Vemurafenib (Zelboraf), a drug for patients with late-stage (metastatic) or unresectable (irremovable by surgery) melanoma, the most dangerous type of skin cancer, was approved by the U.S. Food and Drug Administration.
Vemurafenib is specifically indicated for treating patients with melanoma whose tumors express a gene mutation, BRAF V600E. The drug has not been studied in patients whose melanoma tests negative for that mutation. Therefore, vemurafenib was approved with a new 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.
Normally, the BRAF protein is involved in regulating cell growth, but it is mutated in about 50% of patients with late-stage melanomas, a disease which causes an estimated 8,700 deaths in the U.S. per year. Vemurafenib is a BRAF inhibitor with an ability to impede the function of the V600E-mutated BRAF protein.
The safety and effectiveness of vemurafenib were established in a single international trial involving 675 late-stage melanoma patients with the BRAF V600E mutation who had not received prior therapy. In the study, patients received either vemurafenib or dacarbazine, another anti-cancer therapy.
Researchers studied overall survival of the participating patients. At this time, the median survival of patients receiving vemurafenib has not been reached, however 77% are still living. The median survival for those who received dacarbazine was determined to be 8 months (64% of patients are still living).
“Today’s approval of Zelboraf (vemurafenib) 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.
Joint pain, rash, hair loss, fatigue, nausea, and skin sensitivity when exposed to the sun were the most common side effects reported in patients receiving vemurafenib. Due to the fact that about 26% of patients developed the skin-related cancer, cutaneous squamous cell carcinoma (which was managed with surgery), patients treated with vemurafenib should avoid sun exposure.
Vemurafenib (Zelboraf) is being approved with a Medication Guide to inform health care professionals and patients of the drug’s potential risks.
Source: FDA Press Release