On December 3, 2014, the US Food and Drug Administration announced approval of Blincyto™ (blinatumomab) for the treatment of Philadelphia chromosome–negative precursor B-cell acute lymphoblastic leukemia (ALL), a rare form of ALL. The approval comes more than 5 months ahead of the scheduled application review. Blincyto was granted breakthrough therapy, priority review, and orphan product designations owing to preliminary clinical evidence that the drug offers substantial improvement over available treatments.
Blincyto works like electrical wiring that establishes a connection between CD19 proteins on the surface of overly proliferating B lymphoblasts and the CD3 surface protein on T cells. Once Blincyto engages CD3 on killer T-cells and CD19 on target leukemic B-cells, T-cell activation via CD3 occurs, triggering an immune response against the overly proliferating B-cells. Blincyto is intended to treat cancers that are relapsed or refractory.
The clinical study on which approval was based included 185 adults with Philadelphia chromosome–negative relapsed or refractory precursor B-cell ALL, who received continuous Blincyto intravenous infusion via an infusion pump for at least one 4-week cycle. Complete remission (CR) or complete remission with partial hematologic recovery (CR/CRh) was achieved in 42% (77/185) of patients within 2 treatment cycles. Most (81% [62/77]) responses occurred during the first cycle. Among those patients achieving CR/CRh, 39% (30/77) were enabled to bridge to hematopoietic stem cell transplantation by using Blincyto and 75% achieved minimal residual disease response, an important molecular predictor of relapse. The Blincyto label has a boxed warning concerning cytokine release syndrome and neurologic side effects. Its most common side effects include fever, headache, tissue swelling, febrile neutropenia, nausea, low potassium levels, fatigue, constipation, rash, and tremor.
Philadelphia chromosome-negative precursor B-cell ALL is a fast-moving bone marrow cancer. The National Cancer Institute predicts that 6020 Americans will have been diagnosed and 1440 will have died of the disease by the end of 2014. “Immunotherapies, especially Blincyto, with its unique mechanism of action, are particularly promising for patients with leukemia,” said Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research.
Contributed by William Yarnall, RPh, CCP
Medical Writer, Connexion Healthcare