Pfizer has announced it will discontinue the twice-daily version of its experimental weight loss pill due to high rates of adverse side effects. The decision comes after obese patients on the drug lost weight but had trouble tolerating the pill in a mid-stage clinical study.
The drugmaker observed high rates of adverse side effects in these participants. The unwanted effects were mostly mild and gastrointestinal, including nausea and vomiting.
Furthermore, a significant share of patients also stopped taking the drug in the trial. The company said: “At this time, twice-daily danuglipron formulation will not advance into Phase 3 studies.”
Pfizer’s phase two trial on the twice-daily pill looked at around 600 obese adults without type 2 diabetes. The research examined the drug’s effect on weight loss after 26 or 32 weeks, at different dosage amounts ranging from 40 milligrams to 200 milligrams.
Like weight-loss drugs Wegovy and Ozempic, Pfizer’s pill works by mimicking a hormone produced in the gut called GLP-1. This signals to the brain when a person is full.
The pharmaceutical company said all dose sizes of the pill showed “statistically significant reductions” in body weight. The weight loss ranged from 6.9 percent to 11.7 percent at 32 weeks, and from 4.8 percent to 9.4 percent at 26 weeks.
However, the trial also saw high rates of adverse events among patients in the study. Around 73 percent experienced nausea, up to 47 percent vomiting and up to 25 percent had diarrhoea.
More than 50 percent of the trial participants across all dose sizes stopped taking the pill, compared to roughly 40 percent among those on the placebo. Pfizer said no new safety issues were observed and danuglipron was not linked to increased liver enzymes like Pfizer’s other discontinued weight loss pill.
