Pfizer has decided to discontinue the development of its potential once-daily pill for obesity, halting the drug’s progression before entering the most expensive phase of clinical testing. The company announced on Tuesday that it would cease further studies of danuglipron following an incident in one of its trials, where a participant experienced a possible liver injury linked to the drug. The issue resolved after the participant stopped taking the treatment.
At the time of the decision, danuglipron was still in early-stage trials, with researchers working to determine the optimal dose for patients. Pfizer had planned to move the drug into late-stage testing, the final step before seeking approval from regulatory authorities. However, the company has stated that it will continue developing other potential treatments for obesity that are in earlier stages of testing.
Obesity treatments have become a highly promising and profitable area of pharmaceutical development. Eli Lilly’s Zepbound, for example, generated nearly $5 billion in sales in its first full year on the market in 2024. However, many leading treatments, including Zepbound and Novo Nordisk’s Wegovy, are injectable. As a result, drugmakers are working to create oral pill versions to offer patients an easier alternative to daily injections.
Lilly is also testing oral obesity treatments and expects to share data from those studies this year. While these drugs have become top-sellers, patients often struggle to obtain them due to shortages or inconsistent insurance coverage. Though both Lilly and Novo have recently cut prices, the treatments can still cost hundreds of dollars per month, making them unaffordable for some without insurance.
Pfizer had previously abandoned a twice-daily version of danuglipron in late 2023 after a significant number of participants in its mid-stage trials stopped taking the drug. Following the recent announcement, Pfizer confirmed that it would also cease testing danuglipron in combination with other obesity treatments.
Pfizer’s shares saw a slight increase, rising 12 cents to $22.03 in Monday’s morning trading.