(255d) Manufacturing-Scale Implementation of Enhanced Harvest Process Controls to Inhibit Colored Protein-Adduct Formation in Prokaryotic Host Cell Derived Recombinant Protein

Deepa Nadarajah, Kimberly Kaleas, Jane Gunson, Michael Laird, Rick St. John 

Prokaryotic cells are widely used as host cells for the production of recombinant therapeutic proteins. It was discovered that recombinant proteins produced in prokaryotic host cells are susceptible to modification by a colored adduct when exposed to reducing environment. The colored adduct was identified as 1-4 dihydroxy-2-napthoic acid (DHNA) and is produced inherently as part of the prokaryotic host cell’s metabolic (menoquinone) pathway. DHNA covalently attaches to cysteine residues in the recombinant protein in reducing environment during the harvest operation. An oxidative environment eliminates protein modification by DHNA and was achieved by modifying the process controls that focused on delivering and maintaining positive dissolved oxygen levels during different stages of the harvest operations. This talk will focus on the successful implementation of enhanced harvest process controls at manufacturing-scale to produce a drug substance bulk that does not contain detectable DHNA-recombinant protein adduct.