Pfizer halts testing of twice-daily obesity drug, citing side effects

Pfizer said Friday it is halting the testing of a twice-daily obesity drug, citing side effects.

The company said in a press release it will now focus its future efforts for the drug, danuglipron, on a “once-daily formulation.” It noted high rates of adverse reactions to the twice-daily formulation in its Phase 2b clinical trial of the drug.

“While the most common adverse events were mild and gastrointestinal in nature consistent with the mechanism, high rates were observed,” the company said in the release. “High discontinuation rates, greater than 50%, were seen across all doses compared to approximately 40% with placebo.”

Pfizer said the main adverse effects included nausea, vomiting and diarrhea.

Despite adverse reactions from the twice-daily drug, the study “met its primary endpoint demonstrating statistically significant change in body weight from baseline,” according to Pfizer.

“We believe an improved once-daily formulation of danuglipron could play an important role in the obesity treatment paradigm, and we will focus our efforts on gathering the data to understand its potential profile,” Dr. Mikael Dolsten, chief scientific officer and president of Pfizer Research and Development, said in the release. 

“Results from ongoing and future studies of the once-daily danuglipron modified release formulation will inform a potential path forward with an aim to improve the tolerability profile and optimize both study design and execution,” Dolsten continued. 

Pfizer also discontinued the development of another obesity drug in June. The company announced it was discontinuing the development of lotiglipron due to elevated levels of the enzyme transaminase being detected during both the Phase 1 and Phase 2 studies. Higher levels of transaminase can point to liver disease or liver damage by way of a drug.