Safety and Efficacy of ATIR101 as Adjunctive Treatment to Blood Stem Cell Transplantation From a Haploidentical Family Donor Compared to Post-transplant Cyclophosphamide in Patients With Blood Cancer

Study CR-AIR-009 is a Phase III randomized controlled multicenter open-label study comparing two parallel groups. After signing informed consent, a total of 250 patients will be randomized in a 1:1 fashion to receive either a T-cell depleted hematopoietic stem cell transplantation (HSCT; CD34 selection) from a related, haploidentical donor, followed by ATIR101 infusion, or a T-cell replete HSCT, followed by a high dose of post-transplant cyclophosphamide (PTCy). Randomization will use minimization to balance treatment groups with respect to underlying disease (AML, ALL, or MDS), Disease Risk Index (DRI; intermediate risk, high risk, or very high risk) and center. A stochastic treatment allocation procedure will be used so that the treatment assignment is random for all patients entered in the study. Patients randomized in the ATIR101 group will receive a single ATIR101 dose of 2×10E6 viable T-cells/kg between 28 and 32 days after the HSCT. Patients randomized in the PTCy group will receive cyclophosphamide 50 mg/kg/day at 3 and 4/5 days after the HSCT. All patients will be followed up for at least 24 months post HSCT.