Recently, Actelion Ltd (ALIOF) and partner GlaxoSmithKline (GSK) halted the development of almorexant, which was undergoing late-stage development to treat patients suffering from sleeping disorders or insomnia.
The Switzerland based Actelion inked a global (excluding Japan) deal with Glaxo to develop and commercialize almorexant, an orexin receptor antagonist, in July 2008. They also agreed to evaluate the candidate for other orexin-related disorders. Orexins are proteins that help to control the sleep-wake cycle.
The decision to discontinue the development of almorexant does not come as a surprise as the candidate delivered mixed results in a 16 day late-stage study, RESTORA 1, in December 2009. The multi-center, double-blind, randomized, placebo-controlled study (n=709) evaluated the safety and efficacy of almorexant in adults suffering from chronic primary insomnia.
Even though the candidate proved to be superior to placebo, certain safety concerns led to the expansion of the non-pivotal section of the program for better understanding of the safety and tolerability of the candidate. The decision to halt the development of almorexant came after data from the additional studies were reviewed. However, the partners stated that they will continue to evaluate orexin receptor antagonism in sleep disorders and other indications. Moreover, Actelion and Glaxo will continue to co-develop new orexin receptor antagonist treatments.
The termination of almorexant’s development is the second pipeline failure at Actelion in a span of few months. In September last year, the company decided to stop enrolling patients for the late stage study of its anti-brain bleeding candidate clazosentan after reporting disappointing results in another study.
Our Recommendation
The recent pipeline setbacks form the basis of the Zacks #5 Rank (short-term ‘Strong Sell’ rating) currently carried by Actelion.


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