Public research evidence case
Tirzepatide SURMOUNT-1: 2,539 Adults Over 72 Weeks
A structured reading of the SURMOUNT-1 Phase 3 trial, preserving the randomized design, four-group results, discontinuation data and the distinction between an approved finished drug and research-use material.
- Study design
- Phase 3, double-blind, randomized, placebo-controlled trial
- Sample
- 2,539 adults
- Duration
- 72 weeks, including 20-week dose escalation
- Model / population
- Adults with obesity or overweight, without diabetes
Structured evidence record
What the source actually reports
Primary question and endpoints
Coprimary endpoints were percentage change in body weight from baseline and the proportion of participants achieving at least 5% weight reduction at week 72.
Reported result
Mean weight change at week 72 was −15.0%, −19.5% and −20.9% with 5, 10 and 15 mg, versus −3.1% with placebo. At least 5% reduction occurred in 85%, 89% and 91%, versus 35% with placebo. Treatment discontinuation due to adverse events was 4.3%, 7.1%, 6.2% and 2.6%, respectively.
Limitations
The trial excluded diabetes and used a controlled clinical supply, dose-escalation schedule and protocol. It does not provide a direct comparison with retatrutide, and the 72-week analysis does not by itself answer every question about longer-term maintenance or use after discontinuation.
Material and interpretation boundary
SURMOUNT-1 evidence belongs to the studied clinical intervention and protocol. Approved tirzepatide products have regulator-reviewed manufacturing and labeling; a research-use catalog material is not the approved finished drug and must not borrow its regulatory status.
Why SURMOUNT-1 is a useful anchor study
SURMOUNT-1 is a large, randomized Phase 3 trial with a placebo group and prespecified coprimary endpoints. It therefore supports a stronger clinical evidence discussion than mechanistic claims or uncontrolled observations. The paper also reports the full set of randomized dose groups rather than one selectively chosen number.
Population and endpoints
The trial enrolled adults with BMI of at least 30, or at least 27 with a weight-related complication, and excluded diabetes. Participants were randomized equally to three tirzepatide groups or placebo. The treatment-regimen estimand assessed outcomes regardless of treatment discontinuation in the intention-to-treat population.
Results in context
All three tirzepatide groups differed from placebo for the reported weight endpoints. The paper also reports gastrointestinal adverse events as the most common, generally during escalation, and provides discontinuation percentages for each randomized group. Keeping those denominators and adverse-event data visible prevents an efficacy-only summary.
Finished-drug distinction
Clinical outcomes from a regulator-reviewed finished drug cannot be transferred to material that shares a name but lacks the same formulation, delivery system, release specifications and quality controls. This distinction is part of the evidence record, not a footnote.
Primary records
Sources and traceability
- Tirzepatide Once Weekly for the Treatment of ObesityOpen source ↗
Jastreboff AM, et al. N Engl J Med. 2022;387:205–216. PMID 35658024.
- ClinicalTrials.gov record NCT04184622Open source ↗
SURMOUNT-1 Phase 3 study registry record.
This page is an editorial reading of a public source, not a customer testimonial, medical advice or a claim that a catalog material reproduces the cited intervention.