Immunoglobulin G Receptors (FcγR), in Addition to Target-Antigen and Neonatal Fc Receptor (FcRn), Influence Rituximab Pharmacokinetics.

Introduction: Rituximab, an anti-cluster of differentiation (CD)-20 monoclonal antibody, is used in the treatment of non-Hodgkin lymphoma (NHL), chronic lymphocytic leukemia, and rheumatoid arthritis. The pharmacokinetics of rituximab have been reported to be target mediated, but this alone may not fully explain the nonlinear decay of its concentrations over time.

Objective: This study aimed to explore the potential role of immunoglobulin (Fc gamma receptor; FcγR) and neonatal Fc receptor (FcRn) in the disposition of rituximab.

A Fab of trastuzumab to treat HER2 overexpressing breast cancer brain metastases.

Despite major therapeutic advances for two decades, including the most recently approved anti-HER2 drugs, brain metastatic localizations remain the major cause of death for women with metastatic HER2 breast cancer. The main reason is the limited drug passage of the blood-brain barrier after intravenous injection and the significant efflux of drugs, including monoclocal antibodies, after administration into the cerebrospinal fluid. We hypothesized that this efflux was linked to the presence of a FcRn receptor in the blood-brain barrier.

Confounding mitigation for the exposure-response relationship of bevacizumab in colorectal cancer patients.

Aims: The exposure-response relationship of bevacizumab may be confounded by various factors, including baseline characteristics, time-dependent target engagement and recursive relationships between exposure and response, requiring effective mitigation. This study aimed to investigate the exposure-response relationships of bevacizumab in metastatic colorectal cancer (mCRC) patients while mitigating potential biases.

Methods: Bevacizumab pharmacokinetics was described using target-mediated drug disposition modelling.

Relationship Between Cetuximab Target-Mediated Pharmacokinetics and Progression-Free Survival in Metastatic Colorectal Cancer Patients.

Background And Objective: Cetuximab, an anti-epidermal growth factor receptor (EGFR) monoclonal immunoglobulin (Ig)G1 antibody, has been approved for the treatment of metastatic colorectal cancer (mCRC). The influence of target-antigen on cetuximab pharmacokinetics has never been investigated using target-mediated drug disposition (TMDD) modelling. This study aimed to investigate the relationship between cetuximab concentrations, target kinetics and progression-free survival (PFS).

Infliximab Efficacy May Be Linked to Full TNF-α Blockade in Peripheral Compartment-A Double Central-Peripheral Target-Mediated Drug Disposition (TMDD) Model.

Infliximab is an anti-TNF-α monoclonal antibody approved in chronic inflammatory bowel diseases (IBD). This study aimed at providing an in-depth description of infliximab target-mediated pharmacokinetics in 133 IBD patients treated with 5 mg/kg infliximab at weeks 0, 2, 14, and 22. A two-compartment model with double target-mediated drug disposition (TMDD) in both central and peripheral compartments was developed, using a rich database of 26 ankylosing spondylitis patients as a reference for linear elimination kinetics.

The Influence of Underlying Disease on Rituximab Pharmacokinetics May be Explained by Target-Mediated Drug Disposition.

Background And Objectives: Rituximab is an anti-CD20 monoclonal antibody approved in several diseases, including chronic lymphocytic leukemia (CLL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), rheumatoid arthritis (RA), and anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). The influence of underlying disease on rituximab pharmacokinetics has never been investigated for several cancer and non-cancer diseases simultaneously. This study aimed at assessing this influence using an integrated semi-mechanistic model accounting for target-mediated elimination of rituximab.

Association of IgG1 Antibody Clearance with FcγRIIA Polymorphism and Platelet Count in Infliximab-Treated Patients.

The FcγRIIA/CD32A is mainly expressed on platelets, myeloid and several endothelial cells. Its affinity is considered insufficient for allowing significant binding of monomeric IgG, while its H131R polymorphism (histidine > arginine at position 131) influences affinity for multimeric IgG2. Platelet FcγRIIA has been reported to contribute to IgG-containing immune-complexe clearance.

Panitumumab and cetuximab affect differently miRNA expression in colorectal cancer cells.

Resistance to anti-EGFR monoclonal antibodies in metastatic colorectal cancer (CRC) is frequent and prognostic biomarkers are lacking. MicroRNAs (miR) are good candidates in this context. We aimed to characterize cetuximab and panitumumab exposure influence on miR expression in colorectal cancer cells to identify those regulating the EGFR pathway and implicated in resistance to treatment.

A robust enzyme-linked immunosorbent assay to measure serum ramucirumab concentrations.

Ramucirumab, an anti-VEGFR2 monoclonal antibody, has been approved for the treatment of metastatic gastric and colorectal cancer. An assay measuring ramucirumab serum concentrations was needed to investigate its pharmacokinetics and concentration-response relationship. An ELISA was developed and validated according to the international guidelines for ligand-binding assays.

Antigen Mass May Influence Trastuzumab Concentrations in Cerebrospinal Fluid After Intrathecal Administration.

Intravenous administration of monoclonal antibodies leads to low concentrations in the central nervous system, which is a serious concern in neuro-oncology, especially in leptomeningeal carcinomatosis of HER2-overexpressing breast cancer. Case reports of i.t.

Methotrexate effect on immunogenicity and long-term maintenance of adalimumab in axial spondyloarthritis: a multicentric randomised trial.

Objectives: Anti-drug antibodies (ADA) are responsible for decreased adalimumab efficacy in axial spondyloarthritis (SpA). We aimed to evaluate the ability of methotrexate (MTX) to decrease adalimumab immunisation.

Methods: A total of 110 patients eligible to receive adalimumab 40 mg subcutaneously (s.

A successful compartmental approach for the treatment of breast cancer brain metastases.

Background: Brain metastases are challenging daily practice in oncology and remain a compartmental problem since most anti-cancer drugs do not cross the blood-brain barrier at relevant pharmacological concentrations.

Methods: In a young woman with HER2-overexpressing breast cancer resistant to standard treatments, at the time of brain metastases progression, a ventricular reservoir was implanted for intrathecal drug injections and detailed pharmacokinetic studies.

Results: A first association of intrathecal trastuzumab with intravenous cisplatin was offered to the patient.

Phase I feasibility study for intrathecal administration of trastuzumab in patients with HER2 positive breast carcinomatous meningitis.

Purpose: Leptomeningeal carcinomatosis (MC) is commonly associated with HER2-positive breast cancer (HER2-BC), with a poor prognosis and no standardised treatment. We conducted a phase I dose-escalation study of intrathecal (IT) administration of trastuzumab in HER2-BC patients with MC to determine the maximum tolerated dose (MTD), which was based on both the achievement of a trastuzumab intra-cerebrospinal fluid concentration close to a conventional therapeutic plasma concentration (30 mg/L) and/or dose-limiting toxicity (DLT).

Methods: The protocol planned IT administration of trastuzumab (30 mg, 60 mg, 100 mg or 150 mg dose levels) once a week, over the course of at least 4 weeks.

Development and validation of an ELISA to study panitumumab pharmacokinetics.

Aim: Panitumumab is a monoclonal antibody directed against EGFR that is approved for the treatment of metastatic colorectal cancer. To investigate its pharmacokinetics and concentration-response relationship, a validated assay is required.

Results: An ELISA assay was developed and validated according to international recommendations.

Model-Based Therapeutic Drug Monitoring of Infliximab Using a Single Serum Trough Concentration.

Background And Objectives: The pharmacokinetics of infliximab are highly variable and influence clinical response in chronic inflammatory diseases. The goal of this study was to build a Bayesian model allowing predictions of upcoming infliximab concentrations and dosing regimen adjustment, using only one concentration measurement and information regarding the last infliximab infusion.

Methods: This retrospective study was based on data from 218 patients treated with infliximab in Tours University Hospital who were randomly assigned to learning (two-thirds) or validation (one-third) data subsets.

Development and validation of an enzyme-linked immunosorbent assay to measure free eculizumab concentration in serum.

Aim: Eculizumab is a monoclonal antibody toward C5 fraction of the complement system. It is approved to treat paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome. To perform pharmacokinetic studies and therapeutic drug monitoring, a validated assay is required.

Crucial Role for Immune Complexes but Not FcRn in Immunization against Anti-TNF-α Antibodies after a Single Injection in Mice.

The immunogenicity of infliximab and adalimumab is a major concern because patients may develop Abs also called antidrug Abs (ADA), directed against these anti-TNF-α Abs after just a few weeks of treatment. These ADAs can lead to a decrease in biologic concentration, which is associated with lower treatment efficacy. Our aim was to study the involvement of immune complexes and neonatal Fc receptor (FcRn) in the emergence of ADAs in the case of anti-TNF-α Abs.

Immunoassays for Measuring Serum Concentrations of Monoclonal Antibodies and Anti-biopharmaceutical Antibodies in Patients.

Monoclonal antibodies (mAbs) may be used as biopharmaceuticals to treat various diseases, ranging from oncology to inflammatory and cardiovascular affections. Trustworthy analytical methods are necessary to study their pharmacokinetics, both during their development and in post-marketing studies. Because biopharmaceuticals are macromolecules, ligand-binding assays (both immunoassays and bioassays) are methods of choice to measure their concentrations.

BRAF inhibitor discontinuation and rechallenge in advanced melanoma patients with a complete initial treatment response.

BRAF inhibitors (BRAFi), a targeted therapy, are used to treat metastatic late-stage melanomas harbouring the BRAF-V600 mutation (found in about 50% of melanomas). The targeted therapy is generally maintained until tumour progression or major toxicity occurs, although responses are often limited in time. It is unknown whether melanoma patients achieving a complete response with targeted therapy can safely discontinue treatment.

Antigenic burden and serum IgG concentrations influence rituximab pharmacokinetics in rheumatoid arthritis patients.

Aims: Rituximab is a monoclonal antibody directed against CD20, which is approved in rheumatoid arthritis (RA). This study aimed at assessing the influence of CD19+ cell counts as target-antigen amount, and of immunoglobulin G (IgG) serum concentrations on rituximab pharmacokinetics in RA patients.

Methods: In a cohort of 64 RA patients who had received repetitive courses of rituximab, the influence of CD19+ cell count, IgG serum concentration, body surface area, sex and disease activity score in 28 joints on rituximab pharmacokinetic parameters was assessed using a population pharmacokinetic analysis.

Efficacy of a rituximab regimen based on B cell depletion in thrombotic thrombocytopenic purpura with suboptimal response to standard treatment: Results of a phase II, multicenter noncomparative study.

The standard four-rituximab infusions treatment in acquired thrombotic thrombocytopenic purpura (TTP) remains empirical. Peripheral B cell depletion is correlated with the decrease in serum concentrations of anti-ADAMTS13 and associated with clinical response. To assess the efficacy of a rituximab regimen based on B cell depletion, 24 TTP patients were enrolled in this prospective multicentre single arm phase II study and then compared to patients from a previous study.

Development and validation of an enzyme-linked immunosorbent assay to measure adalimumab concentration.

Background: Adalimumab is a therapeutic antibody used for treating inflammatory diseases. To understand interindividual PK variability, there is a need to develop and validate an assay to measure serum adalimumab concentrations.

Methods: An ELISA was developed on microtiter plates coated with TNF-α.