Multi-institutional study evaluating clinical outcome with allogeneic hematopoietic stem cell transplantation after blinatumomab in patients with B-cell acute lymphoblastic leukemia: real-world data

Safety and efficacy of allogeneic hematopoietic stem cell transplantation (alloHCT) consolidation after blinatumomab is largely undetermined. To address this issue, we assembled multi-center data of relapsed refractory (RR) acute lymphocytic leukemia (ALL) patients who received alloHCT after blinatumomab. From December 2014 to May 2019, 223 patients who received blinatumomab for RR ALL outside clinical trials were identified. Among them, 106 (47%) patients transplanted post blinatumomab were evaluated for response and toxicity. Ninety-two (87%) patients received alloHCT after achieving CR, while remaining received subsequent salvage prior to undergoing alloHCT. Progression free survival (PFS) and overall survival (OS) at 2 years post alloHCT was 48% (95% CI: 36-59%) and 58% (95% CI: 45-69%), respectively. The cumulative incidence of GIII-IV aGVHD at 3 months was 9.9% (95% CI: 5.0-16.6%). Similarly, cumulative incidence of moderate to severe cGVHD at 2 years was 34.4% (95% CI: 23.7-45.3%). The overall survival at 2 years was not significantly different in patient who achieved CR with MRD negative (68.4% [95% CI: 28.5-89.1%]) compared to CR with MRD positive (63.4% [95% CI: 47.8-75.4%]) prior to alloHCT (p = 0.8). Our real-world analysis suggests that alloHCT is feasible and effective post blinatumomab in patients with RR ALL.