Incurred sample reproducibility and stability assessment in a cell-based drug concentration assay

Joleen White is Principal Scientist in Translational Sciences at Biogen Idec. Throughout her career, she has applied her background in biophysical protein chemistry to pharmaceutical development in therapeutic indications with significant unmet medical need. In her current role, she supports method development and regulated bioanalysis of biomarkers, biopharmaceuticals, and immunogenicity in biological samples from nonclinical and clinical studies. Her experience with measuring macromolecules includes enzymes, monoclonal antibodies, Fc fusions, oligonucleotides, PEGylated proteins, and other novel protein constructs. She has supported studies from discovery through all phases of development including GLP nonclinical, clinical, and post-marketing commitments. Incurred samplereproducibility is one aspect of in-study validation, with white papers outlining expectations for chromatographic assays and immunoassays. This manuscript outlines an approach for performing incurred sample reproducibility for a bioequivalence study using a cell-based assay, with the complication of time elapsed between original and repeat assays. The incurred sample reproducibility passed the pre-established acceptance criteria of 45% for at least 2/3 of the samples: 174/216 samples (80.6%). Data trends between the two crossover arms were qualitatively similar. The passed incurred sample reproducibility and stability further supports the validity of the original study conclusion that the two manufacturing processes were bioequivalent. This illustrates one approach to extrapolating industry and regulatory recommendations for situations outside current guidance.