Biostring has developed enzyme-linked immunosorbent assays (ELISAs) for the pharmacokinetic (PK) monitoring of serum antibody levels.

The ELISA is a well established immunoassay, with clear guidelines for validation when used as a quantitative assay. However, these parameters may not always be relevant for a semi-quantitative assay used to assess whether a sample is positive or negative for a novel marker such as an antibody developed against a therapeutic antibody. We here are in the development of a quantitative PK ELISA and the different approaches of validation to prove each assay which are ‘fit for purpose.’ The parameters of linearity, accuracy, lowest level of detection, intra-assay and inter-assay variability were assessed for the quantitative PK assay. The validation outcome showed that each assay was robust, reliable and accurate to meet the requirements of the intended analytical application, that being to 1) quantitatively determine the concentration of antibody in the serum. Each assay has been successfully translated for use in a clinical trial with adequate quality controls and acceptance criteria set for monitoring consistency and performance.