ABSTRACT
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. MATERIALS & METHODS: An indirect ELISA with recombinant human C5 sensitized microtiter plates were developed. RESULTS: The assay allows the measurement of free eculizumab concentration in human serum. The LOD, LLOQ and ULOQ were 0.091, 0.25 and 82.35 mg/l, respectively. The assay meets EMA and US FDA guidelines criteria for the validation of a ligand-binding assay. CONCLUSION: This method is validated and can be used in PK and PK-PD studies as well as to perform therapeutic drug monitoring of free eculizumab.
Subject(s)
Antibodies, Monoclonal, Humanized/blood , Blood Chemical Analysis/methods , Enzyme-Linked Immunosorbent Assay/methods , Adult , Aged , Antibodies, Monoclonal, Humanized/immunology , Antibodies, Monoclonal, Humanized/pharmacokinetics , Complement System Proteins/immunology , Drug Monitoring , Female , Humans , Limit of Detection , Male , Middle Aged , Tissue DistributionABSTRACT
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. Seven nonzero adalimumab standards ranging from 0.05 to 50 mg/l and three quality controls (0.2, 2.5 and 7 mg/l) were tested for their intra and interday precision on six occasions. RESULTS: The LOD, LLOQ and ULOQ of the assay were 0.022, 0.073 and 9 mg/l, respectively. CONCLUSION: This method is accurate, reproducible and may be useful for PK studies and for therapeutic drug monitoring of adalimumab.
Subject(s)
Adalimumab/blood , Anti-Inflammatory Agents/blood , Drug Monitoring/methods , Enzyme-Linked Immunosorbent Assay/methods , Humans , Limit of Detection , Reproducibility of ResultsABSTRACT
INTRODUCTION: Bevacizumab is an antivascular endothelial growth factor humanized monoclonal antibody used to inhibit angiogenesis in cancer. It displays an important interindividual pharmacokinetic variability, which could explain part of the interindividual differences in clinical response. Therefore, an assay to measure bevacizumab serum concentrations is needed. METHODS: An enzyme-linked immunosorbent assay was developed using microtiter plates sensitised with vascular endothelial growth factor 165, a recombinant form of vascular endothelial growth factor. Lower and upper limits of quantitation as well as limit of detection were determined. Eight calibrators and three quality controls, with concentrations of 5 mg/L, 30 mg/L, and 75 mg/L, were tested on five occasions initially and on five subsequent occasions. Trough and peak serum concentrations of bevacizumab were measured in patients with metastatic colorectal cancer. Bevacizumab concentrations were described using a two-compartment population pharmacokinetic model with first-order constants. RESULTS: Imprecision and accuracy of calibrators and quality controls were 20% or less, except for the zero calibrator. The limit of detection was 0.033 mg/L. Lower and upper limits of quantitation were 5 and 75 mg/L, respectively. A total of 175 blood samples was available for analysis from 16 patients. Median (range) trough and peak concentrations during the treatment were 47.2 (9.6-106.9) mg/L and 159.3 (33.0-327.3) mg/L, respectively. CONCLUSION: This method is rapid, accurate, reproducible, and may be useful for pharmacokinetic and pharmacokinetic-pharmacodynamic studies as well as in therapeutic drug monitoring of bevacizumab.
