Patient characteristics

The baseline characteristics of the study population are presented in Table1. A total of 8764 patients were included, from which 7725 (88%) received rATG, and 1039 (12%) received PTCy as GVHD prophylaxis.

Overall, the majority of patients were transplanted for acute leukemia (58%), myelodysplastic syndrome (MDS) (19.7%), myeloproliferative neoplasm (MPN) (9.7%) or lymphoma (9%). A high proportion of patients had a low/intermediate Disease Risk Index (DRI, 72.1%), and myeloablative conditioning (MAC) was more frequently performed (53.3%) than reduced intensity conditioning (RIC).

Patients in the rATG group were older, with a median age of 58.6 years (IQR (48.1, 65.4)) vs. 53 years in the PTCy group (IQR 38.6, 62.3) (p<0.01), with a similar proportion of males (57.3% in rATG vs. 58.9% in PTCy, p=0.33), along with a significantly lower use of TBI (14.5% vs. 24.7%, p<0.01) and lower use of MAC (52% vs. 62.3%, p<0.01). Also, the disease relapse index was lower and the year of transplant was more recent in the PTCy group (Table1). The remaining parameters were balanced between the two groups. Median follow up was 2.1 years in both arms. More detailed information is given in Table1.

Univariate outcomes are shown in Figs.1, 2and Table2. The results of the multivariate analyses are summarized in Table3. The P-values and hazard ratios (HR) presented in the following results section are derived from the multivariate analysis.

A NRM; B Overall survival, C Relapse incidence, D Progression-free survival and E GVHD-free relapse-free survival. Cumulative incidences are shown.

A Acute GVHD grades IIIV; B Acute GVHD grades IIIIV, C Chronic GVHD all grades and D Extensive chronic GVHD - Cumulative incidences are shown.

Patients receiving PTCy had a significantly lower NRM as compared to patients receiving rATG (2y incidence: 12.4% vs. 16.1%; HR: 0.72 [95% CI 0.550.94], p=0.016). Similarly, OS and PFS showed a statistically significant and clinically meaningful benefit for PTCy arm, with a higher OS (2y incidence: 73.9% vs. 65.1%; HR: 0.82 [95% CI 0.720.92], p=0.001), and a higher PFS (2y incidence: 64.9% vs. 57.2%; HR: 0.83 [95% CI 0.740.93], p<0.001). RI was lower in the PTCy arm (2y incidence: 22.8% vs. 26.6%; HR: 0.87 [95% CI 0.751.00], p=0.046).

The causes of death are given in Table4. No major differences between the two groups were apparent. Relapse of the underlying malignancy was the most frequent cause of death, accounting for ~50% of total deaths in both arms, followed by NRM causes: infections ~18%, GVHD~16% and other alloSCT-related causes ~8% of total deaths. Secondary malignancies contributed to approximately 1% of total deaths.

Overall chronic GVHD was lower in the PTCy group (2y incidence: PTCy 28.4% vs. rATG 31.4%; HR: 0.77 [95% CI 0.630.95], p=0.012). Extensive chronic GVHD was also reduced in patients receiving PTCy vs. rATG: (2y incidence: 11.9% vs. 13.5%; HR: 0.75 [95% CI 0.620.91], p=0.004).

The incidence of acute GVHD grades II-IV in patients receiving PTCy, compared to those receiving ATG was not statistically significant: (100d incidence: 24.1% vs. 26.5%; HR: 0.85 [95% CI 0.691.04], p=0.11). Similarly, for severe acute GVHD grades IIIIV (100d incidence: 8.7% vs. 9.7%; HR: 0.76 [95% CI 0.551.05], p=0.091).

GRFS was significantly higher in the PTCy arm compared to the rATG arm (2y incidence: 51% vs. 45%; HR: 0.86 [95% CI 0.750.99], p=0.035).

The EBMT Database does not contain data on graft failure/rejection. To get insight into the initial grafts success and any subsequent requirement for additional transplantation procedures, we investigated neutrophil recovery after the first alloSCT as well as the incidence of a second alloSCT. The median incidence of neutrophil recovery at days +30 and +60 in the ATG vs. PTCy groups was: d+30 ATG 96% (IC95% 95.596.4) vs. PTCy 91% (8992.7) and d+60 ATG 97.9% (97.698.2) vs. PTCy 97.4% (96.298.3). The median incidence of a second alloSCT at 2 years was 4.3% (3.84.8) in the ATG group and 3.2% (2.24.6) in the PTCy group.

Continue reading here:
ATG or post-transplant cyclophosphamide to prevent GVHD in matched unrelated stem cell transplantation? | Leukemia - Nature.com

Comments are closed.