FDA Approval: Blinatumomab for Patients with B-cell Precursor Acute Lymphoblastic Leukemia in Morphologic Remission with Minimal Residual Disease

On March 29, 2018, the FDA granted accelerated approval for blinatumomab (Blincyto; Amgen, Inc.) for the treatment of adults and children with B-cell precursor acute lymphoblastic leukemia (BCP ALL) in first or second complete remission with minimal residual disease (MRD) greater than or equal to 0.1%. Blinatumomab is a CD3xCD19 bispecific antibody approved previously for the treatment of relapsed or refractory BCP ALL. The basis for this accelerated approval was a single-arm trial. For the 86 patients in first and second complete remission with MRD ≥ 0.1%, conversion to MRD < 0.01% was achieved after one cycle of blinatumomab by 85.2% 95% confidence interval (CI): 73.8%, 93.0% and 72.0% (95% CI: 50.6%, 87.9%), respectively, and the estimated median hematologic relapse-free survivals (RFS) were 35.2 months (95% CI: 0.4-53.5) and 12.3 months (95% CI: 0.7-42.3), respectively. Hematologic RFS was considered substantial independent of whether patients underwent subsequent allogeneic stem cell transplantation. The safety profile for blinatumomab was established in prior studies, and no new safety signals were observed in the new population. Cytokine release syndrome and neurotoxicity remain significant risks. The FDA is requiring confirmation of clinical benefit in a randomized trial.