Sean E. Harper, MD
The FDA has granted a priority review to a supplemental biologics license application (sBLA) supporting the conversion of the accelerated approval of blinatumomab (Blincyto) to a full approval as a treatment for patients with Philadelphia chromosome-negative (Ph-) relapsed/refractory B-precursor acute lymphoblastic leukemia (ALL).
The safety analysis for TOWER was based on 376 patients who received at least 1 dose of blinatumomab (n = 267) or standard chemotherapy (n = 109). Of these patients, 57% and 25%, in the blinatumomab and chemotherapy arms, respectively, started ≥2 cycles.
The adverse event (AE) profile was similar between the 2 arms and consistent with previous studies of blinatumomab. The incidence of all-grade AEs was 99% in both treatment arms. Grade 3 AEs occurred in 37% of the blinatumomab arm and 30% of the standard chemotherapy arm. The rates of grade 4 AEs were 31% and 44%, respectively. Grade 5/fatal AEs occurred in 19% of the blinatumomab arm versus 17% of the chemotherapy arm, including grade 5 infection rates of 11% and 12%, respectively.
Grade ≥3 AEs of interest included neutropenia (38% in the blinatumomab arm vs 58% in the standard chemotherapy arm), infection (34% vs 52%), neurologic events (9% vs 8%), and cytokine release syndrome (5% vs 0).
The application also included data from the open-label phase II ALCANTARA study, which evaluated the efficacy and tolerability of blinatumomab in adult patients with Ph+ relapsed or refractory B-cell precursor ALL.3
Sixteen of 45 patients (36%) achieved a CR/CRh during the first 2 cycles of therapy, including 4 of 10 patients with a T315I
mutation. MRD-negative status was achieved by 88% of CR/CRh responders. Seven responders (44%) received allogeneic hematopoietic stem-cell transplantation. The median OS was 7.1 months.
The FDA granted an accelerated approval to blinatumomab in 2014 as a treatment for patients with Ph- relapsed/refractory B-precursor ALL, based on findings from a phase II trial.
According to Amgen, the Blincyto label includes a Boxed Warning regarding cytokine release syndrome and neurological toxicities.
- Kantarjian H, Stein A, Gökbuget N, et al. Blinatumomab versus chemotherapy for advanced acute lymphoblastic leukemia. N Engl J Med. 2017;376(9):836-847. doi:10.1056/NEJMoa1609783.
- Topp MS, Stein A, Nicola Gökbuget N, et al. Blinatumomab improved overall survival in patients with relapsed or refractory Philadelphia negative B-cell precursor acute lymphoblastic leukemia in a randomized, open-label phase 3 study (TOWER). Presented at: 2016 European Hematology Association Congress; June 9-12, 2016; Copenhagen, Denmark. Abstract S149.
- Martinelli G, Boissel N, Chevallier P, et al. Complete hematologic and molecular response in adult patients with relapsed/refractory Philadelphia chromosome–positive b-precursor acute lymphoblastic leukemia following treatment with blinatumomab: results from a phase II, single-arm, multicenter study (published online March 29, 2017). J Clin Oncol. doi:10.1200/JCO.2016.69.3531.
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