Petrelintide: What the Phase 2 Trial Actually Showed
A once-weekly amylin analogue, 485 dosed adults, and up to 9.8% mean weight loss at 28 weeks versus 1.7% on placebo. Here is the published data, arm by arm.
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How It Works
Amylin is co-secreted with insulin from pancreatic beta cells. It slows gastric emptying, suppresses glucagon secretion and promotes meal termination through central mechanisms (PMID 42452898).
Petrelintide works through the amylin pathway, a mechanism its developers describe as distinct from incretin-based treatments like semaglutide and tirzepatide (PMID 42810355).
Petrelintide was engineered for chemical stability so it can be formulated at about neutral pH, which its developers say could allow co-formulation with other weight-loss peptides (PMID 41217931).
In Phase 1 trials petrelintide was slowly absorbed with a half-life of about 10 days, supporting once-weekly injection (PMID 42017294).
What the Data Shows
Petrelintide vs Other Amylin Analogs
Numbers from each drug's own trial. These are different trials with different lengths, populations and dose schedules — not a head-to-head comparison.
| Drug | Trial | Best mean weight change | Placebo | Nausea (drug vs placebo) |
|---|---|---|---|---|
| Petrelintide | Phase 2 ZUPREME 1, 28 weeks | −9.8% (5.0 mg) | −1.7% | 20% vs 6% |
| Cagrilintide | Phase 2 dose-finding, 26 weeks | −10.8% (4.5 mg) | −3.0% | 20–47% vs 18% |
| Eloralintide | Phase 1, single dose, healthy adults | −4.4% at week 4 (12 mg) | +0.6% | Not reported this way |
Sources: petrelintide PMID 42810355; cagrilintide PMID 34798060; eloralintide PMID 41109426.
Key Takeaways
- In ZUPREME 1, all five petrelintide doses beat placebo at 28 weeks: mean weight change -7.9% to -9.8% vs -1.7% (PMID 42810355).
- Placebo-adjusted, that is a 6.2% to 8.1% difference; the 5.0, 7.0 and 9.0 mg arms landed within about half a point of each other.
- Weight kept falling to week 42, with reductions of up to 10.7% (PMID 42810355).
- Nausea was the most common side effect (20% vs 6% on placebo); vomiting (3% vs 6%) and diarrhoea (7% vs 7%) were no more common than placebo.
- Phase 1 trials found a half-life of about 10 days and up to 8.6% weight loss after 16 weeks (PMID 42017294).
- The trial was funded by Zealand Pharma, the drug's developer, and several authors are company employees.
- How petrelintide performs beyond 42 weeks, or whether weight returns after stopping.
- How it works in people with type 2 diabetes, who were excluded from ZUPREME 1.
- How it compares head-to-head with semaglutide, tirzepatide or cagrilintide: no direct comparison trial has been published.
- Why weight loss did not keep rising with dose above 5.0 mg.
- How much of the weight lost was fat versus lean mass: the published abstract does not report the MRI substudy results.
- Whether it will reach the market, or when.
Frequently Asked Questions
What did the petrelintide Phase 2 trial show?
ZUPREME 1 randomised 493 adults without type 2 diabetes (BMI 30+, or 27+ with high blood pressure or abnormal blood lipids) to weekly petrelintide (1.0-9.0 mg) or placebo for 42 weeks. At the 28-week primary endpoint, mean weight change was -7.9% to -9.8% on petrelintide versus -1.7% on placebo, reaching up to -10.7% by week 42.
Is the "petrelintide 9.2% vs 2% placebo" figure accurate?
Not exactly. The published paper reports no 9.2% arm. At 28 weeks the five doses produced -7.9%, -7.9%, -9.8%, -9.3% and -9.4%, against -1.7% for placebo. The viral number is in the right range but blurs five dose arms into one figure.
How is petrelintide different from GLP-1 drugs like semaglutide?
Petrelintide is an analogue of amylin, a hormone co-secreted with insulin that slows stomach emptying, suppresses glucagon and helps end meals. GLP-1 drugs act on the incretin pathway instead. Petrelintide's developers position it as a distinct mechanism, potentially for combination use.
What are the side effects of petrelintide?
In ZUPREME 1 the most common side effect was nausea, reported by 20% of petrelintide participants versus 6% on placebo, mostly mild and during dose escalation. Vomiting (3% vs 6%), diarrhoea (7% vs 7%) and constipation (7% vs 4%) were similar to placebo. No deaths were reported.
Is petrelintide better than cagrilintide?
Nobody knows yet, because the two have never been tested head-to-head. Cagrilintide's Phase 2 reported -10.8% at 26 weeks with 4.5 mg versus -3.0% placebo; petrelintide's reported up to -9.8% at 28 weeks. Different trials, populations and dose schedules make direct comparison unreliable.
Is petrelintide one of the best peptides for weight loss?
It is an investigational drug still in clinical development, so it is not an option you can be prescribed today. Its Phase 2 trial showed clinically meaningful weight loss with mostly mild nausea, but it has not been compared directly with approved drugs, and longer, larger trials are still needed.
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Educational purposes only. Not medical advice.
Petrelintide is an investigational drug in clinical development. Talk to a qualified clinician before starting or changing any weight-loss treatment.
Trial figures are reported as published; cross-trial comparisons are illustrative, not head-to-head.