Assay concept for detecting anti-drug IgM in human serum samples by using a novel recombinant human IgM positive control.

Aim: Development and qualification of an easy-to-use ELISA for detection of IgM anti-drug antibodies (ADA) and its use in a clinical Phase I trial. Results & methodology: During the assay development two positive control (PC) approaches, the preparation of a chemically conjugated and a recombinant PC, were pursued. With both PCs, the assay was developed and successfully qualified considering the regulatory guidelines. For a case study, the IgM ADA isotyping assay with the recombinant PC was selected. Different courses and intensities of immune response regarding IgM signals were demonstrated. Conclusion: The easy-to-use ELISA allowed IgM-ADA detection in clinical samples. Conjugated and recombinant IgM PCs were comparable regarding assay sensitivity, precision and suitability.