New Genetics Based Melanoma Therapy

Posted by Pharmacist on August 30, 2011

Zelboraf Approved for Late-State Melanoma Patients with Mutation V600E

According to Roche Diagnostics, nearly half of all patients with late-stage melanoma have a mutation in BRAF. The American Society of Health-System Pharmacists notes on its website that U.K. researchers found 80% of the BRAF mutations in malignant melanomas were caused by Mutation V600E. This is when a glutamate residue appears in the protein kinase instead of a valine residue.

On August 17, 2011 Roche Diagnostics announced it has received FDA approval for Vemurafenib (brand name Zelboraf), a genetics-based therapy designed to help patients diagnosed with melanoma that has a certain gene mutation that has spread or cannot be removed surgically.

The drug is designed to work specifically with patients who have late-stage melanoma in which the tumors’ protein kinase known as BRAF has the V600E mutation.

Roche Group’s Genentech will market Zelboraf and Roche Diagnostics will sell the companion diagnostic, called the cobas 4800 BRAF V600 Mutation Test. A spokesperson for the company said the diagnostic will on the market “in a few weeks.”

A study of 675 patients with late-stage melanoma and the V600E mutation in BRAF underwent trials to test the safety and effectiveness of vemurafenib; patients with no previous treatment for their melanoma received either dacarbazine or vemurafenib. FDA reports said slightly less than two-thirds of the dacarbazine-treated patients were still living, while more than three-fourths of the vemurafenib-treated patients were alive at the time of data reporting. The drug has not been studied in melanoma patients whose tumors did not have the V600E mutation.

Vemurafenib’s FDA-approved labeling suggests an oral dosage of 960 mg twice daily; the doses should be taken approximately 12 hours apart. The product will come packaged in bottles of 120 240-mg tablets; this is 15 day’s worth of the recommended dosage.

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