ADA assay formats used for cynomolgus monkeys. (a) Biotherapeutic-specific biotin-DIG ELISA used to screen ADAs in samples from two cynomolgus studies with different ADCs. In this assay, the specific ADC reagents conjugated to biotin or digoxigenin are incubated with the samples. The complexes are immobilized using streptavidin-coated plates and then detected using a mouse antidigoxin mAb conjugated to HRP. (b) Generic ADA assay format developed for ADCs and other mAb-derived biotherapeutics, also used for analysis of samples from two studies in cynomolgus monkey with different ADCs. In this generic assay, the samples are incubated with the specific biotherapeutic and the complexes immobilized onto plates coated with a mouse anti-human IgG mAb. A goat anti-monkey IgG polyclonal antibody conjugated to HRP is used for detection of the immune complexes. ADC = antibody-drug conjugate; ADAs = anti-drug antibodies; DIG = digoxigenin; ELISA = enzyme-linked immunosorbent assay; HRP = horseradish peroxidase; mAb = monoclonal antibody; SA = streptavidin.