Published on October 24, 2011
New data has shown that this article is no longer entirely accurate. For up-to-date information on this treatment, read this newer article.
First in a New Class Of “Targeted” Treatments
The US Food and Drug Administration (FDA) has approved a new drug – the first of its kind – for the treatment of inoperable or advanced metastatic (spreading) melanoma. Melanoma is the deadliest form of skin cancer. The drug, called ZelborafTM, was found to delay disease progression and extend life significantly.
ZelborafTM (a.k.a. vemurafenib, or PLX 4032) is the first targeted genetic therapy approved for melanoma, meaning it is appropriate for patients whose melanoma tumors have a particular gene defect. ZelborafTM blocks the function of the defective V600E BRAF gene, which is present in about 40-60 percent of melanomas. ZelborafTM slows or stops the uncontrolled (cancerous) cell growth associated with the gene defect. The drug was approved by the FDA’s priority review program, which “fast tracks” reviews of drugs that may provide significant treatment advances.
In an early clinical trial, ZelborafTM was successful in shrinking the tumors of 81 percent of patients who had the gene defect (or 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 ZelborafTM were 56 percent less likely to die in the study period than those who received standard chemotherapy. Average overall survival for patients receiving ZelborafTM 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 ZelborafTM were also 74 percent less likely to see their disease advance compared with patients on chemotherapy.
Along with ZelborafTM, the FDA approved a test, which determines if a patient has the gene defect and is eligible for the treatment. ZelborafTM is taken orally, and the prescribed dose is 960 mg twice a day. The drug is marketed by Roche’s Genentech division.