Introducing quality by design approach in early process development to improve natural killer cell manufacturing robustness.

Abstract

Process development employing a quality by design (QbD) approach has been applied across various modalities and is also recommended for the development of cell-based therapeutics. Introducing QbD principles from the early stages of process development enables the establishment of manufacturing processes that are robust, high-yield and have a low risk of failure. The aim of this study was to develop a robust manufacturing process for natural killer (NK) cells by implementing a QbD strategy in the initial phase of process development. The QbD approach was applied to enhance NK cell proliferation and cytotoxic activity in vitro, with a particular focus on optimizing the parameters of the stimulation step. Using FMEA, five high-risk parameters were identified: coating duration, coating solution concentration, initial cell density, culture duration and cytokine concentration. Subsequent experimental investigations within a design of experiments framework were conducted to establish statistical models describing NK cell fold expansion and cytotoxicity. Contour profiles of the response surfaces were used to determine optimal parameter settings that satisfied cytotoxicity criterion while maximizing fold expansion. Monte Carlo simulations under these optimized conditions indicated a low probability of failing to meet the cytotoxicity criterion. This study demonstrates that QbD-based assessments can lead to robust manufacturing processes. Furthermore, our findings elucidate the relationships between process parameters, NK cell proliferation and cytotoxicity, contributing to improved quality and productivity in NK cell-based therapeutics.