GSK, Actelion put failed sleep drug to rest

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GlaxoSmithKline and Actelion have discontinued the development of the insomnia drug almorexant, a dual orexin receptor antagonist, over concerns about patients' tolerance of the drug.

GSK inked a deal with Actelion in 2008 worth up to $3.25 billion for the successful development of almorexant; the drug was also slated to treat Alzheimer's and insomnia-related depression. Analysts speculated that almorexant could be worth up to $6 billion annually if approved for all indications. But red flags went up a year later after it was revealed that the insomnia drug met the primary endpoint in a Phase III trial but suffered from unspecified safety issues. Insomnia is a non-life threatening condition, making it unlikely the FDA would approve a therapy with a questionable safety profile.

The partners say they are still committed to studying orexin receptor antagonism in sleep disorders and other indications. Both companies will continue to work on the discovery and development of new orexin receptor antagonist therapies, they said in a brief statement.

Actelion was counting on almorexant to replace sales lost when its pulmonary arterial hypertension drug Tracleer goes off-patent in 2015. In addition to the almorexant failure, Actelion's anti-brain bleeding drug clazosentan also flunked clinical trials. Despite setbacks, Actelion's shares have remained strong on speculation that the company will now be a takeover target. Actelion is Switzerland's largest biotech company.

- here's Actelion's release
- read the Bloomberg article
- get more on the buyout rumors from the WSJ

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