Solving Complex Biologics Truncation Problems by Top-Down Mass Spectrometry

Abstract

With increasing protein therapeutics being designed as non-mAb (non-monoclonal antibody) modalities, additional efforts and resources are required to develop and characterize such therapeutic proteins. Truncation is an emerging issue for manufacturing of non-mAb drug substances and requires sophisticated methods to investigate. In this paper, we describe two cases with complex truncation problems where traditional methods such as intact mass spectrometry led to inclusive or wrong identifications. Therefore, we developed an online top-down LC–MS (liquid chromatography–mass spectrometry) based workflow to study truncated drug substances, and we successfully identified the clipping locations. Compared to other orthogonal methods, this method provides a unique capability of solving protein clipping problems. The successful identification of truncated species and the high compatibility to routine intact MS make it a very valuable tool for resolving truncation problems during protein production in the pharmaceutical industry.