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) < 7% at week 52 were similar (URLi, 26.8%; lispro, 24.5%). Self-monitored blood glucose (SMBG) showed that 1-h (9.23 versus 10.14 mmol/L) and 2-h (8.40 versus 9.53 mmol/L) postmeal daily mean glucose was statistically significantly (p < 0.001) lower with URLi than lispro. The rate and incidence of severe, documented, and postprandial hypoglycemia (< 54 mg/dl [3.0 mmol/L]) were similar between treatments, but URLi demonstrated a 31% lower rate in the period more than 4 h after meals, (p = 0.023). Injection site reactions were reported by 3.3% of patients on URLi and 0.9% on lispro. The incidence of treatment-emergent adverse events was similar between treatments. CONCLUSION: Overall glycemic control and improved postprandial glucose via SMBG were maintained after 52 weeks with URLi versus lispro, suggesting that the efficacy of URLi is preserved during long-term treatment in patients with T1D. No long-term safety issues were identified with URLi. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03214367. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13300-020-00987-8.