Pfizer’s $4.9bn bet on obesity startup Metsera is looking promising, with 14.1% weight loss reported in a Phase IIb trial.
In the VESPER-1 trial (NCT06712836), MET-097i, a glucagon-like peptide-1 receptor agonist (GLP-1RA), demonstrated mean placebo-subtracted weight loss of up to 14.1% with the once-weekly 1.2mg dose for 28 weeks, with individual responses as high as 26.5%. The tolerability profile of higher doses of MET-097i without titration was similar to approved agents that use prolonged titration regimens.
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In the VESPER-3 trial (NCT06973720), while the biotech did not report weight loss data, it did state that the therapy was well tolerated with minimal diarrhoea signal and a risk difference from placebo of 13% nausea and 11% vomiting at 12 weeks after two titration steps. Top-line efficacy data from VESPER-3 is due by year-end 2025 or in early 2026.
Metsera CMO Dr Steve Marso commented: “As a fully biased mono-agonist, MET-097i achieved dual-agonist-like weight loss of 14.1% at 28 weeks in VESPER-1, with only 2.9% study discontinuation. Based on these data, MET-097i is advancing into Phase III clinical trials, accelerating its development as the foundational peptide for Metsera’s combination, oral, and prodrug programmes.”
Metsera is on track to initiate a global Phase III programme of MET-097i in late 2025.
Topline data in the ongoing VESPER-2 (NCT06897202) trial, which is investigating MET-097i in patients with type 2 diabetes, is expected in early 2026.
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By GlobalDataEarlier data from a Phase IIa trial of MET-097i dosed on both a weekly and monthly regimen have demonstrated robust weight loss after 12 weeks.
On 22 September, Pfizer announced it was acquiring Metsera for $4.9bn as it is attempting to enter the weight loss space, with the deal forecast to close in Q4 2025.
The weight loss landscape has recently heated up again as market leaders Novo Nordisk and Eli Lilly have each touted data of their oral GLP-1RAs, semaglutide and orforglipron. Following positive Phase III trials, both pharma companies are in discussions with the US Food and Drug Administration (FDA) for the approval of their respective candidates.
GlobalData predicts the obesity market will exceed $173.5bn in 2031 across the seven major markets (7MM: France, Germany, Italy, Japan, Spain, the UK and the US).
GlobalData is the parent company of Clinical Trials Arena.
