Pfizer's oral GLP-1 drug danuglipron produced up to 12.9% weight loss versus placebo, but 38% of participants dropped out due to side effects — mostly nausea and vomiting.
38% dropoutWhile danuglipron achieved up to 12.9% weight loss vs placebo, nearly 4 in 10 participants quit the trial due to adverse events — mostly nausea and vomiting
What the researchers found
Pfizer's oral GLP-1 drug danuglipron produced statistically significant weight loss in adults with obesity — ranging from 5.0% to 12.9% beyond placebo depending on dose — over 26 to 32 weeks. However, the trial was marred by very high dropout rates: only 39.3% of participants completed treatment, with approximately 38% discontinuing due to adverse events (primarily nausea and vomiting).
The weight loss was dose-dependent, with higher doses producing more weight loss but also more GI side effects. The drug was given twice daily at doses from 40 to 200 mg, escalated over 1, 2, or 4 weeks. While the efficacy signal was clear, the tolerability problem was worse than expected across all treatment groups.
Why it matters
The GLP-1 weight-loss market is dominated by injectable drugs like semaglutide and tirzepatide. An effective oral GLP-1 pill could dramatically expand access — no injections, no refrigeration, easier to prescribe. Danuglipron showed the efficacy is there (up to 12.9% weight loss beyond placebo), but the 38% dropout rate from side effects is a major red flag. This tolerability challenge is the central obstacle Pfizer must solve to compete in the oral GLP-1 space.
The numbers in context
n=628 · 536 danuglipron + 90 placebo · Weight loss: -5.0% to -12.9% vs placebo · 39.3% completed treatment · ~38% discontinued for AEs · 40–200 mg BID · 26–32 weeks
How the study worked
Randomized, double-blind, placebo-controlled Phase 2b dose-ranging study. 628 adults (ages 18–75) with obesity but without diabetes were randomized to various danuglipron doses (40–200 mg twice daily) or placebo for 26 or 32 weeks. Doses were escalated over 1, 2, or 4 weeks. Primary endpoint was percentage change in body weight from baseline.
Who was studied
628 adults aged 18–75 with obesity (BMI criteria) and without diabetes, enrolled across multiple sites
What this study cannot tell us
The 60.7% discontinuation rate (38% from adverse events alone) severely undermines the reliability of efficacy estimates — participants who tolerated the drug may not represent the broader patient population. Twice-daily dosing is a compliance burden compared to once-weekly injectable competitors. The study excluded people with diabetes, so results may differ in diabetic populations. The 26–32 week duration is relatively short for a weight-loss drug intended for long-term use.
How to read the evidence
This is a well-designed Phase 2b randomized, double-blind, placebo-controlled trial with 628 participants. However, the extremely high discontinuation rate (60.7% overall) limits the reliability of efficacy conclusions and raises serious questions about real-world applicability.
When this study was published
Published in 2025 with data from the NCT04707313 trial. This is the most recent large-scale efficacy data for danuglipron in obesity, though Pfizer is developing a modified-release formulation that may address the tolerability issues seen here.
The bigger picture
The race for an effective oral GLP-1 weight-loss pill is one of the highest-stakes competitions in pharma. Novo Nordisk has oral semaglutide (Rybelsus), but its weight-loss efficacy in pill form lags behind the injectable. Pfizer's danuglipron shows strong efficacy but terrible tolerability. This Phase 2b data suggests Pfizer needs significant formulation improvements before danuglipron can compete. The company has been developing a modified-release version to reduce GI side effects — the success of that reformulation will determine danuglipron's future.
Questions still open
- Can Pfizer's modified-release formulation of danuglipron solve the tolerability crisis while maintaining the weight-loss efficacy seen in this trial?
- How does danuglipron's weight loss of up to 12.9% compare to injectable semaglutide (~15%) and tirzepatide (~20%) when accounting for the high dropout rate?
- Would a once-daily formulation rather than twice-daily dosing improve both compliance and tolerability?
Common questions
Is danuglipron an alternative to Ozempic or Wegovy?
Why is an oral GLP-1 drug such a big deal?
Read the original research
Efficacy and safety of danuglipron (PF-06882961) in adults with obesity: A randomized, placebo-controlled, dose-ranging phase 2b study.
Diabetes, obesity & metabolism, 27(9), 4915-4926
Citation
Buckeridge, Clare; Cobain, Sonia; Bays, Harold E; Matsuoka, Osamu; Fukushima, Yasushi; Halstead, Patricia; Tsamandouras, Nikolaos; Sherry, Nicole; Gorman, Donal N; Saxena, Aditi R. (2025). Efficacy and safety of danuglipron (PF-06882961) in adults with obesity: A randomized, placebo-controlled, dose-ranging phase 2b study.. Diabetes, obesity & metabolism, 27(9), 4915-4926. https://doi.org/10.1111/dom.16534