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How effective will MariTide be for weight loss?

Medically reviewed by Kristianne Hannemann, PharmD. Last updated on June 29, 2025.

Official Answer by Drugs.com

The investigational weight loss drug MariTide (maridebart cafraglutide) achieved 12%–16% mean weight loss (intent-to-treat) in obese patients without diabetes, and up to 20% when excluding dropouts after 52 weeks in phase 2 trials, compared to about 2% with placebo. Notably, weight loss was still ongoing at one year, indicating further potential.

MariTide Phase 2 Clinical Trial Results

Phase 2 studies of MariTide included two groups: adults with obesity, and adults with obesity and type 2 diabetes. The primary end point of the studies was the percent change in body weight from baseline over 52 weeks.

In adults with obesity but no diabetes:

In adults with obesity and type 2 diabetes:

Weight loss curves had not plateaued by Week 52, suggesting further loss is possible with continued treatment.

Who Lost How Much?

Proportion of MariTide users achieving weight loss milestones (obesity cohort, highest dose):

Proportion of MariTide users achieving weight loss milestones (obesity and type 2 diabetes cohort, highest dose):

Durability and Trajectory

Weight loss was steady and progressive throughout the 52 weeks of the phase 2 studies, with no plateau reached. Extension studies are needed to test whether monthly or less frequent dosing can maintain or enhance this effect over longer periods. Dose escalation strategies (starting at a lower dose and gradually increasing) have improved tolerability and reduced dropouts due to gastrointestinal (GI) side effects without sacrificing efficacy.

Diabetes vs Non-Diabetes Results

Absolute weight loss was smaller in participants with type 2 diabetes, but they still achieved substantial reductions. In those with type 2 diabetes, HbA1c (blood sugar marker) fell by 1.2%–1.6%, and most met American Diabetes Association (ADA) weight targets. Cardiometabolic improvements (blood pressure, cholesterol, inflammation) were also observed.

How Does MariTide Compare to Today’s Leaders?

Based on phase 2 trials, MariTide’s efficacy is between Wegovy and Zepbound for adults identified as obese, but with only monthly injections, potentially improving convenience and adherence.

Drug & Dose Mean % Loss Duration Frequency Study
MariTide 420 mg 16–20% 52 weeks Monthly NEJM 2025
Semaglutide (Wegovy) 2.4 mg 15% 68 weeks Weekly STEP 1
Tirzepatide (Zepbound) 15 mg 21% 72 weeks Weekly SURMOUNT 1

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What Phase 3 Trials Will Confirm

Phase 3 trials are the critical next step in determining whether MariTide’s promising phase 2 results will hold up in a much larger and more diverse population. These studies are designed to rigorously evaluate the drug’s long-term safety, efficacy, and tolerability over 72 weeks, using optimized dosing strategies and enrolling thousands of participants with obesity, both with and without type 2 diabetes. The outcomes will provide the definitive evidence needed for regulatory approval and to guide future clinical use.

Factors That Influence Individual Response

Individual responses to MariTide can vary widely, with some people experiencing dramatic weight loss while others see more modest results. Several factors influence how much weight a person is likely to lose, how well they tolerate the medication, and whether they can maintain their progress over time.

References
  1. American Diabetes Association Professional Practice Committee. (2023, December 11). 8. Obesity and Weight Management for the Prevention and Treatment of Type 2 Diabetes: Standards of Care in Diabetes–2024. Diabetes Care, 47(Supplement 1), S145. https://diabetesjournals.org/care/article/47/Supplement_1/S145/153942/8-Obesity-and-Weight-Management-for-the-Prevention
  2. Amgen. (2024, November 26). AMGEN ANNOUNCES ROBUST WEIGHT LOSS WITH MARITIDE IN PEOPLE LIVING WITH OBESITY OR OVERWEIGHT AT 52 WEEKS IN A PHASE 2 STUDY. Amgen. https://www.amgen.com/newsroom/press-releases/2024/11/amgen-announces-robust-weight-loss-with-maritide-in-people-living-with-obesity-or-overweight-at-52-weeks-in-a-phase-2-study
  3. Jastreboff, A. M., Ryan, D. H., Bays, H. E., Ebeling, P. R., Mackowski, M. G., Philipose, N., Ross, L., Liu, Y., Burns, C. E., Abbasi, S. A., Pannacciulli, N., & MariTide Phase 2 Obesity Trial Investigators (2025). Once-Monthly Maridebart Cafraglutide for the Treatment of Obesity - A Phase 2 Trial. The New England journal of medicine, 10.1056/NEJMoa2504214. Advance online publication. https://doi.org/10.1056/NEJMoa2504214
  4. Jastreboff, A. M., Aronne, L. J., Ahmad, N. N., Wharton, S., Connery, L., Alves, B., Kiyosue, A., Zhang, S., Liu, B., Bunck, M. C., Stefanski, A., & SURMOUNT-1 Investigators (2022). Tirzepatide Once Weekly for the Treatment of Obesity. The New England journal of medicine, 387(3), 205–216. https://doi.org/10.1056/NEJMoa2206038
  5. Javor, E., Lucijanić, M., & Skelin, M. (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity. The New England journal of medicine, 385(1), e4. https://doi.org/10.1056/NEJMc2106918
  6. MariTime. About the MARITIME-1 study. Accessed on June 29, 2025 at https://www.maritimestudy.com/en-us/maritime-1

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