SURMOUNT-1 (tirzepatide 10 mg)
Trial question
What is the role of mid-dose tirzepatide in adults with obesity?
Study design
Multi-center
Double blinded
RCT
Population
Characteristics of study participants
67.0% female
33.0% male
N = 1279
1279 patients (863 female, 416 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=636 mid-dose tirzepatide (initiated at 2.5 mg SC once weekly and increased by 2.5 mg every 4 weeks to a maintenance dose of 10 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
19.5%
3.1%
19.5 %
14.6 %
9.8 %
4.9 %
0.0 %
Mid-dose
tirzepatide
Placebo
Significant
increase ▲
NNT = 6
Significantly greater reduction in weight at week 72 (19.5% vs. 3.1%; AD 16.4%, 95% CI 14.8 to 17.9).
Secondary outcomes
Significant increase in the percentage of patients achieving a weight reduction of ≥ 5% at week 72 (88.9% vs. 34.5%; AD 54.4%, 95% CI 22.12 to 86.68).
Significant increase in the percentage of patients achieving a weight reduction of ≥ 10% at week 72 (78.1% vs. 18.8%; AD 59.3%, 95% CI 24.11 to 94.49).
Significantly greater reduction in waist circumference (17.7 cm vs. 4 cm; AD 13.8 cm, 95% CI 12.3 to 15.2).
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, mid-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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