Evaluation of the Clinical Effectiveness and Cost-Effectiveness of Tirzepatide for Type 2 Diabetes in Canada Using Bayesian Transportability Analysis.

OBJECTIVES: To estimate the clinical and cost-effectiveness of tirzepatide in Canada using transportability analysis. METHODS: We applied Bayesian transportability analysis to patient-level data from the SURPASS-3 trial and the Canadian Community Health Survey, a nationally and provincially representative survey. After harmonizing the survey data to match the eligibility criteria of the trial participants, we adjusted for differences in effect modifiers (ie, baseline bodyweight, sex, age, and race) to estimate the comparative effectiveness of tirzepatide versus insulin degludec for weight loss. We performed subgroup analyses to estimate the clinical effectiveness of tirzepatide by region, as well as by age and sex. Then, based on a decision tree model, we used a Bayesian approach to estimate the short-term cost-effectiveness of tirzepatide from the perspective of a Canadian payer. We compared incremental cost-effectiveness ratios (ICERs) based on the original and transported treatment effects. RESULTS: The trial and transported effects both showed clinical benefit of tirzepatide for weight loss. These benefits were demonstrated across all provinces and territories, and across age and sex categories. The trial effects, reflecting efficacy, were larger than the transported effects. Although the incremental costs were similar, the reduced incremental benefits estimated with the transported effects resulted in a higher ICER. For tirzepatide compared with insulin, the ICER was $599.40 under the transported scenario versus $577.40 under the original trial scenario. CONCLUSIONS: Our study demonstrates the feasibility of generating locally relevant evidence using transportability analysis and highlights the importance of deriving locally representativeness estimates for local decision making.