Long-Term Efficacy and Safety of Ultra Rapid Lispro (URLi) in Adults with Type 1 Diabetes: The PRONTO-T1D Extension

Introduction The PRONTO-T1D study, which evaluated the efficacy and safety of ultra rapid lispro (URLi) versus lispro in adults with type 1 diabetes (T1D), met the primary endpoint of noninferiority of HbA1c change from baseline compared to lispro at 26 weeks. We present results of an additional 26-week treatment phase evaluating long-term efficacy and safety of URLi. Methods In this phase 3, treat-to-target study, subjects were randomized to double-blind mealtime URLi, lispro, or open-label postmeal URLi with insulin degludec or glargine for 26 weeks. Subjects in the double-blind URLi ( n = 451) and lispro ( n = 442) groups continued for another 26 weeks to assess long-term efficacy and safety. Results HbA1c increased marginally during the long-term maintenance period (week 26–52) in both groups to 7.47% (URLi) and 7.54% (lispro). At week 52, there were no statistically significant treatment differences in change from baseline HbA1c with a least-squares mean treatment difference (95% confidence interval) of − 0.06% (− 0.16, 0.03). Proportions of patients with HbA 1c