On Aug. 17, the Food and Drug Administration approved Zelboraf (vemurafenib) for patients with the BRAF V600E mutation who have late-stage or unresected melanoma. Zelboraf is the second drug for advanced melanoma approved in the past six months. Yervoy (ipilumumab), which works by rallying the body's own immune system to fight the cancer, received FDA approval in March.Zelboraf is a BRAF inhibitor and works by blocking the BRAF mutation, which occurs in about half of advanced melanoma patients. The accompanying genetic test, cobas 4800 BRAF V600 Mutation Test, was also approved to determine if patients carry this genetic mutation. An average course of Zelboraf treatment will last six months, and the estimated cost will be about $56,400 (compared with Yervoy's $120,000). The companion test will cost between $120 and $150.The approval comes after a randomized international trial, which included 675 patients with advanced melanoma and no prior treatment, found that Zelboraf improved overall survival compared with patients receiving the approved decades-old chemotherapy regimen, dacarbazine (6.2 and 4.5 months respectively). At the time of interim review, the median survival for Zelboraf had not been reached and was 7.9 months for dacarbazine. The approval of the companion diagnostics test was also based on the clinical study that evaluated the safety and efficacy of Zelboraf.Patients on Zelboraf should avoid sun exposure as the most common adverse effects include skin sensitivity to sunlight, joint pain and rash. About a quarter of patients developed cutaneous squamous cell carcinoma that was treated with surgery.Roche and Bristol-Meyers Squibb (makers of Zelboraf and Yervoy respectively) will collaborate on a study to determine if the two drugs work better in combination or alone.