Comparable immunogenicity of new modality biotherapeutics delivered subcutaneously or intravenously in non-human primates

Unwanted immunogenicity of therapeutic proteins arises through the combination of many factors, with the route of administration considered a significant contributor. Contrary to historic data on vaccine delivery, analysis of various therapeutic protein products indicates that the subcutaneous route is not a systematic risk. However, individual product assessments may identify factors specific to the circumstance of their use. Preclinical <i>in vivo</i> studies may add additional information to the comparative immunogenicity risk assessment of intravenous versus subcutaneous administrations. Moreover, immunogenicity risk assessment of new biotherapeutic modalities, such as bispecific antibodies and antibody-linked cytokines, may benefit from a full analysis of risk factors, including preclinical <i>in vivo</i> data. The study here provides immunogenicity analysis of an IgG, two CD3 bispecific antibodies, and two Fc-linked immunocytokines administered intravenously and subcutaneously, aiming to highlight similarities and differences between these administration routes. The current results suggest that the development of anti-drug antibodies does not solely depend on the route of administration but is influenced by multiple risk factors, which should be addressed on a case-by-case basis. This paper reflects on the challenges of interpreting the data and propose standards for improving sample and data collection to aid future analysis.