The green light for Zelboraf from the European Medicines Agency -- which Roche said on Friday it expected to be formally endorsed by the European Commission in February -- follows U.S. approval in August.

The new drug is given as a twice-daily pill and is designed to be used alongside a companion diagnostic test, also from Roche, that identifies which patients have a specific genetic mutation that means they will benefit from the treatment.

The London-based agency said the benefits of Zelboraf, particularly the improvements seen in terms of patients going longer before their disease progressed and overall survival, outweighed its potential risks.

Side effects from Zelboraf can include secondary growths, rash, slight hair loss, extreme photosensitivity and joint pain.

Zelboraf was developed in partnership with Daiichi Sankyo and became the second drug to be approved for melanoma in the United States this year, after Yervoy from Bristol-Myers Squibb.

Roche said in August that Zelboraf would cost just over $56,000 for a six-month course of treatment in the United States. It has yet to announce a price in Europe.

Analysts tracked by Thomson Reuters Pharma, on average, forecast annual sales of $930 million for the medicine by 2016, making it a useful addition to Roche's market-leading portfolio of cancer therapies.

Zelboraf, known clinically as vemurafenib, is targeted for patients with tumors that have a mutation in a gene known as BRAF that allows melanoma cells to grow. About half of all melanomas have the genetic aberration the drug targets.

The European drugs watchdog said it backed Zelboraf for treating patients with the BRAF mutation who suffered from metastatic or unresectable melanoma, meaning it cannot be removed by surgery.

Melanoma globally afflicts nearly 160,000 new people each year. It can spread quickly to internal organs and average survival is six to nine months.

(Reporting by Ben Hirschler)

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