Shares of Centessa Pharmaceuticals plc skyrocketed more than 44% Tuesday after the clinical-stage biotech announced it would be acquired by pharmaceutical giant Eli Lilly and Co. in a deal valued at up to $7.8 billion, giving Lilly a promising pipeline of experimental treatments for sleep-wake disorders.

Centessa Pharmaceuticals
Centessa Pharmaceuticals

Centessa stock (NASDAQ: CNTA) surged to around $39.89 in morning trading, up $12.31 or 44.63% from Monday's close near $27.58, with heavy volume as investors cheered the premium offer. The jump pushed the shares to a new 52-week high and reflected strong market enthusiasm for Centessa's orexin receptor 2 (OX2R) agonist program.

Under the agreement announced early Tuesday, Lilly will pay $38 per American Depositary Share in cash upfront, valuing Centessa at approximately $6.3 billion. The deal includes a contingent value right (CVR) of up to $9 per share tied to regulatory milestones, potentially bringing the total to $47 per share or about $7.8 billion. The transaction is expected to close in the third quarter, subject to shareholder approval, court sanction under English law, regulatory clearances and other customary conditions.

"Lilly to acquire Centessa Pharmaceuticals to advance treatments for sleep-wake disorders," the companies said in a joint statement. Centessa's OX2R agonist pipeline, including a potential best-in-class therapeutic, promises to meaningfully improve outcomes for patients with excessive daytime sleepiness and other neurological conditions. The acquisition expands Lilly's neuroscience portfolio and capabilities into the growing sleep medicine space.

Centessa, headquartered in Boston with operations in London, focuses on developing orally administered OX2R agonists. Its lead candidate, ORX750, targets narcolepsy type 1 (NT1), narcolepsy type 2 (NT2) and idiopathic hypersomnia (IH) — conditions characterized by disrupted sleep-wake cycles and often debilitating excessive daytime sleepiness. Orexin, a neuropeptide, plays a key role in promoting wakefulness; patients with NT1, in particular, suffer from orexin deficiency.

Recent Phase 2a data from the CRYSTAL-1 study highlighted ORX750's potential best-in-class profile, showing robust improvements in wakefulness across the three indications. Centessa had planned to initiate registrational studies in the first quarter of 2026, positioning 2026 as a "transformational" year under CEO Mario Alberto Accardi. The company also advanced ORX142 for neurological and neurodegenerative disorders and ORX489 for neuropsychiatric conditions, with additional assets in earlier stages.

For Lilly, the deal bolsters its neuroscience ambitions at a time when the Indianapolis-based company has seen massive success with weight-loss drugs like Mounjaro and Zepbound but faces pressure to diversify. Sleep disorders represent a large unmet need, affecting millions worldwide and carrying significant economic costs from lost productivity and associated health issues. Current treatments for narcolepsy and hypersomnia often come with limitations, including side effects or incomplete efficacy.

Analysts had grown optimistic about Centessa ahead of the announcement. Consensus price targets hovered around $30 to $40 before the deal, with some firms citing strong upside from ORX750's clinical momentum. The acquisition premium — roughly 38% over Monday's close and higher over recent averages — delivers immediate value to shareholders after a volatile period for the stock, which had traded as low as the mid-single digits in prior years but climbed on pipeline progress.

Centessa reported no commercial revenue as a development-stage company. Its financials reflected typical biotech cash burn, with prior quarters showing operating losses and reliance on capital raises and partnerships. Cash runway had extended into 2027 following earlier financings, supporting clinical advancement. The deal provides certainty and resources that could accelerate development and commercialization under Lilly's global infrastructure.

The orexin pathway has attracted increasing attention in neuroscience. Traditional stimulants or wake-promoting agents treat symptoms but do not address underlying orexin deficits as directly as agonists. Centessa's compounds aim for selectivity and potency, potentially offering better safety and efficacy profiles. Preclinical and early clinical data also suggested broader potential in areas like depression, cognitive impairment and fatigue associated with neurological conditions.

Industry observers noted the deal fits a pattern of big pharma acquiring innovative biotechs to refill pipelines amid patent expirations and high R&D costs. Lilly, with its deep pockets and commercial expertise, could rapidly scale manufacturing, global trials and eventual marketing if ORX750 or follow-ons succeed.

Centessa was formed in 2021 through an unusual merger of 10 asset-centric companies backed by U.K. investor Medicxi, creating a diversified portfolio that later narrowed focus to orexin agonists. The streamlined approach allowed rapid progress on ORX750 while maintaining optionality in other CNS areas.

Reaction on Wall Street was swift. Lilly shares rose modestly in early trading despite broader market pressures, as investors weighed the strategic fit against the deal size. Centessa's surge reflected both the takeover premium and relief that its science received validation from a major player.

The transaction underscores growing interest in sleep medicine. With modern lifestyles, shift work and aging populations contributing to rising prevalence of sleep disorders, new therapies could capture substantial market share. Analysts estimate the addressable market for narcolepsy and hypersomnia treatments alone runs into billions annually.

For patients, the backing of Lilly could mean faster access to innovative options. Narcolepsy and idiopathic hypersomnia often go undiagnosed or undertreated, severely impacting quality of life. ORX750's oral administration and targeted mechanism could represent a meaningful advance over existing injectables or less selective drugs.

Details of integration and post-deal strategy remain to be fleshed out. Centessa will continue operating independently until closing, advancing ongoing trials. Lilly emphasized the acquisition's role in enhancing its capabilities in sleep-wake disorders without providing specific financial guidance on synergies or earnings impact.

Some analysts downgraded or adjusted ratings post-announcement as the stock price now reflects the deal value rather than standalone prospects. However, broader coverage remained positive on the science.

Looking ahead, attention will turn to regulatory reviews and any potential antitrust considerations, though the deal size and therapeutic focus suggest relatively smooth passage. Shareholder support appears strong, with about 24% of investors already signing voting agreements.

The dramatic stock reaction — one of the largest single-day gains for a mid-cap biotech in recent memory — highlights the biotech sector's sensitivity to M&A. After periods of funding challenges and clinical risks, strategic acquisitions can deliver outsized returns.

Centessa's journey from a 2021 launch with multiple programs to a focused orexin leader demonstrates the asset-centric model's potential. Its success with OX2R agonists could pave the way for broader applications in CNS disorders, an area where innovation has lagged relative to oncology or immunology.

For Lilly, the move diversifies beyond metabolic diseases into neuroscience, where it has historical strengths but faces competition. Sleep disorders offer a logical adjacency to its existing portfolio.

As markets digested the news Tuesday morning, Centessa shares traded near $40, up sharply on elevated volume. The deal premium appeared rich but aligned with the high-risk, high-reward nature of clinical-stage assets showing compelling early data.

Biotech consolidation is likely to continue as larger firms seek external innovation. Smaller companies with promising but capital-intensive pipelines often find acquisition an attractive exit, providing shareholders liquidity while ensuring therapies reach patients faster.

Centessa did not immediately comment beyond the official release. Lilly officials pointed to the joint statement for details.

The agreement marks a significant milestone for Centessa's leadership and scientific team, validating years of focused research on the orexin system. For the broader industry, it signals confidence in novel mechanisms for chronic neurological conditions.

As the deal progresses toward closing, investors and patients alike will watch for updates on clinical timelines and potential label expansions. In the meantime, Tuesday's surge provides a clear market verdict: the science behind Centessa's sleep-wake therapies is now backed by one of pharma's heaviest hitters.