Pfizer abandons obesity pill after liver injury in setback

Pfizer will stop developing an obesity pill that has been closely watched by investors, a severe blow in its efforts to compete with blockbuster weight-loss shots from Novo Nordisk A/S and Eli Lilly & Co.

The treatment, called danuglipron, was linked to a potentially drug-related liver injury in one patient enrolled in a clinical trial, Pfizer said in a statement. As a result, the company won’t advance the once-daily medicine into the final stage of testing and will instead invest in earlier-stage treatments for obesity.

Pfizer has made competing in the obesity market central to its post-Covid comeback plan. As demand for coronavirus vaccines and therapies ebbs, the business of selling weight-loss treatments has boomed — and is expected to reach $130 billion by the end of the decade.

The shares were down about 1% in premarket trading at 7:07 a.m. in New York. Rivals’ shares advanced, with Novo climbing 4.6% in Copenhagen and Eli Lilly up 2.3%. Viking Therapeutics Inc., a US biotech also working on a weight-loss pill, soared 20% in premarket trading.

Pfizer was already behind the competition. Lilly, whose weekly Zepbound shot rapidly reached nearly $5 billion in annual sales after winning US approval in 2023, also has an oral treatment in the final stage of development. AstraZeneca Plc and Structure Therapeutics Inc. are also developing oral drugs of their own.

Pfizer previously had to halt development of a twice-daily version of danuglipron after high rates of nausea and vomiting led patients to drop out of a mid-stage study of about 1,400 people. Months earlier, the company abandoned another oral obesity drug that showed concerning liver effects in a clinical trial.

Pfizer’s decision could come as a relief to some investors, who have harbored doubts over whether danuglipron could meaningfully compete with other weight-loss drugs. Discontinuing the pill could also lead Pfizer to seek out acquisitions.

Either way, the results will intensify pressure on Pfizer Chief Executive Officer Albert Bourla, who has repeatedly pointed to the drugmaker’s pipeline as an undervalued source of future growth. The company is expected to lose roughly $15 billion in revenue by the end of the decade as key drugs lose patent protection.

A series of multibillion-dollar acquisitions has yet to yield new blockbusters, and Pfizer’s internal pipeline has generated little in the way of excitement. The company’s shares have fallen by more than 60% since their pandemic peak in 2021.