The FDA granted accelerated approval to Blincyto (blinatumomab) to treat adults and children with B-cell precursor acute lymphoblastic leukemia (ALL) who are in remission but still have minimal residual disease (MRD). MRD refers to the presence of cancer cells below a level that can be seen under the microscope. In patients who have achieved remission after initial treatment for this type of ALL, the presence of MRD means they have an increased risk of relapse.
“This is the first FDA-approved treatment for patients with MRD-positive ALL,” said Richard Pazdur, M.D., director of the FDA’s Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “Because patients who have MRD are more likely to relapse, having a treatment option that eliminates even very low amounts of residual leukemia cells may help keep the cancer in remission longer. We look forward to furthering our understanding about the reduction in MRD after treatment with Blincyto. Studies are being conducted to assess how Blincyto affects long-term survival outcomes in patients with MRD.”
B-cell precursor ALL is a rapidly progressing type of cancer in which the bone marrow makes too many B-cell lymphocytes, an immature type of white blood cell. The National Cancer Institute estimates that approximately 5,960 people in the United States will be diagnosed with ALL this year and approximately 1,470 will die from the disease.
Blincyto works by attaching to CD19 protein on the leukemia cells and CD3 protein found on certain immune system cells. Bringing the immune cell close to the leukemia cell allows the immune cells to attack the leukemia cells better. The FDA first approved Blincyto under accelerated approval in December 2014 for the treatment of Philadelphia chromosome (Ph)-negative relapsed or refractory positive B-cell precursor ALL. Full approval for this indication was granted in July 2017, and at that time, the indication was also expanded to include patients with Philadelphia chromosome-positive ALL.
The efficacy of Blincyto in MRD-positive ALL was shown in a single-arm clinical trial that included 86 patients in first or second complete remission who had detectable MRD in at least 1 out of 1,000 cells in their bone marrow. Efficacy was based on achievement of undetectable MRD in an assay that could detect at least one cancer cell in 10,000 cells after one cycle of Blincyto treatment, in addition to the length of time that the patients remained alive and in remission (hematological relapse-free survival). Overall, undetectable MRD was achieved by 70 patients. Over half of the patients remained alive and in remission for at least 22.3 months.
(Source: The U.S. Food and Drug Administration)
