Insulin Icodec Initiation Strategies and Day-4 Supplemental Dosing in Type 2 Diabetes

Overview

The goal of this clinical trial is to find the best way to start once-weekly insulin icodec in adults with type 2 diabetes who have not used insulin in the past 3 months, so that their fasting blood glucose reaches the target range within the first week. The main questions it aims to answer are: * Which of three starting-dose methods brings the most people to their fasting blood glucose target by the end of the first week? * On day 4 after starting, if fasting blood glucose is still high, does giving one extra half-dose of insulin help more people reach target safely? Participants will be randomly placed into one of three starting-dose groups: a fixed weekly dose, a dose based on their fasting blood glucose, or a dose based on their body weight. Within each group, participants will also be randomly assigned either to receive an extra insulin dose on day 4 if their fasting blood glucose is at or above a set level, or to receive no extra dose. Participants will: * Start once-weekly insulin icodec and continue their current non-insulin diabetes medicines * Check their fasting blood glucose, including on day 4 after starting * Wear a blinded continuous glucose monitor during the first 2 weeks and the last 2 weeks * Attend weekly visits for dose adjustment and safety checks over 12 weeks, followed by a 5-week safety follow-up

Background and rationale: Once-weekly insulin icodec has a half-life of approximately 196 hours, so its pharmacokinetic steady state is not reached until 3 to 4 weeks after initiation. This creates a mismatch with the clinical need to assess and achieve early fasting blood glucose (FBG) control within the first week. The glucose-lowering effect of icodec peaks on days 2 to 3 and remains near-maximal on day 4, offering an early time point to identify patients at risk of not reaching target. However, no prospective trial has compared icodec initiation strategies for early glycemic control or validated an early marker to guide supplemental dosing. This trial addresses that gap. Design: This is a multicenter, randomized, open-label trial with a 3-by-2 factorial structure. Insulin-naive adults with type 2 diabetes who have not received insulin in the past 3 months are randomized 1:1:1 (stratified by center and baseline FBG) to one of three icodec initiation strategies: a fixed dose of 70 units per week; a dose based on fasting blood glucose (FBG in mmol/L multiplied by 7); or a dose based on body weight (body weight in kg multiplied by 0.15, then by 7). Within each initiation arm, participants are further randomized 1:1 to one of two day-4 management groups. In Group A, FBG is measured on day 4; if FBG is at or above 6.8 mmol/L, a one-time supplemental dose equal to 50% of the starting dose is given that day. In Group B, FBG is measured on day 4 but no supplemental dose is given. Because day-4 management is randomized independently of the day-4 FBG value, the comparison remains a valid randomized comparison. Treatment and titration: Icodec is injected once weekly, on a fixed weekday, between 6:00 and 9:00 in the morning, in addition to the participant's existing non-insulin glucose-lowering therapy. The first injection defines study Day 1. From Day 15 (for participants who received a day-4 supplemental dose, whose Day 8 dose returns to the original starting dose) or from Day 8 (for those who did not), a standardized weekly titration algorithm adapted from the ONWARDS program is applied through Week 12. A blinded continuous glucose monitor is worn during the first 2 weeks and the last 2 weeks; it is not used for real-time titration decisions. Primary endpoints: This trial has two independent co-primary endpoints, each tested at a two-sided alpha of 0.05 without alpha splitting across objectives. The first is the proportion of participants achieving target FBG (4.4 to 7.0 mmol/L) at the end of Week 1 (Day 8, before the second injection), compared across the three initiation strategies, with Bonferroni correction for the three pairwise comparisons. The second is the effectiveness of the day-4 threshold-based supplemental dosing rule, evaluated by comparing target attainment between the pooled Group A and Group B. Follow-up: The randomized treatment period lasts 12 weeks, followed by a 5-week safety follow-up (Weeks 13 to 17) to capture delayed hypoglycemia after the last dose, given the prolonged action of icodec.