MET-097i by Pfizer: status and timeline

Milestones

Next · Phase 3 enrollment ongoing

Phase 2b VESPER-3 positive topline results (28-week data)2025Complete.
Pfizer completes Metsera acquisition13 Nov 2025Complete.
VESPER-3 detailed results presented at ADA Scientific Sessions6 Jun 2026Complete.
Phase 3 trial initiation (VESPER-4 and VESPER-5)Q4 2025Complete.
Phase 3 enrollment ongoingTarget 2026Current milestone.

Upcoming

2026Phase 3 enrollment ongoing (next)
Q1 2027Phase 3 enrollment expansion and readout planning

Current obstacles

Phase 3 execution and safetyDemonstrating sustained efficacy and tolerability in larger Phase 3 populations while maintaining the convenience advantage of monthly dosing.
Competitive differentiationCompeting against established weekly GLP-1s (Wegovy, Zepbound) and emerging monthly alternatives from Novo Nordisk and others.

Physics limits

Injection burden remainsWhile monthly is more convenient than weekly, subcutaneous injection still requires clinical or home administration; oral formulations offer even less burden but have absorption challenges.
Tolerance and efficacy ceilingGLP-1 drugs plateau in weight loss efficacy and some patients develop tolerance or experience gastrointestinal side effects that limit dose escalation.

How it works

2 parts

Monthly dosing

Extended-release formulation

MET-097i is engineered with an extended-release technology that delivers a therapeutic dose over four weeks, reducing injection frequency from weekly.

GLP-1 signaling

Appetite suppression and metabolic control

The drug activates GLP-1 receptors in the brain and gut, reducing hunger signals, slowing stomach emptying, and improving blood glucose control.

Spec sheet

Spec	MET-097i
Dosing frequency	Monthly injection^R (reported)
Phase 2b weight loss (28 weeks)	12.3% (placebo-adjusted)^R (reported)
Phase 2b maintenance dose	9.6 mg monthly^R (reported)

^R reported by the company

About Pfizer

The team behind MET-097i

Pfizer

Vaccines, biologics, primary care, oncology, GLP-1 obesity

Pfizer is a multinational biopharmaceutical company based in New York. In November 2025, Pfizer acquired Metsera for $10 billion to build out its GLP-1 obesity pipeline.

Pfizer's major portfolios include vaccines (Comirnaty COVID-19, Paxlovid), primary care and oncology.
Acquired Metsera for $10 billion in November 2025 for four differentiated clinical-stage GLP-1 and amylin programs.
MET-097i is a monthly injectable GLP-1 showing 12.3% weight loss in Phase 2b; Phase 3 planned for late 2025.

pfizer.com (opens pfizer.com)Company profile →

Founded: 1849177 yrs
Headquarters: United States
Status: Public
Listed: PFE (opens google.com)NYSE
Valuation: $150Bmarket capOct 2026
Staff: ~75,249Mar 2026
Works in: BiotechObesity & metabolism
Coverage: 1 program · 2 updateslatest 13 Nov 2025checked 10 Oct
Acquired by: Metsera Pharmaceuticals (opens biospace.com)
People: Albert Bourla (opens en.wikipedia.org)Chief Executive Officer

Spec

MET-097i

Dosing frequency

Monthly injection^R (reported)

Phase 2b weight loss (28 weeks)

12.3% (placebo-adjusted)^R (reported)

Phase 2b maintenance dose

9.6 mg monthly^R (reported)