An engineered antibody to treat chronic lymphocytic leukemia developed by the pharmaceutical company Roche is receiving priority review from the U.S. Food and Drug Administration, which sets a goal of six months to complete its evaluation. The therapy is obinutuzumab, code-named GA101, which in May, FDA designated as a “breakthrough” that expedites the review process for treatments aimed at serious and life-threatening diseases.
Chronic lymphocytic leukemia is a cancer of the blood and bone marrow that, according to National Cancer Institute, is the second most common type of leukemia in adults. The disease is a result of too many abnormal lymphocytes (white blood cells) developing in the blood and bone marrow, pushing out the healthy blood cells, and impairing the body’s ability to fight infection, and encouraging anemia and easier bleeding. Those at greater risk for chronic lymphocytic leukemia are older white males, particularly those of Eastern European Jewish origin.
GA101 is a molecularly engineered antibody that targets the CD-20 biomarker expressed on the surfaces of malignant B cells, a type of white blood cells that makes antibodies. GA101 is designed to bind with the CD-20 marker to directly kill cancer cells and has altered sugar molecules that changes the antibody’s interactions with the body’s immune cells to make it more effective in removing cancer cells.
Roche says FDA based the priority review and earlier breakthrough designation on results from a late-stage clinical trial of 781 chronic lymphocytic leukemia patients testing GA101 in combination with the blood cancer drugs rituximab or chlorambucil — a standard chemotherapy — compared to chlorambucil alone. The trial, says the company, included elderly patients with previously untreated chronic lymphocytic leukemia considered not able to tolerate other aggressive forms of treatment.
The results of the trial show patients taking the combination of GA101 and chlorambucil demonstrated an 86 percent reduction in the risk of disease progression, relapse, or death. The findings also showed the median length of time during which people lived without the disease getting worse was 23 months, more than twice the time of progression-free survival for patients taking chlorambucil alone (11 months). The most common severe adverse events reported were were infusion-related reactions that the company says decreased after the first infusions, and neutropenia — low count of neutrophils, a type of white blood cell that helps fight infections.
Roche says FDA confirmed the target date for completing the priority review as 20 December 2013. The company also filed a marketing application for GA101 with the European Medicines Agency in April 2013.
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