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Keywords:

  • active metabolite;
  • Alzheimer's disease;
  • NONMEM;
  • NS2330;
  • population pharmacokinetic modelling;
  • sex

What is already known about this subject

• Several studies in predominantly healthy subjects have investigated the pharmacokinetics of NS2330 and its major metabolite M1.

• However, its pharmacokinetics have not been characterized in Alzheimer's disease patients, the target population for NS2330.

• In addition, no covariates have previously been found to influence the plasma concentration-time profiles of NS2330 and/or M1.

What this study adds

• A descriptive and predictive population pharmacokinetic model for NS2330 and its metabolite was successfully developed in a population of patients with Alzheimer's disease.

• A covariate analysis elucidated sex and creatinine clearance as having an influence on the plasma concentration-time profiles of NS2330 after long-term treatment.

Aims

To develop a population pharmacokinetic model for NS2330 and its major metabolite M1 based on data from a 14 week proof of concept study in patients with Alzheimer's disease, and to identify covariates that might influence the pharmacokinetic characteristics of the drug and/or its metabolite.

Methods

Plasma data from 320 subjects undergoing multiple oral dosing, and consisting of 1969 NS2330 and 1714 metabolite concentrations were fitted simultaneously using NONMEM.

Results

Plasma concentration-time profiles of NS2330 and M1 were best described by one-compartment models with first-order elimination for both compounds. Absorption of NS2330 was best modelled by a first-order process. Low apparent clearances together with large apparent volumes of distribution resulted in long half-lives of 234 h (NS2330) and 374 h (M1). The covariate analysis identified weight, sex, CLCR, BMI and age as influencing the pharmacokinetics of NS2330 and/or M1. However, simulations performed revealed that only CLCR and sex had a significant effect on the steady-state plasma concentration-time profiles. Females with a creatinine clearance of 35.6 ml min−1 showed a 62% increased exposure compared with males without renal impairment. The robustness and accuracy of the model were demonstrated by the successful predictivity of an external dataset.

Conclusions

A descriptive, robust and predictive model for NS2330 and its M1 metabolite was developed. Important covariates influencing pharmacokinetics were identified, which might guide the further development of NS2330 and optimize its long-term use in the treatment of Alzheimer's disease.