GlaxoSmithKline (GSK) and Actelion Ltd have entered into an exclusive worldwide collaboration (excluding Japan) for Actelion's almorexant, an orexin receptor antagonist in phase III development with first-in-class potential as a treatment for primary insomnia.

Under the terms of the agreement, GSK will receive exclusive worldwide rights to co-develop and co-commercialise almorexant. Actelion will continue to lead the ongoing development programme and potential registration for almorexant in the first indication, primary insomnia, with GSK contributing 40 per cent of the costs. Almorexant will also be studied in other orexin-related disorders and all costs related to these programmes will be shared equally.

Actelion will receive an upfront payment of CHF 150 million (approximately £66 million) and will be eligible for additional potential milestone payments of up to CHF 415 million in regards to the successful development and approval of almorexant in primary insomnia. In addition, Actelion will be eligible to receive additional milestone payments, pending successful development of two other major indications for almorexant yet to be evaluated through clinical investigation. If all three indications were successfully registered, approved and commercialised, and exceptional sales targets met for all these indications, Actelion would be eligible to receive additional potential milestone payments of up to CHF 2.735 billion. Also, costs and profits resulting from this collaboration will be shared equally between the two companies.

Actelion and GSK will equally share costs and profit in key pharmaceutical markets worldwide where they will co-commercialise almorexant. In these markets Actelion will book all sales and GSK will book its share of profit. GSK will grant Actelion the right to assist in the commercialisation – as a paid-for sales force – of a GSK product in certain countries and for a limited period of time. In emerging markets, GSK will commercialise the product exclusively, with Actelion receiving a share of profit.

The two companies will continue their important independent efforts in the field of orexin research and under the agreement can exercise the option to jointly select, develop and promote additional new antagonists targeting the orexin system.

Orexins – previously referred to as hypocretins – are proteins produced by the hypothalamus. They play an important role in controlling the sleep-wake cycle. Almorexant is the first-in-class orexin receptor antagonist in clinical development as a potential new treatment for insomnia and other central nervous system disorders. In December 2007, Actelion initiated the registration program RESTORA (REstore normal physiological Sleep with The Orexin Receptor antagonist Almorexant) to evaluate efficacy and safety of almorexant in both adult and elderly patients diagnosed with insomnia. The RESTORA program studies are expected to report first findings in the second half of 2009.