Assay signal as an alternative to titer for assessment of magnitude of an antidrug antibody response.

Abstract

Titer methods are commonly used to characterize the magnitude of an antidrug antibody response. Assay S/N is an appealing alternative, but the circumstances under which use of signal-to-noise (S/N) is appropriate have not been well defined. We validated both titer and S/N-based methods for several therapeutics. S/N correlated strongly with titer both in aggregate and when examined on a per subject basis. Analysis of impact of antibody magnitude on pharmacokinetics yielded the same result using either method. Each assay demonstrated excellent precision, good linearity, and adequate drug tolerance. Under these circumstances, assay S/N is a valid alternative to titer for assessment of the magnitude of an antidrug antibody response.