Pharmaceutical giant Pfizer terminated development of its experimental oral weight-loss drug danuglipron after a clinical trial participant experienced drug-induced liver injury, Reuters reported.
The decision marks another setback for Pfizer’s ambitions in the lucrative obesity treatment market, currently dominated by injectable therapies from Novo Nordisk and Eli Lilly.
The discontinued twice-daily formulation of danuglipron, a GLP-1 receptor agonist, had already shown problematic side effects in 2023 trials, including high rates of nausea and vomiting that led to significant patient dropouts. While Pfizer’s subsequent once-daily version achieved key pharmacokinetic targets in dose-optimization studies involving 1,400 participants, the emergence of liver toxicity in one case proved decisive.
After reviewing “the totality of information, including all clinical data generated to date for danuglipron and recent input from regulators,” Pfizer stated it decided to stop studying the molecule.
The company noted the affected patient’s liver function returned to normal after stopping treatment. Pfizer shares dipped 1.2% in premarket trading following the announcement.
With analysts projecting annual obesity drug sales to reach $150 billion, Pfizer will now concentrate on alternative oral treatments targeting the GIPR hormone and earlier-stage metabolic disease programmes. The abandonment leaves Eli Lilly’s oral orforglipron, currently awaiting Phase 3 trial results, as the most advanced pill-form competitor to dominant injectables Wegovy and Zepbound.
Pfizer plans to publish complete danuglipron trial data at future scientific forums.
