FDA Approves Leukemia Treatment, First Breakthrough Therapy

Lymphocyte (National Cancer Institute)

The U.S. Food and Drug Administration on Friday approved an antibody designed to treat chronic lymphocytic leukemia, when taken with chemotherapy. Obinutuzumabm — developed and marketed as the brand name Gazyva by the biotechnology company Genentech, a division of Roche in South San Francisco, California — is the first drug designated as a breakthrough therapy approved by FDA.

Chronic lymphocytic leukemia is a cancer of the blood and bone marrow, where blood stem cells become abnormal white blood cells or lymphocytes that do not adequately fight infection. The growth of these abnormal lymphocytes, also known as leukemia cells, usually happens slowly and crowds out healthy blood cells, leading to easier bleeding, infections, and anemia.

National Cancer Institute says chronic lymphocytic leukemia is the second most common form of leukemia, expected to strike some 15,700 people in the U.S. in 2013, causing nearly 4,600 deaths. The disease occurs most often among middle age or older adults.

Gazyva is an engineered antibody designed to target a marker called CD20 on the surface of leukemia cells that attacks leukemia cells at that marker. The antibody also works by recruiting the body’s remaining healthy immune system cells to attack leukemia cells at the CD20 marker.

FDA based its approval on a late-stage clinical trial of 356 participants with untreated chronic lymphocytic leukemia that tested Gazyva taken with the chemotherapy drug chlorambucil (marketed as Leukeran by GlaxoSmithKline) compared to chlorambucil given alone. Patients receiving Gazyva and chlorambucil had an average progression-free survival of 23 months, compared to 11 months for chlorambucil alone.

Likewise, says Genentech, three-quarters (76%) of the trial participants receiving Gazyva and chlorambucil responded to the drugs, compared to about a third (32%) responding to chlorambucil alone. Some 28 percent of the patients receiving Gazyva and chlorambucil responded completely — showing no evidence of cancer — for a period of time compared to about 1 percent for patients receiving chlorambucil alone.

The most common adverse events from Gazyva were reactions to the injections (chlorambucil is an oral drug), low platelet counts, and low counts of some white blood cells, although infection rates were not higher among the patients receiving Gazyva. The company plans to report more results from the same clinical trial also testing Gazyva with other engineered antibodies, at a meeting of the American Society of Hematology in December.

FDA designated Gazyva a breakthrough therapy in May 2013. A breakthrough therapy is granted to treatments that address serious conditions and have at least preliminary evidence showing the drug is a substantial improvement over current therapies on at least one clinical outcome. The agency says it is the first approval granted to a breakthrough-designated drug or biologic.

FDA also granted priority review to the therapy in July 2013, which is given to new drugs or biologics that offer significant improvements in safety or effectiveness in treating, preventing, or diagnosing disorders compared to those currently in practice. In addition, FDA designated Gazyva an orphan product, since it treats a rare disease.

Read more:

• Safety Concerns Halt Celgene Leukemia Drug Trial
• FDA Giving Roche Leukemia Antibody Priority Review
• Stem Cell Process Makes Red Blood, Platelets in Quantities
• Leukemia Genetic Signature, Drug Candidates Identified

Hat tip: FirstWord Pharma

*     *     *