GlaxoSmithKline yanks European app for Tafinlar-Mekinist combo in melanoma

The FDA may have given its blessing to GlaxoSmithKline's melanoma combo Tafinlar and Mekinist. But not so fast, says its counterpart across the pond. The European Medicines Agency (EMA) wants more information, and that has prompted GSK to withdraw its application--for now.

Wednesday, the British drugmaker said it would pull its marketing authorization bid--based largely on Phase II results--until it could gather more data. Glaxo ($GSK) will resubmit its filing for the duo once additional results come through from an ongoing Phase III trial, and the decision will not affect a pending application for use of Mekinist on its own in melanoma patients, the company said. Tafinlar is already approved in Europe.

"While significant progress has been made in treating metastatic melanoma over the last few years, we believe more treatment options are needed, and we will work with the European regulators towards making the combination available for patients," Dr. Rafael Amado, GSK's head of oncology R&D, said in a statement.

The FDA put the duo on its priority review track back in September, and by early January, the combination cocktail had won its favor. Though both drugs are separately approved to treat melanoma in the U.S., because they work in different ways--Tafinlar inhibits the action of a mutated BRAF gene, while Mekinist inhibits cancer cell growth by interfering with a key protein known as MEK--they have the potential to be more effective and longer-lasting together. In Phase II trials, the pair delivered a 76% response rate, compared with a 54% rate in patients treated with Tafinlar alone.

Glaxo is counting on the two cancer drugs, as well as fellow 2013 approvals Breo, Anoro and Tivicay, to spur some growth as off-patent respiratory giant Advair inevitably begins its demise. But Tafinlar and Mekinist aren't without their own competition: Cancer leader Roche ($RHHBY) sells its own therapy for BRAF-positive melanoma, Zelboraf, which analysts have said could hit peak sales of $1.5 billion.

- read the release

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