Tirzepatide 10 and 15 mg compared with semaglutide 2.4 mg for the treatment of obesity: An indirect treatment comparison

Aim: To compare the efficacy of tirzepatide 10 and 15 mg with semaglutide 2.4 mg using an indirect treatment comparison. Materials and methods: Using SURMOUNT-1 and STEP 1 trial data, mean percentage change in body weight from baseline and odds ratio (OR) of achieving 5% or greater weight loss were compared between tirzepatide 10 and 15 mg at week 72 and semaglutide 2.4 mg at week 68 using matching-adjusted indirect comparison of the efficacy estimand. Sensitivity analyses were completed using different methods, including the Bucher method, also using different estimands and/or time points. Results: Greater reductions in percentage change in body weight were observed with tirzepatide 10 and 15 mg versus semaglutide 2.4 mg (tirzepatide 10 mg mean difference: -4.67% [95% CI -5.91%, -3.43%]; tirzepatide 15 mg mean difference: -5.92% [95% CI -7.16%, -4.68%]; both P < .001). Similarly, more participants achieved 5% or greater weight loss with tirzepatide 10 mg (OR 2.61 [95% CI 1.48, 4.57]; P < .001) and 15 mg (OR 2.75 [95% CI 1.57, 4.81]; P < .001) compared with semaglutide 2.4 mg. All sensitivity analyses were consistent, except for an OR of achieving 5% or greater weight loss with tirzepatide 10 mg using the Bucher method to analyse the treatment regimen estimand (P = .074). Conclusions: Currently there are no direct comparisons of tirzepatide and semaglutide for weight management. Using the matching-adjusted indirect treatment comparison method to compare the efficacy of tirzepatide and semaglutide for chronic weight management, this analysis showed greater weight loss with tirzepatide 10 and 15 mg versus semaglutide 2.4 mg.