Interpreting immunogenicity in oncology clinical trials

Immunogenicity of a therapeutic protein product may elicit an unintended immune response, and is a critical aspect evaluated in oncology clinical trials. The development of anti-drug antibodies (ADAs) can impact the pharmacokinetics, pharmacodynamics, efficacy, and safety of these therapies. We review the background and nomenclature of immunogenicity assessment in oncology studies and emphasize the complexities in ADA detection arising from assay sensitivity, drug interference, and notably, the frequency of patient sampling for ADA analysis. The applicability of common nomenclature, however, has limitations in the context of oncology. Of prime consideration for physicians is that the clinical impact of ADA is far more important than just their presence. Furthermore, the interpretation of immunogenicity data in oncology is complicated by patient-specific factors, concomitant treatments, and potential survivorship bias. Regulatory guidelines acknowledge these complexities, mandating specific statements on product labels cautioning against cross-trial comparisons of ADA incidence due to variations in assay methods and sampling schedules. Accurate interpretation of immunogenicity data, considering assay methodologies, study design, and sampling frequency, is crucial for clinicians to assess the clinical relevance of ADA findings and make informed treatment decisions for patients receiving therapeutic protein products in oncology. The focus should be on the clinical relevance of ADAs rather than simply their incidence.