These deals radically reshaped the biopharma world, either by one vaccine rival absorbing another, a Big Pharma doubling down after another failed acquisition or, in the case of Pfizer and Novo, two heavyweights duking it out over a hot obesity biotech.
2025 proved to be a high-drama year for dealmaking as pharmas fought over companies, swallowed their rivals and found inspiration in other companies’ transactions. The biggest deal of the year—Johnson & Johnson’s $14.6 billion buy of Intra-Cellular all the way back in January—didn’t even make the list of what BioSpace editors consider the most influential M&A deals of the year.
While the year won’t go down as the biggest in value by any means, some of these deals will have an indelible impact on the industry for years to come.
Pharmas dealt in obesity, cancer, cell therapy, mental health and a slate of others, growing and expanding their businesses. These deals, such as Pfizer’s fight to get an up-and-coming obesity biotech, AbbVie doubling down on psychedelics for mental health conditions and the fall of gene therapy’s darling shook and reshaped the biopharma sector in 2025, setting up excitement for the year ahead.
Read on for 2025’s seven most impactful biopharma M&A deals.
There could only be one story in the top spot, and it was the epic bidding war between Pfizer and Novo Nordisk over obesity startup Metsera. To make a long story short: Pfizer tried and repeatedly failed to develop a competitive obesity pipeline in-house. After several flunks earlier in 2025, the company looked to its business development team. Pfizer made a $4.9 billion offer for Metsera in September, to gain access to a long-acting GLP-1 and a long-acting amylin analogue.
The deal seemed to be on the way to closing, until Novo offered an unsolicited $8.5 billion bid for the company a month later. Facing a different set of problems as the obesity space’s early leader, Novo was looking to rebuild its pipeline as rival Eli Lilly seemingly scored one win after another.
A series of counteroffers, legal threats and FTC scrutiny followed, with Pfizer finally winning out for a price of about $9.2 billion for Metsera.
With the dust now settled, Pfizer is back in the obesity business. The size of the obesity market, according to a Reports and Data analysis, is set to hit $27 billion yearly by as soon as 2028 and $150 billion by the early 2030s.
The fight over Metsera seemed to indicate that Big Pharmas are still willing to go big in the obesity market. On the other hand, analysts wondered: Was it worth it?
Over the course of 2025, there was a massive pullback from cell therapy, with Takeda and Novo Nordisk abandoning billions in long-term investments. But Bristol Myers Squibb doubled down.
The Big Pharma plunked down $1.5 billion to get Orbital Therapeutics, snagging OTX-201, a circular RNA therapy that induces a patient’s own cells to make anti-CD19 CAR type constructs. The therapy is being tested to treat B cell–driven autoimmune disorders.
The Orbital deal deepens BMS’ roots in cell therapy, adding to its approved anti-BCMA therpay Abecma, for relapsed or refractory multiple myeloma, and the CD19-directed Breyanzi for blood cancers.
But the buy also told the industry that there is still potential in cell therapy if you know where to look.
Metabolic dysfunction–associated steatohepatitis—MASH—is suddenly one of the buzziest sectors in the pharma industry again. Novo Nordisk paid $5.2 billion to get Akero Therapeutics in October, adding efruxifermin, which reduced liver fibrosis by 24% in a Phase IIb study that read out earlier this year. It was such a good result that it pushed Roche to go hunting for an anti-MASH molecule, spurring that company’s purchase of 89bio for $3.5 billion in September.
The Akero buy only deepened Novo Nordisk’s presence in the MASH space, as its multi-blockbuster GLP-1 Wegovy received approval for the liver condition in August.
The Roche and Novo deals marked a turning point for the MASH space, which Big Pharma had largely abandoned years ago after numerous failures. The small biopharma Madrigal Pharmaceuticals finally broke through with the 2024 approval of Rezdiffra in MASH, reigniting interest in the space.
AbbVie paid $1.2 billion to get just one asset from neurotech biotech Gilgamesh Pharmaceuticals in August. That gave them an entree at a table that Big Pharma has nibble at for a while: psychedelics.
AbbVie gained bretisilocin, a fast-acting analogue of dimethyltryptamine (DMT) for major depressive disorder (MDD). The rest of Gilgamesh’s pipeline spun out into a separate company, Gilgamesh Pharma Inc., which carries on an existing AbbVie partnership.
The Gilgamesh buy suggested that AbbVie was undeterred after a $9 billion quagmire in the form of Cerevel. AbbVie paid the princely sum to get the company and its schizophrenia asset emraclidine in 2023, which went on to flunk Phase II trials one year later.
The Gilgamesh deal helped galvanize interest in psychedelics. AbbVie’s investment came at a time when most neuropsych-focused pharmas “have kept a distance,” from psychedelics according to Aaron Bartlone, CEO of the Canadian mental health biotech Cybin.
The only other Big Pharmas in the psychedelics space right now are Johnson & Johnson, with its ketamine derivative Spravato, and Japanese giant Otsuka. The latter paid $59 million in 2023 to absorb Mindset, a Canadian psychedelics biotech.
Bluebird was the standard bearer of gene therapy, until it wasn’t. Private equity outfits The Carlyle Group and SK Capital bought the biotech, which at one time had been worth north of $10 billion, for a scant $50 million in February.
It was a precipitous fall for bluebird, which had more than $1 billion in cash the first quarter of 2021. That number fell to just $118.7 million by the third quarter of 2023.
Gene therapy is facing a “cold winter,” as promising science has not translated to good business, with sky-high costs and infrastructure issues hobbling the sector. Still, Carlyle and SK have options for turning bluebird’s assets into profits—including just selling the three approved gene therapies off, as PitchBook Senior Biotech Analyst Kazi Helal suggested to BioSpace in July. Those assets are Lyfgenia for sickle cell disease, Skysona for cerebral adrenoleukodystrophy and Zynteglo for beta thalassemia.
Bluebird’s sale was the biggest indicator of a growing trend: the entry of private equity into the biotechnology space. In the last few years, PE firms like BlackStone have launched life sciences–focused funds, put billions of dollars into backing new ventures and even funded individual professors’ research.
Bluebird renamed itself to Genetix in September, shedding a unique biopharma name adopted in 2010 and returning to its original moniker.
In late November 2024, Sage’s lead asset dalzanemdor flunked a Phase II trial for Huntington’s disease, the third such fail for the drug. It was just the capstone of a series of setbacks for Sage over the last few years; another asset, SAGE-324, flunked a Phase II study for essential tremor and was discontinued, and its Biogen-partnered postpartum depression drug Zurzuvae failed to get FDA approval in major depressive disorder. Maryland-based Supernus stepped in and scooped up Sage for $795 million in June.
It was a “good end” for the company, according to analysts, and represented a much larger buyout than one put forward by long-time partner Biogen in January. Biogen offered $469 million to fold in its partner in Zurzuvae in January 2025. Sage declined the offer with extreme prejudice, going so far as to sue Biogen.
Along with Zurzuvae, Supernus absorbed Sage’s other approved drugs: the ADHD medication Qelbree; Onapgo, a wearable device for treating motor fluctuations associated with Parkinson’s disease; and Gocovri, for treating dyskinesia in Parkinson’s.
Stifel analysts, writing at the time of the Supernus buy, said that it “feels like an unremarkable outcome for a company that was once one of the hottest stories” in treating central nervous system disorders.
In 2022, BioNTech said in a lawsuit that it faced “threats of a groundless patent infringement suit” from a company that was “unable to bring to market any product to help in the fight against COVID-19.”
Three years later, BioNTech bought that company, CureVac, for $1.25 billion, ending a winding legal drama that was still ongoing at the time of the deal. That purchase gave BioNTech a new mRNA-based therapy for the tough brain cancer glioblastoma.
Despite both companies gaining fame for working on vaccines, the deal was motivated mostly by interest in cancer. Getting access to CureVac’s pipeline of cancer immunotherapies “marks the next milestone in the execution of [BioNTech’s] oncology strategy,” the company said in announcing the deal.
Despite regulatory headwinds prevailing against mRNA-based therapies and vaccines in the U.S.—like the federal government canceling hundreds of millions of dollars in research dollars aimed at projects using the technology—BioNTech’s bid to swallow up its rival is a signal that, even as the company diversifies into other modalities like bispecifics, mRNA-based therapies as a platform are here to stay.
