September 29, 2026

Scientist comment on the trial of a new amylin-based weight-loss drug petrelintide, noting fewer side effects than GLP-1-based drugs, as published in The Lancet Diabetes & Endocrinology.

Dr Marie Spreckley, Research Programme Manager, Prevention of Diabetes and Related Metabolic Disorders in High Risk Groups, University of Cambridge, said:

“In this trial, 485 people received at least one dose of petrelintide or placebo, and everyone received lifestyle advice. At 28 weeks, estimated average weight loss ranged from 7.9% to 9.8% across the petrelintide groups, compared with 1.7% in the placebo group. The randomised, blinded design and measured body weights are strengths, and the study provides good evidence that petrelintide produces weight loss over this period.

“However, the press release’s comparison with GLP-1 medicines is too strong. The trial did not test petrelintide against any of those medicines, so we cannot say from these results that it causes fewer side effects. Nausea was reported by 20% of people taking petrelintide and 6% taking placebo, although vomiting and diarrhoea were uncommon. Three serious adverse events were considered related to petrelintide, including two cases of gallstones and one of obstructive pancreatitis.

“Weight loss continued to 42 weeks, reaching 10.7% in one dose group, but this was a secondary result. We also cannot tell from this study whether people would be more likely to stay on petrelintide than on an existing treatment. The results are promising, but larger and longer trials, including a direct comparison, are needed before making claims about better tolerability.”

‘Petrelintide, a human amylin analogue for the treatment of obesity (ZUPREME 1): a randomised, double-blind, placebo-controlled, phase 2 trial’ by W Timothy Garvey et al. was published in The Lancet Diabetes & Endocrinology at 23:01 UK time on Tuesday 29th September.

DOI: 10.1016/S2213-8587(26)00213-5

Declared interests

Dr Marie Spreckley: “Dr Marie Spreckley is a postdoctoral researcher at IMS Epidemiology, University of Cambridge, where her research focuses on nutrition and weight management. She has no financial relationships with food or beverage companies, pharmaceutical companies, or other commercial organisations, and has received no industry funding for her research.”