The pharmacokinetic and pharmacodynamic properties of biphasic insulin aspart 70 (BIAsp 70) are significantly different from those of biphasic insulin aspart 30 (BIAsp 30)

Aims: To evaluate the pharmacokinetic and pharmacodynamic properties of two different formulations of premixed analogue (mixed biphasic insulin aspart [BIAsp]), BIAsp 30 (30% soluble insulin aspart [IAsp] and 70% protaminated IAsp) and BIAsp 70 (70% soluble IAsp and 30% protaminated IAsp), in patients with type I diabetes using a 12-hour euglycaemic clamp technique. Methods: In this randomised, double-blind, two-period crossover trial, 27 patients with type 1 diabetes received 7 days of treatment with BIAsp 30 three times daily (TID) and 7 days of treatment with BIAsp 70 TID, with a 2 - 6 week washout period between treatment periods. At the start (day 1) and end (day 8) of each treatment period, 12-hour serum IAsp profiles and glucose infusion rate (GIR) profiles were determined during an overnight euglycaemic clamp following subcutaneous (sc) administration of a single 0.3 U/kg dose of trial insulin. All pharmacokinetic and pharmacodynamic endpoints were derived from individual serum IAsp and GIR profiles. Results: The larger fraction of soluble IAsp in BIAsp 70 compared with BIAsp 30 resulted in greater metabolic effect during the initial post-dosing phase (0 - 6 hours) and decreased activity during the late phase (6 - 12 hours). On day 8, AUC(GIR0-6 hours) was 16% greater for BIAsp 70 than for BIAsp 30 (p=0.016) and AUC(GIR 6-12 hours) was 90% (p < 0.001) greater for BIAsp 30 relative to BIAsp 70, reflecting the increased proportion of intermediate-acting (protamine co-crystallised) IAsp in BIAsp 30. Overall metabolic effect (AUCGIR 0-12 hours) was similar for both insulin formulations on day 8 (Ratio, BIAsp 30:BIAsp 70 = 1.04, p = 0.538). Likewise, the larger fraction of soluble IAsp in BlAsp 70 compared with BIAsp 30 resulted in greater exposure to IAsp during the initial post-dosing phase (0 - 6 hours) and a smaller exposure to lAsp during the late phase (6-12 hours). On day 8, AUC(IAsp 0-6 hours) was 59% (p<0.001) greater for BlAsp 70 than for BlAsp 30, and AUCIAsp 6-12 hours was 61 % (p < 0.001) greater for BlAsp 30 than for BlAsp 70, reflecting the increased proportion of intermediate-acting (protamine cocrystallised) IAsp in BIAsp 30. However, the overall IAsp exposure (AUC(0-12 hours)) on day 8 was significantly greater for BIAsp 70 than for BIAsp 30 (Ratio, BIAsp 30:BIAsp 70=0.73, p<0.001). The GIR profiles on day 8 were similar to those on day 1. Serum IAsp profiles on day 8 showed a slight increase compared with day 1. Conclusions: The different proportions of soluble and protaminated IAsp result in differences in the pharmacokinetic and pharmacodynamic properties of BIAsp 30 and BIAsp 70. The pharmacokinetic and pharmacodynamic differences observed may allow for flexibility and individualised treatment regimens in patients with diabetes, while maintaining a limited number of daily injections.