Introduction/aim: Insulin degludec/insulin aspart (IDegAsp) is a soluble co-formulation of long-acting and short-acting insulin analogs. The primary objective of this study was to investigate the pharmacodynamic response of once-daily IDegAsp dosing in patients with type 1 diabetes. Pharmacokinetic response, as well as safety and tolerability, were assessed as secondary objectives.
Methodology: This was a single-center, open-label, single-arm study. Twenty-two subjects received once-daily insulin degludec (IDeg) (0.42 U/kg) for five consecutive days [with separate bolus insulin aspart (IAsp) as needed for safety and glycemic control], to achieve clinical steady state of the basal component. On Day 6, they received a single injection of IDegAsp (0.6 U/kg, comprising 0.42 U/kg IDeg and 0.18 U/kg IAsp). Pharmacodynamic response was assessed using a 30-h euglycemic glucose clamp, with blood glucose stabilized at a target of 5.5 mmol/L.
Results: The glucose infusion rate profile showed a rapid onset of action and a distinct peak due to IAsp, followed by a separate, flat and stable basal glucose-lowering effect due to the IDeg component. Modeling data suggested that the pharmacodynamic profile of IDegAsp was retained with twice-daily dosing (allowing for coverage of two main meals daily). IDegAsp was well tolerated and no safety issues were identified in this trial.
Conclusions: In conclusion, the IAsp component of IDegAsp has a fast onset of appearance and a peak covering the prandial phase, while the IDeg component has a flat and an evenly distributed pharmacokinetic profile over 24 h. IDegAsp is the first co-formulation of a basal insulin analog with an ultra-long duration of action and a mealtime insulin analog in a single soluble injection. These properties translate into clinically relevant benefits, including improved glycemic control and reduction in hypoglycemia.