Pfizer ends trials of twice-daily obesity pill due to side effects

Pfizer said on Friday it would not advance a twice-daily version of oral weight-loss drug danuglipron into late-stage studies, after most patients dropped out of a mid-stage trial with high rates of side effects such as nausea and vomiting.

While Pfizer will now focus on a once-daily version, the decision still marks a blow to its ambitions to become an early contender in a booming market for weight-loss drugs that analysts have forecast could be worth $100bn by the end of the decade.

Danuglipron belongs to the same class of diabetes and obesity treatments as Novo Nordisk’s Wegovy and Ozempic, and Eli Lilly's Mounjaro and Zepbound.

Approved drugs in that class are currently injected, though Novo and Lilly are also testing oral versions of their drugs.

Pfizer's shares dropped 3.4% to $29.45 in premarket trading. Shares of Novo Nordisk erased some of their losses and were down 1.1% at 11.52am GMT.

Pfizer said it would instead focus on a once-daily, modified release version of danuglipron and was “gathering the data to understand its potential profile”. Data on how this version interacts with the human body is expected in the first half of 2024.

Danuglipron is among the most high-profile medicines in Pfizer's drug development pipeline as the company works to replace lost revenue from slumping demand for its Covid-19 vaccine and treatment.

Pfizer has high hopes for the products, with CEO Albert Bourla saying an obesity pill could eventually be a $10bn-a-year product for the drugmaker.

In the current study of the twice-daily version, Pfizer said the drug, however, met the main goal of reducing weight in adults with obesity and without type 2 diabetes.

Observed mean weight loss in the trial, across doses, ranged between 6.9% and 11.7% in patients on the drug at 32 weeks, versus weight gain of 1.4% for placebo.

That compared to a nearly 15% drop observed with the highest dose of Eli Lilly's once-daily experimental orforglipron pill after 36 weeks of treatment in a trial of obese or overweight patients.

Pfizer said while the common side effects in the twice-daily version study were mild, it saw high rates of those events in the trial. High discontinuation rates, greater than 50%, were seen across all doses compared to about 40% with placebo.

It said that up to 73% of patients in the trial had nausea; up to 47% vomiting and up to 25% diarrhoea. However, no new safety signals were observed in the study, Pfizer said.

Reuters