Population Pharmacokinetics and Immunogenicity of Adalimumab in Adult Patients with Moderate-to-Severe Hidradenitis Suppurativa

INTRODUCTION

Hidradenitis suppurativa (HS) is a serious, debilitating, chronic inflammatory skin disease. Adalimumab is a fully human, immunoglobulin G1 monoclonal antibody specific for tumor necrosis factor-alpha recently approved for use in patients with HS. The aim of this study is to describe the population pharmacokinetics and immunogenicity of adalimumab in adult patients with HS.

METHODS

Data from one phase II and two phase III studies were included in the analysis. Serial serum adalimumab concentrations and anti-adalimumab antibody (AAA) development status were used to develop the population pharmacokinetic model. The population pharmacokinetic analysis involved evaluating the effects of potential covariates on adalimumab pharmacokinetics.

RESULTS

Mean serum adalimumab concentrations after 40-mg weekly dosing reached steady state (10-12 µg/mL in the phase II study and 7 µg/mL in the phase III studies) by week 2 and were maintained through week 12. The percentage of patients testing positive for AAA was low (10% in the phase II study and 7% in the phase III studies). Adalimumab pharmacokinetics was described by a one-compartment model with first-order absorption. Significant covariates for clearance included the presence of AAA, baseline C-reactive protein, and baseline body weight.

CONCLUSIONS

Adalimumab pharmacokinetics in HS patients was described using a one-compartment model with weight, baseline C-reactive protein, and AAA affecting adalimumab exposure. AAA development results in decreased adalimumab concentrations with a potential decrease in efficacy. Serum adalimumab concentrations in HS patients receiving 40-mg weekly dosing were similar to those observed in other indications under approved dosing regimens.

Target-Mediated Drug Disposition Population Pharmacokinetics Model of Alirocumab in Healthy Volunteers and Patients: Pooled Analysis of Randomized Phase I/II/III Studies

BACKGROUND AND OBJECTIVE

Proprotein convertase subtilisin/kexin type 9 inhibition with monoclonal antibodies such as alirocumab significantly reduces low-density lipoprotein-cholesterol levels ± other lipid-lowering therapies. We aimed to develop and qualify a population pharmacokinetics (PopPK) model for alirocumab in healthy subjects and patients, taking into account the mechanistic target-mediated drug disposition (TMDD) process.

METHODS

This TMDD model was developed using a subset of the alirocumab clinical trial database, including nine phase I/II/III studies (n = 527); the model was subsequently expanded to a larger data set of 13 studies (n = 2870). Potential model parameters and covariate relationships were explored, and predictive ability was qualified using a visual predictive check.

RESULTS

The TMDD model was built using the quasi-steady-state approximation. The final TMDD-quasi-steady-state model included a significant relationship between distribution volume of the central compartment and disease state: distribution volume of the central compartment was 1.56-fold higher in patients vs. healthy subjects. Separately, application of the model to the expanded data set revealed a significant relationship between linear clearance and statin co-administration: linear clearance was 1.27-fold higher with statins. The good predictive performance of the TMDD model was assessed based on graphical and numerical quality criteria, together with the visual predictive check and comparison of the predictions to those from a PopPK model with parallel linear and Michaelis-Menten clearances (i.e., simplification of the TMDD PopPK model).

CONCLUSIONS

This mechanistic TMDD PopPK model integrates the interaction of alirocumab with its target and accurately predicts both alirocumab and total proprotein convertase subtilisin/kexin type 9 concentrations in healthy subjects and patients.

Population Pharmacokinetics of Cladribine in Patients with Multiple Sclerosis

Purpose

The aims of this study were to characterize the concentration–time course of cladribine (CdA) and its main metabolite 2-chloroadenine (CAde), estimate interindividual variability in pharmacokinetics (PK), and identify covariates explaining variability in the PK of CdA.

Methods

This population PK analysis was based on the combined dataset from four clinical studies in patients with multiple sclerosis (MS): three phase I studies, including one food and one drug–drug interaction study, and one phase III clinical study. Plasma and urine concentration data of CdA and CAde were modeled simultaneously.

Results

The analysis comprised a total of 2619 CdA and CAde plasma and urine concentration observations from 173 patients with MS who received an intravenous infusion or oral tablet doses of CdA as a single agent or in combination with interferon (IFN) β-1a. CdA PK data were best described by a three-compartment model, while a one-compartment model best described the PK of CAde. CdA renal clearance (CL_R) was correlated with creatinine clearance (CL_CR), predicting a decrease in the total clearance of 19%, 30% and 40% for patients with mild (CL_CR = 65 ml/min), moderate (CL_CR = 40 ml/min) and severe (CL_CR = 20 ml/min) renal impairment, respectively. Food decreased the extent of CdA absorption by 11.2% and caused an absorption delay. Coadministration with IFNβ-1a was found to increase non-CL_R (CL_NR) by 21%, resulting in an increase of 11% in total clearance.

Conclusions

Both CdA and CAde displayed linear PK after intravenous and oral administration of CdA, with CdA renal function depending on CL_CR.

Trial registration number for study 25643: NCT00213135.

Electronic supplementary material

The online version of this article (doi:10.1007/s40262-017-0516-6) contains supplementary material, which is available to authorized users.

Evaluation of the Population Pharmacokinetic Properties of Lidocaine and its Metabolites After Long-Term Multiple Applications of a Lidocaine Plaster in Post-Herpetic Neuralgia Patients

Background and Objectives

Lidocaine 5% medicated plaster is the first lidocaine containing product for chronic use. As no previous investigations have been conducted to evaluate the population pharmacokinetics of long-term exposure to lidocaine 5% medicated plasters, further insights into the evaluation of the pharmacokinetic properties of lidocaine and its metabolites were needed for the assessment of its safety.

Methods

The population pharmacokinetic properties of lidocaine and its metabolites were evaluated after multiple applications of lidocaine 5% medicated plasters based on data collected for up to 14.5 months from two phase III clinical trials (up to 2.5 months in the first trial, and up to 12 months in a follow-up trial) in post-herpetic neuralgia patients. Modeling was performed using nonlinear mixed effects as implemented in NONMEM^® (nonlinear mixed-effect modeling) v.5. A stepwise forward inclusion and backward elimination procedure were used for covariate model building.

Results

The model provides reliable estimates of the pharmacokinetic behavior of lidocaine after medicated plaster application. It was validated using simulations and showed adequate predictive properties. Apparent Clearance was estimated to be 48 L/h after application of two or fewer plasters, whereas its value increased to 67 L/h after application of three plasters. Model-based simulations predicted no accumulation of lidocaine or any of its metabolites after long-term exposure of three simultaneous plasters up to 1 year. The variability explained by adding covariates into the model for the long-term exposures of lidocaine following one plaster or three simultaneous plaster applications was found to be very small with respect to the overall between-subject variability.

Conclusions

In conclusion, exposure to lidocaine after the application of the lidocaine medicated plaster was found to be primarily affected by the number of plasters simultaneously applied, i.e., it increased with the number of applied patches, but less than proportionally. No clinically relevant effect of other covariates was found to affect the exposure to lidocaine or its metabolites. As no accumulation was predicted by the model, long-term exposure to lidocaine and its metabolites is not expected to lead to any safety concerns in post-herpetic neuralgia patients.