Single Center Retrospective Comparison of Post-Transplant Cyclophosphamide and Standard Graft-Versus-Host Disease Prophylaxis in Matched Donor Allogeneic Transplantation

BACKGROUND: Post-transplant cyclophosphamide (PTCy) was developed to allow the use of haploidentical donors for allogeneic stem cell transplantation (alloHSCT), then tested with matched donors. Cedars-Sinai Medical Center Blood and Marrow Transplant was an early adopter of PTCy for matched alloHSCT in 2016. PURPOSE OF THE RESEARCH: We retrospectively analyzed 15-year outcomes of patients who underwent alloHSCT with matched donor stem cells prior to 2016 (n = 252), with the outcomes of patients who were transplanted in the PTCy era, post-2016 (n = 99), to assess the impact of the switch to PTCy, while controlling for other differences between the cohorts. PRINCIPLE RESULTS: Overall Survival (OS) was better in the PTCy group (at 1 year, 90% vs 62%, P < .0001), and the difference persisted in OS at 2 years and 3 years. There was no difference in relapse (26% non-PTCy vs 19% PTCy; P = .3560). Non-relapse mortality was lower with PTCy, 7% vs 22% without, P = .0002. Acute GVHD was lower in the PTCy group (16% PTCy vs 33% non-PTCy, P = .0013). Chronic GVHD was similar between the two groups, 35% in the PTCy group and 42% in the non-PTCy group (P = .1235), but the rate of extensive cGVHD was lower, 15% with PTCy vs 29% without; P = .0078. Post-transplant hospital stay was shorter, 23 ± 13.1 days in the non-PTCy group and 18 ± 7.0 days with PTCy, P < .0001. CONCLUSIONS: Long-term follow up of patients transplanted using PTCy with matched donors has demonstrated superiority of PTCy compared to tacrolimus methotrexate.