Lilly's $7.8B Centessa Deal; Biogen Buys Apellis for $5.6B; FDA Flags Tavneos Deaths | Mar 31, 2026

Twenty-five and a half billion dollars in acquisitions in eight days. Eli Lilly just added seven point eight billion to the pile with Centessa Pharmaceuticals, and the buying spree shows no signs of slowing.

Meanwhile, Biogen drops five point six billion on Apellis, the FDA ties eight deaths to Amgen's Tavneos, and AstraZeneca's next-gen bone disease program stumbles where it mattered most — in adults. Packed Tuesday. Let's get into it.

Welcome to The Pharma Closeout for Tuesday, March 31st, 2026. I'm Alex Mercer.

And I'm Maya Patel. Let's start with the deal that's defining the morning.

Eli Lilly announced this morning it will acquire Centessa Pharmaceuticals for six point three billion dollars upfront — thirty-eight dollars a share — plus a contingent value right that brings total deal value to seven point eight billion. Centessa stock jumped roughly forty-five percent on the news. The prize here is Centessa's orexin receptor agonist pipeline targeting narcolepsy and excessive daytime sleepiness.

The mechanism is what makes this interesting beyond the dollar figure. Centessa isn't layering another stimulant on top of a broken system. Orexin agonism addresses the actual neuropeptide deficit — it's going upstream to where narcolepsy originates. That's a fundamentally different pharmacological bet, and the competitive field chasing it is getting crowded fast.

Let's bring in Marcus Webb on the deal structure here. Marcus, what does that CVR signal?

And zoom out — this is the third major acquisition from Lilly in under four months. Ventyx in December, Orna in February, now Centessa. Every single one outside the GLP-1 franchise. That pattern tells you something about how Indianapolis is thinking about the next five years.

Or it tells you something about how exposed they feel. When your highest-value franchise carries this much revenue concentration, every acquisition gets scrutinized through that lens. The market will decide whether Lilly is building its next act or hedging its current one.

I'll concede the concentration concern has teeth. But the orexin opportunity stands on its own merits. Narcolepsy plus the broader hypersomnia population represent a large addressable market that doesn't rise or fall with how tirzepatide performs next quarter. Lilly isn't diversifying into random adjacencies — they're stacking a neurology position with real clinical logic.

If orexin agonism delivers what the biology suggests it can, this deal doesn't just give Lilly a new revenue stream. It reprices an entire treatment category that's been stuck with the same pharmacological toolkit for decades.

And Lilly wasn't even alone this morning. Biogen agreed to acquire Apellis Pharmaceuticals for five point six billion dollars. That sent Apellis stock up more than a hundred and thirty-six percent in pre-market. Biogen shares, meanwhile, dropped nearly seven percent — the classic acquirer discount.

The headline says complement biology. The subtext says nephrology. Biogen is leaning hard into kidney disease expansion as the rationale for this deal — C3-targeted therapies repositioned beyond the ophthalmology franchise Apellis has been building. That's a big pivot for a company still mostly known for neuroscience.

And worth noting — Halper Sadeh has already announced an investigation into whether Apellis shareholders are getting a fair price. At a hundred-thirty-six percent premium, that's a high bar to argue, but it signals how fast the deal environment is moving. Marcus Webb, give us the eight-day picture.

One more on the deal front — Merck and biotech startup Infinimmune announced an antibody discovery collaboration worth up to eight hundred and thirty-eight million dollars in milestone payments, using AI-driven discovery to identify immune cell-directed antibodies across multiple targets. Different scale, different risk profile, but it shows Merck layering early-stage platform bets alongside late-stage acquisitions. When the largest companies are simultaneously buying and partnering at this pace, the signal to smaller biotechs with differentiated programs is clear: your leverage just went up.

On the regulatory front — and this one carries real weight — the FDA issued a safety communication today on Amgen's Tavneos, the C5a receptor inhibitor approved for ANCA-associated vasculitis. The agency identified seventy-six cases of drug-induced liver injury in the adverse events database, including eight deaths. For a rare disease drug with a narrow prescriber base, that kind of signal-to-exposure ratio moves past routine pharmacovigilance.

So what's the range of outcomes here — label revision on one end, REMS on the other?

Potentially all of the above. A boxed warning feels almost certain. A REMS with prescriber certification is on the table if the agency decides the current label language isn't sufficient to manage risk. Any of those outcomes adds friction to an already small patient funnel, which is exactly what you don't want in a disease area where treatment inertia is already high.

Separate story, different end of the clinical spectrum. AstraZeneca reported mixed Phase 3 data for efzimfotase alfa in hypophosphatasia.

Three late-stage trials, and the results split cleanly. The pediatric data looked solid. The CHESTNUT switching trial showed patients transitioning from Strensiq maintained bone health through week twenty-five — that's reassuring for the existing franchise. But the adult trial missed its primary endpoint, and that's the readout that determines whether AstraZeneca can expand the HPP market beyond its current pediatric ceiling.

So Strensiq's lifecycle stays intact, but the growth thesis just got capped.

And then a constructive one to close this segment. Agios announced plans to file for accelerated approval of mitapivat in sickle cell disease after a productive pre-sNDA meeting with the FDA. Stock was up about twenty-one percent. Agios has already submitted a proposed confirmatory trial to the agency — that's a prerequisite under accelerated approval — with the formal sNDA filing expected in the coming months. The budget line here: mitapivat is a pyruvate kinase activator already approved in PK deficiency. Extending that mechanism to a second hemoglobinopathy through accelerated review validates the enzyme-level approach in SCD and widens the competitive field in a disease area where the treatment paradigm is finally shifting after decades of underinvestment.

Looking ahead — Novo Nordisk launched a multi-month subscription program for Wegovy today. Eligible self-pay patients who enroll through select telehealth providers get lower, predictable monthly pricing, with the company touting savings of up to twelve hundred dollars a year. Separately — and less cheerfully — Novo cut four hundred roles at its Bloomington manufacturing site.

The subscription model is the part to watch. It doesn't touch the payer coverage problem, but that's not the audience it's aimed at. This is designed to pull cash-pay patients away from compounders by offering branded product with dosing support and adherence infrastructure wrapped around it. If the retention data holds, every other GLP-1 manufacturer will be studying this playbook inside of six months.

And keep your eye on the M&A tempo. Twenty-five point five billion in eight days isn't a coincidence — it's a cycle. Lilly, Biogen, and Merck have all moved in the last week. The remaining mid-cap biotechs sitting on differentiated late-stage assets are now in a very different negotiating position than they were two weeks ago, and the next deal announcement could come from any direction.

That's your Pharma Closeout for Tuesday, March 31st. Lilly betting seven point eight billion on orexin, Biogen going five point six billion deep into complement, the FDA flagging fatal liver signals on Tavneos, AstraZeneca hitting a wall in adult HPP, and Agios clearing a path toward accelerated review in sickle cell. A lot moved today. If this briefing is saving you time, follow us on Spotify, Apple Podcasts, or wherever you listen — and drop us a rating. It helps more than you'd think. We're back tomorrow.

Go enjoy your evening. See you tomorrow.