Monday, November 4, 2013
Capri Ballroom (Marriott Marco Island)
During manufacturing scale qualification of a late stage clinical Escherichia coli (E. coli) recombinant protein product, two Drug Substance lots appeared slightly brown in color and did not meet the expected Yellow series color criterion for the Clarity, Opalescence, and Coloration (COC) assay. The compound modifying the recombinant product was identified as 1,4-dihydroxy-2-naphthoate (DHNA), an E. coli metabolite. The covalent association of DHNA with cysteine residues in the product was determined to occur during the reducing conditions of the harvest operations. Enhanced harvest process controls were developed to deliver and maintain sufficient levels of dissolved oxygen during the different stages of the harvest operations, thereby eliminating the potential for DHNA protein modification by providing an oxidative environment. The development and successful transfer to manufacturing scale of the enhanced harvest process controls will be discussed.