A novel peptide design aids in the expression and its simplified process of manufacturing of Insulin Glargine in Pichia pastoris

Manufacturing of insulin and its analogues relied upon in vitro enzymatic cleavages of its precursor forms (single chain precursor, SCP) at both ends of a connecting peptide (C-peptide) that links the respective B-chain and A-chains to corresponding final forms. We have demonstrated a simplified approach of cleaving P. pastoris expressed SCP, distinctly at one site for conversion to insulin glargine. The design of the precursor was made in such a way that there is no C-peptide in the precursor which needs to be removed in the final product. Instead of traditional both side cleavage of the C-peptide and removing the C-peptide (by trypsin), followed by 2nd enzyme reaction (typically carboxipeptidase B), present work established only one side cleavage of the sequence by only trypsin converts the precursor to final insulin glargine product. The novel design of the precursor helped in producing insulin glargine in a single step with an application of single enzyme brought high degree of process efficiencies. Highly purified product was generated through two reversed phase high pressure chromatographic steps. Purified product was compared with the reference product Lantus®, for various physico-chemical and biological properties. Primary, secondary and tertiary structures as well as biological pharmaco-dynamic effects were found comparable. High cell density fermentation that gave a good yield of the SCP, a single step conversion to insulin glargine, enabled by a unique design of SCP and a distinct purification approach, has led to a simplified and economical manufacturing process of this important drug used to treat diabetes. KEY POINTS: • Novel concept for processing single chain precursor of insulin glargine • Simple and economic process for insulin glargine • Physicochemical characterization and animal Pharmacodynamics show similarity to Lantus