Lilly moves deeper into sleep medicine with up to $7.8 billion Centessa deal

Under the terms, Lilly will pay $38 per share in cash upfront, valuing Centessa at about $6.3 billion, plus a contingent value right worth up to another $9 per share if certain U.S. regulatory milestones are met. The transaction is expected to close in the third quarter of 2026, pending shareholder, court and regulatory approvals. 

The prize for Lilly is Centessa’s orexin receptor 2 (OX2R) agonist pipeline, led by cleminorexton, formerly known as ORX750. The drug is being developed for narcolepsy type 1, narcolepsy type 2 and idiopathic hypersomnia, three disorders marked by excessive daytime sleepiness and impaired wakefulness. Lilly said cleminorexton has shown a “potential best-in-class profile” in Phase 2a studies, while Centessa’s broader orexin portfolio also includes ORX142 and earlier-stage assets that could be relevant beyond sleep disorders, including neurological and neuropsychiatric conditions.

The increasing value of orexin

Orexin is a neuropeptide that helps regulate the sleep-wake cycle by promoting arousal and wakefulness. An OX2R agonist is a drug designed to stimulate that pathway directly. That is different from many older wake-promoting treatments, which mostly manage symptoms without correcting the underlying signaling deficit. In narcolepsy type 1 especially, the loss of orexin signaling is central to disease biology, which is why the mechanism has generated so much excitement recently. 

The $38-per-share cash component represents roughly a 40.5% premium to Centessa’s 30-day volume-weighted average share price through March 30. Lilly is also using milestone-linked contingent payments to reduce some of the risk that comes with buying a clinical-stage biotech before approval. Those extra payments depend on FDA approvals in narcolepsy type 2, idiopathic hypersomnia, and a first approval in any indication before January 1, 2030. In other words, Lilly is paying heavily for promise, but not entirely upfront. 

A validation of Centessa’s pivot

The deal is also a validation of Centessa’s strategic transformation. The company started life as a multi-asset biotech roll-up, but in recent years it narrowed its focus sharply around orexin biology. By late 2025, Centessa was presenting ORX750 as a potential best-in-class asset and said it expected to start a registrational program in the first quarter of 2026. It had also expanded the franchise with ORX142 and ORX489, suggesting that investors were no longer just betting on a single sleep drug, but on a broader platform around orexin signaling. Lilly is now buying that platform before it matures further and becomes even more expensive. 

But Lilly is not buying into an empty market. Takeda is currently the furthest ahead in orexin agonists: in February 2026, the FDA accepted Takeda’s NDA and granted Priority Review for oveporexton in narcolepsy type 1, putting Takeda in position to potentially launch the first approved orexin agonist. Takeda is also advancing a second oral OX2R agonist, TAK-360, for narcolepsy type 2 and idiopathic hypersomnia. That means Lilly’s move looks less like an exploratory bet and more like a decision that it cannot afford to sit out a potentially important new drug class in neuroscience.

How the deal fits Lilly’s strategy

Lilly has been using its strong balance sheet and obesity-driven cash generation to broaden its pipeline through targeted acquisitions, including Ventyx Biosciences in inflammation and Orna Therapeutics in cell therapy earlier this year. Centessa adds another growth engine, this time in neuroscience, where Lilly already has commercial products but has been looking to deepen its next wave of innovation. The market appeared to endorse the move: Centessa shares surged on the announcement, while Lilly stock also traded higher.

If orexin agonists deliver on their promise, Lilly’s agreement to buy Centessa could come to be seen as one of the defining neuroscience deals of 2026. If not, it will be remembered as an expensive wager on one of biotech’s hottest new mechanisms. Either way, it underscores that sleep medicine is becoming a far more strategic battleground than many in biotech once assumed.