GlaxoSmithKline nabs key FDA approvals for two melanoma drugs

Two of GlaxoSmithKline's hopes for 2013 are now fulfilled: The company ($GSK) won FDA approval for its melanoma treatments Tafinlar and Mekinist, both targeted at patients with patients with certain genetic mutations. Together, the two oral drugs may top $600 million in sales by 2016, analysts say.

And GSK needs that money. The U.K.-based drugmaker watched sales stagnate unexpectedly last year as European austerity dampened its comeback from the patent cliff. This year, CEO Andrew Witty has echoed his 2012 promises for a return to growth, staking that pledge on the 6 new drugs Glaxo aims to launch by the end of 2013.

So, with Tafinlar and Mekinist ready for launch in the U.S., one-third of those 6 new treatments has run the FDA gauntlet. Tafinlar is designed for patients with the BRAF V600E gene mutation, while Mekinist is for patients with that mutation or the BRAF V600K mutation. Tafinlar works by directly blocking the BRAF gene, while Mekinist interferes with a protein called MEK that helps defend BRAF-positive tumors. The latter is the first MEK inhibitor to win FDA approval.

Suitable patients have to be identified with a BRAF diagnostic test. Glaxo teamed up with the French company bioMérieux to develop a test, which was approved by FDA along with the two drugs. Roche ($RHHBY), which sells its own treatment for BRAF-positive melanoma, also sells its own FDA-approved diagnostic test for the mutation.

Roche's Zelboraf, approved in 2011, generated about $250 million in sales for the Swiss drugmaker last year, Bloomberg says. Analysts polled by the news service figure that Tafinlar can bring in $279 million by 2016, and Mekinist could deliver $343 milion in sales. Each drug is approved for use as a single agent, at least for now; the company has studied combining the two treatments, but hasn't yet submitted that combination data to the FDA.

- read the GSK release
- see the Bloomberg story
- read FierceMedicalDevices' story on the companion diagnostic