Tirzepatide in obesity and overweight in adults: effect on the anchor outcome
In the population defined for obesity and overweight in adults, what is the effect of Tirzepatide compared with the comparator used in its contributing trials on the anchor outcome for this indication?
Templated review frame. This review question was generated by crossing an indication with a compound for which contributing trials exist. Its prose frame is templated and is shared with other questions of the same shape. Its included studies, its summary of findings and its certainty rating are computed from the underlying records and are not templated. The Institute publishes these questions because the alternative is to leave a question the document set can answer unanswered, and it labels them because the alternative is to present a templated frame as an authored one.
§1Abstract
§1.1Review question
In the population defined for obesity and overweight in adults, what is the effect of Tirzepatide compared with the comparator used in its contributing trials on the anchor outcome for this indication?
§1.2PICO frame
Table 1. The registered PICO frame. Any change made after protocol registration is recorded in the amendment log at §5 and is identified there as post hoc.
| Element | As registered |
|---|---|
| Population | Excess adiposity sufficient to impair health, operationalised in the pivotal incretin programmes as a body-mass index of 30 kg/m² or above, or 27 kg/m² or above with at least one weight-related comorbidity. |
| Intervention | Tirzepatide administered as subcutaneous once weekly. |
| Comparator | The comparator used in each contributing trial, reported per trial rather than pooled across comparator types. |
| Outcomes | Anchor outcome for this indication: Percentage change in body weight from baseline. Additional outcomes: Proportion achieving ≥5 %, ≥10 %, ≥15 % and ≥20 % weight reduction; Change in waist circumference; Change in systolic blood pressure. |
§1.3Method in brief
A review of the effects of an intervention on pre-specified outcomes, with a quantitative synthesis where the contributing studies are sufficiently similar. The protocol was registered with the Institute's secretariat before the search was executed. The search was run on 10 March 2025 across 8 sources and is reproduced in full at §2. Screening, extraction and certainty assessment were performed independently by two members of the secretariat with disagreement resolved by a third.[1,2]
§1.4Conclusion
High certainty evidence from 9 contributing trials bears on the effect of Tirzepatide on the anchor outcome for obesity and overweight in adults. The estimate the Institute carries in the monograph is: −20.9 % body weight at 72 weeks with 15 mg versus −3.1 % with placebo (SURMOUNT-1). The largest placebo-subtracted weight effect of any approved agent at the date of this cycle. SURMOUNT-5 reported superiority over semaglutide 2.4 mg (−20.2 % versus −13.7 %).
The conclusion rests on 9 contributing studies, listed with their extracted data at §3 and summarised outcome by outcome at §4.
§1.5Limitations
References cited on this page
References are numbered in order of first citation in this document. Each superscript in the text links to its entry below.
- Jastreboff AM, Aronne LJ, Ahmad NN, Wharton S, Connery L, Alves B, Kiyosue A, Zhang S, Liu B, Bunck MC, Stefanski A. Tirzepatide once weekly for the treatment of obesity. New England Journal of Medicine 2022;387(3):205–216. doi:10.1056/NEJMoa2206038 · PMID 35658024
- Garvey WT, Frias JP, Jastreboff AM, le Roux CW, Sattar N, Aizenberg D, Mao H, Zhang S, Ahmad NN, Bunck MC, Benabbad I, Zhang XM. Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2): a double-blind, randomised, multicentre, placebo-controlled, phase 3 trial. The Lancet 2023;402(10402):613–626. doi:10.1016/S0140-6736(23)01200-X · PMID 37385275
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