FDA Approves Amgen's Blincyto (Blinatumomab) Immunotherapy

FDA has granted approval of Amgen's Blincyto (blinatumomab) for the treatment of patients with Philadelphia chromosome-negative (Ph-) relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL). This indication is approved under accelerated approval. Continued approval for this indication may be contingent upon verification of clinical benefit in subsequent trials. With this approval, Blincyto becomes the first FDA-approved bispecific CD19-directed CD3 T-cell engager (BiTE) antibody construct product, and the first single-agent immunotherapy to be approved for the treatment of patients with Ph- relapsed or refractory B-cell precursor ALL, a rare and rapidly progressing cancer of the blood and bone marrow.

"The FDA's breakthrough therapy designation and accelerated approval of Blincyto underscores the critical need for new treatment options for patients with relapsed or refractory B-cell precursor ALL, who are often young adults," said Sean E. Harper, MD, Executive Vice President of R&D at Amgen. "Blincyto is the first clinical and regulatory validation of the BiTE platform, a new and innovative approach that helps the body's own immune system fight cancer."

The Blincyto approval is based on results of Amgen's '211 trial, a Phase II, multicenter, single-arm open-label study. Eligible patients were >18 years of age with Ph- relapsed or refractory B-cell precursor ALL. Relapsed or refractory was defined as relapsed with first remission duration of < 12 months in the first salvage, or relapsed or refractory after first salvage therapy, or relapsed within 12 months of allogeneic hematopoietic stem cell transplantation (HSCT), and had >10% blasts in bone marrow. Of the 185 patients evaluated in the trial, 41.6% (77/185; 95% CI: 34.4-49.1) achieved complete remission or complete remission with partial hematologic recovery (CR/CRh*) within two cycles of treatment with Blincyto, which was the primary endpoint of the study. The majority of responses (81 percent [62/77]) occurred within the first cycle of treatment. Among patients who achieved CR/CRh, 39% (30/77) went on to HSCT, and 75.3% (58/77 95% CI: 64.2-84.4) achieved minimal residual disease (MRD) response, a measure of eradication of residual disease at the molecular level.

"The approval of Blincyto represents a significant milestone in immunotherapy research, providing clinicians the opportunity to offer a new single-agent therapy to patients fighting this highly aggressive cancer with previously limited options," said Anthony S. Stein, MD, Clinical Professor, Hematology/Oncology at City of Hope.