MariTide Phase 2 obesity data show up to 20% weight loss at one year

Key Takeaways

• Phase 2 NCT05669599: up to ~20% mean weight loss at week 52 without T2D (efficacy estimand).
• With T2D: up to ~17% weight loss and HbA1c reduction up to 2.2 percentage points.
• Weight loss had not plateaued by 52 weeks in Amgen’s disclosed analyses.
• MariTide Phase 3 MARITIME studies use optimized dose escalation over eight weeks toward three target doses.

What did the Phase 2 trial measure?

Maridebart cafraglutide (MariTide) is a long-acting peptide–antibody conjugate that pairs GLP-1 receptor agonism with GIP receptor antagonism. The Phase 2 study was double-blind, randomized, placebo-controlled, and dose-ranging (NCT05669599).

The primary end point was percent change in body weight from baseline to week 52. An obesity cohort and an obesity-with-T2D cohort tested doses including 140, 280, and 420 mg every 4 weeks, plus less frequent and escalated regimens. See the PubMed Phase 2 abstract and NEJM full report.

How large was the 52-week weight-loss effect?

Amgen said MariTide produced up to about 20% average weight loss at 52 weeks in people with obesity or overweight without T2D, versus about 2.6% on placebo (efficacy estimand). In obesity with T2D, weight loss reached about 17% versus about 1.4% on placebo.

In Cohort A treatment-policy estimates, mean percent weight change ranged from 12.3% to 16.2% with MariTide versus 2.5% with placebo. Efficacy-estimand figures ranged from 16.3% to 19.9%. Details are in the PR Newswire ADA presentation release.

• Without T2D: up to ~20% at 52 weeks
• With T2D: up to ~17% at 52 weeks
• HbA1c: up to 2.2% reduction in T2D cohort
• Dosing intent: monthly or less frequent SC injection

What does this mean for MariTide Phase 3?

Amgen said Phase 2 and Phase 1 PK low-dose initiation data informed MariTide Phase 3. The 72-week chronic weight-management studies will test safety, efficacy, and tolerability in obesity or overweight with and without T2D.

Participants are randomized to one of three target doses after an optimized eight-week escalation starting at 21 mg, then 35 mg, then 70 mg. Company materials also describe planned outcomes work in ASCVD, heart failure, and obstructive sleep apnea. Earlier 52-week topline is on PR Newswire Nov. 2024.

Safety signals called out so far

NEJM authors reported gastrointestinal adverse events were common, though less frequent with dose escalation and a lower starting dose. No unexpected safety signals were highlighted in the published summary language.

Phase 3 escalation design explicitly aims to improve GI tolerability versus abrupt high starting doses used in parts of Phase 2.

What remains unproven

Phase 2 is not Phase 3 confirmation. Head-to-head superiority versus weekly incretin standards, long-term CV outcomes, and real-world persistence are still open.

For investors, MariTide Phase 3 success—not the ~20% Phase 2 signal alone—will decide whether monthly or less frequent dosing becomes a commercial differentiator.

Related NovaPharma coverage

• Amgen company profile
• Pfizer danuglipron discontinuation
• Moderna mRNA-1083 Phase 3

Frequently Asked Questions

Primary Sources

1. PR Newswire: MariTide Phase 2 ADA results
2. PR Newswire: 52-week MariTide topline
3. NEJM: once-monthly maridebart cafraglutide Phase 2
4. ClinicalTrials.gov NCT05669599