Merck & Co's $11.5 billion takeover of Acceleron Pharma was not only one of the largest M&A deals of the year, but also one of the most contentious. Merck finally got it over the line in November despite opposition from rebel investors.
The drug—which could potentially address PAH's underlying disease process, while approved treatments target symptoms by dilating blood vessels—is in phase 3 trials that, if positive, may support regulatory approvals in 2024.
The $180-per-share deal also gave Merck ownership of already-marketed therapy Reblozyl (luspatercept) for anemia associated with the blood disorders beta-thalassemia and myelodysplastic syndromes (MDS). That drug is sold by Bristol Myers Squibb, rumored to have made its own play for Acceleron, only to be outbid by Merck. The drug delivered sales of $400 million in the first nine months of 2021.
BMS will pay low- to mid-20% royalties to Merck based on Reblozyl sales now that Acceleron is in Merck's stable.
Data that could extend Reblozyl's market to include non-transfusion-dependent (NTD) thalassemia patients as well as those reliant on transfusions—plus a potential move into front-line MDS therapy—has some analysts predicting peak sales for the drug of $4 billion or more.
Some of Acceleron's shareholders pushed back against the transaction, arguing that it offered a premium significantly lower than previous deals within the sector and significantly undervalued the company. It should be delayed until after the FDA completes its review of sotatercept as an add-on therapy for PAH, the investors argued.
Meanwhile, Merck has billed the deal as a way to rebuild its cardiovascular portfolio, which once boasted products like cholesterol-lowering drugs Zetia (ezetimibe) and Vytorin (ezetimibe and simvastatin) until they were spun off along with the drugmaker's Organon unit.
And the deal was pushed through despite concerns that it may fall foul of antitrust regulations in the U.S. because Merck already has a drug for PAH—Adempas (riociguat), partnered with Bayer—and is developing an inhaled follow-up called MK-5475, which is now in phase 2/3 trials.
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Merck had to refile the premerger notification with the FTC in November to allow the agency additional time for review, but eventually closed the deal on Nov. 22.
After years of relying heavily on its in-house R&D engine to fill its pipeline, Merck has latterly been much more willing to look for external candidates. That effort has gathered momentum as it looks to reduce its reliance on Keytruda, which appears set to approach $17 billion in sales this year.
Acceleron wasn't Merck's only big deal for 2021, either. It came after a $1.85 billion deal for immunotherapy specialist Pandion Therapeutics, just under the threshold needed for inclusion in this list.
Merck has used some of its Keytruda proceeds to make other big deals in the last couple of years, including 2020's $2.75 billion takeover of antibody-drug conjugate company VelosBio and 2019's purchase of Peloton Therapeutics and its oncology pipeline for $2.2 billion.