(64e) Improved Process Development Based On Increased Understanding of Metabolism

The drive towards high titer and chemically defined medium based processes has introduced new challenges.  We have demonstrated a robust, scalable process platform with titers over 3 g L^-1.  However, large variations in metabolism were observed at extended cultivation times when applied to an antibody program.  These metabolic shifts are undesirable and limit process options.  We investigated the causes of the metabolic variability and have identified several triggers which ultimately result in high lactate production rates.  By implementing an intracellular fluorescent staining protocol, a likely mechanism inducing the variability was elucidated.  Risk mitigation techniques were implemented taking direct advantage of the mechanistic knowledge, and these mitigation steps will also be discussed.