New drug treats late-stage skin cancer

The U.S. Food and Drug Administration last week approved Zelboraf, a drug to treat patients with late-stage (metastatic) or unresectable (cannot be removed by surgery) melanoma, the most dangerous type of skin cancer.Zelboraf is specifically indicated for the treatment of patients with melanoma whose tumors express a gene mutation called BRAF V600E. The drug has not been studied in patients whose melanoma tests negative for that mutation by an FDA approved diagnostic. Zelboraf is being approved with a first-of-a-kind test called the cobas 4800 BRAF V600 Mutation Test, a companion diagnostic that will help determine if a patient's melanoma cells have the BRAF V600E mutation. The BRAF protein is normally involved in regulating cell growth, but is mutated in about half of the patients with late-stage melanomas. Zelboraf is a BRAF inhibitor that is able to block the function of the V600E-mutated BRAF protein. "This has been an important year for patients with late-stage melanoma. Zelboraf is the second new cancer drug approved that demonstrates an improvement in overall survival," said Richard Pazdur, M.D., director of the Office of Oncology Drug Products in the FDA's Center for Drug Evaluation and Research. "In March, we approved Yervoy (ipilimumab), another new treatment for late-stage melanoma that also showed patients live longer after receiving the drug." Zelboraf was reviewed under the FDA's priority review program that provides for an expedited six-month review of drugs that may offer major advances in treatment or that provide a treatment when no adequate therapy exists. Zelboraf and the companion BRAF V600E test are being approved ahead of the drug's Oct. 28, 2011 goal date and the companion diagnostics' Nov. 12, 2011 goal date. Zelboraf's safety and effectiveness were established in a single international trial of 675 patients with late-stage melanoma with the BRAF V600E mutation who had not received prior therapy. Patients were assigned to receive either Zelboraf or dacarbazine, another anti-cancer therapy. The trial was designed to measure overall survival (the length of time between start of treatment and death of a patient). The median survival (the length of time a patient lives after treatment) of patients receiving Zelboraf has not been reached (77 percent still living) while the median survival for those who received dacarbazine was 8 months (64 percent still living). "Approval of Zelboraf and the cobas test is a great example of how companion diagnostics can be developed and used to ensure patients are exposed to highly effective, more personalized therapies in a safe manner," said Alberto Gutierrez, Ph.D., director of the Office of In Vitro Diagnostic Device Evaluation and Safety in the FDA's Center for Devices and Radiological Health. The FDA's approval of the cobas 4800 BRAF V600 Mutation Test was based on data from the clinical study that also evaluated the safety and effectiveness of Zelboraf. Samples of a patient's melanoma tissue were collected to test for the mutation. The most common side effects reported in patients receiving Zelboraf included joint pain, rash, hair loss, fatigue, nausea, and skin sensitivity when exposed to the sun. About 26 percent of patients developed a skin-related cancer called cutaneous squamous cell carcinoma, which was managed with surgery. Patients treated with Zelboraf should avoid sun exposure. Melanoma is the leading cause of death from skin disease. The National Cancer Institute estimated that 68,130 new cases of melanoma were diagnosed in the United States during 2010; about 8,700 people died from the disease. Zelboraf is marketed by South San Francisco based-Genentech, a member of the Roche Group. The cobas 4800 BRAF V600 Mutation Test is manufactured by Roche Molecular Systems in Pleasanton, Calif.

********** Published: August 25, 2011 - Volume 10 - Issue 19