Pharmacokinetics and pharmacodynamics of monoclonal antibodies: concepts and lessons for drug development

Pharmacokinetics and Safety of Intravenous Candidate Biosimilar CT-P47 and Reference Tocilizumab: A Randomized, Double-Blind, Phase 1 Study

CT-P47 is a candidate biosimilar of tocilizumab. This 12-week, randomized, double-blind, parallel-design, phase 1 study aimed to demonstrate pharmacokinetic (PK) equivalence of CT-P47 and reference tocilizumab. Participants were healthy Japanese adults aged 18-55 years. Participants were randomized (1:1:1) to receive a single intravenous dose (8 mg/kg) of CT-P47, EU-approved tocilizumab (EU-tocilizumab), or US-licensed tocilizumab (US-tocilizumab). Primary PK endpoints were area under the concentration-time curve (AUC) from time zero to infinity, AUC from time zero to the last quantifiable concentration, and maximum serum concentration. Additional PK variables, safety, and immunogenicity were evaluated. The study was conducted from January 20 to May 26, 2023, in three centers in Japan. In total, 133 male participants were randomized (n = 45 to CT-P47, n = 44 to EU-tocilizumab, and n = 44 to US-tocilizumab). For all primary PK variables, 90% confidence intervals of the ratio of geometric least squares means were within the predefined equivalence margin of 0.80-1.25. Secondary PK variables were similar across groups. The most common treatment-emergent adverse event (TEAE) was neutrophil count decreased, occurring in 15 (33.3%), 13 (30.2%), and 12 (27.3%) participants in the CT-P47, EU-tocilizumab, and US-tocilizumab groups, respectively. There were no serious TEAEs, deaths, or study drug discontinuations due to TEAEs. Few participants were anti-drug antibody (ADA)- or neutralizing antibody (NAb)-positive. At the end of study, four (8.9%), one (2.3%), and two (4.5%) participants in the CT-P47, EU-tocilizumab, and US-tocilizumab groups, respectively, were ADA-positive; two (4.4%), zero (0%), and one (2.3%) in the respective groups were NAb-positive. CT-P47 demonstrated PK equivalence and comparable safety to EU- and US-tocilizumab.

PBPK-based translation from preclinical species to humans for the full-size IgG therapeutic efalizumab

Introduction

Animal models play a vital role in pharmaceutical research and development by supporting the planning and design of later clinical studies. To improve confidence and reliability of first in human dose estimates it is essential to assess the comparability of animal studies with the human situation. In the context of large molecules, it is particularly important to evaluate the cross-species-translatability of parameters related to neonatal fragment crystallizable receptor (FcRn) binding and target mediated drug disposition (TMDD), as they greatly influence distribution and disposition of proteins in the body of an organism.

Methods

Plasma pharmacokinetic data of the therapeutic protein efalizumab were obtained from literature. Physiologically based pharmacokinetic (PBPK) models were built for three different species (rabbit, non-human primate (NHP), human). Target binding was included in the NHP and human models. The assumption of similar target turnover and target-binding in NHP and human was explored, to gain insights into how these parameters might be translated between species.

Results

Efalizumab PBPK models were successfully developed for three species and concentration-time-profiles could be described appropriately across different intravenously administered doses. The final NHP and human models feature a common set of parameters for target turnover and drug-target-complex internalization, as well as comparable target-binding parameters. Our analyses show that different parameter values for FcRn affinity are crucial to accurately describe the concentration-time profiles.

Discussion

Based on the available data in rabbits, NHP and humans, parameters for FcRn affinity cannot be translated between species, but parameters related to target mediated drug disposition can be translated from NHP to human. The inclusion of additional pharmacokinetic (PK) data including different efalizumab doses would further support and confirm our findings on identifying TMDD and, thus, binding kinetics of efalizumab in NHPs. Furthermore, we suggest that information on target expression and internalization rates could make it possible to develop comprehensive human PBPK models with minimal animal testing. In this project, we compared the pharmacokinetics of a therapeutic protein in rabbit, NHP and human using an open PBPK modeling platform (Open Systems Pharmacology Suite, http://www.open-systems-pharmacology.org). Our findings could support similar translatory studies for first in human dose predictions in the future.

Clinical Pharmacokinetics and Pharmacodynamics of Letermovir in Allogenic Hematopoietic Cell Transplantation

Letermovir is a newly developed antiviral agent used for the prophylaxis of human cytomegalovirus infections in patients undergoing allogeneic hematopoietic cell transplantation. This novel anti-cytomegalovirus drug, used for the prophylaxis of cytomegalovirus reactivation until approximately 200 days after transplantation, effectively reduces the risk of clinically significant cytomegalovirus infection. No human counterpart exists for the terminase complex; letermovir is virus specific and lacks some toxicities previously observed with other anti-cytomegalovirus drugs, such as cytopenia and nephrotoxicity. The absolute bioavailability of letermovir in healthy individuals is estimated to be 94% based on a population-pharmacokinetic analysis. In contrast, oral administration of letermovir to patients undergoing hematopoietic cell transplantation results in lower exposure than that in healthy individuals. Renal or hepatic impairment does not influence the intrinsic clearance of letermovir. Co-administration of letermovir may alter the plasma concentrations of other drugs, including itself, as it acts as a substrate and inhibitor/inducer of several drug-metabolizing enzymes and transporters. In particular, attention should be paid to the drug-drug interactions between letermovir and calcineurin inhibitors or azole antifungal agents, which are commonly used in patients undergoing hematopoietic cell transplantation. This article reviews and summarizes the clinical pharmacokinetics and pharmacodynamics of letermovir, focusing on patients undergoing hematopoietic cell transplantation, healthy individuals, and specific patient subsets.

Fixed Versus Body-Sized-Based Dosing of Monoclonal Antibodies

Monoclonal antibody products are an increasing portion of novel drug approvals. The labeling of initial drug approvals frequently involves body-size-based rather than fixed-dose administration regimens for adults without clear rationale for doing so. This presents challenges when prescribing these products for patients with extremes of body habitus who constitute a small portion of enrollment in pre-approval investigations. Fixed-dose regimens allow for standardized preparation with the potential to reduce the risk of calculation errors, drug waste, and make home administration more practical. Fixed-dose rather than body-size-based monoclonal antibody regimens should serve as the initial approach in early phase 1 clinical trials.

Physiologically based pharmacokinetic (PBPK) model that describes enhanced FcRn-dependent distribution of monoclonal antibodies (mAbs) by pI-engineering in mice

We previously reported that monoclonal antibodies (mAbs) with a high isoelectric point (pI) value tended to exhibit fast plasma clearance (CL) and large steady-state volume of distribution (Vdss) in mice. However, the positive correlation between pI, CL, and Vdss cannot be described by the reported physiologically based pharmacokinetic (PBPK) models, in which FcRn-mediated transcytosis of mAbs is set to be minimal compared to convection-mediated transport. To address this issue, physiological parameters (lymph flow rate, reflection coefficient, endothelial uptake clearance, and FcRn concentration) were optimized based on the pharmacokinetic profiles of mAbs with various pI values in wild type and FcRn-deficient (beta-2-microglobulin knockout [KO]) mice. Simulations using the PBPK model developed in this study showed a positive correlation between pI, CL and Vdss observed in wild-type mice. Therefore, this model successfully characterized our hypothetical mechanism that an electrostatic positive interaction between mAbs and the endothelial membrane enhances FcRn-mediated transcytosis of mAbs, resulting in large Vdss. We sought to determine the right contribution of the two pathways of antibody distribution to the interstitial space and established a new model that could effectively capture the effect of pI on FcRn-mediated distribution of mAbs in the body.

Myeloma bone disease: pathogenesis and management in the era of new anti-myeloma agents

INTRODUCTION

Multiple myeloma (MM) is a malignancy of plasma cells with characteristic bone disease. Despite recent great strides achieved in MM treatment owing to the implementation of new anti-MM agents, MM is still incurable and bone destruction remains a serious unmet issue in patients with MM.

APPROACH

In this review, we will summarize and discuss the mechanisms of the formation of bone disease in MM and the available preclinical and clinical evidence on the treatment for MM bone disease.

CONCLUSIONS

MM cells produce a variety of cytokines to stimulate receptor activator of nuclear factor-κB ligand-mediated osteoclastogenesis and suppress osteoblastic differentiation from bone marrow stromal cells, leading to extensive bone destruction with rapid loss of bone. MM cells alter the microenvironment through bone destruction where they colonize, which in turn favors tumor growth and survival, thereby forming a vicious cycle between tumor progression and bone destruction. Denosumab or zoledronic acid is currently recommended to be administered at the start of treatment in newly diagnosed patients with MM with bone disease. Proteasome inhibitors and the anti-CD38 monoclonal antibody daratumumab have been demonstrated to exert bone-modifying activity in responders. Besides their anti-tumor activity, the effects of new anti-MM agents on bone metabolism should be more precisely analyzed in patients with MM. Because prognosis in patients with MM has been significantly improved owing to the implementation of new agents, the therapeutic impact of bone-modifying agents should be re-estimated in the era of these new agents.

Engineering cytokine therapeutics

Cytokines have pivotal roles in immunity, making them attractive as therapeutics for a variety of immune-related disorders. However, the widespread clinical use of cytokines has been limited by their short blood half-lives and severe side effects caused by low specificity and unfavourable biodistribution. Innovations in bioengineering have aided in advancing our knowledge of cytokine biology and yielded new technologies for cytokine engineering. In this Review, we discuss how the development of bioanalytical methods, such as sequencing and high-resolution imaging combined with genetic techniques, have facilitated a better understanding of cytokine biology. We then present an overview of therapeutics arising from cytokine re-engineering, targeting and delivery, mRNA therapeutics and cell therapy. We also highlight the application of these strategies to adjust the immunological imbalance in different immune-mediated disorders, including cancer, infection and autoimmune diseases. Finally, we look ahead to the hurdles that must be overcome before cytokine therapeutics can live up to their full potential.

Recent advances in the translation of drug metabolism and pharmacokinetics science for drug discovery and development

Drug metabolism and pharmacokinetics (DMPK) is an important branch of pharmaceutical sciences. The nature of ADME (absorption, distribution, metabolism, excretion) and PK (pharmacokinetics) inquiries during drug discovery and development has evolved in recent years from being largely descriptive to seeking a more quantitative and mechanistic understanding of the fate of drug candidates in biological systems. Tremendous progress has been made in the past decade, not only in the characterization of physiochemical properties of drugs that influence their ADME, target organ exposure, and toxicity, but also in the identification of design principles that can minimize drug-drug interaction (DDI) potentials and reduce the attritions. The importance of membrane transporters in drug disposition, efficacy, and safety, as well as the interplay with metabolic processes, has been increasingly recognized. Dramatic increases in investments on new modalities beyond traditional small and large molecule drugs, such as peptides, oligonucleotides, and antibody-drug conjugates, necessitated further innovations in bioanalytical and experimental tools for the characterization of their ADME properties. In this review, we highlight some of the most notable advances in the last decade, and provide future perspectives on potential major breakthroughs and innovations in the translation of DMPK science in various stages of drug discovery and development.

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.

Pharmacokinetic/Pharmacodynamic Considerations of Alternate Dosing Strategies of Tocilizumab in COVID-19

Tocilizumab is one of few treatments that have been shown to improve mortality in patients with coronavirus disease 2019 (COVID-19), but increased demand has led to relative global shortages. Recently, it has been suggested that lower doses, or fixed doses, of tocilizumab could be a potential solution to conserve the limited global supply while conferring equivalent therapeutic benefit to the dosing regimens studied in major trials. The relationship between tocilizumab dose, exposure, and response in COVID-19 has not been adequately characterized. There are a number of pharmacokinetic (PK) parameters that likely differ between patients with severe COVID-19 and patients in whom tocilizumab was studied during the US FDA approval process. Likewise, it is unclear whether a threshold exposure is necessary for tocilizumab efficacy. The safety and efficacy of fixed versus weight-based dosing of tocilizumab has been evaluated outside of COVID-19, but it is uncertain if these observations are generalizable to severe or critical COVID-19. In the current review, we consider the potential advantages and limitations of alternative tocilizumab dosing strategies. Leveraging PK models and simulation analyses, we demonstrate that a fixed single dose of tocilizumab 400 mg is unlikely to produce PK exposures equivalent to those achieved in the REMAP-CAP trial, although weight-stratified dosing appears to produce more uniform exposure distribution. Data from current and future trials could provide PK/pharmacodynamic insight to better inform dosing strategies at the bedside. Ultimately, rational dosing strategies that balance available limited supply with patient needs are required.

Eculizumab precision dosing algorithm for thrombotic microangiopathy in children and young adults undergoing HSCT

This large study examined eculizumab PK/PD in bleeding and nonbleeding patients with TA-TMA.

PK/PD model-based eculizumab dosing is needed for bleeding in TA-TMA, whereas fixed-dose regimens are effective in nonbleeding patients.

Transplant-associated thrombotic microangiopathy (TA-TMA) is a fatal posttransplant complication of hematopoietic stem cell transplantation. We recently reported that survival for TA-TMA has been improved by early intervention with eculizumab, a complement C5 inhibitor, guided by pharmacokinetic/pharmacodynamic (PK/PD) model-informed precision dosing. However, patients with gastrointestinal bleeding showed poor survival, even when treated with more frequent doses. Our objective was to develop separate models in bleeding and nonbleeding patients with TA-TMA and to propose precision dosing algorithms. Eculizumab PK/PD was analyzed in 19 bleeding and 38 nonbleeding patients (0.5-29.9 years of age). A complement activation biomarker (sC5b-9) and body weight were identified as significant determinants of eculizumab clearance regardless of bleeding. Eculizumab clearance after the first dose was higher in bleeding than in nonbleeding patients (83.8 vs 61.3 mL/h per 70 kg; P = .07). The high clearance was maintained over treatment doses in bleeding patients, whereas nonbleeding patients showed a time-dependent decrease in clearance. sC5b-9 levels were highest before the first dose and decreased over time, regardless of bleeding complications. A Monte Carlo Simulation analysis showed that the current dosing protocols recommended for atypical hemolytic uremic syndrome had <15% probability of attaining the target concentration of >100 μg/mL eculizumab in nonbleeding patients. We identified an intensified loading protocol to reach 80% target attainment. Our data clearly showed the need for individualized dosing for patients with significant bleeding and for ongoing dose adjustments to optimize outcomes. The developed models will be incorporated into a clinical decision guideline for precision dosing to improve outcomes in children and young adults with TA-TMA.

Tumor Necrosis Factor's Pathway in Crohn's Disease: Potential for Intervention

Crohn’s disease (CD) is a chronic disorder characterized by full thickness patchy inflammation of the gastrointestinal tract. The pathogenesis is multifactorial and involves defective innate immune responses, microbiome alterations, and dysregulated activation of the acquired component of mucosal immunity. One of the molecular mediators that is involved at different levels in the initiation and progression of intestinal inflammation characteristic of CD is tumor necrosis factor (TNF). The present manuscript provides a comprehensive review focused on the potential role of TNF in the different phases of CD pathogenesis, particularly in light of its potential clinical implications. Currently available drugs blocking TNF are evaluated and discussed, specifically for open issues that still remain utilizing such therapy. TNF exerts a paramount role in the established phase of intestinal inflammation that characterizes CD patients, and anti-TNF biologics have definitely changed patient management, offering effective and safe options of treatment. Nonetheless, many patients still do not respond to anti-TNF therapy or experience unwanted side-effects. This could partially be due to the role that TNF plays in intestinal homeostasis that is particularly important during the early phase of the inflammatory process. In fact, emerging evidence supporting the dichotomous role of TNF and the identification of molecular markers will guide a more tailored and refined therapy for CD patients in the near future.

Atezolizumab and Bevacizumab in Patients with Unresectable Hepatocellular Carcinoma: Pharmacokinetic and Safety Assessments Based on Hepatic Impairment Status and Geographic Region

INTRODUCTION

Phase 1b GO30140 and phase 3 IMbrave150 studies evaluated first-line atezolizumab + bevacizumab for unresectable hepatocellular carcinoma (HCC). Here, we evaluated pharmacokinetics (PK) and safety by hepatic impairment status and geographic region.

METHODS

Patients received atezolizumab 1,200 mg + bevacizumab 15 mg/kg IV every 3 weeks. Drug concentrations were evaluated by descriptive statistics and population PK. PK and adverse event frequencies were evaluated by hepatic impairment status and region.

RESULTS

323 IMbrave150 patients and 162 GO30140 patients were PK evaluable. Compared with IMbrave150 patients who had normal hepatic function per the National Cancer Institute Organ Dysfunction Working Group (NCI-ODWG) criteria (n = 123), patients with mild impairment (n = 171) had a geometric mean ratio (GMR) of 0.92 for cycle 1 atezolizumab area under the concentration-time curve (AUC); patients with moderate impairment (n = 27) had a GMR of 0.88. Patients in Asia ([n = 162] vs. outside [n = 161]) had a GMR of 1.25 for cycle 1 atezolizumab AUC. Compared with GO30140 patients who had normal hepatic function (NCI-ODWG [n = 61]), patients with mild impairment (n = 92) had a GMR of 0.97 for cycle 1 peak bevacizumab concentrations; those with moderate impairment (n = 9) had a GMR of 0.94. Patients in Asia (n = 111) versus outside Asia (n = 51) had a GMR of 0.94 for cycle 1 peak bevacizumab concentration. PK results were generally comparable when evaluated based on additional hepatic functional definitions (Child-Pugh or albumin/bilirubin criteria) or study enrollment in Japan. No associations between atezolizumab PK and HCC etiology were seen. Adverse event frequencies were similar across evaluated groups.

CONCLUSIONS

IMbrave150 and GO30140 patients with unresectable HCC had varying baseline hepatic impairment and high enrollment from Asia. PK data demonstrated considerable exposure overlap across groups. Treatment was tolerable across groups. No need for dose adjustment based on mild or moderate hepatic impairment or region is recommended based on this analysis.

Unraveling the complexity of therapeutic drug monitoring for monoclonal antibody therapies to individualize dose in oncology

Monoclonal antibodies (Mabs) have become key drugs in cancer treatment, either as targeted therapies or more recently as immune checkpoint inhibitors (ICIs). The fact that only some patients benefit from these drugs poses the usual question in the field of onco-hematology: that of the benefit of individual dosing and the potential of therapeutic drug monitoring (TDM) to carry out this individualization. However, Mabs present unique pharmacological characteristics for TDM, and the pharmacokinetic-pharmacodynamic relationship observed should be interpreted differently than that observed for conventional drugs and small molecules. This pharmacology practice review has been summarized from a public debate between the authors at the International TDM and Clinical Toxicology meeting in Banff, 2020, regarding the potential roles of TDM in the Mab/ICI setting.

Identification of nanobodies against hepatocellular carcinoma marker glypican-3

Glypican-3 (GPC3) is a highly specific diagnostic marker for hepatocellular carcinoma (HCC) diagnosis and a potential target in HCC therapy. Nanobodies (Nbs) are promising targeting molecules due to their high specificity and strong affinities to antigens, high stability, deep tissue penetration, and low immunogenicity. In this study, we isolated Nbs against GPC3 marker protein from a synthetic Nb library by phage display. To characterize these Nbs, we performed enzyme-linked immunosorbent assay, immunoprecipitation assay, and immunofluorescent assay to demonstrate that four (G8, G10, G11, and G64) of them bound specifically to recombinant as well as endogenous GPC3, and epitope mapping showed they all bound to N-terminal subunit of GPC3. Furthermore, we found that G64 exhibited high protein stability and GPC3 binding activity in serum at 37℃ for at least 96 h, and G64 did not affect the proliferation of HEK293T cells and HCC cell line HepG2. Our study provides four anti-GPC3 Nbs as promising targeting molecules for HCC diagnostic and therapeutic drugs.

Allometric scaling of therapeutic monoclonal antibodies in preclinical and clinical settings

Constant technological advancement enabled the production of therapeutic monoclonal antibodies (mAbs) and will continue to contribute to their rapid expansion. Compared to small-molecule drugs, mAbs have favorable characteristics, but also more complex pharmacokinetics (PK), e.g., target-mediated nonlinear elimination and recycling by neonatal Fc-receptor. This review briefly discusses mAb biology, similarities and differences in PK processes across species and within human, and provides a detailed overview of allometric scaling approaches for translating mAb PK from preclinical species to human and extrapolating from adults to children. The approaches described here will remain vital in mAb drug development, although more data are needed, for example, from very young patients and mAbs with nonlinear PK, to allow for more confident conclusions and contribute to further growth of this field. Improving mAb PK predictions will facilitate better planning of (pediatric) clinical studies and enable progression toward the ultimate goal of expediting drug development.

Safety and efficacy of interleukin inhibitors in elderly patients with rheumatoid arthritis, psoriasis, and psoriatic arthritis

Elderly patients with rheumatoid arthritis, psoriasis and psoriatic arthritis encompass those with elderly-onset disease, over 60 years of age, but also those with earlier disease onset who entered old age. Considering the age-related changes of the immune system, possible frailty, susceptibility to infection and concomitant comorbidity that implies multiple medicines, the treatment of these diseases in elderly patients can be challenging. Interleukin inhibitors have been shown to be an efficient and safe treatment for these diseases. However, elderly patients with these diseases were often included in the pivotal clinical trials for interleukin inhibitors in numbers insufficient to determine whether they responded differently from younger subjects. The aim of this paper was to review the findings on the efficacy and safety of interleukin inhibitor treatment in elderly patients with rheumatoid arthritis, psoriasis, and psoriatic arthritis. The findings suggest that, for all the interleukin inhibitors reviewed herein, used in elderly patients with rheumatoid arthritis, or with psoriasis and psoriatic arthritis, the efficacy was comparable to younger patients. Furthermore, the incidence of reported adverse events was similar in these two age groups. Severe adverse events, which were related to sarilumab treatment for rheumatoid arthritis and secukinumab treatment for psoriasis, were higher in elderly patients. The reviewed findings suggest that the interleukin inhibitors approved and currently in use in clinical practice for the treatment of rheumatoid arthritis, psoriasis, and psoriatic arthritis can be considered a safe and efficient option for these diseases in elderly patients.

The safety profile of denosumab in oncology beyond the safety of denosumab as an anti-osteoporotic agent: still more to learn

INTRODUCTION

Initially endorsed as an antiosteoporotic agent, denosumab ‒ human monoclonal antibody inhibiting the receptor activator of nuclear factor kappa-B ligand (RANKL)‒ has currently shown an anticancer potential, rationalizing its exploitation in oncology. A prerequisite for leveraging denosumab in oncology is a favorable safety profile.

AREAS COVERED

The present review provides an overview of the adverse events of denosumab in oncology, with a focus on hypocalcemia, medication-related osteonecrosis of the jaw, atypical femoral fracture(s), post-denosumab vertebral fractures, increased risk of infections, and excess of second primary cancer. Representative studies addressing the safety and efficacy of denosumab compared to bisphosphonates in oncology are summarized. Critical gaps in the literature concerning the safety of denosumab in oncology are highlighted as opposed to plenty of available safety data on denosumab as an antiosteoporotic agent.

EXPERT OPINION

Despite the generally acceptable safety profile of denosumab in oncology, many issues remain unresolved. Further research is mandatory to counteract current challenges, namely: (i) validation of risk factors for adverse events; (ii) elucidation of the pathophysiology of the adverse events in search of actionable molecular pathways; (iii) illumination of the association of denosumab with increased risk of infections and/or second primary cancer; (iv) establishment of optimal diagnostic, and therapeutic protocols.

Simultaneous quantification of rituximab and eculizumab in human plasma by liquid chromatography-tandem mass spectrometry and comparison with rituximab ELISA kits

OBJECTIVES

Specific and sensitive analytical techniques to quantify therapeutic monoclonal antibodies (mAbs) are required for therapeutic drug monitoring. The quantification of mAbs has been historically performed using enzyme-linked immunosorbent assays (ELISAs), for which the limitations in terms of specificity have led to the development of alternative analytical strategies.

METHODS

Here, we describe the validation of a liquid chromatography tandem mass-spectrometry (LC-MS/MS) method for the simultaneous quantification of rituximab (RTX - anti-CD20) and eculizumab (ECU - anti-C5). Sample preparation was based on our previously published method, using protein G purification and trypsin digestion. A new specific peptide for RTX, containing an N-terminal pyroglutamine and a trypsin miss-cleavage, enables better sensitivity, while peptide of ECU was chosen thanks to an in silico trypsin digestion and the Skyline® software. Full-length stable-isotope-labeled adalimumab was added to plasma samples as an internal standard. RTX in 50 human serum samples was quantified by LC-MS/MS and the concentrations obtained compared to those obtained with two commercial ELISA kits (Lisa Tracker® and Promonitor®).

RESULTS

Calibration curves were linear from 1 to 200 µg.mL^-1 for RTX and 5 to 200 µg.mL^-1 for ECU, and within-day and between-day accuracy and precision fulfilled Food and Drug Administration validation criteria. Comparison of the LC-MS/MS method with ELISA showed a negligible bias with the Lisa Tracker® kit (4%), but significant bias with the Promonitor® assay (mean underestimation of 69% for the Promonitor® assay).

CONCLUSIONS

This new LC-MS/MS method allows the simultaneous quantification of RTX and ECU in human samples and could be used for therapeutic drug monitoring.

Immune Checkpoint Inhibitors in Melanoma: A Review of Pharmacokinetics and Exposure-Response Relationships

Immune checkpoint inhibitors are a new class of monoclonal antibodies that amplify T-cell-mediated immune responses against cancer cells. The introduction of these new drugs, first anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4) and then anti-programmed death-1 (anti-PD1), was a major improvement in the treatment of advanced or metastatic melanoma, a highly immunogenic tumour. The development strategy for immune checkpoint immunotherapies differed from that traditionally used for cytotoxic therapies in oncology. The choices of doses at which to conduct clinical trials, and subsequently the choice of doses at which to use these new therapies, were not based on the identification of a maximum tolerated dose from dose-escalation studies; thus, pharmacokinetic and pharmacokinetic-pharmacodynamic modelling was essential. The studies conducted have shown that the pharmacokinetics of ipilimumab were linear and not time-dependent. In addition, there was a correlation between the trough concentrations of ipilimumab and its therapeutic efficacy. On the contrary, the anti-PD1 immunotherapies nivolumab and pembrolizumab had time-dependent pharmacokinetics. Their therapeutic efficacy was not related to their trough concentration, but there was a correlation between the clearance of anti-PD1 and the survival of melanoma patients. This review highlights the complexity of interpreting the exposure-response relationships of these agents. Further studies are needed to assess the value of therapeutic drug monitoring of immune checkpoint inhibitors in the treatment of melanoma.

Population Pharmacokinetics of Risankizumab in Healthy Volunteers and Subjects with Moderate to Severe Plaque Psoriasis: Integrated Analyses of Phase I-III Clinical Trials

Background and Objective

Risankizumab is an anti-interleukin (IL)-23 monoclonal antibody being developed for treatment of moderate to severe plaque psoriasis. This study provided a comprehensive analysis of risankizumab pharmacokinetics in healthy subjects and patients with plaque psoriasis using data across phase I–III clinical trials.

Methods

Plasma pharmacokinetic data from 1899 subjects, including 13,123 observations, who received single or multiple intravenous or subcutaneous doses of risankizumab (0.01–5 mg/kg intravenous [IV], 200–1200 mg IV, 0.25–1 mg/kg subcutaneous [SC], and 18–300 mg SC) across the phase I–III clinical program were analyzed using a non-linear mixed-effects modeling approach. The developed model was qualified and the clinical relevance of covariates statistically correlated with risankizumab clearance (CL) was evaluated using simulation analyses.

Results

Risankizumab pharmacokinetics were best described using a two-compartment model with first-order absorption and elimination. Risankizumab CL, volume of distribution at steady state (V_ss), and terminal-phase elimination half-life (t_½) were estimated to be approximately 0.31 L/day, 11.2 L, and 28 days, respectively, for a typical 90 kg psoriatic subject, approaching steady-state plasma exposures by week 16 of dosing. Absolute SC bioavailability (F) was 89%. Bodyweight, anti-drug antibody (ADA) titers ≥ 128 (detected in only 1% of ADA-evaluable subjects in phase III studies), baseline serum albumin, high-sensitivity C-reactive protein (hs-CRP), and serum creatinine were statistically correlated with risankizumab CL; however, they had no clinically relevant impact on exposure.

Conclusion

Risankizumab is characterized by dose-proportional, bi-exponential disposition with no difference in exposure between healthy subjects and patients with psoriasis. None of the covariates identified as being statistically correlated with risankizumab CL has a clinically meaningful impact on its exposure with the proposed psoriasis clinical regimen of 150 mg administered SC at weeks 0 and 4, and every 12 weeks thereafter.

ClinicalTrials.gov Identifiers

NCT01577550, NCT02054481, NCT02596217, NCT02684370, NCT02672852, NCT02684357, NCT02694523.

Novel strategies in immune checkpoint inhibitor drug development: How far are we from the paradigm shift?

The development of immune checkpoint inhibitors (ICI) represents a major milestone in immune-oncology. Over the years these agents have demonstrated efficacy in an increasing array of malignancies. Despite this success however, significant challenges remain. Novel approaches to both drug development and trial design are required to incorporate the unique pharmacokinetic and pharmacodynamic properties of ICIs. Further, it has also been established that the benefit of ICIs is limited to only a subset of patients. The molecular interactions between native immune cells and tumorigenesis and progression represent an active area of biomarker research, and elucidating the mechanisms of response and resistance is crucial to develop rational trial designs for the next wave of immune-oncology (IO) clinical trials, particularly in patients with primary and/or acquired resistance. Efforts are now being made to integrate both biological and clinical information using novel multi-omic approaches which are now being developed to further elucidate the molecular signatures associated with IO treatment response and resistance and enable rational drug development and trial design processes. As such, precision IO and the ability to deliver patient-specific choices for ICI monotherapies or combination therapies has become an increasingly tangible goal. We herein describe the current landscape in ICI drug development and discuss the challenges and future directions in this exciting and evolving era in immune-oncology.

Pharmacogenomics, Pharmacokinetics and Circulating Proteins as Biomarkers for Bevacizumab Treatment Optimization in Patients with Cancer: A Review

Bevacizumab is a monoclonal antibody that targets VEGF-A and inhibits tumor angiogenesis. Bevacizumab is approved for the treatment of various cancer, including metastatic colorectal cancer (mCRC), ovarian cancer, lung cancer, and others. Thus, it is widely used in oncology, but contrary to other therapeutic classes, there is still a lack of validating predictive factors for treatment outcomes with these agents. In recent years, the research for factors predictive of anti-VEGF treatments and especially bevacizumab response has been one of the most competitive translational research fields. Herein, we review and present the available literature of the clinical use of biomarkers, pharmacogenomics (PG), and therapeutic drug monitoring (TDM) approaches that can be used for the optimization of bevacizumab use in the era of precision medicine.

Dose recommendations for anticancer drugs in patients with renal or hepatic impairment

Renal or hepatic impairment is a common comorbidity for patients with cancer either because of the disease itself, toxicity of previous anticancer treatments, or because of other factors affecting organ function, such as increased age. Because renal and hepatic function are among the main determinants of drug exposure, the pharmacokinetic profile might be altered for patients with cancer who have renal or hepatic impairment, necessitating dose adjustments. Most anticancer drugs are dosed near their maximum tolerated dose and are characterised by a narrow therapeutic index. Consequently, selecting an adequate dose for patients who have either hepatic or renal impairment, or both, is challenging and definitive recommendations on dose adjustments are scarce. In this Review, we discuss the effect of renal and hepatic impairment on the pharmacokinetics of anticancer drugs. To guide clinicians in selecting appropriate dose adjustments, information from available drug labels and from the published literature were combined to provide a practical set of recommendations for dose adjustments of 160 anticancer drugs for patients with hepatic and renal impairment.

A clinical population pharmacokinetic/pharmacodynamic model for BIIB059, a monoclonal antibody for the treatment of systemic and cutaneous lupus erythematosus

A population pharmacokinetic/pharmacodynamic (popPK/PD) model for BIIB059 (anti-blood dendritic cell antigen 2 [anti-BDCA2]), a humanized immunoglobulin G1 monoclonal antibody currently under development for the treatment of SLE and CLE, is presented. BIIB059 binds BDCA2, a plasmacytoid dendritic cell (pDC)-specific receptor that inhibits the production of IFN-I and other inflammatory mediators when ligated. Phase 1 PK and PD data of healthy adult volunteers (HV, n = 87) and SLE subjects (n = 22) were utilized for the development of the popPK/PD model. The data included single and multiple dosing of intravenous and subcutaneous BIIB059. BDCA2 internalization (PD marker) was measured for all subjects by monitoring reduction of BDCA2 on pDC cell surface and used for development of the popPD model. A two-compartment popPK model with linear plus non-linear elimination was found to best describe BIIB059 PK. BDCA2 levels were best captured using an indirect response model with stimulation of the elimination of BDCA2. Clearance in SLE subjects was 25% higher compared to HV (6.87 vs 5.52 mL/h). Bodyweight was identified as only other covariate on clearance and central volume. The estimates of EC₅₀ and E_max were 0.35 μg/mL and 8.92, respectively. No difference in EC₅₀ and E_max was observed between SLE and HV. The popPK/PD model described the data accurately, as evaluated by pcVPCs and bootstrap. The presented popPK/PD model for BIIB059 provides valuable insight into the dynamics and dose-response relationship of BIIB059 for the treatment of SLE and CLE and was used to guide dose selection for the Phase 2 clinical study (NCT02847598).

Modeling and Simulation of the Pharmacokinetics and Target Engagement of an Antagonist Monoclonal Antibody to Interferon-γ-Induced Protein 10, BMS-986184, in Healthy Participants to Guide Therapeutic Dosing

BMS‐986184 is a human, second‐generation, anti–interferon‐γ–induced protein 10 (IP‐10) monoclonal antibody. In this study the pharmacokinetics and target engagement (TE) of BMS‐986184 in healthy participants were characterized using population‐based target‐mediated drug disposition (TMDD) modeling and data from a first‐in‐human study (NCT02864264). The results of the first‐in‐human study and the model generated were used to conduct stochastic simulations of a virtual population of healthy participants to predict pharmacokinetic exposures and TE responses for different dosage regimens. A 2‐compartment, 2‐target, TMDD structural model, assuming quasi‐steady‐state and stimulated production on treatment, was developed by simultaneous fitting of the total drug, serum‐free IP‐10, and serum total IP‐10 concentration data, with the second unobservable target contribution to drug elimination described by the Michaelis‐Menten elimination term. Model evaluation confirmed agreement between model predictions and observed data. Simulation of a virtual population of healthy individuals demonstrated that steady state was reached at the eighth dosing interval, and that around 150 mg subcutaneously every other week could be a suitable target dosage regimen for future clinical trials. Integrated modeling strategies such as this can be used to help guide rational clinical trial development of drugs with TMDD, leading to improved dose selection and greater patient benefits.

Population Pharmacokinetics of MCLA-128, a HER2/HER3 Bispecific Monoclonal Antibody, in Patients with Solid Tumors

BACKGROUND AND OBJECTIVES

MCLA-128 is a bispecific monoclonal antibody targeting the HER2 and HER3 receptors and is in development to overcome HER3-mediated resistance to anti-HER2 therapies. The aims of this analysis were to characterize the population pharmacokinetics of MCLA-128 in patients with various solid tumors, to evaluate patient-related factors that affect the disposition of MCLA-128, and to assess whether flat dosing is appropriate.

METHODS

MCLA-128 concentration data following intravenous administration were collected in a phase I/II clinical trial. Pharmacokinetic data were analyzed using non-linear mixed-effects modeling. Different compartmental models were evaluated. Various body size parameters including body weight, body surface area, and fat-free mass were evaluated as covariates in addition to age, sex, HER2 status, and tumor burden.

RESULTS

In total, 1115 serum concentration measurements were available from 116 patients. The pharmacokinetics of MCLA-128 was best described by a two-compartment model with linear and non-linear (Michaelis-Menten) clearance. Fat-free mass significantly affected the linear clearance and volume of distribution of the central compartment of MCLA-128, explaining 8.4% and 5.6% of inter-individual variability, respectively. Tumor burden significantly affected the non-linear clearance capacity. Simulations demonstrated that dosing based on body size parameters resulted in similar area under the plasma concentration-time curve for a dosing interval (AUC_0-τ), maximum and trough concentrations of MCLA-128, compared to flat dosing.

CONCLUSIONS

This analysis demonstrated that the pharmacokinetics of MCLA-128 exhibits similar disposition characteristics to other therapeutic monoclonal antibodies and that a flat dose of MCLA-128 in patients with various solid tumors is appropriate.

Optimizing Patient Outcomes with PD-1/PD-L1 Immune Checkpoint Inhibitors for the First-Line Treatment of Advanced Non-Small Cell Lung Cancer

The rapidly expanding repertoire of immune checkpoint inhibitors (ICIs) now includes two agents, pembrolizumab and atezolizumab, approved for first-line treatment of advanced non-small cell lung cancer (aNSCLC) as monotherapy or as part of chemoimmunotherapy. This review summarizes the clinical evidence supporting these indications, with a focus on strategies to optimize patient outcomes. These strategies include patient and tumor factors, adverse-effect profiles, pharmacokinetic and pharmacodynamic drug interactions, and quality of life and cost-effectiveness considerations. We performed a systematic literature search of the PubMed, Scopus, and Google Scholar databases, as well as a search of the conference proceedings of the American Society of Clinical Oncology, European Society for Medical Oncology, and American Association for Cancer Research (through August 31, 2019). The addition of ICIs to conventional chemotherapy as first-line treatment against aNSCLC is now part of the standard of care options. However, even though ICIs may be cost-effective in patients with aNSCLC, high drug and other associated costs can still be a barrier to treatment for patients. Moreover, the adverse-effect profiles of ICIs differ significantly from conventional chemotherapy, and some immune-related adverse effects may have a lasting impact on quality of life. Therefore, in adhering to a patient-centered model of care, clinicians should be mindful of patient- and treatment-specific factors when considering therapeutic options for patients with aNSCLC. Although the role of the immune system in cancer progression and regression has not been fully elucidated, the full clinical potential of immunotherapeutics in the treatment of cancer likely remains to be unleashed.

Population Pharmacokinetics of Alemtuzumab (Campath) in Pediatric Hematopoietic Cell Transplantation: Towards Individualized Dosing to Improve Outcome

BACKGROUND AND OBJECTIVE

Alemtuzumab (Campath^®) is used to prevent graft-versus-host disease and graft failure following pediatric allogeneic hematopoietic cell transplantation. The main toxicity includes delayed immune reconstitution, subsequent viral reactivations, and leukemia relapse. Exposure to alemtuzumab is highly variable upon empirical milligram/kilogram dosing.

METHODS

A population pharmacokinetic (PK) model for alemtuzumab was developed based on a total of 1146 concentration samples from 206 patients, aged 0.2-19 years, receiving a cumulative intravenous dose of 0.2-1.5 mg/kg, and treated between 2003 and 2015 in two centers.

RESULTS

Alemtuzumab PK were best described using a two-compartment model with a parallel saturable and linear elimination pathway. The linear clearance pathway, central volume of distribution, and intercompartmental distribution increased with body weight. Blood lymphocyte counts, a potential substrate for alemtuzumab, did not impact clearance.

CONCLUSION

The current practice with uniform milligram/kilogram doses leads to highly variable exposures in children due to the non-linear relationship between body weight and alemtuzumab PK. This model may be used for individualized dosing of alemtuzumab.

The impact of body composition parameters on severe toxicity of nivolumab

BACKGROUND

The occurrence of severe, acute limiting toxicity in patients receiving anti-programmed cell death receptor-1 monoclonal antibodies, such as nivolumab, is largely unpredictable. Sarcopenia was found to be associated with anti-cytotoxic T-lymphocyte-associated protein 4 acute toxicity. We explore the clinical and pharmacological parameters influencing nivolumab toxicity, including body composition.

METHODS

From June 2015 to January 2017, all consecutive patients treated with nivolumab in our institution were prospectively included. We studied the relationship between muscle mass assessed by computed tomography, nivolumab trough level (C_min) at day 14 assessed using the enzyme-linked immunosorbent assay method, and the occurrence of immune grade III or IV toxicity or any toxicity leading to treatment discontinuation (immune-related acute limiting toxicity [irALT]).

RESULTS

In our population (n = 92) with a majority of lung cancer (72%), forty-five (51.7%) patients were sarcopenic. The median plasma nivolumab C_min at day 14 was 15.4 μg/mL (interquartile range = 11.8-21.0). In multivariate analysis, hypoalbuminaemia (<35 g/L) was independently associated with low nivolumab C_min on day 14 (odds ratio [OR] = 0.09; 95% confidence interval [CI] = 0.01-0.59, p = 0.01) and overweight/obesity with high nivolumab C_min on day 14 (OR = 5.94; 95% CI = 1.25-28.29, p = 0.03). We observed 22 irALTs in 19 patients (21%). The most frequent irALT was respiratory (6.5%) disorders and gastrointestinal (4.3%) disorders. Patients with sarcopenia were at significantly increased risk of experiencing an irALT (OR = 3.84; 95% CI = 1.02-14.46, p = 0.047). No association was found between toxicity and nivolumab plasma C_min at day 14.

CONCLUSIONS

Our results highlight the importance of assessing body composition and suggest that sarcopenia could predict severe immune-related toxicity of nivolumab in real life.

Similar overall survival with reduced vs. standard dose bevacizumab monotherapy in progressive glioblastoma

INTRODUCTION

Bevacizumab has demonstrated activity in glioblastoma (GBM), but the true benefits and optimal dose-schedule are debated. A lower dose-schedule than standard-dose bevacizumab (10 mg/kg 2-weekly) might offer similar benefits with lower costs. At our Institution, patients are randomly assigned at time of primary diagnosis to Neuro-Oncologists, who have varying practices in terms of bevacizumab dose-schedule upon progression.

METHODS

In a retrospective analysis we examined overall survival (OS), measured from first administered bevacizumab dose until death, according to dose-schedule. Patients with de novo WHO Grade IV GBM who received standard- or reduced-dose (5 mg/kg 2-weekly) bevacizumab were included. MGMT methylation status and time from diagnosis to bevacizumab start were examined as prognostic variables. Clinical benefit and a comparative cost analysis were assessed.

RESULTS

In total, 1127 bevacizumab doses were administered to 118 patients [Median: 7, Range: 1-44]. Median OS (mOS) was 5.8 months. 69 (59%) patients received standard-dose bevacizumab (mOS: 5.97 months) and 49 patients received reduced-dose (mOS: 5.7 months). No statistically significant difference in OS between dosing schedule was seen (HR: 1.11, P-value: .584). Patients with MGMT methylated tumors (43%) had improved OS compared to those with unmethylated tumors; 7.03 vs 4.97 months (HR: 0.61, P-value: .027). If all patients were treated with reduced-dose bevacizumab, an estimated €2.4M cost reduction would be observed.

CONCLUSIONS

In this retrospective study, reduced-dose bevacizumab schedule resulted in similar OS to standard-dose bevacizumab monotherapy with substantial cost savings. MGMT methylation appears to convey a survival benefit in the setting of bevacizumab treatment for progressive GBM.

Clinical and Pharmacologic Features of Monoclonal Antibodies and Checkpoint Blockade Therapy in Multiple Myeloma

Background:

Survival of multiple myeloma patients has considerably improved in the last decades thanks to the introduction of many new drugs, including immunomodulatory agents, proteasome inhibitors and, more recently, monoclonal antibodies.

Methods:

We analyzed the most recent literature focusing on the clinical and pharmacologic aspects of monoclonal antibody-based therapies in multiple myeloma, including monoclonal antibodies directed against plasma cell antigens, as well as checkpoint blockade therapy directed against immune inhibitory molecules, used as single agents or in combination therapy.

Results:

Anti-CD38 monoclonal antibodies including daratumumab, isatuximab and MOR202 have shown outstanding results in relapsed and/or refractory multiple myeloma patients. The addition of daratumumab to bortezomib-dexamethasone or lenalidomidedexamethasone substantially improved patients’ outcome in this patient population. The anti- SLAMF7 molecule elotuzumab in combination with lenalidomide-dexamethasone showed to be superior to lenalidomide-dexamethasone alone, without adding meaningful toxicity. Checkpoint blockade therapy in combination with immunomodulatory agents produced objective responses in more than 50% of treated patients. However, this combination was also associated with an increase in toxicity and a thorough safety evaluation is currently ongoing.

Conclusion:

Monoclonal antibodies are reshaping the standard of care for multiple myeloma and ongoing trials will help physicians to optimize their use in order to further improve patients’ outcome.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Inflammatory Bowel Disease

According to recent clinical consensus, pharmacotherapy of inflammatory bowel disease (IBD) is, or should be, personalized medicine. IBD treatment is complex, with highly different treatment classes and relatively few data on treatment strategy. Although thorough evidence-based international IBD guidelines currently exist, appropriate drug and dose choice remains challenging as many disease (disease type, location of disease, disease activity and course, extraintestinal manifestations, complications) and patient characteristics [(pharmaco-)genetic predisposition, response to previous medications, side-effect profile, necessary onset of response, convenience, concurrent therapy, adherence to (maintenance) therapy] are involved. Detailed pharmacological knowledge of the IBD drug arsenal is essential for choosing the right drug, in the right dose, in the right administration form, at the right time, for each individual patient. In this in-depth review, clinical pharmacodynamic and pharmacokinetic considerations are provided for tailoring treatment with the most common IBD drugs. Development (with consequent prospective validation) of easy-to-use treatment algorithms based on these considerations and new pharmacological data may facilitate optimal and effective IBD treatment, preferably corroborated by effectiveness and safety registries.

Immune Checkpoint Inhibitors: Toward New Paradigms in Renal Cell Carcinoma

Immune modulatory treatment regimens, led by immune checkpoint inhibitors, have transformed the treatment of clear-cell renal cell carcinoma. First-in-class, the PD-1 inhibitor nivolumab improved overall survival in advanced renal cell carcinoma following prior anti-angiogenic therapy, an important shift in the management of clear-cell renal cell carcinoma. Further improvements of long-term outcomes will be driven by combinations in the first-line setting, including PD-1/PD-L1 associated with antiangiogenic therapies, or PD1/PD-L1 inhibitors with other immune checkpoint inhibitors such as anti-CTLA-4, anti-LAG-3 or TIM-3 targeted therapies. The first two randomized Phase 3 trials assessing these combinations have now challenged sunitinib in first-line setting. First, the CheckMate 214 trial demonstrated an objective response rate and overall survival benefit for the combination of nivolumab plus ipilimumab in the intermediate- and poor-risk patients. Second, the IMMotion 151 study demonstrated a progression-free survival benefit for the atezolizumab plus bevacizumab combination by investigator assessment. Further Phase 3 trials are awaited with tyrosine kinase and immune checkpoint inhibitor combinations. Clinical trials of immune checkpoint inhibitors are also actively investigated in the localized adjuvant or neoadjuvant setting. Nevertheless, the search for biomarkers along with new clinical trial designs will be crucial to better select the patients that may derive the greatest benefit from these advances. The continuing improvement of antitumor immunity comprehension and the emergence of new immune modulatory treatments will deeply change the management of renal cell carcinoma for the years to come.

Pharmacokinetics of Risankizumab in Asian Healthy Subjects and Patients With Moderate to Severe Plaque Psoriasis, Generalized Pustular Psoriasis, and Erythrodermic Psoriasis

Risankizumab, a humanized monoclonal antibody that targets interleukin-23 p19 subunit, was developed for the treatment of psoriasis. This work characterizes risankizumab pharmacokinetics in Japanese and Chinese healthy subjects compared with white healthy subjects and in Japanese patients with moderate to severe plaque psoriasis, generalized pustular psoriasis, or erythrodermic psoriasis. A phase 1, single-dose study evaluated risankizumab pharmacokinetics and safety/tolerability in healthy white (18 and 300 mg subcutaneous [SC]), Japanese (18, 90, and 300 mg SC and 200, 600, and 1200 mg intravenous [IV]), and Chinese (18, 90, and 300 mg SC) subjects; pharmacokinetic data were analyzed using noncompartmental methods. Risankizumab pharmacokinetic data from phase 2/3 studies in Japanese patients with plaque psoriasis, generalized pustular psoriasis, or erythrodermic psoriasis following multiple SC doses of 75 mg or 150 mg were analyzed using a population pharmacokinetic approach along with data from the phase 1 and global phase 1 to 3 studies. Risankizumab plasma exposures (peak plasma concentration and area under the concentration-time curve) were approximately dose-proportional across 18- to 300-mg SC or 200- to 1200-mg IV doses. Risankizumab terminal elimination half-life (harmonic mean 27-34 days) was comparable across doses and ethnicities. Risankizumab exposures were approximately 20% to 30% higher in Japanese and Chinese healthy subjects compared with white healthy subjects or in Japanese patients compared with non-Japanese patients. After accounting for body-weight differences, risankizumab exposures were comparable across ethnicities. Overall, there was no ethnic impact on risankizumab pharmacokinetics, and the small difference in exposure due to body weight has no clinical relevance.

Monoclonal antibodies for severe asthma: Pharmacokinetic profiles

Several monoclonal antibodies (mAbs) (omalizumab, mepolizumab, reslizumab, benralizumab, and dupilumab) are currently approved for the treatment of severe asthma. They have complex pharmacokinetic profiles. These profiles are unique in that they are dependent on their structure as well as can be markedly influenced by the biology of their target antigen, but their general behaviour can still be considered a class property, similar to their endogenous IgG counterpart. They cannot be administered by oral route, have a slow distribution into tissue, are metabolized to peptides and amino acids in several tissues but are protected from degradation by binding to protective receptors (the FcRn), which explains their long elimination half-lives. Their clearance is nonlinear because of the saturation of the target-mediated elimination. Also anti-drug antibody (ADA) response and off-target binding, as well as their glycosylation pattern, can influence the pharmacokinetics of mAbs.

Key insights from therapeutic drug monitoring in Crohn's disease patients

INTRODUCTION

The incidence and prevalence of Crohn's disease are increasing causing a significant disease burden. Therapeutic drug monitoring (TDM) is advocated as a promising tool for personalized or individual-tailored therapy strategies and has been welcomed as a new means to improve current therapy strategies. Nevertheless, pharmacokinetic-based TDM has limitations, and straightforward target concentrations for most therapies are lacking. Areas covered: In the following concise review of literature, key insights of TDM in thiopurine, methotrexate, anti-TNF, vedolizumab and ustekinumab therapy for Crohn's disease are being described. Expert opinion: Therapeutic drug monitoring may, up till now, be helpful to adjust thiopurine and infliximab therapy, primarily in a reactive setting, in case of inefficacy and of occurrence of adverse event. With this restricted application, the goal of individualized therapy based on TDM has not yet been achieved.

Correlation between nivolumab exposure and treatment outcomes in non-small-cell lung cancer

INTRODUCTION

Nivolumab treatment is subject to large interpatient variability in both efficacy and toxicity, which may partly be explained by differences in nivolumab exposure. Exposure-response relationships in regular healthcare have not been extensively investigated for nivolumab. Therefore, we aimed to identify possible exposure-response relationships in nivolumab-treated patients with non-small-cell lung cancer (NSCLC).

METHODS

Patients with NSCLC who started second-line nivolumab therapy (3 mg/kg Q2W) between May 5th 2016 and August 1st 2017, and from whom serial blood samples, toxicity data and outcome data were prospectively collected, were included. Follow-up was carried out until November 1st 2017. Patients were classified according to the best overall response (BOR) based on the Response Evaluation Criteria in Solid Tumours, v1.1, and toxicities according to the Common Terminology Criteria for Adverse Events. Nivolumab trough concentrations were measured after 2, 4 and 10 weeks of treatment, excluding dose delays, and calculated geometric means were tested versus BOR or toxicity using analysis of variance and an independent samples t-test, respectively. Overall survival (OS) and progression-free survival were compared between high and low trough concentration groups.

RESULTS

Seventy-six patients were evaluable for analyses. Responders (n = 15) had higher mean trough concentrations than patients with progression (n = 33): 47% higher after 2 weeks (p = 0.001), 53% higher after 4 weeks (p = 0.008) and 73% higher after 10 weeks (p = 0.002). Higher trough concentrations were associated with longer OS (p = 0.001).

CONCLUSIONS

This study shows that patients with NSCLC with a response to nivolumab had a higher nivolumab exposure than patients with progression, indicating a potential exposure-response relationship. Further clinical research should focus on clarifying these exposure-response relationships.

mRNA as novel technology for passive immunotherapy

While active immunization elicits a lasting immune response by the body, passive immunotherapy transiently equips the body with exogenously generated immunological effectors in the form of either target-specific antibodies or lymphocytes functionalized with target-specific receptors. In either case, administration or expression of recombinant proteins plays a fundamental role. mRNA prepared by in vitro transcription (IVT) is increasingly appreciated as a drug substance for delivery of recombinant proteins. With its biological role as transient carrier of genetic information translated into protein in the cytoplasm, therapeutic application of mRNA combines several advantages. For example, compared to transfected DNA, mRNA harbors inherent safety features. It is not associated with the risk of inducing genomic changes and potential adverse effects are only temporary due to its transient nature. Compared to the administration of recombinant proteins produced in bioreactors, mRNA allows supplying proteins that are difficult to manufacture and offers extended pharmacokinetics for short-lived proteins. Based on great progress in understanding and manipulating mRNA properties, efficacy data in various models have now demonstrated that IVT mRNA constitutes a potent and flexible platform technology. Starting with an introduction into passive immunotherapy, this review summarizes the current status of IVT mRNA technology and its application to such immunological interventions.

Lack of ethnic differences in the pharmacokinetics and pharmacodynamics of evolocumab between Caucasian and Asian populations

AIMS

To evaluate the potential ethnic differences in the pharmacokinetics (PK) and pharmacodynamics (PD) of evolocumab in Caucasian and Asian populations using population PK/PD modelling analysis.

METHODS

Data from different ethnic groups in 5 Phase I clinical trials, including two American studies, one Japanese study and two Chinese studies, were chosen for model building and evaluation. A target-mediated drug disposition model together with an indirect response model best captured evolocumab binding and the removal of unbound proprotein convertase subtilisin/kexin type 9 (PCSK9) as well as a reduction in circulating low-density lipoprotein cholesterol (LDL-C). Ethnicity and other related factors (body weight, target expression level etc.) were analysed as potential covariates.

RESULTS

The estimated linear clearance and volume of evolocumab were 0.24 l day^-1 and 2.75 l, respectively, which was consistent with the previous modelling results from the American trials. The time course of the LDL-C reduction was described by an indirect response model with the elimination rate of LDL-C being modulated by unbound PCSK9. The concentration of unbound PCSK9 associated with the half-maximal inhibition of LDL-C elimination was 1.28 nmol l^-1 . Both the PK and PD characteristics were consistent between the Caucasian and Asian populations.

CONCLUSION

The target-mediated drug disposition model successfully described the PK and PD characteristics of evolocumab, and this analysis found no significant differences in the PK/PD relationship for its LDL-C lowering effects between Caucasians and Asians.

Dose dependence and durability of the therapeutic effects of Asparagus cochinchinensis fermented extract in an ovalbumin-challenged asthma model

The butanol extract of Asparagus cochinchinensis roots fermented with Weissella cibaria (BAfW) significantly suppressed the inflammatory response induced by lipopolysaccharide (LPS) treatment in RAW264.7 cells. To investigate the dose dependence and durability of BAfW on the anti-asthma effects, alterations in key parameters were measured in ovalbumin (OVA)-challenged Balb/c mice treated with the different doses of BAfW at three different time points. The number of immune cells, OVA-specific IgE level, thickness of respiratory epithelium and mucus score decreased significantly in a dose-dependent manner in response to treatment with 125 to 500 mg/kg BAfW (P<0.05), although the highest level was detected in the 500 mg/kg treated group. Moreover, the decrease in these parameters was maintained from 24 to 48 h in the 500 mg/kg of BAfW treated group. At 72 h, the effects of BAfW on the number of immune cells, OVA-specific IgE level and thickness of respiratory epithelium partially disappeared. Overall, this study provides the first evidence that the anti-asthma effect of BAfW may reach the maximum level in OVA-challenged Balb/c mice treated with 500 mg/kg and that these effects can last for 48 h.

Anti-TNF Therapy in Crohn's Disease

Crohn’s disease (CD) accounts for a variety of clinical manifestations or phenotypes that stem from chronic inflammation in the gastrointestinal tract. Its worldwide incidence is increasing including younger or childhood-onset of disease. The natural history of Crohn’s disease is characterized by a remitting and relapsing course that progresses to complications and surgery in most patients. The goals of treatment are to achieve clinical and endoscopic remission, to avoid disease progression and minimise surgical resections. Medical treatment usually features antibiotics, corticosteroids, immunomodulators (thiopurines, methotrexate). Anti-TNF (tumour necrosis factor) therapy was approved for use in Crohn’s disease in 1998, and has changed the paradigm of treatment, leading to improved rates of response and remission in patients. There are significant considerations that need to be borne in mind, when treating patients including immunogenicity, safety profile and duration of treatment.

Effects of an Unlabeled Loading Dose on Tumor-Specific Uptake of a Fluorescently Labeled Antibody for Optical Surgical Navigation

PURPOSE

Intraoperative optical imaging to guide surgeons during oncologic resections offers a unique and promising solution to the ambiguity of cancer margins to tactile and visual assessment that results in devastatingly high rates of positive margins. Sequestering of labeled antibodies by normal tissues with high expression of the antibody target, or "antigen sinks", diminishes the efficacy of these probes to provide contrast between the tumor and background tissues by decreasing the amount of circulating probe available for uptake by the tumor and by increasing the fluorescence of non-tumor tissues. We hypothesized that administering a dose of unlabeled antibody prior to infusion of the near-infrared (NIR) fluorescently labeled antibody would improve tumor-specific uptake and contrast of the fluorescently labeled probe by occupying extra-tumoral binding sites, thereby increasing the amount of labeled probe available for uptake by the tumor.

PROCEDURES

In this study, we explore this concept by testing two different "pre-load" doses of unlabeled cetuximab (the standard 10-mg test dose, and a larger, experimental 100-mg test dose) in six patients receiving cetuximab conjugated to the fluorescent dye IRDye800CW (cetuximab-IRDye800CW) in a clinical trial, and compared the amount of fluorescent antibody in tumor and background tissues, as well as the tumor-specific contrast of each.

RESULTS

The patients receiving the larger preload (100 mg) of unlabeled cetuximab demonstrated significantly higher concentrations (9.5 vs. 0.1 μg) and a longer half-life (30.3 vs. 20.6 days) of the labeled cetuximab in plasma, as well as significantly greater tumor fluorescence (32.3 vs. 9.3 relative fluorescence units) and tumor to background ratios (TBRs) (5.5 vs. 1.7).

CONCLUSIONS

Administering a preload of unlabeled antibody prior to infusion of the fluorescently labeled drug may be a simple and effective way to improve the performance of antibody-based probes to guide surgical resection of solid malignancies.

The comparative immunogenicity of biologic therapy and its clinical relevance in psoriatic arthritis: a systematic review of the literature

INTRODUCTION

Biologic agents have demonstrated efficacy in treating patients with psoriatic arthritis (PsA). Biologic agents also have an intrinsic capacity to induce an immune response in patients that could result in unwanted adverse events and/or treatment failure.

AREAS COVERED

In this systematic literature review, the authors document the incidence of immune responses, primarily anti-drug antibodies (ADA), to the biologic therapeutic agents currently in clinical practice for the treatment of PsA. The authors discuss the importance of these responses with respect to clinical practice.

EXPERT OPINION

Our evaluation of the published literature shows that the immune responses to the various biologic therapeutic agents currently being used to treat PsA are similar to those observed for these agents in other rheumatic diseases. Moreover, similar to observations in other rheumatic diseases, the incidence of ADA formation to biologic agents in patients with PsA is often decreased when patients are given concomitant treatment with disease-modifying anti-rheumatic drugs. These data strongly suggest that the immune response is a characteristic of the biologic agent. Using therapeutic drug monitoring may be an approach to assess the immune response to the agent and to mitigate the potential impact on efficacy and safety, and consequently optimize treatment.