Eisai buys Purdue stake in insomnia drug as PDUFA date nears

Eisai will fully fund all further work on the drug around the world. (Eisai)

Eisai is buying Purdue Pharma’s stake in sleep disorder drug lemborexant. The deal gives Eisai sole responsibility for global development and commercialization of a drug that is nearing FDA approval.

Purdue bought a stake in the Eisai-discovered dual orexin receptor antagonist in 2015 and co-funded phase 3 development. But it has now decided to accept an upfront payment of undisclosed size from Eisai in return for its stake in the candidate, which could win FDA approval in insomnia by the end of the year. 

“Purdue's business priorities have shifted since this collaboration was initiated,” Purdue CEO Craig Landau said in a statement. “This mutual decision enables us to dedicate our resources to our oncology, non-opioid pain and other CNS programs.”

Eisai will fully fund all further work on the drug around the world. With lemborexant having come through two phase 3 clinical trials in insomnia, there is currently little active clinical development of the drug. But the end-of-year PDUFA date means Eisai will face near-term regulatory and, potentially, commercial costs, plus the prospect of bringing lemborexant to market itself.

The pitch for FDA approval rests on two phase 3 clinical trials, one of which compared lemborexant to zolpidem. The studies linked lemborexant to statistically significant improvements in patient-reported sleep onset latency and other endpoints.

Clinical development activities may ramp up down the line, too. The one active study of the drug on ClinicalTrials.gov is a phase 2 trial in Alzheimer's disease patients with irregular sleep-wake rhythm disorder. Eisai presented data from the trial last year and outlined plans for further development.