Tirzepatide maximum tolerated dose leads weight reduction ranking in obesity network meta-analysis

This publication is a systematic review and network meta-analysis of phase 3 trials evaluating pharmacologic treatments for obesity. The population included adult patients 18 years or older with obesity without type 2 diabetes mellitus. The total sample size across included studies was 14,059 participants. The setting was not reported. The interventions were GLP-1 receptor agonists, specifically semaglutide and liraglutide, and the dual agonist tirzepatide. The comparator for all analyses was placebo. The primary outcome was body weight reduction.

The main results indicated that all agents significantly reduced body weight compared to placebo. However, the exact effect sizes, absolute numbers, p-values, and confidence intervals for this primary outcome were not reported. A key secondary outcome was a ranking of weight reduction by agent and dose. The largest reduction occurred with the maximum tolerated dose of tirzepatide, followed by tirzepatide 15 mg, tirzepatide 10 mg, semaglutide 2.4 mg, tirzepatide 5 mg, and liraglutide 3 mg. No specific effect sizes, absolute numbers, p-values, or confidence intervals were provided for this ranking.

Regarding safety, tirzepatide and semaglutide were associated with a higher risk of any adverse event compared with placebo. In contrast, liraglutide was not associated with a higher risk of any adverse event compared to placebo. Data on serious adverse events, study discontinuations, and overall tolerability were not reported.

This synthesis compares these results to prior landmark studies in obesity pharmacotherapy. Previous large trials of these agents have demonstrated significant weight loss versus placebo, but this network meta-analysis provides a comparative ranking across multiple agents and doses. The lack of reported effect sizes and confidence intervals limits direct comparison with individual trial results.

Key methodological limitations include the absence of reported study settings, follow-up periods, and detailed safety data. The network meta-analysis relies on indirect comparisons, which can introduce bias if the underlying trials have differing methodologies or populations. The certainty of the evidence is not noted, and funding or conflicts of interest were not reported.

For clinical practice, these findings suggest that tirzepatide, particularly at higher doses, may offer superior weight reduction compared to other GLP-1 receptor agonists in adults with obesity without diabetes. However, the evidence is based on indirect comparisons, and clinicians should consider individual patient factors, tolerability, and cost when selecting therapy.

Unanswered questions include the long-term durability of weight loss, comparative effects on cardiovascular outcomes, and real-world effectiveness across diverse populations. Future primary trials and patient-level data are needed to confirm these rankings and inform personalized treatment decisions.