Assay Development for Immunogenicity Testing of Therapeutic Proteins

PDA is pleased to have the opportunity to comment on this draft. The updated version of this guidance document provides useful clarifications of strategies provided in the original 2009 guidance based on increased experiences with immunogenicity assays, and includes twice as many key literature references. PDA recognizes this draft adds information regarding immunogenicity assays for combination products and ADC's; points to information regarding immunogenicity assays for biosimilar products; and utilizes the current FDA terminology. It also clarifies the relationship of this guidance to animal immunogenicity assays and points to relevant guidance documents for those. The tests proposed in the guidance are all looking at antibodies to the therapeutic protein and not other types of immune responses (eg. innate immune response) therefor PDA recommends that the scope statement be tightened to reflect this and has suggested language in the attached comments.