Subgroup analysis finds tirzepatide superior to dulaglutide for HbA1c and weight in type 2 diabetes

INTRODUCTION: In SURPASS-SWITCH, switching from dulaglutide to tirzepatide resulted in greater improvements in glycemic control and body weight in adults with type 2 diabetes (T2D). This study aimed to investigate the efficacy and safety of switching from weekly dulaglutide to weekly tirzepatide in adults with T2D in prespecified baseline subgroups from SURPASS-SWITCH. RESEARCH DESIGN AND METHODS: This phase IV, randomized, open-label, active-controlled, parallel-group, multicenter, multinational trial included adults with hemoglobin A1c (HbA1c) ≥7.0% to ≤9.5%, on a stable dose of dulaglutide for at least 6 months, on a stable dose of 0-3 oral antihyperglycemic medications for at least 3 months, with stable body weight, and body mass index (BMI) ≥25 kg/m at screening. Participants were randomly assigned 1:1 to continue with and escalate to dulaglutide 4.5 mg or maximum tolerated dose (MTD) or switch to tirzepatide with escalation to 15 mg or MTD. Changes from baseline in HbA1c and body weight at week 40 in baseline subgroups of age (<65, ≥65 years), HbA1c (≤8.5%, >8.5%), duration of T2D (≤5, >5 to ≤10, >10 years), baseline dulaglutide dose (0.75 mg, 1.5 mg), duration of dulaglutide dose (<1, ≥1 year), BMI (<27, ≥27; <30, ≥30 to <35, ≥35 kg/m), and ethnicity (Hispanic or Latino, non-Hispanic or non-Latino), and sex (female, male) were determined. RESULTS: Reductions in HbA1c and body weight at week 40 were significant and consistently greater with tirzepatide across all prespecified baseline subgroups. HbA1c reduction was greater in the subgroups with higher baseline HbA1c and low baseline BMI. Weight reduction was greater for participants in the non-Hispanic or non-Latino subgroup. The safety profile was similar across subgroups. Nausea and diarrhea were usually the most frequently reported treatment-emergent adverse events in each subgroup. CONCLUSIONS: In this subgroup analysis of SURPASS-SWITCH, switching to tirzepatide from dulaglutide was generally well-tolerated and associated with significant and consistent improvements in HbA1c and weight reductions versus dulaglutide across all baseline subgroups evaluated. These results indicate that switching to tirzepatide may provide a clinical option across a range of baseline characteristics when treatment goals are not being met with dulaglutide. TRIAL REGISTRATION NUMBER: NCT05564039.