Speedy FDA Approval For Amgen's Leukemia Immunotherapy BLINCYTO

December 4, 2014

By Jessica Wilson, BioSpace.com Breaking News Staff

Amgen today announced that the U.S. Food and Drug Administration has approved its immunotherapy drug Blincyto, also known as blinatumomab, for the treatment of a rare blood cancer. The approval came five months before the FDA’s expected decision date of May 19, 2015, an unusually quick approval process that has Wall Street closely watching the progress of the drug.

Blincyto, which uses Bispecific T cell engager (BiTE) antibody constructs to help the body’s immune system fight cancer, is the first of its kind to be approved by the FDA. The drug is now approved for the treatment of patients with Philadelphia chromosome-negative precursor B-cell acute lymphoblastic leukemia (B-cell ALL), an uncommon form of ALL.

“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,” Sean Harper, executive vice president of Research and Development at Amgen, said in a statement. He noted that the “accelerated approval” of the drug “underscores the critical need for new treatment options for patients with relapsed or refractory B-cell precursor ALL, who are often young adults.”

BiTE antibody constructs work by placing the body’s T cells, a type of white blood cell capable of killing other cells perceived as threats, within reach of a target cancer cell. This action facilitates the T cell’s injection of toxins into the malignant cell to trigger cell death, according to Amgen. The drug is not without side effects, however. It will carry a boxed warning on its label about the risk of developing Cytokine Release Syndrome (CRS), which may be life-threatening or fatal, and of developing neurological toxicities, which may be severe, life-threatening or fatal.

“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 Stein, a clinical professor of hematology and oncology at City of Hope hospital outside Los Angeles who worked on clinical trials of the drug.

Blincyoto’s approval was based on the results of a Phase 2 multicenter, single-arm open-label study. Of the 185 patients evaluated in the trial, 41.6 percent achieved complete remission or complete remission with partial hematologic recovery within two cycles of treatment with Blincyto, which was the primary endpoint of the study, according to Amgen.

“Immunotherapies, especially Blincyto with its unique mechanism of action, are particularly promising for patients with leukemia,” Richard Pazdur, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, said in a statement. “Recognizing the potential of this novel therapy, the FDA worked proactively with the sponsor under our breakthrough therapy designation program to facilitate the approval of this novel agent.”

The National Cancer Institute estimates that 6,020 Americans will be diagnosed with ALL and 1,440 will die from the disease in 2014.