A bounded review of two sponsor-funded randomized Phase 3 trials: one in adults with obesity without diabetes and one in adults with type 2 diabetes treated with diet and exercise alone.12
Bottom line from this bounded source set
The reviewed obesity trial reported greater weight reduction with tirzepatide than placebo, and the reviewed type 2 diabetes trial reported lower glycated hemoglobin and body weight than placebo. These trials do not answer every population, long-term outcome, or post-discontinuation question.12
Reviewed study record
SURMOUNT-1 obesity trial
Design
A double-blind, randomized, placebo-controlled Phase 3 trial assessed body-weight change over 72 weeks.1
Population
The trial randomized 2,539 adults with obesity, or overweight plus at least one weight-related complication, and excluded people with diabetes.1
Outcomes reported
Reported mean body-weight change at week 72 ranged from -15.0% to -20.9% across tirzepatide groups and was -3.1% with placebo. Gastrointestinal events were the most common adverse events, and discontinuation for adverse events was more frequent in the tirzepatide groups.1
Limitations
The sponsor-funded trial used a dose-escalation period, excluded diabetes, and does not by itself establish outcomes after treatment stops or uncommon harms over longer periods.1
Reviewed study record
SURPASS-1 type 2 diabetes trial
Design
A double-blind, randomized, placebo-controlled Phase 3 trial assessed glycated hemoglobin, body weight, safety, and tolerability over 40 weeks.2
Population
The trial randomized 478 adults with type 2 diabetes inadequately controlled by diet and exercise who had not previously used injectable diabetes therapy.2
Outcomes reported
Reported mean glycated-hemoglobin change ranged from -1.87 to -2.07 percentage points across tirzepatide groups and was +0.04 with placebo. Reported body-weight reduction ranged from 7.0 to 9.5 kilograms, and gastrointestinal events were the most frequent adverse events.2
Limitations
The sponsor-funded trial was limited to 40 weeks and a treatment-naive type 2 diabetes population. Crossref also registers a publisher erratum for this publication; metadata alone does not describe the corrected wording.2
No registered Crossref update in the reviewed snapshotChecked August 19, 2026 for DOI 10.1056/nejmoa2206038. This bounded result is not proof that the publication has never been corrected or retracted. Open the pinned Crossref work endpoint ↗
Publication update registered by CrossrefErratum ↗ · publisher metadata · July 17, 2021. Crossref metadata identifies the notice but does not by itself explain what wording changed.