Bioanalytics – Biomolecular
Establishing interchangeability for a biosimilar and innovator therapeutic is complex. FDA guidance requires that the two products be structurally similar, having no clinically meaningful differences. As such, regulatory submissions for biosimilar therapeutics require the evaluation of the efficacy, pharmacokinetic (PK) profile, and safety. To meet these regulatory requirements, samples collected during a Phase 3, double blind, randomized study for patients with the targeted disease state were analyzed using a validated immunoassay. The observed maximum serum concentration after administration and trough concentration level for each cycle were analyzed. The measured concentrations of both the circulating biosimilar and innovator therapeutics were > 50% reduced when compared to the results of the phase 3 innovator study. While the presence of the innovator drug in the biosimilar trial serves as an internal control and there is no requirement to reproduce historic data, such a large disparity indicates the method used for PK assessment in the biosimilar study may be unacceptable. Presentation data will support the significant impact that assay reagents and assay format may have on the detection of a targeted analyte. In addition, inconsistencies observed when analyzing QC samples versus patient samples will also be presented.