Aim: 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. Results: Both assays showed biotin-related interference, with the peptide-based assay being less affected than the antibody-based assay. BI was reduced by minimum required dilution adaption from 10 to 1% and eliminated by a depletion-based sample pretreatment. Conclusion: Increased biotin levels have the potential to interfere with immunogenicity testing methods that use biotin technology. Since the extent of interference differs from assay to assay, assessment during development phase is recommended. Minimum required dilution adjustment or sample pretreatment are options to reduce or eliminate BI.

Aim: 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. Results: The results confirmed the expected assay difference regarding isotype detectability. Tested drug candidates were identified as preADA-reactive using the immune-complex ADA assay despite its limitation of not being able to detect IgM-type preADAs. Conclusion: We recommend a purpose-driven use of the two assay formats. For the purpose of ranking different Pro329Gly mutation-bearing drug candidates, the immune-complex ADA assay is preferred in the phase before selecting a drug for clinical development.