Eisai has bought the rights to investigational drug lemborexant from Purdue Pharma , ending a global development and commercialisation alliance signed in 2015.

Lemborexant is a small-molecule sleep-wake regulation agent discovered by Eisai scientists. The compound inhibits orexin signalling, which is believed to function abnormally in patients suffering from sleep-wake conditions.

The drug is being developed for a variety of conditions, including insomnia and irregular sleep-wake rhythm disorder (ISWRD) in Alzheimer’s patients.

“This mutual decision enables us to dedicate our resources to our oncology, non-opioid pain, and other CNS programmes.”

As part of the original partnership, Eisai and Purdue agreed to share the costs of lemborexant’s clinical studies and commercialisation. The latest buyout deal will see Eisai take full responsibility for future development and marketing of the therapeutic globally.

Purdue Pharma president and CEO Craig Landau said: “As a result of the ongoing diversification of our research product portfolio, Purdue’s business priorities have shifted since this collaboration was initiated.

“This mutual decision enables us to dedicate our resources to our oncology, non-opioid pain, and other CNS programmes.”

In January 2019, the companies submitted a new drug application to the US Food and Drug Administration (FDA) seeking approval for lemborexant as a treatment for insomnia. The regulator agreed to review the submission in March.

A marketing authorisation application (MAA) for the same indication was also submitted to the Pharmaceuticals and Medical Devices Agency (PMDA) in Japan.

Eisai chairman and CEO Ivan Cheung said: “Lemborexant’s unique profile was established by the results of two pivotal Phase III clinical studies in patients with insomnia, including the first-ever head-to-head trial with zolpidem extended-release with objectively assessed sleep parameters, and important safety studies, such as a next-morning driving study.”

The drug is currently being studied in a Phase II trial for the treatment of ISWRD in patients with Alzheimer’s.