Difference in background responses across three biotherapeutics resulted in molecule specific screening cut points following a floating population data approach. Serum samples from 30 cynomolgus monkeys were spiked with 3 mAbs in early assay development experiments. The unspiked and mAb-spiked samples were analyzed in the generic assay format and a floating population screening cut point was evaluated. Different backgrounds were observed in the samples spiked with three mAbs compared to the unspiked corresponding samples. Therefore, molecule specific screening cut points were obtained for each mAb.
| ||Unspiked||mAb 2||mAb 5||mAb 6|
|Cut point (AU)||0.241||0.263||0.426||0.190|
|AU = absorbance units.|