Tirzepatide doses of 10 mg and 15 mg demonstrated greater weight loss than high-dose semaglutide 7.2 mg in adults with obesity, according to an indirect treatment comparison presented at the 62nd Annual Meeting of the European Association for the Study of Diabetes in Milan, Italy. Pharmacy Times reported that while the advantage appeared statistically significant under certain analytical frameworks, no direct randomized trial has yet compared the medications at these specific dosages.
The analysis evaluated data drawn from two separate 72-week clinical trials. The SURMOUNT-1 trial, funded by Eli Lilly, randomly assigned adults without diabetes who had obesity or overweight with at least one weight-related complication to receive tirzepatide at 5 mg, 10 mg, or 15 mg, or a placebo. In contrast, semaglutide 7.2 mg, semaglutide 2.4 mg, or a placebo were given to adults without diabetes and with a body mass index of 30 kg/m² or greater in the STEP UP trial, which was funded by Novo Nordisk.
Researchers applied adjustments for gender, age, baseline weight, and baseline hemoglobin A1c to compare the outcomes. Based on the treatment-regimen estimand—which calculates the average impact regardless of whether individuals discontinued therapy—individuals receiving tirzepatide 15 mg experienced an average weight reduction that was 4.5% greater than that of individuals on semaglutide 7.2 mg, accompanied by a 95% credible interval spanning from -6.3 to -2.8. Those taking tirzepatide 10 mg lost 3.2% more body weight, with a credible interval of -5.0 to -1.4.
In Plain English: The Clinical Takeaway
- Hypothesis-Generating: Clinicians view these findings as a starting point for discussion rather than a definitive rule, especially as pharmacists field patient questions regarding newer, higher semaglutide strengths.
Statistical Significance Across Different Analytic Approaches
When the analysis shifted to the efficacy estimand—which reflects effects observed before any discontinuation of the study drug—the percentage differences narrowed considerably. The advantage for tirzepatide 15 mg dropped to 1.8% with a credible interval of -3.8 to 0.1, and the advantage for tirzepatide 10 mg decreased to 0.7% with a credible interval of -2.6 to 1.3. Neither of these efficacy-estimand figures reached statistical significance.
Regarding the proportion of participants achieving at least 20% weight loss, tirzepatide 15 mg showed higher odds than semaglutide 7.2 mg under both the efficacy estimand (odds ratio, 4.15; 95% credible interval, 1.02 to 15.64) and the treatment-regimen estimand (odds ratio, 3.54; 95% credible interval, 1.05 to 11.05). Results for the tirzepatide 10 mg dose on this specific endpoint did not reach statistical significance.
| Treatment Group | Treatment-Regimen Weight Loss Difference | Efficacy Estimand Weight Loss Difference | Odds Ratio for ≥20% Weight Loss (Treatment-Regimen) |
|---|---|---|---|
| Tirzepatide 15 mg | 4.5% greater (CrI: -6.3 to -2.8) | 1.8% greater (Not significant) | 3.54 (CrI: 1.05 to 11.05) |
| Tirzepatide 10 mg | 3.2% greater (CrI: -5.0 to -1.4) | 0.7% greater (Not significant) | Not statistically significant |
Contraindications & When to Consult a Doctor
While Eli Lilly reported comparable rates of discontinuation due to adverse events between tirzepatide and semaglutide 7.2 mg, exact figures were omitted from the presentation data. The absence of direct, head-to-head randomized controlled trials leaves open questions regarding how these molecules perform against each other in diverse patient populations over extended periods.
References
- Pharmacy Times. Tirzepatide Linked to More Weight Loss Than Semaglutide 7.2 mg. European Association for the Study of Diabetes Annual Meeting Coverage.
- ScienceDirect. Head-to-head comparison of tirzepatide and semaglutide for weight management. Diabetes, Obesity and Metabolism.
Disclaimer: This article is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider regarding any questions about a medical condition or prescription medication.
