SURMOUNT-1 (tirzepatide 15 mg)
Trial question
What is the role of high-dose tirzepatide in people with obesity?
Study design
Multi-center
Double blinded
RCT
Population
Characteristics of study participants
68.0% female
32.0% male
N = 1273
1273 patients (861 female, 412 male).
Inclusion criteria: adults with a BMI > 30 kg/m², or > 27 kg/m² and at least one weight-related complication, excluding diabetes.
Key exclusion criteria: diabetes; a change in body weight > 5 kg within 90 days before screening; previous or planned surgical treatment for obesity; treatment with a medication that promotes weight loss within 90 days before screening.
Interventions
N=630 high-dose tirzepatide (initiated at 2.5 mg SC once weekly and increased by 2.5 mg every 4 weeks to a maintenance dose of 15 mg once weekly for a total of 72 weeks).
N=643 placebo (matching placebo once weekly for 72 weeks).
Primary outcome
Reduction in weight at week 72
20.9%
3.1%
20.9 %
15.7 %
10.4 %
5.2 %
0.0 %
High-dose
tirzepatide
Placebo
Significant
increase ▲
NNT = 5
Significantly greater reduction in weight at week 72 (20.9% vs. 3.1%; AD 17.8%, 95% CI 16.3 to 19.3).
Secondary outcomes
Significant increase in the percentage of patients achieving a weight reduction of ≥ 5% at week 72 (90.9% vs. 34.5%; AD 56.4%, 95% CI 22.93 to 89.87).
Significant increase in the percentage of patients achieving a weight reduction of ≥ 10% at week 72 (83.5% vs. 18.8%; AD 64.7%, 95% CI 26.31 to 103.09).
Significantly greater reduction in waist circumference (18.5 cm vs. 4 cm; AD 14.5 cm, 95% CI 5.9 to 23.1).
Safety outcomes
No significant difference in serious adverse events.
Conclusion
In adults with a BMI > 30 kg/m², or > 27 kg/m² and at least one weight-related complication, excluding diabetes, high-dose tirzepatide was superior to placebo with respect to reduction in weight at week 72.
Reference
Ania M Jastreboff, Louis J Aronne, Nadia N Ahmad et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022 Jul 21;387(3):205-216.
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