Cost-Effectiveness of Tirzepatide Versus Semaglutide (Both Adjunct to a Reduced-Calorie Diet and Increased Physical Activity) in Patients With Obesity or Overweight From a UK Perspective

OBJECTIVES: This study estimated the cost-effectiveness of tirzepatide (5mg, 10mg, 15mg) compared to semaglutide (2.4mg) both adjunct to a reduced-calorie diet and increased physical activity in patients with a body mass index (BMI) ≥30kg/m² (obesity), or with a BMI ≥27 to <30kg/m² (overweight) + ≥1 weight-related complication using UK inputs.

METHODS: A lifetime individual patient simulation model evaluated the costs and long-term clinical outcomes of tirzepatide versus semaglutide. The base case population was the population from the pivotal, phase 3, placebo-controlled SURMOUNT-1 trial, with a subgroup analysis in semaglutide’s UK reimbursed population (patients with BMI ≥30kg/m² + ≥1 weight-related complication) which includes a two-year stopping rule for semaglutide to reflect the reimbursement criteria. Using published risk equations, patients were at risk of developing weight-related complications including type-2 diabetes, cardiovascular disease, and obstructive sleep apnoea. Outcomes were modelled using relevant risk factors including weight and systolic blood pressure, assessing their impact on healthcare costs, quality of life, and mortality. Efficacy for tirzepatide and semaglutide were informed by a network meta-analysis using an efficacy estimand. Net health benefit (NHB; incremental quality-adjusted life year [QALY]–incremental costs/willingness-to-pay threshold [WTP]) and incremental cost-effectiveness ratios (ICERs; cost/QALY) were calculated for each population.

RESULTS: In the trial population, over the course of patient life, per patient cost savings of tirzepatide compared to semaglutide ranged from £11,500–£17,000 across tirzepatide doses with positive NHBs (0.8−0.9 per patient). For the subgroup analysis aligned to semaglutide’s UK reimbursed population, tirzepatide remained cost-effective versus semaglutide with estimated ICERs of £11,300−£13,200. Cost-effectiveness results are driven by the lower drug price and improved clinical results of tirzepatide.

CONCLUSIONS: Based on this simulation model, at the UK WTP of £20,000, tirzepatide is estimated to be a cost-effective treatment for obesity and overweight compared to semaglutide in both the SURMOUNT-1 trial population and semaglutide’s UK reimbursed population.