OUTCOMES FOLLOWING HCT USING FLUDARABINE BUSULFAN AND THYMOGLOBULIN: A MATCHED COMPARISON TO ALLOGENEIC TRANSPLANTS CONDITIONED WITH BUSULFAN AND CYCLOPHOSPHAMIDE

摘要

We have reported a lower incidence of acute graft versus host disease (aGVHD) with a novel conditioning regimen using low dose rabbit anti-thymocyte globulin (TG, Thymoglobulin) with fludarabine and intravenous busulfan (FluBuTG). To assess further this single center experience, we performed a retrospective matched pair analysis comparing outcomes of adult patients transplanted using the FluBuTG conditioning regimen with matched controls from patients reported to the CIBMTR receiving a first allogeneic hematopoietic stem cell transplant (HCT) after standard oral busulfan and cyclophosphamide (BuCy). 120 cases and 215 matched controls were available for comparison. Patients receiving FluBuTG had significantly less treatment related mortality (12% vs 34%, p<0.001) and grades II–IV aGVHD (15% vs 34% p<0.001) compared to BuCy patients. The risk of relapse was higher in the FluBuTG patients (42% vs 20%, p<0.001). The risks of chronic GVHD (cGVHD) and disease free survival (DFS) were similar in the cases and controls. These results suggest that the novel regimen FluBuTG decreases the risk of aGVHD and transplant mortality after HLA-identical sibling HCT, but is associated with an increased risk of relapse, resulting in similar DFS. Whether these conditioning regimens may be more suitable for specific patient populations based on relapse risk requires testing in prospective randomized trials.