Method Transfer and Optimization of a Flow Cytometry Method Following Best Practice in a Regulated Environment

A global pharmaceutical company contracted Eurofins Bioanalytical Services to develop and then apply a Fit-for-Purpose validation assay utilizing frozen PBMC samples. This was to facilitate analysis of PBMC samples prepared at the clinical sites and shipped to Eurofins Bioanalytical Services for the analysis.

The clinical study objectives were to determine the safety, tolerability, and recommended intradermal peptide vaccine in a combination therapy regimenwith checkpoint inhibitors atezolizumab (anti-PD-L1 monoclonal antibody), or nivolumab (anti-PD-1 monoclonal antibody), in adult subjects with advancedsolid tumors. The project required Eurofins Bioanalytical Services to identify and quantitate the phenotype and extent of activation in treated PBMC samples. The primary cells of interest within the PBMC samples were the WT1-restricted CD8+cytotoxic T lymphocytes (CTL). Using a multi-parameter immuno-phenotyping panel and MHC-restricted tetramer reagents of activation state, a number of different HLA-A haplotype CD8+
T cells of varying MHC could be identified. In addition to the identification/quantitation, we were also asked to generate WT1-
restricted CD8+ CTL, using client-provided vaccine peptides to serve as Process QCs for both method qualification assays and sample analysis QCs.