Press release
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Metsera Announces Positive Phase 1 Data of First-in-Class Once-Monthly Amylin Candidate MET-233i Jun 09, 2025 Placebo-subtracted mean weight loss up to 8.4% at Day 36 19-day observed half-life supports once-monthly dosing as monotherapy and potential first-in-category monthly GLP-1 + Amylin combination Well-tolerated with no safety signals Company to host conference call and webcast today at 8:00 A.M. ET NEW YORK, June 09, 2025 (GLOBE NEWSWIRE) -- Metsera, Inc. (Nasdaq: MTSR), today announced positive 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. “We are excited by these impressive results from MET-233i, which demonstrate exceptional efficacy with no safety signals, and enable the potential first monthly multi-NuSH combination,” said Steve Marso, M.D., Chief Medical Officer of Metsera. “We observed five-week body weight loss comparable to that of leading GLP-1-based medicines, and we identified efficacious starting doses with placebo-like tolerability. These data position MET-233i as a potential best-in-class amylin and support a category- leading profile in combination with MET-097i.” The randomized, placebo-controlled, double-blind Phase 1 trial was designed to evaluate the pharmacokinetics, efficacy, and safety of subcutaneous MET-233i in 80 participants with overweight or obesity without type 2 diabetes. 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. The trial population was broadly balanced in gender between MET-233i and placebo and had a mean baseline body mass index of approximately 32. 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 . This represents the most durable pharmacokinetic profile of any known amylin analog and supports the potential for once-monthly dosing with simplified titration. MET-233i’s exposure profile after multiple doses matched that of MET-097i, supporting combinability as a potential first-in-category once-monthly multi-NuSH combination. These data further substantiate HALO™, Metsera’s proprietary, novel peptide stabilization and lipidation platform technology. Body weight loss up to 8.4%. Body weight loss was dose-dependent, ranging up to 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 single ascending dose (SAD) portion of the trial, substantial weight loss was maintained more than four weeks after dosing, supported by the ultra-long pharmacokinetics observed for MET-233i. Favorable tolerability results. Gastrointestinal adverse events in the multiple ascending dose (MAD) portion of the trial were all mild, dose-dependent, and primarily confined to the first week of dosing, implying rapid onset of tolerance despite a three-fold accumulation of exposure over five weeks. Anticipated starting doses of 0.15 mg and 0.3 mg demonstrated tolerability results comparable to placebo in both the SAD and the MAD portions of the trial. No safety signals. There were no severe or serious adverse events observed in the SAD or MAD portion of the trial to date. “Amylin agonism has emerged as a central therapeutic mechanism for metabolic diseases, but candidates in development have been limited to weekly dosing,” said Professor Carel le Roux, Director of the Metabolic Medicine Group and Chair in Experimental Pathology at University College Dublin. “The durability and efficacy of MET-233i in this trial, along with its combinability with Metsera’s GLP-1 RA, make it the potential first monthly multi-NuSH combination candidate for patients seeking greater levels of well-tolerated weight loss with a more convenient dosing schedule.” Next Steps
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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 twelve weeks, with topline data 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. We anticipate that MET-034i will be the third peptide engineered with Metsera’s HALO™ platform to enter clinical testing. Conference Call and Webcast Information Metsera will host a conference call and webcast today, June 9, 2025, at 8:00 A.M. Eastern Time to discuss the Phase 1 clinical trial of MET-233i. A live webcast of the call and a replay will be available on the Events page in the Investors & News section of the Metsera website at investors.metsera.com. To access the call by phone, participants should visit this link to receive dial-in details: https://register-conf.media-server.com/register/BI658482ecfbdb4146996744dd3d86c481. About MET-233i MET-233i is an ultra-long acting, subcutaneously injectable monthly amylin analog engineered for class-leading durability, potency, and combinability in solution with Metsera’s fully-biased, ultra-long acting GLP-1 RA candidate MET-097i, with matched solubility parameters and observed half-lives. MET-233i is being explored in clinical studies as a monotherapy and in combination with MET-097i. Metsera is developing the combination of MET-233i and MET-097i via the FDA biologic pathway with the intent to pursue the combination’s regulatory approval in the United States under a BLA. About Metsera’s HALO™ peptide stabilization and lipidation platform HALO™ is Metsera’s novel peptide stabilization and lipidation platform technology that enables peptides to bind simultaneously to albumin and to a drug target, designed to facilitate a half-life approaching that of albumin and exceeding that of other NuSH peptides. This ultra-long half-life may enable monthly dosing, improved tolerability, and improved scalability. About Metsera, Inc. Metsera is a clinical-stage biopharmaceutical company accelerating the next generation of medicines for obesity and metabolic diseases. Metsera is advancing a broad portfolio of oral and injectable incretin, non-incretin and combination therapies with potential best-in-class profiles to address multiple therapeutic targets and meet the future needs of a rapidly evolving weight loss treatment landscape. Metsera was founded in 2022 and is based in New York City. For more information, please visit us at www.metsera.com and follow us on LinkedIn and X. Metsera may use its website as a distribution channel of material information about the Company. Financial and other important information regarding the Company is routinely posted on and accessible through the Investors & News section of its website at investors.metsera.com. In addition, you may sign up to automatically receive email alerts and other information about the Company by using the “Email Alerts” option on the Investors & Media page and submitting your email address. Forward Looking Statements This press release includes “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. The Company intends such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in Section 27A of the Securities Act of 1933, as amended and Section 21E of the Securities Exchange Act of 1934, as amended. All statements contained in this press release other than statements of historical fact should be considered forward-looking statements, including, without limitation, statements related to the timelines, design and results of the Company’s clinical trials and data releases; the Company’s product candidate pipeline and milestone events; potential benefits of treatment with the Company’s product candidates; and anticipated market opportunity and strategy. When used herein, words including “anticipate,” “believe,” “can,” “continue,” “could,” “designed,” “estimate,” “expect,” “forecast,” “goal,” “intend,” “may,” “might,” “plan,” “possible,” “potential,” “predict,” “project,” “should,” “target,” “will,” “would” and similar expressions are intended to identify forward- looking statements, though not all forward-looking statements use these words or expressions. All forward-looking statements are based upon the Company’s current expectations and various assumptions. The Company believes there is a reasonable basis for its expectations and beliefs, but they are inherently uncertain. The Company may not realize its expectations, and its beliefs may not prove correct. Actual results could differ materially from those described or implied by such forward-looking statements as a result of various important factors, including, without limitation, our limited operating history; our ability to generate revenue or become profitable; failure to obtain additional capital when needed on acceptable terms or at all; raising additional capital may cause dilution to our stockholders or require us to relinquish rights to our technologies or product candidates; our dependence on the success of our product candidates; risks associated with preclinical and clinical development; difficulties or delays in the commencement or completion, or the termination or suspension, of clinical trials; our ability to timely enroll patients in our clinical trials; if our current or future product candidates are associated with side effects, adverse events or other properties or safety risks; risks associated with the regulatory approval processes of the FDA and comparable foreign authorities; risks associated with conducting clinical trials and preclinical studies outside of the United States; our reliance on third parties to conduct clinical trials and preclinical studies; our reliance on third parties for the manufacture and shipping of our product candidates; risks associated with our license and collaboration agreements and future strategic alliances; significant competition in our industry; product candidates for which we intend to seek approval as biologic products may face competition sooner than anticipated; our success
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is dependent on our ability to attract and retain highly qualified management and other clinical and scientific personal; if we or our licensors are unable to obtain, maintain, defend and enforce patent or other intellectual property protection for our current or future product candidates or technology; risks associated with our common stock and the other important factors discussed under the caption “Risk Factors” in its filings with the Securities and Exchange Commission, including in its Annual Report on Form 10-K for the year ended December 31, 2024 and its Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2025, which are accessible on the SEC’s website at www.sec.gov and the Investors section of the Company’s website at investors.metsera.com. Any such forward-looking statements represent management’s estimates as of the date of this press release. While the Company may elect to update such forward-looking statements at some point in the future, except as required by law, it disclaims any obligation to do so, even if subsequent events cause the Company’s views to change. These forward- looking statements should not be relied upon as representing the Company’s views as of any date subsequent to the date of this press release. Contact: Jono Emmett Metsera media@metsera.com