Ligand binding assays and anti-drug antibodies, analytical approaches and validation issues

Drug assays using ligand binding assays for determining the pharmacokinetics of macromolecules was the subject of a major international conference held in 2000, sponsored by the FDA and the American Association of Pharmaceutical Scientists (AAPS). The various analytical approaches using these techniques and the potential evaluation strategies are discussed in the context of assay calibration, precision, accuracy, recovery, and dilution linearity assays. Assays to measure anti-drug antibodies, raisedin vivo following therapy, represent a unique class of bioanalytical procedure that have very distinct requirements for assay evaluation. The regulatory guidelines that apply to the pharmacokinetic evaluation of drugs although not directly applicable can be loosely interpreted to fit this specific group of assays.