Long-Term Survival Outcomes With Orca-T vs PTCy-Based GVHD Prophylaxis
Olai CH, Gandhi A, Hoeg RT, et al. Observational Comparison of Overall Survival Between Phase Ib Orca-T and Registry-Based Post-Transplant Cyclophosphamide Patients. Transplantation and Cellular Therapy. 2026; (doi: 10.1016/j.jtct.2026.08.037).
A retrospective analysis suggests that cellular immunotherapy may offer a survival advantage over pharmacological immunosuppression in the setting of graft-versus-host disease (GVHD) following allogeneic hematopoietic stem cell transplantation (allo-HCT). The research leveraged data from a 2019 Phase Ib study. Investigators compared long-term overall survival (OS) in 76 patients who received Orca-T immunotherapy, which includes purified donor hematopoietic progenitor stem cells, regulatory T cells, and conventional T cells, with that of 360 patients who underwent post-transplant cyclophosphamide (PTCy)-based GVHD prophylaxis. OS at 1, 2, and 3 years was 96%, 86%, and 83%, respectively, in the Orca-T cohort versus 81%, 72%, and 66%, respectively, in the PTCy group. The benefit seen with Orca-T, driven primarily by reductions in both nonrelapse mortality and deaths due to relapse, applied across patient age, disease type, and additional clinical subgroups, the study authors reported. The primary findings were validated in a propensity score-matched analysis.