Subjects who developed anti-drug antibodies (ADAs) to bococizumab are unlikely to develop clinically relevant cross-reactivity to marketed anti-proprotein convertase subtilisin/kexin type-9 (PCSK9) monoclonal antibodies. This is based on the weak and transient cross-reactivity signal observed in 0.6% (1/155) of the subjects evaluated.

ADA cross-reactivity was evaluated using a novel ADA assay approach within the context of a single validated assay that helped minimize problems associated with assessing cross-reactivity in separate assays. This approach may be applicable to other biotherapeutics where cross-reactivity of ADA is a potential concern, especially for those within the same therapeutic class.