Pfizer Discontinues Danuglipron, Faces Setback in Obesity Drug Development

Pharmaceutical giant Pfizer has announced the discontinuation of its oral GLP-1 drug danuglipron, dealing a significant blow to the company's efforts to enter the lucrative obesity treatment market. The decision comes after the detection of a potential case of drug-induced liver injury during dose-optimization studies, marking another setback in Pfizer's pursuit of weight loss medications.

Safety Concerns Lead to Program Termination

Pfizer revealed that a patient in the danuglipron trials experienced asymptomatic liver injury, which resolved after discontinuation of the drug. Despite the overall occurrence of liver enzyme elevations being "in-line" with other approved therapies in this class across more than 1,400 treated patients, the company has chosen to halt further development of danuglipron.

Chris Boshoff, Pfizer's chief scientific officer, expressed disappointment but reaffirmed the company's commitment to advancing promising programs in the obesity space. The decision to discontinue danuglipron was made after a comprehensive review of all clinical data and recent input from regulators.

Implications for Pfizer's Obesity Pipeline

The termination of the danuglipron program leaves Pfizer with a single clinical-stage obesity asset: PF-07976016, an oral GIP analog currently in Phase II development. This setback significantly impacts Pfizer's position in the highly competitive obesity drug market, currently dominated by Novo Nordisk and Eli Lilly.

Danuglipron's discontinuation follows the earlier axing of lotiglipron in June 2023, another GLP-1 therapy that was associated with liver safety issues. These consecutive failures highlight the challenges Pfizer faces in developing safe and effective oral weight loss medications.

Market Dynamics and Future Prospects

The obesity treatment market has seen explosive growth, with combined sales of $13 billion for injectable obesity medicines in the previous year. Drugmakers are racing to develop oral alternatives to these successful injectable therapies, with Eli Lilly and Novo Nordisk leading the pack with oral drugs in Phase 3 testing.

Pfizer's setbacks have sparked speculation among analysts about potential strategic moves, including the possibility of acquisitions to bolster its obesity drug pipeline. Companies such as Viking Therapeutics, Altimmune, Structure Therapeutics, and Metsera, all with weight loss drugs in clinical testing, have seen their stock prices rise following the news of danuglipron's discontinuation.

As Pfizer regroups, the company continues to explore other avenues in obesity treatment, including a Phase 2 trial of a GIP-targeting pill and a Phase 1 GLP-1 drug being developed in collaboration with Nxera Pharma. Additionally, Pfizer's broad alliance with startup creator Flagship Pioneering may yield new opportunities in the obesity space.