Why was danuglipron discontinued?

A single asymptomatic participant experienced potential drug-induced liver injury, which resolved after stopping. Pfizer concluded the risk-benefit profile did not support further development.

Were its liver signals worse than other GLP-1 drugs?

No. Pfizer stated that across over 1,400 participants, liver enzyme elevation frequency was in line with approved agents in the class.

Did the drug fail on efficacy?

No. The dose-optimisation studies met their key pharmacokinetic objectives before the programme was stopped.

GLP-1 & Incretin Science

Danuglipron: The Oral GLP-1 Pfizer Stopped

JMWritten & reviewed by Jack Muncaster · Founder, UK PeptidesLast reviewed 2026-08-233 cited sources

Danuglipron, or PF-06882961, was Pfizer's oral small-molecule GLP-1 receptor agonist for chronic weight management. Development was discontinued in April 2025 after a single asymptomatic participant experienced potential drug-induced liver injury, which resolved after the drug was stopped.

Key facts

Development code: PF-06882961
Developer: Pfizer
Class: Oral small-molecule GLP-1 receptor agonist
Phase 2b published: Diabetes Obes Metab 2025 (PMID 40539310)
Discontinued: April 2025
Trigger: One asymptomatic DILI case, resolved on stopping
Safety database: Over 1,400 participants
Enzyme elevations overall: In line with approved agents in the class

What it was

A non-peptide GLP-1 receptor agonist small enough to survive the digestive tract and be absorbed as an ordinary tablet — the same basic proposition as orforglipron and aleniglipron. Its Phase 2b results in adults with obesity were published in Diabetes, Obesity and Metabolism in September 2025, after the programme had already been stopped.

Why the discontinuation is more interesting than it looks

The dose-optimisation studies had met their key pharmacokinetic objectives. Pfizer's own update stated that across a safety database of more than 1,400 participants, the frequency of liver enzyme elevations was in line with approved agents in the class. So the programme was not stopped because danuglipron looked worse than the drugs already on the market.

Research material referenced

Retatrutide 10mg — third-party HPLC tested

View — £59.99

What actually ended it

One participant. A single asymptomatic case of potential drug-induced liver injury in a dose-optimisation study, which resolved after the drug was discontinued. Pfizer described the decision as following a review of the totality of information including regulator input, and concluded the risk-benefit profile did not support continuing.

Why one case can be decisive

Because of what obesity medicine is. A drug for a chronic condition, taken by very large numbers of people for years, with several effective alternatives already licensed, has almost no tolerance for a serious idiosyncratic risk. The same single case in a compound treating a condition with no alternatives would be weighed completely differently. Risk-benefit is a ratio, and the denominator here was crowded.

What it changed for everything that followed

It made hepatic safety the question every subsequent oral small molecule had to answer first. When the aleniglipron Phase 2b appeared in Nature Medicine in August 2026, the sentence that mattered to the field was not the 12.1% weight reduction — it was that no cases of drug-induced liver injury occurred. Most coverage led with the weight number.

What this does not concern

Research material of any kind. Danuglipron was an investigational medicine in registered clinical trials under clinical supervision, it was never licensed, and its development has ceased. Nothing supplied here is related to it or to any other GLP-1 receptor agonist.

Extended research context

The GLP-1 & Incretin Science deep dive

Deep dive: the two routes to a bigger effect

Every compound trying to beat GLP-1 alone has taken one of two routes. The first adds more receptors from the same hormone family — GIP in tirzepatide, GIP and glucagon in retatrutide. The second adds a non-incretin satiety hormone, which in practice means amylin: CagriSema combines cagrilintide with semaglutide, and amycretin engages both receptors from one molecule. Both routes work, because they recruit signalling pathways that do not fully overlap. Neither has escaped the constraint that binds all of them, which is that gastrointestinal tolerability worsens as effect size grows.

Deep dive: why a percentage is not a result

The most-quoted numbers in this field are the least comparable. REDEFINE 1 reported 22.7% and 20.4% for the same compound in the same trial — the first among participants who adhered to treatment, the second across everyone randomised. TRIUMPH-1 reported 28.3% in an uncomplicated obesity population while TRIUMPH-3 reported up to 22.6% in adults with established cardiovascular disease, using the same compound. Before any two figures can be compared they have to match on estimand, population, duration, comparator and whether the number is placebo-adjusted. Most published comparisons match on none of them.

Deep dive: what happens after the trial stops

Every headline figure describes weight while treatment continues. The STEP-1 extension found that a year after semaglutide was stopped, participants had given back roughly two-thirds of what they lost, moving from 17.3% mean reduction to a net 5.6% — though average weight remained below baseline and nearly half stayed at least 5% down. Meta-analysis puts regain at around 0.8 kg per month. This is why maintenance studies such as TRIUMPH-6 matter more to the field's future than another two points of peak reduction.

Research applications

▸Comparing incretin and amylin compounds on a like-for-like basis
▸Interpreting estimands, thresholds and placebo-adjusted figures in trial reports
▸Tracking the obesity pipeline across sponsors and jurisdictions
▸Understanding receptor pharmacology behind GLP-1, GIP, glucagon and amylin
▸Distinguishing licensed medicines from investigational compounds

Handling checklist

✓Identify which estimand a quoted percentage comes from before citing it
✓Check the trial population and baseline BMI against the comparison you are making
✓Confirm the duration and whether the reduction curve had plateaued
✓Read discontinuation rates alongside efficacy figures
✓Verify every NCT identifier against ClinicalTrials.gov rather than secondary reporting

Common research-handling mistakes

Learnt from thousands of researcher orders across our UK labs.

✗ Comparing headline percentages across different trials

Fix: Population, duration, estimand and comparator all differ; the numbers are not interchangeable.

✗ Quoting the larger of two figures from the same trial

Fix: Name the estimand. Efficacy and treatment-policy answer different questions.

✗ Treating peak reduction as a durable outcome

Fix: Substantial regain follows cessation across the class; peak figures describe a maintained state.

✗ Assuming an oral route means a weaker mechanism

Fix: Route and receptor count are independent. Orforglipron is weaker because it hits one receptor, not because it is a tablet.

✗ Reading investigational compounds as available treatments

Fix: Most of this pipeline holds no authorisation anywhere; mazdutide is approved only in China.

Continue researching

Peer-reviewed guides, comparators and matched reference materials.

Frequently asked questions

Why was danuglipron discontinued?: A single asymptomatic participant experienced potential drug-induced liver injury, which resolved after stopping. Pfizer concluded the risk-benefit profile did not support further development.
Were its liver signals worse than other GLP-1 drugs?: No. Pfizer stated that across over 1,400 participants, liver enzyme elevation frequency was in line with approved agents in the class.
Did the drug fail on efficacy?: No. The dose-optimisation studies met their key pharmacokinetic objectives before the programme was stopped.

Primary sources & clinical trials

Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab and point to the primary source, so every claim can be verified at origin.

Written and reviewed by

Jack Muncaster · Founder, UK Peptides

Jack founded UK Peptides in Manchester after repeatedly receiving research compounds with missing or recycled paperwork. He is responsible for supplier selection, batch release decisions and the content published in this research library. Every article here is sourced to primary literature and every product page to a signed third-party certificate.

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