A platform immunoassay for the quantification of biotherapeutics with glycine-serine linkers.

Assessing the pharmacokinetics of biotherapeutics is essential across all phases of drug development to understand drug exposure. At early stages, platform drug quantification immunoassays offer a versatile method for evaluating exposure for diverse biotherapeutics when specific reagents are not yet available, providing fast data for molecules with common structural features. To ensure clearly defined bioanalytical data, it is essential to conduct interference testing for anti-drug antibodies (ADA) or soluble target (starget), although these assays measure total exposure.

Comparison of assay formats used for the detection of pre-existing anti-drug antibodies against monoclonal antibodies.

Assessment of pre-existing anti-drug antibody (preADA) reactivity at early drug development stages can be beneficial for candidate selection. We investigated the applicability of a generic immune-complex anti-drug antibody (ADA) assay for early preADA assessment as an easily available alternative to the commonly used ADA bridging assay. The results confirmed the expected assay difference regarding isotype detectability.

Evaluation of potential biotin interference in immunogenicity testing.

One-step bridging assays typically used for immunogenicity testing may be challenged by biotin interference (BI) caused by widely available dietary supplementation or medically prescribed high-dose therapies. We investigated BI in two one-step antidrug antibody assays. Both assays showed biotin-related interference, with the peptide-based assay being less affected than the antibody-based assay.

Pharmacokinetics and metabolism of formestane in breast cancer patients.

Formestane (Lentaron(R), 4-hydroxyandrostenedione) is a steroidal aromatase inhibitor used for treatment of advanced breast cancer. Clinically, it is administered as a depot form once fortnightly by intramuscular (i.m.

Characterization of a novel diclofenac metabolite in human urine by capillary gas chromatography-negative chemical ionization mass spectrometry.

A sensitive analytical method was developed to characterize diclofenac metabolites in small amounts of body fluids. Desalted and lyophilized urine samples were extracted with supercritical carbon dioxide directly or after acidic hydrolysis. The extracts were derivatized with N-tert.