Novo Nordisk launches an unsolicited counterbid for Metsera

Novo Nordisk launched an unsolicited bid of about $9 billion for the obesity biotech Metsera on October 30, 2025, moving in on a company that had already agreed to be bought by Pfizer ^[1]. The counteroffer touched off a takeover battle that has since produced two Pfizer lawsuits and a court hearing in Delaware ^[2].

Pfizer had agreed in September to pay $4.9 billion upfront plus up to $2.4 billion in milestone payments, for a potential total of $7.3 billion ^[1]. That agreement followed months of private bidding against Novo, and Metsera had rejected Novo's offers six times, saying Novo already held a large share of the obesity market and could face antitrust scrutiny ^[2]. After Novo's controlling shareholder overhauled the company's board, Novo came back with the unsolicited bid, and Metsera's board then called Novo's offer superior and gave Pfizer until Tuesday to raise its price ^[2].

Pfizer sued Metsera's board and Novo in Delaware's Court of Chancery on Friday, then filed a second, antitrust-focused suit in Delaware federal court on Monday, November 3 ^[2]. Pfizer argues Novo's bid is not a real attempt to buy the company but a maneuver to delay Metsera's drugs and protect Wegovy and Ozempic, pointing to a 30-month "outside date" before either side could walk away, compared with the nine-month timeline in Pfizer's own deal ^[2]. Pfizer also says Novo offered shareholders $6.5 billion upfront before regulatory review and attached covenants that could slow clinical work ^[2]. Pfizer received early termination of antitrust review for its deal on October 31 ^[2]. Novo and Metsera rejected the claims; Metsera called them "nonsense" and accused Pfizer of trying to drive down its price, while Novo said Pfizer's suggestion that it would impair a US competitor is "absurd" ^[2]. A Delaware judge, Vice Chancellor Morgan Zurn, scheduled a hearing for Tuesday morning ^[2].

What Metsera is actually developing

The asset at the center of the fight is MET-097i, an ultra-long-acting GLP-1 receptor agonist designed for possible monthly dosing, versus the weekly injections used with semaglutide (Wegovy) and tirzepatide (Zepbound, Mounjaro) ^[1][2]. In the Phase 2b VESPER-1 study, the highest dose (1.2 mg) produced mean placebo-subtracted weight loss of 14.1% at 28 weeks, with some individuals losing as much as 26.5% of body weight, and exploratory 36-week data showed continued loss without a plateau ^[1]. In VESPER-1, 2.9% of participants (two of 239) stopped because of side effects ^[1]. In the VESPER-3 trial of monthly dosing, people titrated to 1.2 mg had a 13% increase in nausea and an 11% increase in vomiting compared with placebo ^[1]. Metsera's pipeline also includes MET-233, an ultra-long-acting amylin analog, and MET-815, an oral version of MET-097i ^[1].

These are mid-stage results. Phase 3 trials were expected to start in late 2025, with possible FDA approval projected for 2027 or 2028 ^[1].

Why it matters for patients

Nothing about this fight changes what is on pharmacy shelves today. Metsera has no approved product, and its lead drug has not started Phase 3 testing, so any monthly injection is years away at best ^[1].

The longer-term question is who controls that timeline. Pfizer's core allegation is that a Novo purchase could slow Metsera's drugs from reaching the market, which would matter to people hoping for a once-monthly option or for more competition to bring down prices in a market analysts think could reach $150 billion a year ^[2]. Novo disputes that, saying it would use its expertise to speed commercialization for US patients ^[2]. Neither claim has been tested in court.

It is also not yet known how regulators will treat Novo's unusual deal structure. Sources here describe Pfizer's early antitrust clearance and its allegations, but do not detail any formal Federal Trade Commission action against Novo's bid ^[1][2].

What happens next

A Delaware Chancery Court hearing on Pfizer's claims was set for Tuesday, November 4 ^[2]. Metsera's shareholder meeting was scheduled for November 13, 2025, after which Pfizer could potentially close its deal if it prevails ^[1]. Metsera shares closed at $60.73 on Monday, down 3.7% ^[2].