Population Pharmacokinetic and Pharmacodynamic Modeling to Support Molar Dose Ratio Determination of Long-Acting...

INS068 is a new soluble, long-acting insulin analog intended to cover basal insulin requirements in patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM). The purpose of this study was to determine the molar dose ratio of INS068 to insulin degludec (IDeg) by comparing the clinical pharmacokinetic (PK) and pharmacodynamic (PD) profiles of INS068 and IDeg. The PD endpoints include glucose infusion rate (GIR) and glycated hemoglobin (HbA1c).

Population pharmacokinetic and pharmacodynamic (PopPK/PD) analysis was performed to characterize INS068 and IDeg PK and PD profiles. Data from 307 subjects across three Phase I studies and one Phase II study were used to establish the population pharmacokinetic (PopPK) model, of which two euglycemic clamp (Phase I) studies were used to establish PopPK-GIR model, and one Phase II study was used to establish PopPK-HbA1c model. Nonlinear mixed-effects modeling was used to investigate the PK and PD relationships of INS068 and IDeg. Model-based simulations were performed to determine the molar dose ratio of INS068 to IDeg.

The PopPK model of INS068 and IDeg was described by a one-compartment model with linear absorption with a lag time and elimination. Significant covariate effects of body weight, population, and treatment (INS068 vs IDeg) were identified for PK parameters of INS068 and IDeg. However, except for body weight and T2DM patients, the other significant covariates (treatment and T1DM patients) had no clinically relevant effects on PK exposures. The relationship between GIR and insulin concentrations in effect compartment was described by a direct response model with sigmoidal E_max drug effect. The relationship between insulin concentration and HbA1c was well described by an indirect response model. The covariate analysis of the PopPK-GIR and PopPK-HbA1c models showed that treatment (INS068 vs IDeg) had no significant impact on the PD parameters. The results of model-based simulation demonstrated that the PK and PD of INS068 and IDeg were comparable.

This analysis supported molar dose ratio of INS068 to IDeg as 1. INS068 had similar potency compared to IDeg, with one unit of INS068 composed of 6 nmol of active ingredient (1 U = 6 nmol).