A semi-mechanistic model to characterize the pharmacokinetics and pharmacodynamics of brodalumab in healthy volunteers and subjects with psoriasis in a first-in-human single ascending dose study

Population pharmacokinetic/pharmacodynamic analysis of AK111, an IL-17A monoclonal antibody, in subjects with moderate-to-severe plaque psoriasis

AK111 is an innovative IL-17A antibody, presenting high affinity to IL-17A and showing similar pharmacokinetic (PK) characteristics to those of typical immunoglobulin (Ig) G1 antibodies. To optimize the dosage regimen for phase 2/3 clinical trials, PK and pharmacodynamics (PD) of AK111 were first characterized in Chinese moderate-to-severe plaque psoriasis patients in a phase 1b study. AK111 PK serum sample and Psoriasis Area and Severity Index (PASI) score data were collected from 48 moderate-to-severe psoriasis patients in this study. Non-linear mixed-effects modeling was used for the population PK/PD analysis. A one-compartment model with a first-order absorption and a first-order elimination best described the PK behavior of AK111. The apparent systemic clearance was 0.182 L/day, and the central volume was 6.65 L. The exposure–response relationship was characterized using an indirect response model. The pharmacological effect of AK111 was described in the form of inhibiting the formation of psoriatic plaque, whereas placebo was quantified in the form of promoting the degradation of psoriatic skin lesions. The maximum effect of drug effect (I_max) and placebo effect (PLB_max) was 1 and 0.429, respectively. The rate constant for psoriatic plaque production (K_in) was 0.474 PASI/day and psoriatic plaque loss (K_out) was 0.024 day⁻¹. The body surface area (BSA) affected by psoriasis was identified as a significant covariate on Kout. The simulation results confirmed that all of the predicted PASI90 response rates at week 12 were higher than 60% at 150 and 300 mg dose levels with different regimens and could reach higher than 80% at week 24. We hope this first PK/PD study of AK111 in Chinese moderate-to-severe plaque psoriasis patients will be of help in the further clinical development of AK111 and provide a reference to the dosage optimization for similar antibodies with a long half-life.

Recent Advances in Translational Pharmacokinetics and Pharmacodynamics Prediction of Therapeutic Antibodies Using Modeling and Simulation

Therapeutic monoclonal antibodies (mAbs) have been a promising therapeutic approach for several diseases and a wide variety of mAbs are being evaluated in clinical trials. To accelerate clinical development and improve the probability of success, pharmacokinetics and pharmacodynamics (PKPD) in humans must be predicted before clinical trials can begin. Traditionally, empirical-approach-based PKPD prediction has been applied for a long time. Recently, modeling and simulation (M&S) methods have also become valuable for quantitatively predicting PKPD in humans. Although several models (e.g., the compartment model, Michaelis–Menten model, target-mediated drug disposition model, and physiologically based pharmacokinetic model) have been established and used to predict the PKPD of mAbs in humans, more complex mechanistic models, such as the quantitative systemics pharmacology model, have been recently developed. This review summarizes the recent advances and future direction of M&S-based approaches to the quantitative prediction of human PKPD for mAbs.

Impact of Pharmacokinetic and Pharmacodynamic Properties of Monoclonal Antibodies in the Management of Psoriasis

The treatment of psoriasis has been revolutionized by the emergence of biological therapies. Monoclonal antibodies (mAb) generally have complex pharmacokinetic (PK) properties with nonlinear distribution and elimination. In recent years, several population pharmacokinetic/pharmacodynamic (PK/PD) models capable of describing different types of mAb have been published. This study aims to summarize the findings of a literature search about population PK/PD modeling and therapeutic drug monitoring (TDM) of mAb in psoriasis. A total of 22 articles corresponding to population PK/PD models of tumor necrosis factor (TNF)-α inhibitors (adalimumab and golimumab), interleukin (IL)-23 inhibitors (guselkumab, tildrakizumab, and risankizumab), IL-23/IL-12 inhibitor (ustekinumab), and IL-17 inhibitors (secukinumab, ixekizumab, and brodalumab) were collected. A summary of the clinical trials conducted so far in psoriasis was included, together with the current structural population PK and PD models. The most significant and clinical covariates were body weight (BW) and the presence of immunogenicity on clearance (CL). The lack of consensus on PK/PD relationships has prevented establishing an adequate dosage and, therefore, accentuates the need for TDM in psoriasis.

Multiscale pharmacokinetic modeling of systemic exposure of subcutaneously injected biotherapeutics

Subcutaneously injected formulations have been developed for many biological products including monoclonal antibodies (mAbs). A knowledge gap nonetheless remains regarding the absorption and catabolism mechanisms and kinetics of a large molecule at the administration site. A multiscale pharmacokinetic (PK) model was thus developed by coupling multiphysics simulations of subcutaneous (SC) absorption kinetics with whole-body pharmacokinetic (PK) modeling, bridged by consideration of the presystemic clearance by the initial lymph. Our local absorption simulation of SC-injected albumin enabled the estimation of its presystemic clearance and led to the whole-body PK modeling of systemic exposure. The local absorption rate of albumin was found to be influential on the PK profile. Additionally, nineteen mAbs were explored via this multiscale simulation and modeling framework. The computational results suggest that stability propensities of the mAbs are correlated with the presystemic clearance, and electrostatic charges in the complementarity-determining region influence the local absorption rate. Still, this study underscores a critical need to experimentally determine various biophysical characteristics of a large molecule and the biomechanical properties of human skin tissues.

Pharmacokinetic-Pharmacodynamic Modeling of Tumor Targeted Drug Delivery Using Nano-Engineered Mesenchymal Stem Cells

Nano-engineered mesenchymal stem cells (nano-MSCs) are promising targeted drug delivery platforms for treating solid tumors. MSCs engineered with paclitaxel (PTX) loaded poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) are efficacious in treating lung and ovarian tumors in mouse models. The quantitative description of pharmacokinetics (PK) and pharmacodynamics (PD) of nano-MSCs is crucial for optimizing their therapeutic efficacy and clinical translatability. However, successful translation of nano-MSCs is challenging due to their complex composition and physiological mechanisms regulating their pharmacokinetic-pharmacodynamic relationship (PK-PD). Therefore, in this study, a mechanism-based preclinical PK-PD model was developed to characterize the PK-PD relationship of nano-MSCs in orthotopic A549 human lung tumors in SCID Beige mice. The developed model leveraged literature information on diffusivity and permeability of PTX and PLGA NPs, PTX release from PLGA NPs, exocytosis of NPs from MSCs as well as PK and PD profiles of nano-MSCs from previous in vitro and in vivo studies. The developed PK-PD model closely captured the reported tumor growth in animals receiving no treatment, PTX solution, PTX-PLGA NPs and nano-MSCs. Model simulations suggest that increasing the dosage of nano-MSCs and/or reducing the rate of PTX-PLGA NPs exocytosis from MSCs could result in improved anti-tumor efficacy in preclinical settings.

Exposure-response characterisation of tildrakizumab in chronic plaque psoriasis: Pooled analysis of 3 randomised controlled trials

AIMS

In this exposure-response analysis, the dosing regimen for tildrakizumab, an antibody for treating moderate-to-severe chronic plaque psoriasis, was determined using data from 3 randomised controlled trials (P05495/NCT01225731: phase 2b, n = 355; reSURFACE 1/NCT01722331: phase 3, n = 772; reSURFACE 2/NCT01729754: phase 3, n = 1090).

METHODS

A maximum drug effect (Emax ) logistic-regression exposure-efficacy model was used to describe the week 12 Psoriasis Area and Severity Index (PASI) responses with average concentration of tildrakizumab during weeks 1-12 (Cavg12 ) as exposure metric. The impact of covariates (e.g., body weight, region) was tested. Exposure-safety, longitudinal pharmacokinetic-pharmacodynamic and risk-benefit analyses were also conducted.

RESULTS

At week 12, Emax was estimated at 62.2, 37.9 and 14.6% of responders for PASI75/90/100, respectively. Exposure-response curves plateaued at exposures >5 μg mL-1 . Heavier subjects had a lower response rate to placebo as measured by PASI75/90/100 than lighter subjects. PASI100 placebo response was less in subjects with higher baseline PASI score and older age. Simulated week 12 PASI75 increased by ≤4% on increasing the dose from 100 to 200 mg every 12 weeks (Q12W). The pharmacokinetic-pharmacodynamic model adequately described the time course of PASI change after treatment in the entire population and in each subject. Risk-benefit profiles were favourable for the 100- and 200-mg doses in different weight subgroups.

CONCLUSIONS

Patients with moderate-to-severe psoriasis should receive 100-mg subcutaneous tildrakizumab Q12W. Patients with high body weight (>90 kg) may benefit from a higher dose (200-mg Q12W).

Brodalumab in the treatment of chronic plaque psoriasis

INTRODUCTION

A number of highly selective biologic therapies that target specific immunological pathways of psoriasis have emerged, including molecules that target interleukin (IL)-17. IL-17 has been identified as a key effector pathogenic cytokine in psoriasis, and validated as a highly effective therapeutic target for the treatment of plaque psoriasis.

AREA COVERED

This review examines the therapeutic efficacy and safety of IL-17 inhibitors in plaque psoriasis and provides an overview of the efficacy and safety data of brodalumab compared with other IL-17 inhibitors.

EXPERT OPINION

In the real world, the treatment of psoriasis has been revolutionized by the new class of drugs belonging to IL-17 inhibitors, with secukinumab, ixekizumab, and brodalumab currently licensed and approved for the treatment of moderate-to-severe plaque psoriasis. With its distinct mechanism of action, brodalumab may offer a unique advantage over other IL-17 inhibitors due to its rapid onset of action, achievement of complete skin clearance in a high proportion of patients, and its overall favorable safety profile. Importantly, treatment with systemic biologic drugs should be established early on in the course of the disease in order to prevent comorbidities and to allow patients to achieve a stable and persistent remission.

Brodalumab: A Review in Moderate to Severe Plaque Psoriasis

Brodalumab (Kyntheum^®) is a human anti-interleukin-17 receptor A (IL-17RA) monoclonal antibody available for use in patients with moderate to severe plaque psoriasis. In the phase III AMAGINE trials in this patient population, 12 weeks of induction therapy with subcutaneous brodalumab was superior to placebo in terms of the proportion of patients with ≥ 75% improvement in the Psoriasis Area and Severity Index score (PASI 75) and the proportion of patients with a static Physician Global Assessment score of 0 or 1. Brodalumab was also superior to ustekinumab for PASI 100 (i.e. complete skin clearance) at week 12. Health-related quality of life (HR-QOL) outcomes improved to a significantly greater extent with brodalumab than with placebo. Moreover, brodalumab was more effective than placebo in patients with difficult-to-treat nail or scalp psoriasis. Brodalumab was generally well tolerated, with low rates of immunogenicity. Efficacy was sustained and brodalumab remained well tolerated during up to 52 weeks of maintenance therapy. Thus, subcutaneous brodalumab is a useful addition to the treatment options currently available for patients with moderate to severe plaque psoriasis.

Population pharmacokinetics of brodalumab in patients with moderate to severe plaque psoriasis

Brodalumab is a fully human monoclonal antibody targeting the IL‐17 receptor A leading to an inhibition of the biological effect of IL‐17A, IL‐17F, IL‐17A/F heterodimer, IL‐17C and IL‐17E isoforms. It has shown to be efficacious in the treatment of moderate to severe plaque psoriasis (210 mg administered subcutaneously at weeks 0, 1 and 2 followed by 210 mg every 2 weeks [Q2W+1]). A population pharmacokinetic model based on psoriasis patients only from six clinical trials was developed to describe the pharmacokinetics and identify sources of variability. In patients with psoriasis, Brodalumab exhibits non‐linear pharmacokinetics due to target‐mediated drug disposition resulting in concentration‐dependent clearance. The pharmacokinetics was best described by a two‐compartment model with linear absorption and combined linear and Michaelis‐Menten elimination. The subcutaneous bioavailability of Brodalumab was 55%, absorption rate was 0.30 day⁻¹, and body‐weight was found to affect the volume of distribution and clearance. For a reference patient with plaque psoriasis (body‐weight of 90 kg), the estimates were 0.16 L/d for linear serum clearance, 6.1 mg/d for the maximum non‐linear clearance rate, and 4.7 and 2.4 L for central and peripheral volume of distribution, respectively. For the approved dosing regimen, time to maximum concentration was 4 days and 90% of steady‐state was achieved after 10 weeks for a reference patient. Following last dose at steady‐state, 90% of the population of reference patients will reach serum concentrations below lower limit of quantification after 45 days.

Improvement of pharmacokinetic properties of therapeutic antibodies by antibody engineering

Monoclonal antibodies (mAbs) have become an important therapeutic option for several diseases. Since several mAbs have shown promising efficacy in clinic, the competition to develop mAbs has become severe. In efforts to gain a competitive advantage over other mAbs and provide significant benefits to patients, innovations in antibody engineering have aimed at improving the pharmacokinetic properties of mAbs. Because engineering can provide therapeutics that are more convenient, safer, and more efficacious for patients in several disease areas, it is an attractive approach to provide significant benefits to patients. Further advances in engineering mAbs to modulate their pharmacokinetics were driven by the increase of total soluble target antigen concentration that is often observed after injecting a mAb, which then requires a high dosage to antagonize. To decrease the required dosage, several antibody engineering techniques have been invented that reduce the total concentration of soluble target antigen. Here, we review the various ways that antibody engineering can improve the pharmacokinetic properties of mAbs.

Spotlight on brodalumab in the treatment of moderate-to-severe plaque psoriasis: design, development, and potential place in therapy

Brodalumab is a novel fully human immunoglobulin G2 monoclonal antibody that antagonizes the interleukin (IL)-17 pathway by binding with high affinity to human IL-17RA. The role of IL-17A in the pathogenesis of psoriasis, as well as the remarkable effectiveness of IL-17 inhibitors in the treatment of moderate-to-severe plaque psoriasis, is well established. The mechanism of action of brodalumab is unique in that it inhibits the IL-17 receptor compared to the two other currently FDA-approved IL-17 inhibitors, secukinumab and ixekizumab, which inhibit the IL-17A molecule itself. The efficacy of brodalumab in the treatment of moderate-to-severe plaque psoriasis has been demonstrated in phase 2 and 3 trials, and subsequently the FDA approved this medication in February 2017. Brodalumab was approved in Japan in July 2016 and approval is pending in Europe. The safety and adverse effects of brodalumab were reviewed across several clinical trials, which, similar to other IL-17 inhibitors, demonstrated increased rates of neutropenia and Candida infections. Brodalumab treatment, similar to ixekizumab and secukinumab, showed no improvement in inflammatory bowel disease patients, and on the contrary, more exacerbations were encountered. Suicidal ideation and behavior events have been reported with brodalumab treatment and are of significant concern. Brodalumab provides another highly effective treatment option for moderate-to-severe plaque psoriasis.

Improvement in latent variable indirect response modeling of multiple categorical clinical endpoints: application to modeling of guselkumab treatment effects in psoriatic patients

Exposure-response modeling plays an important role in optimizing dose and dosing regimens during clinical drug development. The modeling of multiple endpoints is made possible in part by recent progress in latent variable indirect response (IDR) modeling for ordered categorical endpoints. This manuscript aims to investigate the level of improvement achievable by jointly modeling two such endpoints in the latent variable IDR modeling framework through the sharing of model parameters. This is illustrated with an application to the exposure-response of guselkumab, a human IgG1 monoclonal antibody in clinical development that blocks IL-23. A Phase 2b study was conducted in 238 patients with psoriasis for which disease severity was assessed using Psoriasis Area and Severity Index (PASI) and Physician's Global Assessment (PGA) scores. A latent variable Type I IDR model was developed to evaluate the therapeutic effect of guselkumab dosing on 75, 90 and 100% improvement of PASI scores from baseline and PGA scores, with placebo effect empirically modeled. The results showed that the joint model is able to describe the observed data better with fewer parameters compared with the common approach of separately modeling the endpoints.

Brodalumab: First Global Approval

Brodalumab (Lumicef(®)) is a human monoclonal immunoglobulin G antibody that is being developed by Kyowa Hakko Kirin in Japan, where it has been approved for the treatment of psoriasis vulgaris, psoriatic arthritis, pustular psoriasis and psoriatic erythroderma. Brodalumab binds with high affinity to interleukin (IL)-17 receptor A, thereby inhibiting several pro-inflammatory cytokines from the IL-17 family. Regulatory applications for brodalumab in plaque psoriasis are also under review in the USA, EU and Canada. This article summarizes the milestones in the development of brodalumab leading to this first approval for the treatment of psoriasis.

A Study to Evaluate the Safety, Tolerability, and Efficacy of Brodalumab in Subjects with Rheumatoid Arthritis and an Inadequate Response to Methotrexate

Objective.

To evaluate the efficacy and safety of brodalumab, a human monoclonal antibody inhibitor of the interleukin 17 receptor, in subjects with rheumatoid arthritis (RA).

Methods.

Patients (n = 252) with inadequate response to methotrexate (MTX) were randomized to receive subcutaneous injections of brodalumab (70 mg, 140 mg, or 210 mg) or placebo. The primary endpoint was the American College of Rheumatology 50% response (ACR50) at Week 12.

Results.

Demographics and baseline characteristics were generally balanced among treatment groups. At Week 12, ACR50 occurred in 16% (70 mg), 16% (140 mg), 10% (210 mg), and 13% (placebo; all nonsignificant vs placebo) of subjects. No significant treatment effects were observed for the secondary endpoints, including ACR20, ACR70, and Disease Activity Score in 28 joints. Incidences of all adverse events (AE), including serious AE (SAE), were similar across treatment groups. A total of 7 subjects reported SAE during the study (2 in the placebo group and 5 in the brodalumab groups), none of which was treatment related. There was 1 death (cardiopulmonary failure) ∼1 week after the last dose in the 140 mg group.

Conclusion.

Our study failed to find evidence of meaningful clinical efficacy with brodalumab treatment in subjects with RA who had an inadequate response to MTX. These preliminary results do not support further evaluation of brodalumab as a treatment for RA. Clinicaltrials.gov number: NCT00950989.

Network biology in development of monoclonal antibody therapeutics

Monoclonal antibodies (mAbs) are large glycoproteins that recognize and remove/neutralize a specific target. Inflammation and inflammatory diseases are often treated with mAb-based therapeutics. Mathematical modeling is widely used in development of mAbs. Bioinformatics and structural modeling is used for humanization of mAbs and PK/PD modeling is extensively used in preclinical and clinical development. The objective of this commentary is to introduce systems biology-based modeling that can accelerate and improve development of mAbs.

Clinical Trial Simulation to Inform Phase 2: Comparison of Concentrated vs. Distributed First-in-Patient Study Designs in Psoriasis

Clinical trial simulation (CTS) and model-based meta-analysis (MBMA) can increase our understanding of small, first-in-patient (FIP) trial design performance to inform Phase 2 decision making. In this work, we compared dose-ranging designs vs. designs testing only placebo and the maximum dose for early decision making in psoriasis. Based on MBMA of monoclonal antibodies in the psoriasis space, a threshold of greater than a 50 percentage point improvement over placebo effect at the highest feasible drug dose was required for the advancement in psoriasis. Studies testing only placebo and the maximum dose made the correct advancement decision marginally more often than dose-ranging designs in the majority of the cases. However, dose-ranging studies in FIP trials offer important design advantages in the form of dose–response (D–R) information to inform Phase 2 dose selection. CTS can increase the efficiency and quality of drug development decision making by studying the limitations and benefits of study designs prospectively.