Pharma Rivalry Intensifies: Novo Nordisk Looks to Wrest Metsera from Pfizer

In an unprecedented move that has sent shockwaves through the pharmaceutical industry, Danish drugmaker Novo Nordisk launched an unsolicited ~$9 billion bid to acquire obesity-focused biotech Metsera, directly challenging a deal Pfizer had already secured. The aggressive counteroffer, announced on October 30, 2025, marks a dramatic escalation in the race to dominate the rapidly expanding weight-loss drug market and signals a strategic shift for Novo Nordisk under new leadership.

The Bidding War Intensifies

Novo Nordisk’s bold proposal offers $56.50 per share in cash upfront ($6 billion) plus an additional $21.25 per share in contingent value rights (CVRs) tied to clinical and regulatory milestones, totaling approximately $9 billion in potential value. This represents a substantial increase over Pfizer’s September agreement, which valued Metsera at $4.9 billion upfront plus $2.37 billion in milestone payments for a total of approximately $7.27 billion.

The Danish pharmaceutical giant’s offer represents a 133% premium to Metsera’s closing price on September 19, the last trading day before Pfizer’s acquisition was announced. Metsera’s board quickly declared Novo’s proposal “superior” to Pfizer’s existing agreement and formally notified Pfizer, triggering a four-business-day negotiation period during which the New York-based pharma can attempt to match or exceed the offer.

Metsera shareholders responded enthusiastically to the news, with the biotech’s stock surging more than 17% to $61.46 in pre-market trading on October 30, compared to $52.21 at the previous day’s close. The stock has nearly doubled since the beginning of 2025, climbing from $26.50 per share on January 31 to over $64 following Novo’s bid announcement.

Pfizer issued a strongly worded statement condemning Novo’s counteroffer as “reckless and unprecedented”. The pharmaceutical giant accused Novo Nordisk of attempting to suppress competition in the obesity drug market through what it characterized as anticompetitive behavior.

“It is an attempt by a company with a dominant market position to suppress competition in violation of law by taking over an emerging American challenger,” Pfizer stated. “It is also structured in a way to circumvent antitrust laws and carries substantial regulatory and executional risk.”

Pfizer further argued that Novo’s proposal “is illusory and cannot qualify as a superior proposal under Pfizer’s agreement with Metsera” and pledged to “pursue all legal avenues to enforce its rights under its agreement”. The company maintains that its transaction “creates real, certain and immediate value for Metsera’s stockholders and ensures Metsera’s important drug candidate can emerge as a key competitor available to all Americans in this important therapeutic area”.

However, Metsera publicly disagreed with Pfizer’s interpretation, stating plainly, “Metsera disagrees with Pfizer’s view.” If Metsera’s board determines, after the four-day negotiation period, that Novo’s offer remains superior, the biotech could terminate its agreement with Pfizer by paying a $190 million termination fee—a cost that Novo Nordisk has offered to cover on Metsera’s behalf.

Furthermore, Pfizer’s accusation that Novo’s bid violates antitrust laws raises critical questions about regulatory approval. According to SEC documents filed after Pfizer’s September offer, Metsera’s board initially rejected an earlier Novo proposal due to “a variety of risks,” including “potential regulatory concerns” that could delay closing by up to 24 months.​

These concerns are not without merit. Novo Nordisk already holds a dominant market position in obesity medications, with WEGOVY and OZEMPIC, collectively generating tens of billions of dollars in annual revenue. Acquiring Metsera would further consolidate Novo’s control over the GLP-1 market, potentially limiting competition and consumer choice in a therapeutic area of immense public health importance.

The Prize: Metsera’s Promising Obesity Pipeline

At the heart of this corporate showdown is Metsera’s innovative portfolio of obesity treatments, particularly its lead candidate MET-097i, a first-in-class, ultra-long-acting GLP-1 receptor agonist designed for potentially monthly dosing. This represents a significant advancement over current market leaders, such as Novo’s WEGOVY and Eli Lilly’s ZEPBOUND, which require weekly injections.

Recent Phase IIb trial results have demonstrated MET-097i’s impressive profile. In the VESPER-1 study, the drug achieved a mean placebo-subtracted weight loss of 14.1% after 28 weeks at the highest dose (1.2 mg), with some individuals losing as much as 26.5% of their body weight. Exploratory analysis of 36-week data revealed substantial continued weight loss, with no plateau reached, suggesting that the drug’s full effects extend beyond the initial trial period.

Equally compelling is MET-097i’s tolerability profile. In the VESPER-3 trial evaluating monthly dosing regimens, participants who titrated to the highest dose of 1.2 mg experienced minimal diarrhea, with only a 13% increase in nausea and an 11% increase in vomiting compared to placebo, substantially lower rates than those seen with competing GLP-1 drugs. Only 2.9% of participants (two out of 239) discontinued treatment due to adverse events in the VESPER-1 study, compared to discontinuation rates of up to 10% for other obesity medications.

The drug’s potency is remarkable, requiring 5-10 times lower doses than current GLP-1 options while achieving comparable efficacy to tirzepatide, the active ingredient in Eli Lilly’s ZEPBOUND. This translates to significant manufacturing and scalability advantages in a market currently constrained by supply limitations.

Based on these positive results, Metsera is on track to initiate Phase III trials in late 2025, with potential FDA approval projected for 2027 or 2028. Beyond MET-097i as a monotherapy, Metsera’s pipeline includes MET-233. This ultra-long-acting amylin analog could be combined with MET-097i as a first-in-category monthly multi-hormone therapy, as well as MET-815, an oral prodrug of MET-097i.

Market Implications and Industry Outlook

The Metsera bidding war reflects broader trends in pharmaceutical M&A, particularly in the obesity and cardiometabolic space. Novo Nordisk has dominated obesity-focused dealmaking, signing 17 obesity-focused deals between 2020 and Q1 2025, while Eli Lilly announced seven deals during the same period. Obesity partnering deal volume doubled in 2024 to 36 agreements, up from 18 in 2023, with licensing deals experiencing the most significant jump.

However, merger and acquisition activity specifically in the obesity sector showed a “yo-yo effect,” with deal volume declining from $7.5 billion across 21 deals in 2023 to $1.4 billion across 20 deals in 2024. This slowdown reflected acquirers waiting for next-generation medicines to be sufficiently de-risked before committing significant capital.

The Metsera competition signals that this cautious period may be coming to an end. Companies like Viking Therapeutics, Altimmune, and Structure Therapeutics, all developing weight-loss drugs in clinical testing, saw their shares rise following the announcement.

Pfizer’s Troubled Obesity Journey

For Pfizer, the loss of Metsera would represent a significant setback in its renewed effort to re-enter the obesity market after a series of clinical disappointments. The company had already terminated two oral GLP-1 programs due to safety concerns: Lotiglipron was discontinued in late 2023 after elevated liver enzymes were detected in clinical trials, and Danuglipron was abandoned in April 2025 following a suspected case of drug-induced liver injury in a Phase I participant. Pfizer’s third and final in-house GLP-1 agonist, PF-06954522, was discontinued in August 2025, though not for safety-related reasons. These repeated failures left Pfizer without a viable obesity candidate in its internal pipeline, aside from early-stage collaborations with other companies. The acquisition of Metsera therefore represented Pfizer’s best opportunity to quickly re-establish a competitive position in this rapidly expanding market. Losing Metsera to Novo would effectively send Pfizer back to square one, forcing it to pursue more costly alternatives or accept a diminished role in the obesity space.

A Defining Moment for the Obesity Drug Race

The obesity drug market is largely a battle of Novo Nordisk vs Eli Lilly, and this deal has strengthened Novo’s position. The fierce competition for Metsera reflects the extraordinary growth trajectory of the obesity drug market. The anti-obesity medication market, valued at approximately $12 billion in 2024 across the leading markets (the US, EU4, the UK, and Japan), is projected to reach between $88 billion by 2034, representing a compound annual growth rate of 20.6%.

The runaway success of GLP-1 therapies drives this explosive growth. Novo Nordisk’s OZEMPIC and WEGOVY, along with Eli Lilly’s MOUNJARO and ZEPBOUND, have collectively generated $71 billion in US revenue since 2018, with OZEMPIC alone accounting for approximately half of that total. With the market projected to become “the largest drug class,” reaching up to 222 million patients across the leading markets by 2034, access to next-generation therapies like Metsera’s pipeline could determine competitive positioning for decades to come.​

The outcome will have far-reaching implications beyond the immediate financial terms. If Novo succeeds in acquiring Metsera despite antitrust concerns, it could embolden other market leaders to pursue aggressive consolidation strategies. Conversely, if regulatory scrutiny or legal challenges derail Novo’s bid, it may establish precedents limiting how dominant players can expand their obesity portfolios through M&A.As the November 3 deadline approaches for Pfizer’s response, the pharmaceutical world watches to see whether this dramatic corporate showdown will reshape the competitive landscape of the obesity drug market, and whether the promise of monthly dosing, superior tolerability, and transformative weight loss will ultimately belong to the Danish giant that pioneered the GLP-1 revolution or the American challenger seeking redemption after repeated setbacks.