Pfizer ends oral GLP-1 danuglipron after one liver injury case

Pfizer announced on April 14, 2025 that it will not continue developing danuglipron (PF-06882961), an oral GLP-1 receptor agonist the company was studying for chronic weight management ^[1]. The decision followed a single case of possible drug-induced liver injury in a trial volunteer ^[1][2].

The volunteer had no symptoms, and the liver problem went away once the person stopped taking the medicine, Pfizer said ^[1][2]. The case occurred in one of two studies of once-daily danuglipron formulations, listed in federal trial records as NCT06567327 and NCT06568731 ^[1]. Pfizer has not said which of the two studies it was, what dose the participant received, or how far the liver enzyme readings rose. The company also has not disclosed how long that participant was followed afterward.

Pfizer said that, taken across the whole program, abnormal liver enzyme readings were about as common as they are with GLP-1 medicines already on the market. Its safety database for danuglipron covers more than 1,400 participants ^[1]. The company said it weighed that data along with recent feedback from regulators before ending the program ^[1].

Until this point, the program had been moving forward. Pfizer said the once-daily dose-finding studies met their key pharmacokinetic goals and identified a formulation and dose that could be competitive in Phase 3 trials, based on earlier testing of a twice-daily version of the drug ^[1]. That places danuglipron in mid-stage testing at the time it was stopped, before the large trials usually required before a company seeks approval.

"While we are disappointed to discontinue the development of danuglipron, we remain committed to evaluating and advancing promising programs in an effort to bring innovative new medicines to patients," Chris Boshoff, Pfizer's chief scientific officer and president of research and development, said in the announcement ^[1].

Pfizer said it will keep working on an oral GIPR antagonist candidate and other obesity programs at earlier stages ^[1]. STAT described the move as the close of more than two years of stock swings and reported that Pfizer is now putting its effort behind a medicine that works differently ^[2].

Why it matters for patients

Danuglipron was never approved for sale, so nobody currently taking a prescribed GLP-1 medicine loses a treatment option because of this decision ^[1]. The liver finding is tied to this one experimental molecule and was not reported in connection with any approved product ^[1].

For people who were hoping for more oral choices in this drug class, one candidate that had reached mid-stage testing is now off the table. Pfizer has not reported whether other participants in the program had liver-related findings, and it has not published the enzyme numbers behind its comparison with approved agents in the class ^[1]. It also has not said what dose the affected participant took or whether any other safety signals appeared ^[1].

What happens next

Pfizer said results from the danuglipron development program will be presented at a scientific forum or submitted to a peer-reviewed journal at some point in the future ^[1]. No date or venue has been disclosed, and the company has not said when its oral GIPR antagonist candidate or its other early obesity programs might move into later-stage trials ^[1].