“For patients with advanced melanoma, Zelboraf means hope — extending life for months, and in some cases, years,” said Rex Amonette, MD, Senior Vice President of The Skin Cancer Foundation. “Zelboraf represents yet another significant recent medical advancement in the fight against this disease, which claims 8,700 American lives each year.”
Zelboraf (a.k.a. vemurafenib, or PLX 4032) is the first targeted genetic therapy for melanoma approved to date. It is approved for patients whose tumors harbor a mutation (defect) in the BRAF V600E gene, which is present in about 40-60 percent of melanomas. By inhibiting the defective BRAF gene, Zelboraf slows or halts the uncontrolled (cancerous) cell growth associated with the gene mutation.
In an early clinical trial, Zelboraf was successful in shrinking the tumors of 81 percent of patients who had the mutation, the greatest response rate a melanoma drug has ever had. In more recent trials of melanoma patients, all of whom had the mutated gene, those who received Zelboraf were 56 percent less likely to die in the study period than those who received standard chemotherapy. Average overall survival for patients receiving Zelboraf could not be determined because so many patients remained alive; in contrast, average survival for patients on chemotherapy was only 7.9 months. Patients on Zelboraf were also 74 percent less likely to see their disease advance compared with patients on chemotherapy.
Along with Zelboraf, the FDA approved the cobas 4800 BRAF V600 Mutation Test, which determines if a patient has the BRAF mutation and is eligible for the treatment. Zelboraf is taken orally, and the prescribed dose is 960 mg twice a day. The drug is marketed by Roche’s Genentech, and will be available within two weeks.