A phase 1 multiple-ascending dose study of tirzepatide in Japanese participants with type 2 diabetes

Aim To investigate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of tirzepatide in Japanese participants with type 2 diabetes (T2D). Methods This phase 1, double-blind, placebo-controlled, parallel-dose, multiple-ascending dose study randomized participants to once-weekly subcutaneous tirzepatide or placebo. The tirzepatide treatment groups were: 5 mg (5 mg, weeks 1-8), 10 mg (2.5 mg, weeks 1-2; 5 mg, weeks 3-4; 10 mg, weeks 5-8), and 15 mg (5 mg, weeks 1-2; 10 mg, weeks 3-6; 15 mg, weeks 7-8). The primary outcome was tirzepatide safety and tolerability. Results Forty-eight participants were randomized. The most frequently reported treatment-emergent adverse events (AEs) were decreased appetite and gastrointestinal AEs, which were generally dose-dependent and mild in severity. The plasma tirzepatide concentration half-life was approximately 5 days. After 8 weeks of treatment, fasting plasma glucose decreased from baseline with tirzepatide versus placebo; the least squares (LS) mean decrease compared with placebo (95% confidence interval [CI]) was 52.7 (35.9-69.6), 69.1 (52.3-85.9), and 68.9 (53.2-84.6) mg/dL in the 5-, 10-, and 15-mg treatment groups, respectively (P < .0001 for all treatment groups). Tirzepatide also resulted in LS mean decreases from baseline versus placebo at 8 weeks in HbA1c up to 1.6% (95% CI 1.2%-1.9%; P < .0001 for all treatment groups) and body weight up to 6.6 kg (95% CI 5.3-7.9; P < .0001 for all treatment groups). Conclusions All tirzepatide doses were well tolerated. The safety, tolerability, PK, and PD profiles of tirzepatide support further evaluation of once-weekly dosing in Japanese people with T2D.