Finance
Pfizer weight-loss drug data raises questions about side effects, shares fall
Published by Global Banking & Finance Review®
Posted on February 3, 2026
4 min readLast updated: February 3, 2026
Global Banking & Finance Review®
Company
Published by Global Banking & Finance Review®
Posted on February 3, 2026
4 min readLast updated: February 3, 2026
Pfizer's Q4 profit beat expectations due to strong drug demand, despite challenges from declining COVID product sales and upcoming patent expirations.
By Mrinalika Roy and Michael Erman
Feb 3(Reuters) - Pfizer on Tuesday released trial data on a high-profile obesity drug from its recent $10 billion Metsera purchase that raises questions about its tolerability for patients, and shares of the U.S. drugmaker fell 5%.
The drug, given as a monthly injection, showed sustained weight loss at 28 weeks, Pfizer said, adding that it is targeting 2028 for its first approval in the fast-growing weight-loss drug market.
The company made the disclosure alongside reporting fourth-quarter earnings, which beat analysts' estimates.
The latest data sets the stage for a year in which Pfizer said it plans to advance more than 20 clinical trials involving obesity treatments, an area that one day could help it offset new competition for older drugs losing patent exclusivity.
"The foundation of our strategy in obesity and adjacent conditions is targeting breakthrough medicines in what could be a $150 billion market," CEO Albert Bourla said.
In a mid-stage trial, the treatment, known as PF-3944, led to up to 12.3% weight loss in patients without diabetes, with no plateau observed at week 28, the company said, adding that it expects the trend to continue through the 64-week study.
Chief Scientific Officer Chris Boshoff said the company is confident the drug "has the potential to deliver efficacy that is competitive with the standard of care."
Pfizer shares were down 4.9% at $25.36 in morning trading.
SIDE EFFECTS LEAD TO DISCONTINUATIONS
Cantor Fitzgerald analyst Carter Gould said the weight loss reached in Pfizer's trial was comparable to Eli Lilly's market leader Zepbound, known chemically as tirzepatide.
"Achieving tirzepatide-like levels of efficacy with (monthly) dosing suggests potentially relevant commercial differentiation," Gould wrote in a research note.
Of around 108 patients who received the drug in two separate arms of the trial, 10% dropped out due to adverse side effects.
Gould said he is looking for more detail on tolerability of the shot from the drugmaker.
Pfizer last year won a bidding war with Novo Nordisk for obesity drug developer Metsera, securing a foothold in the booming weight-loss drug market.
The company, which has warned of challenges over the next few years and does not expect to return to revenue growth until 2029, is banking on developing new blockbuster medicines, including obesity drugs acquired through recent deals, to help drive that recovery.
David Wagner, portfolio manager at Aptus Capital Advisors, was taking a cautious approach to Pfizer. "The big question is, will we see sizeable returns from their M&A spend, and will they make all the right development choices over this and next year to support the longer-term return to growth?"
UPBEAT QUARTERLY RESULTS
For the fourth quarter, the company saw sales rise to $17.56 billion, helped by sustained demand for the blood thinner Eliquis that Pfizer shares with Bristol Myers and growth of its newer RSV vaccine Abrysvo. Analysts were expecting $16.95 billion in sales, according to LSEG data.
Abrysvo fourth-quarter sales of $481 million more than doubled Wall Street estimates of $170 million.
Still, BMO analyst Evan Seigerman said he expects most investor interest to be captured by the obesity data.
On an adjusted basis, the company reported a profit of 66 cents per share, topping analysts' estimates by 9 cents.
Pfizer reaffirmed its 2026 forecast for revenue of $59.5 to $62.5 billion and adjusted earnings of $2.80 to $3.00 per share and said it reflects the expected hit from drug pricing dealswith the Trump administration.
(Reporting by Mrinalika Roy in Bengaluru and Michael Erman in New Jersey, additional reporting by Sneha S K in Bengaluru; Editing by Anil D'Silva and Bill Berkrot)
Revenue growth refers to the increase in a company's sales over a specific period, often expressed as a percentage. It indicates the company's ability to expand its business and increase its market share.
Patent expiration occurs when the legal protection granted to an invention or product ends, allowing other companies to produce generic versions. This can significantly impact a company's revenue from patented products.
A blockbuster medicine is a pharmaceutical product that generates annual sales of over $1 billion. These drugs are often critical to a company's revenue and market position.
Adjusted profit is a measure of a company's profitability that excludes certain one-time expenses or income, providing a clearer view of ongoing operational performance.
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