Metsera Stock Rises As Company Advances Obesity Pipeline With Encouraging Weight Loss Data

Metsera, Inc. MTSR on Monday released topline data from the Phase 1 clinical trial of MET-233i, an ultra-long-acting amylin analog engineered for class-leading durability, potency and combinability with Metsera’s fully-biased monthly GLP-1 receptor agonist candidate, MET-097i.

In the study, MET-233i demonstrated up to 8.4% mean placebo-subtracted weight loss at Day 36, a 19-day observed half-life supporting once-monthly dosing, and a favorable tolerability profile with no safety signals.

MET-233i was evaluated at single doses from 0.15 mg to 2.4 mg and multiple doses from 0.15 mg to 1.2 mg given once weekly over five weeks without titration.

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Topline results from the Phase 1 trial include:

• Dose-linear pharmacokinetics with an observed half-life of 19 days from dose to 50% of Cmax, supporting the potential for once-monthly dosing with simplified titration.
• Body weight loss was dose-dependent, ranging from a placebo-subtracted mean of 8.4% at Day 36 after five weekly doses of 1.2 mg, with individual responses as high as 10.2%.
  • In the trial’s single ascending dose (SAD) portion, substantial weight loss was maintained more than four weeks after dosing, supported by the ultra-long pharmacokinetics observed for MET-233i.
• Gastrointestinal adverse events in the trial’s multiple ascending dose (MAD) portion were all mild, dose-dependent, and primarily confined to the first week of dosing, implying rapid tolerance onset despite a three-fold exposure accumulation over five weeks. Anticipated starting doses of 0.15 mg and 0.3 mg demonstrated tolerability results comparable to placebo in both the trial’s SAD and the MAD portions.
• To date, no severe or serious adverse events have been observed in the SAD or MAD portion of the trial.

Next Steps: Based on these positive topline data, Metsera is rapidly advancing MET-233i as a monotherapy and in combination with MET-097i:

• An ongoing monotherapy trial evaluates 12 weekly doses of MET-233i with dose titration, followed by an exposure-matched monthly dose at week 13. Topline data from this trial are expected in late 2025.
• Metsera has extended an ongoing co-administration trial of MET-233i and MET-097i to 12 weeks. Topline data are expected by year-end 2025 or early 2026.

The company also expects to report topline clinical data from its ultra-long-acting GIP receptor agonist, MET-034i, in combination with MET-097i, in late 2025.

The company anticipates that MET-034i will be the third peptide engineered with Metsera’s HALO platform to enter clinical testing.

MTSR Price Action: Metsera stock is up 13.24% at $31.13 at publication on Monday

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