Formulaic Definition of the Strength of a Gene-Edited EGFR CAR-T Drug Product

Abstract

The goal of this work was to define a relative formulaic potency score for use in autologous chimeric antigen receptor (CAR)-T drug products (DP), as an alternative to the use of absolute potency reporting of identity, purity, and viability assays, and explore how this score could be used to detect differences between a baseline and an improved CAR-T manufacturing process. Lentiviral vector-transduced T-cell DPs were successfully produced from n=2 healthy donor apheresis products, with and without a gene edit via megaTAL electroporation. Three in vitro assays were developed and performed on the DPs to investigate the proportion of perforin-granzyme expressing T-cells, the proportion of early memory subset T-cells, and the capacity for T-cell proliferation after antigen stimulation. A formulaic Overall Strength Index (OSI) was proposed to define potency as performance of a new DP lot against a reference or performance control. The OSIs calculated were effective at detecting a difference between DP produced in either manufacturing process by t-test. A formulaic method of potency definition was shown to be an intriguing paradigm that can more deeply characterize the multiple biological mechanisms of action in an autologous CAR-T DP.