Eisai Inc., the US subsidiary of Eisai Co.,and Purdue Pharma L.P. have entered into a worldwide collaboration agreement for the development and commercialization of Eisai’s clinical candidate lemborexant, a dual orexin receptor antagonist entering Phase III clinical development for treating insomnia.

Under the terms of the agreement, Eisai Inc. and Purdue Pharma will share the costs of lemborexant global clinical studies. While the potential indication for the product candidate is for the treatment of insomnia, the companies may also seek to develop other indications in the future. The two companies will form a joint steering committee to manage development and pursue marketing authorizations for lemborexant worldwide. Once approved, Eisai and Purdue Pharma will co-promote the product and share co-promotion costs and profits in the United States and other territories (to be agreed by the parties), which may include the European Union, China, Japan, and Canada. Eisai will book sales in all co-promotion territories. In certain other countries, either Eisai or Purdue Pharma may solely commercialize lemborexant and pay the other party a royalty. Eisai Inc. will receive an upfront payment from Purdue Pharma, and is also eligible to receive certain other milestone payments that are contingent upon achieving regulatory approval and certain commercial milestones.

Discovered by Eisai, lemborexant is a dual orexin receptor antagonist which competitively binds to the two subtypes of orexin receptors. It is believed that the orexin system promotes wakefulness, and therefore, orexin receptor antagonists such as lemborexant have the potential to promote sleep.

With the signing of this agreement, the Phase III clinical development program will commence immediately. The global trial program is designed to evaluate the efficacy of lemborexant on both objective and subjective measures of sleep. In addition, the development program will evaluate the impact of treatment of insomnia on daytime function. Safety and tolerability will also be evaluated during the clinical program.

Lemborexant, a dual orexin receptor antagonist, is an in-house discovered and developed small-molecule compound by Eisai. The drug inhibits orexin by binding competitively to two subtypes of orexin neuron receptors (orexin receptor 1 and 2). In individuals with insomnia disorder, it is possible that the orexin system which regulates sleep and wakefulness is not functioning normally. During normal periods of sleep, orexin system activity is suppressed, suggesting it is possible to purposefully counteract inappropriate wakefulness and facilitate the initiation and maintenance of sleep by interfering with orexin neurotransmission. Eisai has been developing lemborexant as a treatment for insomnia.

Source: Eisai