Kinetic Analysis of Recombinant BHK Roller Bottle Cultures

A BHK cell line that secretes recombinant porcine Factor VIII is being used in a roller bottle based manufacturing process to supply clinical product for Phase III trials. A chemically-defined medium is used to feed confluent cultures in iterative fashion over a 5 day period, during which the recombinant product is harvested on a daily basis. In order to better understand process capability, a study was performed to more closely examine the kinetics of recombinant protein production over each 24 h iterative batch period. The results showed that the majority of recombinant product was secreted within the first 18 h of the incubation period, with no additional product being made over the final 6 h interval. Spent media analysis revealed that certain amino acids were notably depleted by the end of each day. Another study was performed to evaluate whether recombinant protein production could be boosted during the final 12 h of the batch period. The amino acids which were rapidly depleted during the initial study were added back to production cultures halfway through the batch period on each production day. This strategy resulted in a 23% increase in rpFVIII yield by the end of the production process.