Super7 passaging method to improve Chinese hamster ovary cell fed‐batch performance

Abstract Chinese hamster ovary (CHO) cells are widely used to manufacture biopharmaceuticals, most of all monoclonal antibodies (mAbs). Some CHO cell lines exhibit production instability, where the productivity of the cells decreases as a function of time in culture. To counter this, we designed a passaging strategy that, rather than maximizing the time spent in log‐growth phase, mimics the first 7 days of a fed‐batch production process. Cultures passaged using this method had lower net growth rates and were more oxidative throughout 6 weeks of passaging. Fed‐batch cultures inoculated by cells passaged using this method had increased net growth rates, oxidative metabolism, and volumetric productivity compared to cells passaged using a conventional strategy. Cells from unstable cell lines passaged by this new method produced 80%–160% more mAbs per unit volume than cells passaged by a conventional method. This new method, named Super7, provides the ability to mitigate the impact of production instability in CHO‐K1 cell lines without a need for further cell line creation, genetic engineering, or medium development.