Thomas R. Pieber

OBJECTIVE To evaluate the pharmacokinetics, pharmacodynamics, and safety of a novel U500 insulin aspart formulation (AT278 U500) compared with insulin aspart (IAsp U100). RESEARCH DESIGN AND METHODS This single-center, randomized, double-blind study was conducted in 38 men with type 1 diabetes (body weight ≤100 kg and total insulin dose <1.2 units/kg/day). Participants received a single dose of either AT278 U500 or IAsp U100 (0.3 units/kg s.c.) in a crossover design, followed by an 8-h euglycemic clamp in the absence of basal insulin. RESULTS With AT278 U500, onset of appearance in serum was 6 min earlier (P < 0.0001) and reached 50% of maximum concentration 23 min faster (P < 0.0001). Insulin exposure with AT278 U500 was 4.0-fold higher within the first 30 min (95% CI 3.29, 4.90), 1.5-fold higher within the first 60 min (95% CI 1.35, 1.76), and statistically superior up to 90 min postdose (P < 0.05). With AT278 U500, onset of action was 10 min earlier (P < 0.0001) and reached 50% of maximum glucose infusion rate 20 min faster (P < 0.0001). The glucose-lowering effect with AT278 U500 was 8.9-fold higher within the first 30 min (95% CI 5.96, 17.46), 2.4-fold higher within the first 60 min (95% CI 1.92, 3.22), and statistically superior up to 2 h postdose (P < 0.0001). Overall insulin exposure and glucose-lowering effect were comparable. No significant safety findings were observed. CONCLUSIONS AT278 U500 offers rapid-acting characteristics in a reduced dose volume, with accelerated absorption and onset of action compared with IAsp U100 in the studied population.