Development and Analytical Validation of a BT-474 Anti-Proliferation Assay Targeting HER2

Abstract

Human Epidermal Growth Factor Receptor 2 (HER2) is an ideal target for anti-tumor drug development especially for breast cancer. Based on this target, either for new drug, bio-better, bio-similar screening at discovery level, or for drug substance and drug product release at QC or industry level, a reliable and robust biological potency assay is urgently needed. In this study, a BT-474 cell based anti-proliferation biological potency assay targeting HER2 was developed after an optimization of some key aspects, including cell line, seeded cell density, incubation time, and usable method for viable cell staining. Following optimization, the assay was validated to identify its specificity, precision, accuracy, linearity, range, and robustness. It was proven a highly accurate assay with good fit (R2 > 0.98), low RSD (even <5%) of replicates, and broad range (50%–150%) and could be used for drug candidates screening and quality control. This study also provides a good example for cell-based biological potency assay development aimed at other targets.