LAUSR

Use of full intensity conditioning regimens with haplo-HCT in younger patients lowered the risk of relapse; however, this is often not an option especially for older patients and for those with higher comorbidities due to high risk of treatment related mortality (TRM). Novel RIC regimens to reduce the risk of relapse and improve survival are in great demand. We hypothesize that intensification of the widely used PT-Cy RIC regimen (Flu150/Cy29/TBI 200) by adding intermediate dose melphalan and increasing the TBI to 400 cGy would reduce the risk of relapse and improve DFS without increasing TRM. We report an interim analysis of our age- and risk-adapted phase II trial.  We treated 27 Haplo-HCT patients on one of 2 arms based on age and HCT-CI. Arm A (n=10) included patients The 12 month estimated DFS and OS were 80% vs 25 % and 90% vs 23% in Arms A and B, respectively. There was a significant correlation between advanced age and both DFS and OS. The 12-month TRM was significantly lower in Arm A vs Arm B; 10% and 69% respectively. Only 1 of 6 patients over age 65 survived. Grade II-IV acute GVHD occurred in 20% and 26% of patients in each arm. Neutrophil and platelet engraftment were prompt in both arms. Although follow-up is still short, the estimated 1-year relapse rates were low at 10% in Arm A and 6% in Arms B. This planned interim analysis demonstrated that patients