Dive Brief:

• Pfizer is scrapping another obesity pill, announcing Monday it will stop testing an experimental therapy called danuglipron after uncovering a case of possible liver damage in one study participant.
• The announcement marks the second time Pfizer has given up on an oral weight loss medicine since 2023 and is its latest setback in obesity, a lucrative market it seeks to break into. In a statement, Chris Boshoff, Pfizer’s top scientist, said the company is “disappointed” but remains “committed to evaluating and advancing promising programs.”
• Drugmakers are racing to develop an oral alternative to the injectable obesity medicines that generated a combined $13 billion in sales last year. But they’ll have to leap frog market leaders Eli Lilly and Novo Nordisk, both of which have oral drugs in Phase 3 testing.

Dive Insight:

Danuglipron’s development has already been a roller coaster ride for Pfizer. Testing of a twice-daily regimen revealed a high rate of side effects in Phase 2 studies. Pfizer was confident a once-daily formulation would perform better, however. Last year, CEO Albert Bourla claimed the company could be second to market, behind only Lilly, with an obesity pill.

Pfizer will now have to look elsewhere. The company said the frequency of liver enzyme elevations, a sign of possible organ damage, in testing of danuglipron was “in-line” with other obesity medicines. But the “totality of information” from the danuglipron trials, the case of possible liver damage and recent input from regulators have led it to discontinue development, the company said.

Pfizer still has other candidates in its pipeline. One pill targeting a gut hormone called GIP is in Phaes 2 testing, while another GLP-1 drug it’s working on with Nxera Pharma is in Phase 1. The company is also searching for obesity drugs through a broad alliance with startup creator Flagship Pioneering.

Nonetheless, the setback sparked speculation among Wall Street analysts that Pfizer might turn to deals for new obesity medicines, particularly if the drugs in its pipeline have a similar molecular structure to danuglipron. Shares of Viking Therapeutics, Altimmune, Structure Therapeutics and Metsera — all of which have weight loss drugs in clinical testing — rose in trading Monday.

Viking has injectable and oral obesity drugs in advanced testing, while Altimmune has released promising Phase 2 data for a dual-acting treatment. Structure released positive Phase 2 data last year, and Metsera had strong enough data from a long-acting GLP-1 shot it’s developing that it was able to raise $275 million in an initial public offering in January.