inherited COPD, using its proprietary SDF (Salt Diafiltration) ethanol-free process. For more information, visit http://www.abeonatherapeutics.com.

This press release contains certain statements that are forward-looking within the meaning of Section 27a of the Securities Act of 1933, as amended, and that involve risks and uncertainties. These statements are subject to numerous risks and uncertainties, including but not limited to continued interest in our rare disease portfolio, our ability to enroll patients in clinical trials, the impact of competition; the ability to develop our products and technologies; the ability to achieve or obtain necessary regulatory approvals; the impact of changes in the financial markets and global economic conditions; and other risks as may be detailed from time to time in the Company's Annual Reports on Form 10-K and other reports filed by the Company with the Securities and Exchange Commission. The Company undertakes no obligations to make any revisions to the forward-looking statements contained in this release or to update them to reflect events or circumstances occurring after the date of this release, whether as a result of new information, future developments or otherwise.

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Abeona Therapeutics Announces Presentations and Posters at the 13th Annual WORLDSymposium 2017 - GlobeNewswire (press release)

After a long summer break it is time to review recent events and update the portfolio. As far as clinical readouts go, my portfolio had a brutal summer with one complete P3 failure from Array Biopharma (ARRY), a mixed data set from Aurinia (AUPH) and a win from SAGE (SAGE) that resulted in limited share appreciation. This was offset by strong performance from Exelixis (EXEL), my biggest holding which is up 48% quarter to date.

For the remainder of 2016 I plan to gradually increase exposure to gene therapy, which I hope will become one of the industrys primary growth drivers in the coming years. In parallel, as I am still pessimistic about the biotech field in general (R&D productivity, pricing, biosimilars), I intend to keep my short ETFs and a significant cash position.

Data readouts Array and Aurinia disappoint, SAGE delivers

Array Biopharma Astrazenecas (AZN) selumetinib, originally developed by Array, failed to improve PFS or overall survival in KRAS-mutated lung cancer. This P3 failure demonstrates once again the challenges in corroborating positive P2 data and joins a series of disappointing news for MEK inhibitors. In 2015, selumetinib failed another P3 study in uveal melanoma and earlier this year, Array terminated a P3 study for its wholly-owned MEK inhibitor, binimetinib, in ovarian cancer. Recent P3 data for binimetinib in NRAS+ melanoma was technically a success but benefit was underwhelming (improvement in PFS without a survival benefit).

MEK inhibitors are still being explored in multiple indications that may enable developers to expand their use beyond BRAF+ melanoma. At ASCO 2016, Roche and Exelixis reported an intriguing efficacy signal with Cotellic in KRAS+ colon cancer. Another indication that is not discussed much is neurofibromatosis type 1 where selumetinib demonstrated strong efficacy but timelines and registration strategy are not clear. Later in 2016, Array will report data for binimetinib in BRAF+ melanoma, where two other MEK inhibitors (Mekinist and Cotellic) are already approved. Array hopes to demonstrate a differentiated safety profile but penetrating the BRAF+ market is going to be challenging.

Aurinia Aurinia reported results from a P2b evaluating two doses of its calcineurin inhibitor (voclosporin) in lupus nephritis. While voclosporin demonstrated superiority over the control arm at the low dose in inducing remission (32.6% vs. 19.3%), there was no effect with the high dose and there was an alarming imbalance in deaths between the low dose cohort (13 cases overall, 10 of which occurred in the lower dose arm). The fact the active arm had such a high mortality obviously raises safety concerns but also casts a shadow on the efficacy signal and trial design.

SAGE SAGE reported a strong efficacy signal for its lead program, SAGE-547, in a placebo- controlled P2 in postpartum depression (PPD). Despite the typically high placebo response in depression trials, the drug led to a clinically meaningful reduction in depression with a ~12 point reduction from placebo on the HAM-D scale. Importantly, the effect had a quick onset and appears durable almost a month following treatment cessation.

These results are very significant for SAGE-547 becausethey validate the initial signal observed to date in single arm open label trials or case studies, which are rightfully viewed as unreliable (especially in CNS indications). Despite the small sample size, the strength and consistency of the PPD data imply the drug is active and de-risk the program.

Going forward, SAGE decided to focus on SRSE with SAGE-547 (P3 data pushed out to 1H:2017) while pursuing PPD as well as other CNS diseases (essential tremor, Parkinsons) with a next-generation oral drug (SAGE-217). This decision makes sense in light of the different clinical settings (SRSE patients are hospitalized and need immediate solution for their seizures whereas PPD may require more prolonged treatment). SAGE-217 appears more potent and selective than SAGE-547 with good pharmacologic profile based on P1, but it is still not validated in the clinic.

Momentum continues to build around gene therapy

There have been some notable news in the gene therapy space including three data readouts and an acquisition. This gradual but consistent progress helps to build confidence around gene therapy and makes it one of the most important segments in the industry.

The combined recent data set from all gene therapy companies still comprises less than 100 patients with limited follow up, but for the first time in more than25years, we are starting to get positive answers on three major questions: Efficacy, durability and safety. With tens of active clinical programs, strong data across multiple domains (liver, CNS, retina, bone marrow) and an armamentarium of tissue-specific vectors, gene therapy may be ready for primetime. The field will surely see its share of failures but the path to commercial success with gene therapy is finally visible.

Biomarin

Biomarin (BMRN) made a big splash with its hemophilia A treatment, BMN-270, demonstrating that gene therapy can lead to a functional cure (at least for a period of time). Results from 7 patients treated at the highest dose demonstrated quick and robust expression of factor VIII (hemophilia A is caused by low factor VIII activity). Strikingly, all but one patient achieved normal levels and this was accompanied by a dramatic reduction in bleeding events despite taking patients off prophylactic FVIII treatment. Follow up is still limited (up to 20 weeks) but Factor VIII production appears to be stabilizing or even increasing in some cases.

The study was a major win but there were two safety signals: ALT elevation (marker for liver damage) and an above normal FVIII levels in two patients.

ALT elevations are closely watched in every liver-targeted gene therapy study because earlier products led to ALT elevations (probably an immunogenic response against the viral vector) that led to clinically relevant elevations and were associated with loss of transgene expression. There is still not enough follow up to rule out any chronic liver toxicity but according to Biomarin, the ALT elevations were not clinically meaningful and appear to be manageable with steroids (in some cases patients were taken off steroids and liver functions returned to normal). Fortunately, the ALT elevations do not seem to correlate with loss FVIII expression as production continued to rise or stabilized during these events.

The excessive FVIII levels in two patients are troubling on paper (especially if production keeps going up) because elevated levels of FVIII are associated with higher risk of thrombotic complications according to several studies, reviewed here. This demonstrates a primary concern with gene therapy its irreversible and cannot be switched off. While the company disclosed patients are not experiencing any thrombosis-related events, they will have to be monitored and potentially treated in case FVIII continue to climb or any abnormalities emerge. Going forward Biomarin plans to evaluate a lower dose to avoid such cases.

Overall, Biomarins hem A data are impressive and together with data from hemophilia B programs from Spark (ONCE)/Pfizer (PFE) and UniQure (QURE), they lay the groundwork for registration programs in hemophilia potentially next year.

Avexis

While Biomarins gene therapy for hemophilia demonstrated both protein production (FVIII in the blood) and clinical improvement (bleeding incidence), Avexis (AVXS) AVXS-101 demonstrated only the latter. Nevertheless, the dramatic clinical signal coupled with the fact that the target tissue are neurons make AVXS-101 one of the most important gene therapies in development (and personally speaking, the most intriguing one).

Last month, Avexis provided an update from a clinical trial evaluating AVXS-101 for SMA1, a fatal disease in infants that affects the motor neurons and is invariably fatal by 2 years of age. Following the previous data readout (which I discussed here), the clinical effect appears to hold with unprecedented functional and survival improvements over historical data. All but one patient on the high dose cohort had a dramatic functional improvement vs. the expected persistent decline that is the hallmark of SMA1. Importantly, none of the patients had an event (defined as ventilation or death) despite crossing 8 months of age where a recent study showed an event rate of 50%. Duration of the effect is still unknown due to limited follow up (appears to be at least 1 year).

The trial did not have a control arm but the difference is so dramatic that I find it hard to believe it is just a statistical artifact. The recent breakthrough therapy designation the FDA granted to AVXS-101 is another testament to the robustness of the data. Biogen (BIIB) and Ionis (IONS) reported P3 success for nusinersen in SMA1, which validates the signal observed in a previous single-arm study and this strengthens the notion that single-arm trials in SMA1 can generate a reliable signal. Although nusinersen can theoretically be seen as a competitive threat to AVXS-101, if both drugs are approved, nusinersen will probably be used on top of a one-time gene therapy like AVXS-101.

AVXS-101s effect, if real, implies that AAV9 vectors Avexis utilizes can cross the blood-brain-barrier and reach the central nervous system. This could have dramatic implications for many rare genetic diseases (and down the road more prevalent diseases like Parkinsons and Alzheimers disease) where the nerve system is damaged but cannot be modulated by existing drugs. In this perspective, companies like REGENXBIO (RGNX) and Abeona (ABEO) are very interesting opportunities as both target neurologic diseases (or ones with neurologic manifestations) with AAV9-based gene therapies.

Spark

Spark reported updated results from its pivotal trial for its RPE65 gene therapy (Voretigene neparvovec) for inherited retinal disease. The study was overwhelmingly positive and will likely be the basis of the first ever FDA approval for gene therapy next year. In contrast to other gene therapy programs in development, Sparks program has up to 3 years of follow-up and so far the effect appears to hold.

RPE65 gene therapy is to retinal diseases what hemophilia gene therapy is to liver diseases a proof of concept that paves the way for other genetic retinal diseases like XLRS, XLRP, achromatopsia and choroideremia. Spark will have first clinical data for its choroideremia program later in 2016. AGTC (AGTC) is expected to report initial clinical data in XLRS and achromatopsia also in 2016.

Spark also has a Hemophilia A program (SPK-8011), which is about to enter P1. Despite being more than a year behind Biomarin, recent results for Sparks Hemophilia B program (partnered with Pfizer) were very encouraging and may point to some advantages with Sparks vectors. These include better potency and lower immunogenicity that could translate to a more compelling clinical profile (i.e achieving the required protein levels with limited immune reaction, and down the road better durability and dosing flexibility).

Pfizer acquires Bamboo

One item that went relatively unnoticed is the acquisition of Bamboo by Pfizer. Bamboo is developing gene therapies for neuronal and neuromuscular indications with a program in P1 for Giant Axonal Neuropathy. Despite the modest deal size ($150M upfront), it is an important milestone in big pharmas venture into gene therapy, which historically has not been aligned with the pharma business model (one time genetic treatment vs. recurring sales of small molecules or biologics). The title of Pfizers press release (Pfizer aims to become industry leader in gene therapy with aquisition of bamboo therapeutics) clearly demonstrates this trend.

If gene therapy is indeed going to become a central component of the biopharma industry, the demand for validated platforms with clinical data and CMC capabilities could grow dramatically in the near future. In contrast to cell therapies such as CARs and TCRs, gene therapy may be more palatable to pharma because the end product is still a drug in a vial and not a process.

Portfolio updates

Given the early stage and inherent risk in gene therapy, I intend to build a diversified portfolio with the goal of starting 2017 with 7-8 stocks that will comprise a third of the portfolio. Today I am starting with Spark, Avexis, REGENXBIO and Abeona (Next on the list is Bluebird going into ASH 2016)

I am selling Array Biopharma, Aurinia, Genocea (GNCA) and Conatus (CNAT). In addition, I am selling part of my ArQule (ARQL) and Foundation Medicine (FMI) position.

Lastly, I am initiating a small position in Kura Oncology (KURA) following an early signal in HRAS+ H&N cancer.

Portfolio holdings September 4th, 2016

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Biotech portfolio update Jumping into gene therapy ...

NHGRI-ASHG fellowships fulfill critical need in science policy and education

For several years, NHGRI and the American Society of Human Genetics (ASHG) have provided a pathway for scientists who want to pursue careers in science policy or education. The Genetics and Public Policy Fellowship and the Genetics and Education Fellowship offer effective experiences in the public, private and non-profit arenas to those with graduate education in genetics. These fellowships help build the skills required to inform science policy and education. Our 2016-2017 fellows share what they've accomplished.

Geared to students grade 9-12 worldwide, the American Society of Human Genetics (ASHG) DNA Day Essay Contest celebrates National DNA Day by asking students to examine, question and reflect on important concepts in genetics. This year's question asks students to describe a disease or condition researchers are attempting to treat and how gene therapy might repair the underlying cause of the disease or condition. Deadline: March 10, 2017, at 5 p.m. U.S. Eastern Time. See: DNA Day Essay Contest

Your family health history can identify whether you are at a higher risk for some diseases. But people don't necessarily know their entire family's health history. A new study shows that asking multiple family members for family health histories can improve the accuracy of both the family's health history and personalized risk assessments. NHGRI intramural researchers published the study in the American Journal of Preventive Medicine on January 4, 2016.

On June 5-7, 2017, the conference Genomics and Society: Expanding the ELSI Universe will gather ethical, legal and social implications researchers to reflect on current research and discuss future directions. With keynote speakers, plenary panels, workshops, and a wide range of paper, panel, and poster presentations, the Congress will provide an opportunity for scholars to reflect on current research and envision future directions for ELSI research. For more information and to register: elsicon2017.org.

Through a simple blood test, physicians will soon be able to map the fetus' entire collection of genes (the whole genome) using fetal DNA that floats in the mother's blood. But a survey of 1,000 physicians says that ethical guidelines must be developed first. Researchers with the National Human Genome Research Institute published their findings in the December 6th issue of the journal Prenatal Diagnosis.

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National Human Genome Research Institute

Gene Therapy Phone: 617-632-5064

From the first attempt at modifying human DNA in the early 1980s to the first clinical trials based on genetic engineering of the mid 1990s to the first commercialization of a genetically engineered cell product in 2002 gene therapy has moved from being a pioneering research field to becoming one of the most technologically advanced and promising clinical realities for the treatment of a wide spectrum of diseases and tumors.

Founded in 2010, our Gene Therapy Program has been at the forefront of the fight against rare genetic disorders affecting children. The success of our gene therapy clinical trials is due to our programs unique combination of basic research and clinical care and our ability to translate what we learn at the laboratory bench to the bedside care of the patients we treat.

Through our research capabilities and partnerships, we strive to excel in every step of the gene therapy process. Our research includes:

We work closely with industrial and translational academic partners, such as the Translab and Cell Manipulation cores at Dana-Farber Cancer Institute, to:

Learn more

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Gene Therapy Research - Dana-Farber/Boston Children's ...

In amyotrophic lateral sclerosis (ALS), gene therapy may help if it can deliver a beneficial protein to salvage dying nerve cells. Gene therapy can be simply a means to boost on site production of a helpful factor, at places where nerve cells are in trouble. Researchers can disarm many types of viruses, and put in the genetic instructions to make therapeutic protein. The redesigned viruses are called vectors. They are simply carriers for therapeutic genes. Knowledge of the SOD1 mutations linked to some forms of ALS has produced a vast body of evidence, pointing to a general strategy for the disease that might be successfully implemented through gene therapy.

Gene therapy is the use of genetic instructions to produce a protein to treat a disorder or deficiency. It can aid in a disease even if the therapy is not directly targeting a gene defect that causes the disease. In amyotrophic lateral sclerosis (ALS), gene therapy may help if it can deliver a beneficial protein, to salvage dying nerve cells. The gene therapy simply is a means to boost on site production of a trophic (growth enhancing) factor, at places where nerve cells are in trouble.

Genes are the molecules in all cells of our bodies that carry the instructions to make all of the materials that comprise the body. In the 1950s, scientists determined that genes code precisely for proteins, with a sequence that specifies the order of the building blocks of proteins, the amino acids. Each gene corresponds to a protein. Each base in a gene codes for an amino acid. The order of bases in a gene produces the ordered chain of amino acids that produce a working protein.

At the turn of the current century, scientists determined, in rough draft form, the sequence of all of the human genes. By this time, they also knew how to create a gene construct, and move that construct into cells, to get the cells to make the corresponding protein.

In some diseases, researchers already know that a defective gene is not able to work. They have the potential means to cure the disease, by replacing the defective gene with a correct, working copy. In ALS, only a few percent of patients have a known gene defect. For the rest, it may be one undiscovered gene that is the problem, or it may be several. But gene therapy can still be designed to aid patients with ALS by providing supportive proteins for nerve cells.

Genes normally reside in the nucleus, the core of a cell, separated from the surrounding materials by a membrane. The chromosomes are the structures within the cell nucleus that contain the DNA that comprises the genes. It is very challenging to get a gene made in the lab to cross both the outer envelope of a cell, and the nuclear membrane as well, to reach the chromosomes.

Scientists studying viruses have discovered natures own solution to the problem of moving genes. Viruses are essentially genes that have evolved to hijack cells, instead of forming cells for themselves. So viruses have strategies to enter cells and take over the protein production process, to produce instead, the virus. Researchers have figured out how to use viruses as Trojan horses, to bring in genes that can then carry out genetic repairs, replacing defective DNA.

For many viruses, researchers can disarm the genes responsible for the damaging properties and put in, instead, genetic instructions to make therapeutic proteins. These viruses, redesigned by researchers, are called vectors. They are simply a means to smuggle in therapeutic genes.

Investigators must demonstrate that the viral vector is not going to revert back to an infectious form, or cause any side effects.

Genes normally are read out only when a protein is needed, and operate under feedback control. If adequate amounts of protein are already there, then the gene is turned off. Scientists have to be able to devise the proper switch elements to accompany a therapeutic gene, to make sure that a gene is expressed in proper amounts, and only in an intended target tissue.

To gauge adequate delivery of the vector, and sufficient levels of gene expression, researchers have to have animal models that reflect the key manifestations of a human disease. Despite preclinical work with animals, it is not always possible to extrapolate to patients.

A patients immune system may mount an attack on viral vectors (after all, that is what the immune system is primed to do), or on the newly introduced therapeutic gene product.

In ALS, a few percent of patients have a known defect in a gene. This genetic mistake, in the gene coding for the SOD1 protein, produces disease no different from any other form of ALS, inherited or not. Gene therapy might be designed for a particular SOD1 defect, but that therapy may or may not work for other ALS patients.

What is encouraging is that the knowledge of the SOD1 mutations has produced a vast body of evidence for what does go wrong in other cases of ALS. And that evidence is pointing to a general strategy that might be successfully implemented through gene therapy.

ALS research has produced the notion that the neighborhood surrounding the motor neurons can be nurturing or detrimental to these crucial cells affected in ALS. Even if a neuron carries a mutated SOD1 gene, that nerve cell can survive if neighboring support cells, the glia, have the normal gene (see section on Cell Targets).

Glial cells surround neurons. Some glial functions produce the hallmarks of damage in the nervous system, either inflammation or scarring. Other glial actions are protective, for instance, sweeping away excess excitatory signal molecules before they can do damage. Gene therapy in ALS may be able to target the glial cells as well as neurons, to produce positive effects.

Studies in animal models of ALS show increased survival after treatment with trophic factors (see section on trophic factors), small proteins that support the growth and metabolic activities of nerve cells, most recently with IGF-1 and also after vascular endothelial growth factor (VEGF). However, clinical trials of trophic factors in ALS patients have been disappointing. The challenge of delivering these proteins to the site of damage is likely the underlying cause of the failures in the clinic.

Gene therapy may be the way to provide a steady supply of trophic factors to neurons damaged in ALS, directly at the place where the damage exists. The ALS Association is supporting various avenues of research that seek to implement gene therapies to deliver trophic factors, and is encouraging entry into clinical trials as quickly as possible.

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Gene Therapy - alsa.org

This article is about the heritable unit for transmission of biological traits. For other uses, see Gene (disambiguation).

A gene is a locus (or region) of DNA which is made up of nucleotides and is the molecular unit of heredity.[1][2]:Glossary The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. Most biological traits are under the influence of polygenes (many different genes) as well as geneenvironment interactions. Some genetic traits are instantly visible, such as eye colour or number of limbs, and some are not, such as blood type, risk for specific diseases, or the thousands of basic biochemical processes that comprise life.

Genes can acquire mutations in their sequence, leading to different variants, known as alleles, in the population. These alleles encode slightly different versions of a protein, which cause different phenotype traits. Colloquial usage of the term "having a gene" (e.g., "good genes," "hair colour gene") typically refers to having a different allele of the gene. Genes evolve due to natural selection or survival of the fittest of the alleles.

The concept of a gene continues to be refined as new phenomena are discovered.[3] For example, regulatory regions of a gene can be far removed from its coding regions, and coding regions can be split into several exons. Some viruses store their genome in RNA instead of DNA and some gene products are functional non-coding RNAs. Therefore, a broad, modern working definition of a gene is any discrete locus of heritable, genomic sequence which affect an organism's traits by being expressed as a functional product or by regulation of gene expression.[4][5]

The existence of discrete inheritable units was first suggested by Gregor Mendel (18221884).[6] From 1857 to 1864, he studied inheritance patterns in 8000 common edible pea plants, tracking distinct traits from parent to offspring. He described these mathematically as 2ncombinations where n is the number of differing characteristics in the original peas. Although he did not use the term gene, he explained his results in terms of discrete inherited units that give rise to observable physical characteristics. This description prefigured the distinction between genotype (the genetic material of an organism) and phenotype (the visible traits of that organism). Mendel was also the first to demonstrate independent assortment, the distinction between dominant and recessive traits, the distinction between a heterozygote and homozygote, and the phenomenon of discontinuous inheritance.

Prior to Mendel's work, the dominant theory of heredity was one of blending inheritance, which suggested that each parent contributed fluids to the fertilisation process and that the traits of the parents blended and mixed to produce the offspring. Charles Darwin developed a theory of inheritance he termed pangenesis, from Greek pan ("all, whole") and genesis ("birth") / genos ("origin").[7][8] Darwin used the term gemmule to describe hypothetical particles that would mix during reproduction.

Mendel's work went largely unnoticed after its first publication in 1866, but was rediscovered in the late 19th century by Hugo de Vries, Carl Correns, and Erich von Tschermak, who (claimed to have) reached similar conclusions in their own research.[9] Specifically, in 1889, Hugo de Vries published his book Intracellular Pangenesis,[10] in which he postulated that different characters have individual hereditary carriers and that inheritance of specific traits in organisms comes in particles. De Vries called these units "pangenes" (Pangens in German), after Darwin's 1868 pangenesis theory.

Sixteen years later, in 1905, the word genetics was first used by William Bateson,[11] while Eduard Strasburger, amongst others, still used the term pangene for the fundamental physical and functional unit of heredity.[12] In 1909 the Danish botanist Wilhelm Johannsen shortened the name to "gene". [13]

Advances in understanding genes and inheritance continued throughout the 20th century. Deoxyribonucleic acid (DNA) was shown to be the molecular repository of genetic information by experiments in the 1940s to 1950s.[14][15] The structure of DNA was studied by Rosalind Franklin and Maurice Wilkins using X-ray crystallography, which led James D. Watson and Francis Crick to publish a model of the double-stranded DNA molecule whose paired nucleotide bases indicated a compelling hypothesis for the mechanism of genetic replication.[16][17]

In the early 1950s the prevailing view was that the genes in a chromosome acted like discrete entities, indivisible by recombination and arranged like beads on a string. The experiments of Benzer using mutants defective in the rII region of bacteriophage T4 (1955-1959) showed that individual genes have a simple linear structure and are likely to be equivalent to a linear section of DNA.[18][19]

Collectively, this body of research established the central dogma of molecular biology, which states that proteins are translated from RNA, which is transcribed from DNA. This dogma has since been shown to have exceptions, such as reverse transcription in retroviruses. The modern study of genetics at the level of DNA is known as molecular genetics.

In 1972, Walter Fiers and his team at the University of Ghent were the first to determine the sequence of a gene: the gene for Bacteriophage MS2 coat protein.[20] The subsequent development of chain-termination DNA sequencing in 1977 by Frederick Sanger improved the efficiency of sequencing and turned it into a routine laboratory tool.[21] An automated version of the Sanger method was used in early phases of the Human Genome Project.[22]

The theories developed in the 1930s and 1940s to integrate molecular genetics with Darwinian evolution are called the modern evolutionary synthesis, a term introduced by Julian Huxley.[23] Evolutionary biologists subsequently refined this concept, such as George C. Williams' gene-centric view of evolution. He proposed an evolutionary concept of the gene as a unit of natural selection with the definition: "that which segregates and recombines with appreciable frequency."[24]:24 In this view, the molecular gene transcribes as a unit, and the evolutionary gene inherits as a unit. Related ideas emphasizing the centrality of genes in evolution were popularized by Richard Dawkins.[25][26]

The vast majority of living organisms encode their genes in long strands of DNA (deoxyribonucleic acid). DNA consists of a chain made from four types of nucleotide subunits, each composed of: a five-carbon sugar (2'-deoxyribose), a phosphate group, and one of the four bases adenine, cytosine, guanine, and thymine.[2]:2.1

Two chains of DNA twist around each other to form a DNA double helix with the phosphate-sugar backbone spiralling around the outside, and the bases pointing inwards with adenine base pairing to thymine and guanine to cytosine. The specificity of base pairing occurs because adenine and thymine align to form two hydrogen bonds, whereas cytosine and guanine form three hydrogen bonds. The two strands in a double helix must therefore be complementary, with their sequence of bases matching such that the adenines of one strand are paired with the thymines of the other strand, and so on.[2]:4.1

Due to the chemical composition of the pentose residues of the bases, DNA strands have directionality. One end of a DNA polymer contains an exposed hydroxyl group on the deoxyribose; this is known as the 3'end of the molecule. The other end contains an exposed phosphate group; this is the 5'end. The two strands of a double-helix run in opposite directions. Nucleic acid synthesis, including DNA replication and transcription occurs in the 5'3'direction, because new nucleotides are added via a dehydration reaction that uses the exposed 3'hydroxyl as a nucleophile.[27]:27.2

The expression of genes encoded in DNA begins by transcribing the gene into RNA, a second type of nucleic acid that is very similar to DNA, but whose monomers contain the sugar ribose rather than deoxyribose. RNA also contains the base uracil in place of thymine. RNA molecules are less stable than DNA and are typically single-stranded. Genes that encode proteins are composed of a series of three-nucleotide sequences called codons, which serve as the "words" in the genetic "language". The genetic code specifies the correspondence during protein translation between codons and amino acids. The genetic code is nearly the same for all known organisms.[2]:4.1

The total complement of genes in an organism or cell is known as its genome, which may be stored on one or more chromosomes. A chromosome consists of a single, very long DNA helix on which thousands of genes are encoded.[2]:4.2 The region of the chromosome at which a particular gene is located is called its locus. Each locus contains one allele of a gene; however, members of a population may have different alleles at the locus, each with a slightly different gene sequence.

The majority of eukaryotic genes are stored on a set of large, linear chromosomes. The chromosomes are packed within the nucleus in complex with storage proteins called histones to form a unit called a nucleosome. DNA packaged and condensed in this way is called chromatin.[2]:4.2 The manner in which DNA is stored on the histones, as well as chemical modifications of the histone itself, regulate whether a particular region of DNA is accessible for gene expression. In addition to genes, eukaryotic chromosomes contain sequences involved in ensuring that the DNA is copied without degradation of end regions and sorted into daughter cells during cell division: replication origins, telomeres and the centromere.[2]:4.2 Replication origins are the sequence regions where DNA replication is initiated to make two copies of the chromosome. Telomeres are long stretches of repetitive sequence that cap the ends of the linear chromosomes and prevent degradation of coding and regulatory regions during DNA replication. The length of the telomeres decreases each time the genome is replicated and has been implicated in the aging process.[29] The centromere is required for binding spindle fibres to separate sister chromatids into daughter cells during cell division.[2]:18.2

Prokaryotes (bacteria and archaea) typically store their genomes on a single large, circular chromosome. Similarly, some eukaryotic organelles contain a remnant circular chromosome with a small number of genes.[2]:14.4 Prokaryotes sometimes supplement their chromosome with additional small circles of DNA called plasmids, which usually encode only a few genes and are transferable between individuals. For example, the genes for antibiotic resistance are usually encoded on bacterial plasmids and can be passed between individual cells, even those of different species, via horizontal gene transfer.[30]

Whereas the chromosomes of prokaryotes are relatively gene-dense, those of eukaryotes often contain regions of DNA that serve no obvious function. Simple single-celled eukaryotes have relatively small amounts of such DNA, whereas the genomes of complex multicellular organisms, including humans, contain an absolute majority of DNA without an identified function.[31] This DNA has often been referred to as "junk DNA". However, more recent analyses suggest that, although protein-coding DNA makes up barely 2% of the human genome, about 80% of the bases in the genome may be expressed, so the term "junk DNA" may be a misnomer.[5]

The structure of a gene consists of many elements of which the actual protein coding sequence is often only a small part. These include DNA regions that are not transcribed as well as untranslated regions of the RNA.

Firstly, flanking the open reading frame, all genes contain a regulatory sequence that is required for their expression. In order to be expressed, genes require a promoter sequence. The promoter is recognized and bound by transcription factors and RNA polymerase to initiate transcription.[2]:7.1 A gene can have more than one promoter, resulting in messenger RNAs (mRNA) that differ in how far they extend in the 5'end.[32] Promoter regions have a consensus sequence, however highly transcribed genes have "strong" promoter sequences that bind the transcription machinery well, whereas others have "weak" promoters that bind poorly and initiate transcription less frequently.[2]:7.2Eukaryotic promoter regions are much more complex and difficult to identify than prokaryotic promoters.[2]:7.3

Additionally, genes can have regulatory regions many kilobases upstream or downstream of the open reading frame. These act by binding to transcription factors which then cause the DNA to loop so that the regulatory sequence (and bound transcription factor) become close to the RNA polymerase binding site.[33] For example, enhancers increase transcription by binding an activator protein which then helps to recruit the RNA polymerase to the promoter; conversely silencers bind repressor proteins and make the DNA less available for RNA polymerase.[34]

The transcribed pre-mRNA contains untranslated regions at both ends which contain a ribosome binding site, terminator and start and stop codons.[35] In addition, most eukaryotic open reading frames contain untranslated introns which are removed before the exons are translated. The sequences at the ends of the introns, dictate the splice sites to generate the final mature mRNA which encodes the protein or RNA product.[36]

Many prokaryotic genes are organized into operons, with multiple protein-coding sequences that are transcribed as a unit.[37][38] The genes in an operon are transcribed as a continuous messenger RNA, referred to as a polycistronic mRNA. The term cistron in this context is equivalent to gene. The transcription of an operons mRNA is often controlled by a repressor that can occur in an active or inactive state depending on the presence of certain specific metabolites.[39] When active, the repressor binds to a DNA sequence at the beginning of the operon, called the operator region, and represses transcription of the operon; when the repressor is inactive transcription of the operon can occur (see e.g. Lac operon). The products of operon genes typically have related functions and are involved in the same regulatory network.[2]:7.3

Defining exactly what section of a DNA sequence comprises a gene is difficult.[3]Regulatory regions of a gene such as enhancers do not necessarily have to be close to the coding sequence on the linear molecule because the intervening DNA can be looped out to bring the gene and its regulatory region into proximity. Similarly, a gene's introns can be much larger than its exons. Regulatory regions can even be on entirely different chromosomes and operate in trans to allow regulatory regions on one chromosome to come in contact with target genes on another chromosome.[40][41]

Early work in molecular genetics suggested the concept that one gene makes one protein. This concept (originally called the one gene-one enzyme hypothesis) emerged from an influential 1941 paper by George Beadle and Edward Tatum on experiments with mutants of the fungus Neurospora crassa.[42]Norman Horowitz, an early colleague on the Neurospora research, reminisced in 2004 that these experiments founded the science of what Beadle and Tatum called biochemical genetics. In actuality they proved to be the opening gun in what became molecular genetics and all the developments that have followed from that.[43] The one gene-one protein concept has been refined since the discovery of genes that can encode multiple proteins by alternative splicing and coding sequences split in short section across the genome whose mRNAs are concatenated by trans-splicing.[5][44][45]

A broad operational definition is sometimes used to encompass the complexity of these diverse phenomena, where a gene is defined as a union of genomic sequences encoding a coherent set of potentially overlapping functional products.[11] This definition categorizes genes by their functional products (proteins or RNA) rather than their specific DNA loci, with regulatory elements classified as gene-associated regions.[11]

In all organisms, two steps are required to read the information encoded in a gene's DNA and produce the protein it specifies. First, the gene's DNA is transcribed to messenger RNA (mRNA).[2]:6.1 Second, that mRNA is translated to protein.[2]:6.2 RNA-coding genes must still go through the first step, but are not translated into protein.[46] The process of producing a biologically functional molecule of either RNA or protein is called gene expression, and the resulting molecule is called a gene product.

The nucleotide sequence of a gene's DNA specifies the amino acid sequence of a protein through the genetic code. Sets of three nucleotides, known as codons, each correspond to a specific amino acid.[2]:6 The principle that three sequential bases of DNA code for each amino acid was demonstrated in 1961 using frameshift mutations in the rIIB gene of bacteriophage T4[47] (see Crick, Brenner et al. experiment).

Additionally, a "start codon", and three "stop codons" indicate the beginning and end of the protein coding region. There are 64possible codons (four possible nucleotides at each of three positions, hence 43possible codons) and only 20standard amino acids; hence the code is redundant and multiple codons can specify the same amino acid. The correspondence between codons and amino acids is nearly universal among all known living organisms.[48]

Transcription produces a single-stranded RNA molecule known as messenger RNA, whose nucleotide sequence is complementary to the DNA from which it was transcribed.[2]:6.1 The mRNA acts as an intermediate between the DNA gene and its final protein product. The gene's DNA is used as a template to generate a complementary mRNA. The mRNA matches the sequence of the gene's DNA coding strand because it is synthesised as the complement of the template strand. Transcription is performed by an enzyme called an RNA polymerase, which reads the template strand in the 3' to 5'direction and synthesizes the RNA from 5' to 3'. To initiate transcription, the polymerase first recognizes and binds a promoter region of the gene. Thus, a major mechanism of gene regulation is the blocking or sequestering the promoter region, either by tight binding by repressor molecules that physically block the polymerase, or by organizing the DNA so that the promoter region is not accessible.[2]:7

In prokaryotes, transcription occurs in the cytoplasm; for very long transcripts, translation may begin at the 5'end of the RNA while the 3'end is still being transcribed. In eukaryotes, transcription occurs in the nucleus, where the cell's DNA is stored. The RNA molecule produced by the polymerase is known as the primary transcript and undergoes post-transcriptional modifications before being exported to the cytoplasm for translation. One of the modifications performed is the splicing of introns which are sequences in the transcribed region that do not encode protein. Alternative splicing mechanisms can result in mature transcripts from the same gene having different sequences and thus coding for different proteins. This is a major form of regulation in eukaryotic cells and also occurs in some prokaryotes.[2]:7.5[49]

Translation is the process by which a mature mRNA molecule is used as a template for synthesizing a new protein.[2]:6.2 Translation is carried out by ribosomes, large complexes of RNA and protein responsible for carrying out the chemical reactions to add new amino acids to a growing polypeptide chain by the formation of peptide bonds. The genetic code is read three nucleotides at a time, in units called codons, via interactions with specialized RNA molecules called transfer RNA (tRNA). Each tRNA has three unpaired bases known as the anticodon that are complementary to the codon it reads on the mRNA. The tRNA is also covalently attached to the amino acid specified by the complementary codon. When the tRNA binds to its complementary codon in an mRNA strand, the ribosome attaches its amino acid cargo to the new polypeptide chain, which is synthesized from amino terminus to carboxyl terminus. During and after synthesis, most new proteins must fold to their active three-dimensional structure before they can carry out their cellular functions.[2]:3

Genes are regulated so that they are expressed only when the product is needed, since expression draws on limited resources.[2]:7 A cell regulates its gene expression depending on its external environment (e.g. available nutrients, temperature and other stresses), its internal environment (e.g. cell division cycle, metabolism, infection status), and its specific role if in a multicellular organism. Gene expression can be regulated at any step: from transcriptional initiation, to RNA processing, to post-translational modification of the protein. The regulation of lactose metabolism genes in E. coli (lac operon) was the first such mechanism to be described in 1961.[50]

A typical protein-coding gene is first copied into RNA as an intermediate in the manufacture of the final protein product.[2]:6.1 In other cases, the RNA molecules are the actual functional products, as in the synthesis of ribosomal RNA and transfer RNA. Some RNAs known as ribozymes are capable of enzymatic function, and microRNA has a regulatory role. The DNA sequences from which such RNAs are transcribed are known as non-coding RNA genes.[46]

Some viruses store their entire genomes in the form of RNA, and contain no DNA at all.[51][52] Because they use RNA to store genes, their cellular hosts may synthesize their proteins as soon as they are infected and without the delay in waiting for transcription.[53] On the other hand, RNA retroviruses, such as HIV, require the reverse transcription of their genome from RNA into DNA before their proteins can be synthesized. RNA-mediated epigenetic inheritance has also been observed in plants and very rarely in animals.[54]

Organisms inherit their genes from their parents. Asexual organisms simply inherit a complete copy of their parent's genome. Sexual organisms have two copies of each chromosome because they inherit one complete set from each parent.[2]:1

According to Mendelian inheritance, variations in an organism's phenotype (observable physical and behavioral characteristics) are due in part to variations in its genotype (particular set of genes). Each gene specifies a particular trait with different sequence of a gene (alleles) giving rise to different phenotypes. Most eukaryotic organisms (such as the pea plants Mendel worked on) have two alleles for each trait, one inherited from each parent.[2]:20

Alleles at a locus may be dominant or recessive; dominant alleles give rise to their corresponding phenotypes when paired with any other allele for the same trait, whereas recessive alleles give rise to their corresponding phenotype only when paired with another copy of the same allele. For example, if the allele specifying tall stems in pea plants is dominant over the allele specifying short stems, then pea plants that inherit one tall allele from one parent and one short allele from the other parent will also have tall stems. Mendel's work demonstrated that alleles assort independently in the production of gametes, or germ cells, ensuring variation in the next generation. Although Mendelian inheritance remains a good model for many traits determined by single genes (including a number of well-known genetic disorders) it does not include the physical processes of DNA replication and cell division.[55][56]

The growth, development, and reproduction of organisms relies on cell division, or the process by which a single cell divides into two usually identical daughter cells. This requires first making a duplicate copy of every gene in the genome in a process called DNA replication.[2]:5.2 The copies are made by specialized enzymes known as DNA polymerases, which "read" one strand of the double-helical DNA, known as the template strand, and synthesize a new complementary strand. Because the DNA double helix is held together by base pairing, the sequence of one strand completely specifies the sequence of its complement; hence only one strand needs to be read by the enzyme to produce a faithful copy. The process of DNA replication is semiconservative; that is, the copy of the genome inherited by each daughter cell contains one original and one newly synthesized strand of DNA.[2]:5.2

The rate of DNA replication in living cells was first measured as the rate of phage T4 DNA elongation in phage-infected E. coli and found to be impressively rapid.[57] During the period of exponential DNA increase at 37 C, the rate of elongation was 749 nucleotides per second.

After DNA replication is complete, the cell must physically separate the two copies of the genome and divide into two distinct membrane-bound cells.[2]:18.2 In prokaryotes(bacteria and archaea) this usually occurs via a relatively simple process called binary fission, in which each circular genome attaches to the cell membrane and is separated into the daughter cells as the membrane invaginates to split the cytoplasm into two membrane-bound portions. Binary fission is extremely fast compared to the rates of cell division in eukaryotes. Eukaryotic cell division is a more complex process known as the cell cycle; DNA replication occurs during a phase of this cycle known as S phase, whereas the process of segregating chromosomes and splitting the cytoplasm occurs during M phase.[2]:18.1

The duplication and transmission of genetic material from one generation of cells to the next is the basis for molecular inheritance, and the link between the classical and molecular pictures of genes. Organisms inherit the characteristics of their parents because the cells of the offspring contain copies of the genes in their parents' cells. In asexually reproducing organisms, the offspring will be a genetic copy or clone of the parent organism. In sexually reproducing organisms, a specialized form of cell division called meiosis produces cells called gametes or germ cells that are haploid, or contain only one copy of each gene.[2]:20.2 The gametes produced by females are called eggs or ova, and those produced by males are called sperm. Two gametes fuse to form a diploid fertilized egg, a single cell that has two sets of genes, with one copy of each gene from the mother and one from the father.[2]:20

During the process of meiotic cell division, an event called genetic recombination or crossing-over can sometimes occur, in which a length of DNA on one chromatid is swapped with a length of DNA on the corresponding homologous non-sister chromatid. This can result in reassortment of otherwise linked alleles.[2]:5.5 The Mendelian principle of independent assortment asserts that each of a parent's two genes for each trait will sort independently into gametes; which allele an organism inherits for one trait is unrelated to which allele it inherits for another trait. This is in fact only true for genes that do not reside on the same chromosome, or are located very far from one another on the same chromosome. The closer two genes lie on the same chromosome, the more closely they will be associated in gametes and the more often they will appear together; genes that are very close are essentially never separated because it is extremely unlikely that a crossover point will occur between them. This is known as genetic linkage.[58]

DNA replication is for the most part extremely accurate, however errors (mutations) do occur.[2]:7.6 The error rate in eukaryotic cells can be as low as 108 per nucleotide per replication,[59][60] whereas for some RNA viruses it can be as high as 103.[61] This means that each generation, each human genome accumulates 12 new mutations.[61] Small mutations can be caused by DNA replication and the aftermath of DNA damage and include point mutations in which a single base is altered and frameshift mutations in which a single base is inserted or deleted. Either of these mutations can change the gene by missense (change a codon to encode a different amino acid) or nonsense (a premature stop codon).[62] Larger mutations can be caused by errors in recombination to cause chromosomal abnormalities including the duplication, deletion, rearrangement or inversion of large sections of a chromosome. Additionally, DNA repair mechanisms can introduce mutational errors when repairing physical damage to the molecule. The repair, even with mutation, is more important to survival than restoring an exact copy, for example when repairing double-strand breaks.[2]:5.4

When multiple different alleles for a gene are present in a species's population it is called polymorphic. Most different alleles are functionally equivalent, however some alleles can give rise to different phenotypic traits. A gene's most common allele is called the wild type, and rare alleles are called mutants. The genetic variation in relative frequencies of different alleles in a population is due to both natural selection and genetic drift.[63] The wild-type allele is not necessarily the ancestor of less common alleles, nor is it necessarily fitter.

Most mutations within genes are neutral, having no effect on the organism's phenotype (silent mutations). Some mutations do not change the amino acid sequence because multiple codons encode the same amino acid (synonymous mutations). Other mutations can be neutral if they lead to amino acid sequence changes, but the protein still functions similarly with the new amino acid (e.g. conservative mutations). Many mutations, however, are deleterious or even lethal, and are removed from populations by natural selection. Genetic disorders are the result of deleterious mutations and can be due to spontaneous mutation in the affected individual, or can be inherited. Finally, a small fraction of mutations are beneficial, improving the organism's fitness and are extremely important for evolution, since their directional selection leads to adaptive evolution.[2]:7.6

Genes with a most recent common ancestor, and thus a shared evolutionary ancestry, are known as homologs.[64] These genes appear either from gene duplication within an organism's genome, where they are known as paralogous genes, or are the result of divergence of the genes after a speciation event, where they are known as orthologous genes,[2]:7.6 and often perform the same or similar functions in related organisms. It is often assumed that the functions of orthologous genes are more similar than those of paralogous genes, although the difference is minimal.[65][66]

The relationship between genes can be measured by comparing the sequence alignment of their DNA.[2]:7.6 The degree of sequence similarity between homologous genes is called conserved sequence. Most changes to a gene's sequence do not affect its function and so genes accumulate mutations over time by neutral molecular evolution. Additionally, any selection on a gene will cause its sequence to diverge at a different rate. Genes under stabilizing selection are constrained and so change more slowly whereas genes under directional selection change sequence more rapidly.[67] The sequence differences between genes can be used for phylogenetic analyses to study how those genes have evolved and how the organisms they come from are related.[68][69]

The most common source of new genes in eukaryotic lineages is gene duplication, which creates copy number variation of an existing gene in the genome.[70][71] The resulting genes (paralogs) may then diverge in sequence and in function. Sets of genes formed in this way comprise a gene family. Gene duplications and losses within a family are common and represent a major source of evolutionary biodiversity.[72] Sometimes, gene duplication may result in a nonfunctional copy of a gene, or a functional copy may be subject to mutations that result in loss of function; such nonfunctional genes are called pseudogenes.[2]:7.6

"Orphan" genes, whose sequence shows no similarity to existing genes, are less common than gene duplicates. Estimates of the number of genes with no homologs outside humans range from 18[73] to 60.[74] Two primary sources of orphan protein-coding genes are gene duplication followed by extremely rapid sequence change, such that the original relationship is undetectable by sequence comparisons, and de novo conversion of a previously non-coding sequence into a protein-coding gene.[75] De novo genes are typically shorter and simpler in structure than most eukaryotic genes, with few if any introns.[70] Over long evolutionary time periods, de novo gene birth may be responsible for a significant fraction of taxonomically-restricted gene families.[76]

Horizontal gene transfer refers to the transfer of genetic material through a mechanism other than reproduction. This mechanism is a common source of new genes in prokaryotes, sometimes thought to contribute more to genetic variation than gene duplication.[77] It is a common means of spreading antibiotic resistance, virulence, and adaptive metabolic functions.[30][78] Although horizontal gene transfer is rare in eukaryotes, likely examples have been identified of protist and alga genomes containing genes of bacterial origin.[79][80]

The genome is the total genetic material of an organism and includes both the genes and non-coding sequences.[81]

The genome size, and the number of genes it encodes varies widely between organisms. The smallest genomes occur in viruses (which can have as few as 2 protein-coding genes),[90] and viroids (which act as a single non-coding RNA gene).[91] Conversely, plants can have extremely large genomes,[92] with rice containing >46,000 protein-coding genes.[93] The total number of protein-coding genes (the Earth's proteome) is estimated to be 5million sequences.[94]

Although the number of base-pairs of DNA in the human genome has been known since the 1960s, the estimated number of genes has changed over time as definitions of genes, and methods of detecting them have been refined. Initial theoretical predictions of the number of human genes were as high as 2,000,000.[95] Early experimental measures indicated there to be 50,000100,000 transcribed genes (expressed sequence tags).[96] Subsequently, the sequencing in the Human Genome Project indicated that many of these transcripts were alternative variants of the same genes, and the total number of protein-coding genes was revised down to ~20,000[89] with 13 genes encoded on the mitochondrial genome.[87] Of the human genome, only 12% consists of protein-coding genes,[97] with the remainder being 'noncoding' DNA such as introns, retrotransposons, and noncoding RNAs.[97][98] Every multicellular organism has all its genes in each cell of its body but not every gene functions in every cell .

Essential genes are the set of genes thought to be critical for an organism's survival.[100] This definition assumes the abundant availability of all relevant nutrients and the absence of environmental stress. Only a small portion of an organism's genes are essential. In bacteria, an estimated 250400 genes are essential for Escherichia coli and Bacillus subtilis, which is less than 10% of their genes.[101][102][103] Half of these genes are orthologs in both organisms and are largely involved in protein synthesis.[103] In the budding yeast Saccharomyces cerevisiae the number of essential genes is slightly higher, at 1000 genes (~20% of their genes).[104] Although the number is more difficult to measure in higher eukaryotes, mice and humans are estimated to have around 2000 essential genes (~10% of their genes).[105] The synthetic organism, Syn 3, has a minimal genome of 473 essential genes and quasi-essential genes (necessary for fast growth), although 149 have unknown function.[99]

Essential genes include Housekeeping genes (critical for basic cell functions)[106] as well as genes that are expressed at different times in the organisms development or life cycle.[107] Housekeeping genes are used as experimental controls when analysing gene expression, since they are constitutively expressed at a relatively constant level.

Gene nomenclature has been established by the HUGO Gene Nomenclature Committee (HGNC) for each known human gene in the form of an approved gene name and symbol (short-form abbreviation), which can be accessed through a database maintained by HGNC. Symbols are chosen to be unique, and each gene has only one symbol (although approved symbols sometimes change). Symbols are preferably kept consistent with other members of a gene family and with homologs in other species, particularly the mouse due to its role as a common model organism.[108]

Genetic engineering is the modification of an organism's genome through biotechnology. Since the 1970s, a variety of techniques have been developed to specifically add, remove and edit genes in an organism.[109] Recently developed genome engineering techniques use engineered nuclease enzymes to create targeted DNA repair in a chromosome to either disrupt or edit a gene when the break is repaired.[110][111][112][113] The related term synthetic biology is sometimes used to refer to extensive genetic engineering of an organism.[114]

Genetic engineering is now a routine research tool with model organisms. For example, genes are easily added to bacteria[115] and lineages of knockout mice with a specific gene's function disrupted are used to investigate that gene's function.[116][117] Many organisms have been genetically modified for applications in agriculture, industrial biotechnology, and medicine.

For multicellular organisms, typically the embryo is engineered which grows into the adult genetically modified organism.[118] However, the genomes of cells in an adult organism can be edited using gene therapy techniques to treat genetic diseases.

Alberts B, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2002). Molecular Biology of the Cell (Fourth ed.). New York: Garland Science. ISBN978-0-8153-3218-3. A molecular biology textbook available free online through NCBI Bookshelf.

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Gene - Wikipedia

Despite bouncing off a 2-year low, biotech is still an unpopular sector and investors are rightfully concerned about its near-term prospects. Recent drug failures, growing pricing pressure and the potential impact of biosimilars all contribute to the negative sentiment, but the main problem is the lack of growth drivers for the remainder of 2016 (and potentially 2017).

The biotech industry relies on innovation cycles to create new revenue sources. This was the case in the 2013-2014 biotech bull market, which was driven by a wave of medical breakthroughs (PD-1, HCV, CAR/TCR, oral MS drugs, CF etc.). These waves typically involve new therapeutic approaches coupled with disruptive technologies as their enablers.

In oncology, for example, the understanding that cancer is driven by aberrant signaling coupled with advances in medicinal chemistry and antibody engineering led to the development of kinase inhibitors and monoclonal antibodies as blockers of signaling. A decade later, insights around cancer immunology gave rise to the immuno-oncology field and PD-1 inhibitors in particular, which are expected to become the biggest oncology franchise ever.

Gene therapy ticks all the boxes

While there are several hot areas in biotech such as gene editing and microbiome, most are still early and their applicability is unclear. Gene therapy, on the other hand, is more mature and de-risked with tens of clinical studies and the potential to treat (and perhaps cure) a wide range of diseases where treatment is inadequate or non-existent. The commercial upside from these programs is huge and should expand as additional indications are pursued.

As I previously discussed, the past two years saw a surge in the number of clinical-stage gene therapies, some of which already generated impressive efficacy across multiple indications. This makes gene therapy the only truly disruptive field which is mature enough not only from a technology but also from a clinical standpoint. Importantly, most studies are conducted by companies according to industry and regulatory standards, in contrast to historical gene therapy studies that were run by academic groups.

To me, the striking thing about the results is the breadth of technologies, indications and modes of administrations evaluated to date. This versatility is very important for the future of gene therapy as it reduces overall development risk and increases likelihood of success by allowing companies to tailor the right product for each indication. Parameters include mode of administration (local vs. systemic vs. ex vivo), tropism for the target tissue (eye, bone marrow, liver etc.), immunogenicity and onset of activity.

Building a diversified gene therapy basket

Given the early development stage and large number of technologies, I prefer to own a basket of gene therapy stocks with a focus on the more clinically validated ones: Spark (ONCE), Bluebird (BLUE) and Avexis (AVXS).

Bluebird and Spark are the most further along (and also the largest based on market cap) gene therapy companies and should be the basis for any gene therapy portfolio. With two completely different technologies, the two companies have strong clinical proof-of-concept for their respective lead programs.

Avexis is less advanced without a clinically validated product, but recent data for its lead program are too promising to ignore.

Spark Clinical validation for retinal and liver indications

Sparks lead programs (SPK-RPE65) will probably become the first gene therapy to get FDA approval. In October, the company reported strong P3 data in rare genetic retinal conditions caused by RPE65 mutations, the first randomized and statistically significant data for a gene therapy. The company is expected to complete its BLA submission later in 2016 which should lead to FDA approval in 2017. Sparks second ophthalmology program for choroideremia is in P1 with efficacy data expected later in 2016.

Earlier this month, Spark released an encouraging update for its Hemophilia B program, SPK-9001 (partnered with Pfizer [PFE]). A single administration of SPK-9001 led to a sustained and clinically meaningful production of Factor IX, a clotting factor which is dysfunctional in Hemophilia B patients. All four treated patients experienced a clinically significant increase in Factor IX activity from <2% to 26%-41% (12% is predicted to be sufficient for minimizing incidence bleeding events). Due to the limited follow up (under 6 months), durability is still an open question.

Spark intends to advance its wholly-owned Hemophilia A program (SPK-8011) to the clinic later in 2016 with initial data expected in H1:2017. Results in the Hemophilia B should be viewed as a positive read-through but Hemophilia A still presents certain technical challenges (e.g. missing protein is several fold larger) which required Spark to use a different vector. Hemophilia A represents a $5B opportunity compared to $1B for Hemophilia B.

Bluebird

Despite being one of the worst biotech performers, Bluebird remains the largest and most visible gene therapy company. In contrast to most gene therapy companies, Bluebird treats patients cells ex-vivo (outside of the body) in a process that resembles stem cell transplant or adoptive cell transfer (CAR, TCR). Progenitor cells are collected from the patient, a genetic modification is integrated into the genome followed by infusion of the cells that repopulate the bone marrow. This enables Bluebird to go after hematologic diseases like beta thalassemia and Sickle-cell disease (SCD) where target cells are constantly dividing.

Sentiment around Bluebirds lead program, Lenti-globin , plummeted last year after a series of disappointing results in a subset of beta-thal patients and preliminary data in SCD, which represents the more important commercial opportunity. Particularly in SCD patients, post-treatment hemoglobin levels were relatively low and although some increase has been noted with time, it is still unclear what the maximal effect would be. Market reaction was brutal, sending shares down 75% in just over a year.

Next update for Lenti-globin is expected at ASH in December. Despite the disappointing efficacy observed in SCD and beta-thal, I am cautiously optimistic about Bluebirds efforts to optimize treatment protocols and regimens. These include specific conditioning regimens and ex-vivo treatment of cells that may improve transduction rate and hemoglobin production in patients. Some of these modifications are already being implemented in newly recruited patients and hopefully longer follow up will lead to higher hemoglobin levels in already-reported patients.

The only clinical update so far in 2016 was for Lenti-D in C-ALD, a rare neurological disease that affects infants in their first years. Results demonstrated that of 17 patients treated to date (median follow-up of 16 months), all remain alive and free of major functional deterioration (defined as major functional disabilities, MFD). The primary endpoint, defined as no MFD at 2 years, was reached for 3/3 patients with sufficient follow-up and assuming the trend continues Bluebird may be in a position to file for approval in H2:2017.

Lenti-Ds commercial opportunity is limited (200 patients diagnosed each year in developed countries) so investors understandably focus on Lenti-globin, which is being developed for beta thal (~20k patients in developed countries) and SCD (~160k patients).

Bluebird is expected to end 2016 with ~$650M in cash. Current market cap is $1.7B.

Avexis

Avexis is developing AVXS-101 for Spinal muscular atrophy Type 1 (SMA1), a rapidly deteriorating and fatal neuro-muscular disease. SMA1 is characterized by rapid deterioration in motor and neuronal functions with 50% of patients experiencing death or permanent ventilation by their first anniversary. Most patients die from respiratory failure by the age of two. SMA Type 2 and Type 3 are also caused by SMN1 mutations and are characterized by a later onset and milder disease burden (but unmet need is still significant in these indications). The US prevalence of SMA is 10,000, 600 of which are SMA1.

In contrast to Bluebird and Spark, Avexis does not have conclusive proof it can lead to expression of the missing protein (SMN1) in the target tissue nor does it have randomized clinical data but the results generated to date are simply too provocative to ignore.

At the most recent update, Avexis presented data for 15 patients who received AVXS-101 in their first months of life. 3 patients were treated with a low dose and 12 were treated with a high dose. Strikingly, none of the children experienced an event (defined as ventilation or death), including patients who reached 2 years of age. All 9 patients with sufficient follow up, reached the age of 13.6 months without an event in contrast to historical data that show an event-free survival of 25%. AVXS-101 also led to a dose dependent increase in motor function which had a quick onset especially at the higher dose.

As with any results from an open label study without a control arm, these data should be analyzed with caution, as they need to be corroborated by large controlled studies (expected to start next year). Still, the data point to an overwhelming benefit in a very aggressive disease. One of the most exciting aspects of this program is the fact that it is given systemically via IV administration, which implies the treatment reaches the neurons in the CNS. Avexis plans to start a trial in SMA2 in H2:16 using intrathecal delivery (directly to the spinal canal). This decision is surprising given the results with IV administration in SMA1 and the fact that the BBB immaturity hypothesis in babies is not considered relevant anymore. (See this review)

AVXS-101s main competitor is Biogens (BIIB) and Ionis (IONS) nusinersen, an antisense molecule that needs to be intrathecally injected 3-4 times a year. As both drugs generated encouraging clinical data in small non-randomized studies, it is hard to compare them, however, AVXS-101 has an obvious advantage of being a potentially one time IV injection. Nusinersen is in P3 with topline data expected in mid-2017.

AVXS-101 is based on an AAV9 vector developed by REGENXBIO (RGNX), which licensed the technology to Avexis. Beyond the 5%-10% in royalties REGENXBIO is eligible to receive, data for AVXS-101 bode well for the companys proprietary programs in MPS-I and MPS-II, two other rare diseases with neurological involvement where BBB penetration is crucial. These programs are also based on REGENXBIOs AAV9.

Beyond AVXS-101, REGENXBIO has an impressive partnered pipeline which includes collaborations with Voyager (VYGR), Dimension (DMTX) , Baxalta and Lysogene.

Portfolio updates Immunogen, Marinus, Esperion

June was a rough month for three of my holdings. Immunogen (IMGN) had a disappointing data set at ASCO, Marinus (MRNS) reported a P3 failure in epilepsy and most recently, Esperion was dealt a regulatory blow from the FDA that may push development timelines by several years. I am selling Immunogen and Marinus due to the lack of near-term catalysts although long-term their respective drugs could still be valuable. I decided to keep Esperion as I still find ETC-1002 very attractive and hope that PCSK9s CVOT data will soften FDAs concerns about LDL-C reduction as an approvable endpoint.

Three additional companies with important binary readouts in the coming months are Array Biopharma (ARRY), SAGE (SAGE) and Aurinia (AUPH). Array will have P3 data for selumetinib (partnered with AstraZeneca) in KRAS+ NSCLC. SAGE will report data from a randomized P2 in PPD following a promising single-arm data set. Aurinia will report results from the AURA study in lupus nephritis patients, where there is a strong rationale for using the companys drug (voclosporin) but limited direct clinical validation.

Portfolio holdings July 4, 2016

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Could gene therapy become biotechs growth driver in 2017 ...

Gene therapy is the therapeutic delivery of nucleic acid polymers into a patient's cells as a drug to treat disease.[1] The first attempt at modifying human DNA was performed in 1980 by Martin Cline, but the first successful and approved[by whom?] nuclear gene transfer in humans was performed in May 1989.[2] The first therapeutic use of gene transfer as well as the first direct insertion of human DNA into the nuclear genome was performed by French Anderson in a trial starting in September 1990.

Between 1989 and February 2016, over 2,300 clinical trials had been conducted, more than half of them in phase I.[3]

It should be noted that not all medical procedures that introduce alterations to a patient's genetic makeup can be considered gene therapy. Bone marrow transplantation and organ transplants in general have been found to introduce foreign DNA into patients.[4] Gene therapy is defined by the precision of the procedure and the intention of direct therapeutic effects.

Gene therapy was conceptualized in 1972, by authors who urged caution before commencing human gene therapy studies.

The first attempt, an unsuccessful one, at gene therapy (as well as the first case of medical transfer of foreign genes into humans not counting organ transplantation) was performed by Martin Cline on 10 July 1980.[5][6] Cline claimed that one of the genes in his patients was active six months later, though he never published this data or had it verified[7] and even if he is correct, it's unlikely it produced any significant beneficial effects treating beta-thalassemia.[8]

After extensive research on animals throughout the 1980s and a 1989 bacterial gene tagging trial on humans, the first gene therapy widely accepted as a success was demonstrated in a trial that started on September 14, 1990, when Ashi DeSilva was treated for ADA-SCID.[9]

The first somatic treatment that produced a permanent genetic change was performed in 1993.[10]

This procedure was referred to sensationally and somewhat inaccurately in the media as a "three parent baby", though mtDNA is not the primary human genome and has little effect on an organism's individual characteristics beyond powering their cells.

Gene therapy is a way to fix a genetic problem at its source. The polymers are either translated into proteins, interfere with target gene expression, or possibly correct genetic mutations.

The most common form uses DNA that encodes a functional, therapeutic gene to replace a mutated gene. The polymer molecule is packaged within a "vector", which carries the molecule inside cells.

Early clinical failures led to dismissals of gene therapy. Clinical successes since 2006 regained researchers' attention, although as of 2014, it was still largely an experimental technique.[11] These include treatment of retinal diseases Leber's congenital amaurosis[12][13][14][15] and choroideremia,[16]X-linked SCID,[17] ADA-SCID,[18][19]adrenoleukodystrophy,[20]chronic lymphocytic leukemia (CLL),[21]acute lymphocytic leukemia (ALL),[22]multiple myeloma,[23]haemophilia[19] and Parkinson's disease.[24] Between 2013 and April 2014, US companies invested over $600 million in the field.[25]

The first commercial gene therapy, Gendicine, was approved in China in 2003 for the treatment of certain cancers.[26] In 2011 Neovasculgen was registered in Russia as the first-in-class gene-therapy drug for treatment of peripheral artery disease, including critical limb ischemia.[27] In 2012 Glybera, a treatment for a rare inherited disorder, became the first treatment to be approved for clinical use in either Europe or the United States after its endorsement by the European Commission.[11][28]

Following early advances in genetic engineering of bacteria, cells, and small animals, scientists started considering how to apply it to medicine. Two main approaches were considered replacing or disrupting defective genes.[29] Scientists focused on diseases caused by single-gene defects, such as cystic fibrosis, haemophilia, muscular dystrophy, thalassemia and sickle cell anemia. Glybera treats one such disease, caused by a defect in lipoprotein lipase.[28]

DNA must be administered, reach the damaged cells, enter the cell and express/disrupt a protein.[30] Multiple delivery techniques have been explored. The initial approach incorporated DNA into an engineered virus to deliver the DNA into a chromosome.[31][32]Naked DNA approaches have also been explored, especially in the context of vaccine development.[33]

Generally, efforts focused on administering a gene that causes a needed protein to be expressed. More recently, increased understanding of nuclease function has led to more direct DNA editing, using techniques such as zinc finger nucleases and CRISPR. The vector incorporates genes into chromosomes. The expressed nucleases then knock out and replace genes in the chromosome. As of 2014 these approaches involve removing cells from patients, editing a chromosome and returning the transformed cells to patients.[34]

Gene editing is a potential approach to alter the human genome to treat genetic diseases,[35] viral diseases,[36] and cancer.[37] As of 2016 these approaches were still years from being medicine.[38][39]

Gene therapy may be classified into two types:

In somatic cell gene therapy (SCGT), the therapeutic genes are transferred into any cell other than a gamete, germ cell, gametocyte or undifferentiated stem cell. Any such modifications affect the individual patient only, and are not inherited by offspring. Somatic gene therapy represents mainstream basic and clinical research, in which therapeutic DNA (either integrated in the genome or as an external episome or plasmid) is used to treat disease.

Over 600 clinical trials utilizing SCGT are underway in the US. Most focus on severe genetic disorders, including immunodeficiencies, haemophilia, thalassaemia and cystic fibrosis. Such single gene disorders are good candidates for somatic cell therapy. The complete correction of a genetic disorder or the replacement of multiple genes is not yet possible. Only a few of the trials are in the advanced stages.[40]

In germline gene therapy (GGT), germ cells (sperm or eggs) are modified by the introduction of functional genes into their genomes. Modifying a germ cell causes all the organism's cells to contain the modified gene. The change is therefore heritable and passed on to later generations. Australia, Canada, Germany, Israel, Switzerland and the Netherlands[41] prohibit GGT for application in human beings, for technical and ethical reasons, including insufficient knowledge about possible risks to future generations[41] and higher risks versus SCGT.[42] The US has no federal controls specifically addressing human genetic modification (beyond FDA regulations for therapies in general).[41][43][44][45]

The delivery of DNA into cells can be accomplished by multiple methods. The two major classes are recombinant viruses (sometimes called biological nanoparticles or viral vectors) and naked DNA or DNA complexes (non-viral methods).

In order to replicate, viruses introduce their genetic material into the host cell, tricking the host's cellular machinery into using it as blueprints for viral proteins. Scientists exploit this by substituting a virus's genetic material with therapeutic DNA. (The term 'DNA' may be an oversimplification, as some viruses contain RNA, and gene therapy could take this form as well.) A number of viruses have been used for human gene therapy, including retrovirus, adenovirus, lentivirus, herpes simplex, vaccinia and adeno-associated virus.[3] Like the genetic material (DNA or RNA) in viruses, therapeutic DNA can be designed to simply serve as a temporary blueprint that is degraded naturally or (at least theoretically) to enter the host's genome, becoming a permanent part of the host's DNA in infected cells.

Non-viral methods present certain advantages over viral methods, such as large scale production and low host immunogenicity. However, non-viral methods initially produced lower levels of transfection and gene expression, and thus lower therapeutic efficacy. Later technology remedied this deficiency[citation needed].

Methods for non-viral gene therapy include the injection of naked DNA, electroporation, the gene gun, sonoporation, magnetofection, the use of oligonucleotides, lipoplexes, dendrimers, and inorganic nanoparticles.

Some of the unsolved problems include:

Three patients' deaths have been reported in gene therapy trials, putting the field under close scrutiny. The first was that of Jesse Gelsinger in 1999.[52] One X-SCID patient died of leukemia in 2003.[9] In 2007, a rheumatoid arthritis patient died from an infection; the subsequent investigation concluded that the death was not related to gene therapy.[53]

In 1972 Friedmann and Roblin authored a paper in Science titled "Gene therapy for human genetic disease?"[54] Rogers (1970) was cited for proposing that exogenous good DNA be used to replace the defective DNA in those who suffer from genetic defects.[55]

In 1984 a retrovirus vector system was designed that could efficiently insert foreign genes into mammalian chromosomes.[56]

The first approved gene therapy clinical research in the US took place on 14 September 1990, at the National Institutes of Health (NIH), under the direction of William French Anderson.[57] Four-year-old Ashanti DeSilva received treatment for a genetic defect that left her with ADA-SCID, a severe immune system deficiency. The effects were temporary, but successful.[58]

Cancer gene therapy was introduced in 1992/93 (Trojan et al. 1993).[59] The treatment of glioblastoma multiforme, the malignant brain tumor whose outcome is always fatal, was done using a vector expressing antisense IGF-I RNA (clinical trial approved by NIH n 1602, and FDA in 1994). This therapy also represents the beginning of cancer immunogene therapy, a treatment which proves to be effective due to the anti-tumor mechanism of IGF-I antisense, which is related to strong immune and apoptotic phenomena.

In 1992 Claudio Bordignon, working at the Vita-Salute San Raffaele University, performed the first gene therapy procedure using hematopoietic stem cells as vectors to deliver genes intended to correct hereditary diseases.[60] In 2002 this work led to the publication of the first successful gene therapy treatment for adenosine deaminase-deficiency (SCID). The success of a multi-center trial for treating children with SCID (severe combined immune deficiency or "bubble boy" disease) from 2000 and 2002, was questioned when two of the ten children treated at the trial's Paris center developed a leukemia-like condition. Clinical trials were halted temporarily in 2002, but resumed after regulatory review of the protocol in the US, the United Kingdom, France, Italy and Germany.[61]

In 1993 Andrew Gobea was born with SCID following prenatal genetic screening. Blood was removed from his mother's placenta and umbilical cord immediately after birth, to acquire stem cells. The allele that codes for adenosine deaminase (ADA) was obtained and inserted into a retrovirus. Retroviruses and stem cells were mixed, after which the viruses inserted the gene into the stem cell chromosomes. Stem cells containing the working ADA gene were injected into Andrew's blood. Injections of the ADA enzyme were also given weekly. For four years T cells (white blood cells), produced by stem cells, made ADA enzymes using the ADA gene. After four years more treatment was needed.[citation needed]

Jesse Gelsinger's death in 1999 impeded gene therapy research in the US.[62][63] As a result, the FDA suspended several clinical trials pending the reevaluation of ethical and procedural practices.[64]

The modified cancer gene therapy strategy of antisense IGF-I RNA (NIH n 1602)[65] using antisense / triple helix anti IGF-I approach was registered in 2002 by Wiley gene therapy clinical trial - n 635 and 636. The approach has shown promising results in the treatment of six different malignant tumors: glioblastoma, cancers of liver, colon, prostate, uterus and ovary (Collaborative NATO Science Programme on Gene Therapy USA, France, Poland n LST 980517 conducted by J. Trojan) (Trojan et al., 2012). This antigene antisense/triple helix therapy has proven to be efficient, due to the mechanism stopping simultaneously IGF-I expression on translation and transcription levels, strengthening anti-tumor immune and apoptotic phenomena.

Sickle-cell disease can be treated in mice.[66] The mice which have essentially the same defect that causes human cases used a viral vector to induce production of fetal hemoglobin (HbF), which normally ceases to be produced shortly after birth. In humans, the use of hydroxyurea to stimulate the production of HbF temporarily alleviates sickle cell symptoms. The researchers demonstrated this treatment to be a more permanent means to increase therapeutic HbF production.[67]

A new gene therapy approach repaired errors in messenger RNA derived from defective genes. This technique has the potential to treat thalassaemia, cystic fibrosis and some cancers.[68]

Researchers created liposomes 25 nanometers across that can carry therapeutic DNA through pores in the nuclear membrane.[69]

In 2003 a research team inserted genes into the brain for the first time. They used liposomes coated in a polymer called polyethylene glycol, which, unlike viral vectors, are small enough to cross the bloodbrain barrier.[70]

Short pieces of double-stranded RNA (short, interfering RNAs or siRNAs) are used by cells to degrade RNA of a particular sequence. If a siRNA is designed to match the RNA copied from a faulty gene, then the abnormal protein product of that gene will not be produced.[71]

Gendicine is a cancer gene therapy that delivers the tumor suppressor gene p53 using an engineered adenovirus. In 2003, it was approved in China for the treatment of head and neck squamous cell carcinoma.[26]

In March researchers announced the successful use of gene therapy to treat two adult patients for X-linked chronic granulomatous disease, a disease which affects myeloid cells and damages the immune system. The study is the first to show that gene therapy can treat the myeloid system.[72]

In May a team reported a way to prevent the immune system from rejecting a newly delivered gene.[73] Similar to organ transplantation, gene therapy has been plagued by this problem. The immune system normally recognizes the new gene as foreign and rejects the cells carrying it. The research utilized a newly uncovered network of genes regulated by molecules known as microRNAs. This natural function selectively obscured their therapeutic gene in immune system cells and protected it from discovery. Mice infected with the gene containing an immune-cell microRNA target sequence did not reject the gene.

In August scientists successfully treated metastatic melanoma in two patients using killer T cells genetically retargeted to attack the cancer cells.[74]

In November researchers reported on the use of VRX496, a gene-based immunotherapy for the treatment of HIV that uses a lentiviral vector to deliver an antisense gene against the HIV envelope. In a phase I clinical trial, five subjects with chronic HIV infection who had failed to respond to at least two antiretroviral regimens were treated. A single intravenous infusion of autologous CD4 T cells genetically modified with VRX496 was well tolerated. All patients had stable or decreased viral load; four of the five patients had stable or increased CD4 T cell counts. All five patients had stable or increased immune response to HIV antigens and other pathogens. This was the first evaluation of a lentiviral vector administered in a US human clinical trial.[75][76]

In May researchers announced the first gene therapy trial for inherited retinal disease. The first operation was carried out on a 23-year-old British male, Robert Johnson, in early 2007.[77]

Leber's congenital amaurosis is an inherited blinding disease caused by mutations in the RPE65 gene. The results of a small clinical trial in children were published in April.[12] Delivery of recombinant adeno-associated virus (AAV) carrying RPE65 yielded positive results. In May two more groups reported positive results in independent clinical trials using gene therapy to treat the condition. In all three clinical trials, patients recovered functional vision without apparent side-effects.[12][13][14][15]

In September researchers were able to give trichromatic vision to squirrel monkeys.[78] In November 2009, researchers halted a fatal genetic disorder called adrenoleukodystrophy in two children using a lentivirus vector to deliver a functioning version of ABCD1, the gene that is mutated in the disorder.[79]

An April paper reported that gene therapy addressed achromatopsia (color blindness) in dogs by targeting cone photoreceptors. Cone function and day vision were restored for at least 33 months in two young specimens. The therapy was less efficient for older dogs.[80]

In September it was announced that an 18-year-old male patient in France with beta-thalassemia major had been successfully treated.[81] Beta-thalassemia major is an inherited blood disease in which beta haemoglobin is missing and patients are dependent on regular lifelong blood transfusions.[82] The technique used a lentiviral vector to transduce the human -globin gene into purified blood and marrow cells obtained from the patient in June 2007.[83] The patient's haemoglobin levels were stable at 9 to 10 g/dL. About a third of the hemoglobin contained the form introduced by the viral vector and blood transfusions were not needed.[83][84] Further clinical trials were planned.[85]Bone marrow transplants are the only cure for thalassemia, but 75% of patients do not find a matching donor.[84]

Cancer immunogene therapy using modified anti gene, antisense / triple helix approach was introduced in South America in 2010/11 in La Sabana University, Bogota (Ethical Committee 14.12.2010, no P-004-10). Considering the ethical aspect of gene diagnostic and gene therapy targeting IGF-I, the IGF-I expressing tumors i.e. lung and epidermis cancers, were treated (Trojan et al. 2016). [86][87]

In 2007 and 2008, a man was cured of HIV by repeated Hematopoietic stem cell transplantation (see also Allogeneic stem cell transplantation, Allogeneic bone marrow transplantation, Allotransplantation) with double-delta-32 mutation which disables the CCR5 receptor. This cure was accepted by the medical community in 2011.[88] It required complete ablation of existing bone marrow, which is very debilitating.

In August two of three subjects of a pilot study were confirmed to have been cured from chronic lymphocytic leukemia (CLL). The therapy used genetically modified T cells to attack cells that expressed the CD19 protein to fight the disease.[21] In 2013, the researchers announced that 26 of 59 patients had achieved complete remission and the original patient had remained tumor-free.[89]

Human HGF plasmid DNA therapy of cardiomyocytes is being examined as a potential treatment for coronary artery disease as well as treatment for the damage that occurs to the heart after myocardial infarction.[90][91]

In 2011 Neovasculgen was registered in Russia as the first-in-class gene-therapy drug for treatment of peripheral artery disease, including critical limb ischemia; it delivers the gene encoding for VEGF.[92][27] Neovasculogen is a plasmid encoding the CMV promoter and the 165 amino acid form of VEGF.[93][94]

The FDA approved Phase 1 clinical trials on thalassemia major patients in the US for 10 participants in July.[95] The study was expected to continue until 2015.[96]

In July 2012, the European Medicines Agency recommended approval of a gene therapy treatment for the first time in either Europe or the United States. The treatment used Alipogene tiparvovec (Glybera) to compensate for lipoprotein lipase deficiency, which can cause severe pancreatitis.[97] The recommendation was endorsed by the European Commission in November 2012[11][28][98][99] and commercial rollout began in late 2014.[100]

In December 2012, it was reported that 10 of 13 patients with multiple myeloma were in remission "or very close to it" three months after being injected with a treatment involving genetically engineered T cells to target proteins NY-ESO-1 and LAGE-1, which exist only on cancerous myeloma cells.[23]

In March researchers reported that three of five subjects who had acute lymphocytic leukemia (ALL) had been in remission for five months to two years after being treated with genetically modified T cells which attacked cells with CD19 genes on their surface, i.e. all B-cells, cancerous or not. The researchers believed that the patients' immune systems would make normal T-cells and B-cells after a couple of months. They were also given bone marrow. One patient relapsed and died and one died of a blood clot unrelated to the disease.[22]

Following encouraging Phase 1 trials, in April, researchers announced they were starting Phase 2 clinical trials (called CUPID2 and SERCA-LVAD) on 250 patients[101] at several hospitals to combat heart disease. The therapy was designed to increase the levels of SERCA2, a protein in heart muscles, improving muscle function.[102] The FDA granted this a Breakthrough Therapy Designation to accelerate the trial and approval process.[103] In 2016 it was reported that no improvement was found from the CUPID 2 trial.[104]

In July researchers reported promising results for six children with two severe hereditary diseases had been treated with a partially deactivated lentivirus to replace a faulty gene and after 732 months. Three of the children had metachromatic leukodystrophy, which causes children to lose cognitive and motor skills.[105] The other children had Wiskott-Aldrich syndrome, which leaves them to open to infection, autoimmune diseases and cancer.[106] Follow up trials with gene therapy on another six children with Wiskott-Aldrich syndrome were also reported as promising.[107][108]

In October researchers reported that two children born with adenosine deaminase severe combined immunodeficiency disease (ADA-SCID) had been treated with genetically engineered stem cells 18 months previously and that their immune systems were showing signs of full recovery. Another three children were making progress.[19] In 2014 a further 18 children with ADA-SCID were cured by gene therapy.[109] ADA-SCID children have no functioning immune system and are sometimes known as "bubble children."[19]

Also in October researchers reported that they had treated six haemophilia sufferers in early 2011 using an adeno-associated virus. Over two years later all six were producing clotting factor.[19][110]

Data from three trials on Topical cystic fibrosis transmembrane conductance regulator gene therapy were reported to not support its clinical use as a mist inhaled into the lungs to treat cystic fibrosis patients with lung infections.[111]

In January researchers reported that six choroideremia patients had been treated with adeno-associated virus with a copy of REP1. Over a six-month to two-year period all had improved their sight.[112][113] By 2016, 32 patients had been treated with positive results and researchers were hopeful the treatment would be long-lasting.[16] Choroideremia is an inherited genetic eye disease with no approved treatment, leading to loss of sight.

In March researchers reported that 12 HIV patients had been treated since 2009 in a trial with a genetically engineered virus with a rare mutation (CCR5 deficiency) known to protect against HIV with promising results.[114][115]

Clinical trials of gene therapy for sickle cell disease were started in 2014[116][117] although one review failed to find any such trials.[118]

In February LentiGlobin BB305, a gene therapy treatment undergoing clinical trials for treatment of beta thalassemia gained FDA "breakthrough" status after several patients were able to forgo the frequent blood transfusions usually required to treat the disease.[119]

In March researchers delivered a recombinant gene encoding a broadly neutralizing antibody into monkeys infected with simian HIV; the monkeys' cells produced the antibody, which cleared them of HIV. The technique is named immunoprophylaxis by gene transfer (IGT). Animal tests for antibodies to ebola, malaria, influenza and hepatitis are underway.[120][121]

In March scientists, including an inventor of CRISPR, urged a worldwide moratorium on germline gene therapy, writing scientists should avoid even attempting, in lax jurisdictions, germline genome modification for clinical application in humans until the full implications are discussed among scientific and governmental organizations.[122][123][124][125]

Also in 2015 Glybera was approved for the German market.[126]

In October, researchers announced that they had treated a baby girl, Layla Richards, with an experimental treatment using donor T-cells genetically engineered using TALEN to attack cancer cells. Two months after the treatment she was still free of her cancer (a highly aggressive form of acute lymphoblastic leukaemia [ALL]). Children with highly aggressive ALL normally have a very poor prognosis and Layla's disease had been regarded as terminal before the treatment.[127]

In December, scientists of major world academies called for a moratorium on inheritable human genome edits, including those related to CRISPR-Cas9 technologies[128] but that basic research including embryo gene editing should continue.[129]

In April the Committee for Medicinal Products for Human Use of the European Medicines Agency endorsed a gene therapy treatment called Strimvelis and recommended it be approved.[130][131] This treats children born with ADA-SCID and who have no functioning immune system - sometimes called the "bubble baby" disease. This would be the second gene therapy treatment to be approved in Europe.[132]

In October, Chinese scientists reported they had started a trial to genetically modify T-cells from 10 adult patients with lung cancer and reinject the modified T-cells back into their bodies to attack the cancer cells. The T-cells had the PD-1 protein (which stops or slows the immune response) removed using CRISPR-Cas9.[133][134]

Speculated uses for gene therapy include:

Gene Therapy techniques have the potential to provide alternative treatments for those with infertility. Recently, successful experimentation on mice has proven that fertility can be restored by using the gene therapy method, CRISPR.[135] Spermatogenical stem cells from another organism were transplanted into the testes of an infertile male mouse. The stem cells re-established spermatogenesis and fertility.[136]

Athletes might adopt gene therapy technologies to improve their performance.[137]Gene doping is not known to occur, but multiple gene therapies may have such effects. Kayser et al. argue that gene doping could level the playing field if all athletes receive equal access. Critics claim that any therapeutic intervention for non-therapeutic/enhancement purposes compromises the ethical foundations of medicine and sports.[138]

Genetic engineering could be used to change physical appearance, metabolism, and even improve physical capabilities and mental faculties such as memory and intelligence. Ethical claims about germline engineering include beliefs that every fetus has a right to remain genetically unmodified, that parents hold the right to genetically modify their offspring, and that every child has the right to be born free of preventable diseases.[139][140][141] For adults, genetic engineering could be seen as another enhancement technique to add to diet, exercise, education, cosmetics and plastic surgery.[142][143] Another theorist claims that moral concerns limit but do not prohibit germline engineering.[144]

Possible regulatory schemes include a complete ban, provision to everyone, or professional self-regulation. The American Medical Associations Council on Ethical and Judicial Affairs stated that "genetic interventions to enhance traits should be considered permissible only in severely restricted situations: (1) clear and meaningful benefits to the fetus or child; (2) no trade-off with other characteristics or traits; and (3) equal access to the genetic technology, irrespective of income or other socioeconomic characteristics."[145]

As early in the history of biotechnology as 1990, there have been scientists opposed to attempts to modify the human germline using these new tools,[146] and such concerns have continued as technology progressed.[147] With the advent of new techniques like CRISPR, in March 2015 a group of scientists urged a worldwide moratorium on clinical use of gene editing technologies to edit the human genome in a way that can be inherited.[122][123][124][125] In April 2015, researchers sparked controversy when they reported results of basic research to edit the DNA of non-viable human embryos using CRISPR.[135][148]

Regulations covering genetic modification are part of general guidelines about human-involved biomedical research.

The Helsinki Declaration (Ethical Principles for Medical Research Involving Human Subjects) was amended by the World Medical Association's General Assembly in 2008. This document provides principles physicians and researchers must consider when involving humans as research subjects. The Statement on Gene Therapy Research initiated by the Human Genome Organization (HUGO) in 2001 provides a legal baseline for all countries. HUGOs document emphasizes human freedom and adherence to human rights, and offers recommendations for somatic gene therapy, including the importance of recognizing public concerns about such research.[149]

No federal legislation lays out protocols or restrictions about human genetic engineering. This subject is governed by overlapping regulations from local and federal agencies, including the Department of Health and Human Services, the FDA and NIH's Recombinant DNA Advisory Committee. Researchers seeking federal funds for an investigational new drug application, (commonly the case for somatic human genetic engineering), must obey international and federal guidelines for the protection of human subjects.[150]

NIH serves as the main gene therapy regulator for federally funded research. Privately funded research is advised to follow these regulations. NIH provides funding for research that develops or enhances genetic engineering techniques and to evaluate the ethics and quality in current research. The NIH maintains a mandatory registry of human genetic engineering research protocols that includes all federally funded projects.

An NIH advisory committee published a set of guidelines on gene manipulation.[151] The guidelines discuss lab safety as well as human test subjects and various experimental types that involve genetic changes. Several sections specifically pertain to human genetic engineering, including Section III-C-1. This section describes required review processes and other aspects when seeking approval to begin clinical research involving genetic transfer into a human patient.[152] The protocol for a gene therapy clinical trial must be approved by the NIH's Recombinant DNA Advisory Committee prior to any clinical trial beginning; this is different from any other kind of clinical trial.[151]

As with other kinds of drugs, the FDA regulates the quality and safety of gene therapy products and supervises how these products are used clinically. Therapeutic alteration of the human genome falls under the same regulatory requirements as any other medical treatment. Research involving human subjects, such as clinical trials, must be reviewed and approved by the FDA and an Institutional Review Board.[153][154]

Gene therapy is the basis for the plotline of the film I Am Legend[155] and the TV show Will Gene Therapy Change the Human Race?.[156]

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Gene therapy - Wikipedia