Continuous manufacturing of tirzepatide using online UHPLC-based PAT: An enabling technology for commercialization of a synthetic peptide

Tirzepatide is a GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) receptor agonist recently approved in the United States for the treatment of type 2 diabetes. Commercial manufacture of a complex synthetic peptide presents significant challenges to obtaining the desired product of high quality and yield. Recently, a hybrid solid-phase peptide synthesis/liquid-phase peptide synthesis (SPPS/LPPS) approach was demonstrated at scale to leverage the benefits of continuous processing and online UHPLC-based process analytical technology (PAT). The hybrid SPPS/LPPS synthesis of tirzepatide utilizes four high purity fragments synthesized via traditional SPPS methodologies and released as GMP intermediates. Fragments are coupled in three continuous LPPS reactions performed in dedicated plug flow reactors (PFR) with two nanofiltration-based impurity purge points between chemical reactions. Each PFR is equipped with an online UHPLC, and a Lilly developed process sampler to monitor reaction completion and residual starting materials. Brief discussion on how to effectively implement online UHPLC for a peptide synthesis with a PAT-directed control strategy for control of key impurities will be presented.