Orca puts numbers on its Precision-T win

Last month privately held Orca Bio announced a pivotal win with its lead project, Orca-T, and now it’s disclosed survival numbers that appear to show the therapy holding up against its phase 1 trial. Orca-T, an engineered cell preparation derived from partially matched donors, could improve tolerance versus allogeneic stem cell transplantation; the phase 3 Precision-T study aimed to show an increase in chronic graft-versus-host disease-free survival with Orca-T plus tacrolimus, compared with conventional alloHSCT plus tacrolimus and methotrexate. This goal was achieved, the latest numbers show. But there are questions about the control arm used in Precision-T, because this didn't use post-transplant cyclophosphamide, the so-called Baltimore regimen, a recently emerging standard of care for partially matched transplants. A cross-trial comparison could bolster Orca’s cause: an interim analysis of Precision-T found overall survival of 94% with Orca-T, similar to the 96% seen at one year in phase 1. At ASH last year Orca cited an 82% OS rate in a historical cohort of alloHSCT plus post-transplant cyclophosphamide – in line with Precision-T’s control arm. Orca plans to file Orca-T with the FDA this year, and to present full results from Precision-T at the European Society for Blood and Marrow Transplantation meeting in early April. One-year results from Precision-T Orca-T + tacrolimusalloHSCT + tacrolimus + methotrexateN9394cGvHD-free survival (primary endpoint)78%38%StatsHR=0.26; p<0.000011-year OS* (secondary endpoint)94%83%StatsHR=0.49; p=0.11823Cumulative incidence of moderate-to-severe cGvHD (secondary endpoint)13%44%StatsHR=0.19; p<0.000021-year relapse-free survival (exploratory endpoint)76%74%StatsHR=0.80, p=0.49Note: *interim analysis. Source: company release.