Modernizing the platform process of antibody purification for enhanced impurity clearance

The established platform for monoclonal antibody (mAb) purification, centered on Protein A affinity capture and subsequent polishing steps, has enabled large-scale manufacturing of therapeutic antibodies. However, persistent host cell proteins (HCPs), antibody aggregates, and product fragments remain challenging to clear, particularly as novel mAb formats and intensified upstream processes introduce higher impurity loads. In this study, we present transformative mAb purification platforms that combine novel multimodal resins operating in flow-through mode with conventional Protein A chromatography to address these limitations. Our new platform utilizes LigaGuard for the selective removal of high-risk and persistent HCPs, chromatin, and aggregates by flow-through affinity chromatography; and a size-exclusion-mixed-mode (SEMM) resin for the efficient removal of product-related low and high molecular weight impurities and residual process-related impurities. Several alternative process configurations were systematically assessed to maximize purification performance and robustness. A novel process configuration comprising an initial impurity-stripping step using LigaGuard followed by a capture step by Protein A chromatography and a polishing step using SEMM resin achieved global yields up to 86 %, with residual product-related impurities <1 %, HCPs <60 ppm, and hcDNA <10 ppb across diverse industrial feedstocks. The proteomic analyses of the polished streams confirmed the depletion of high-risk and persistent HCPs, including hydrolases and polysorbate-degrading enzymes. The use of two flow-through operations flanking a central affinity capture step enhances the performance of the Protein A resin alongside process productivity and robustness to feedstock variability. These results support a new paradigm for mAb purification, offering scalable and robust solutions for both legacy and emerging antibody modalities. • Integrating Protein A with LigaGuard and SEMM resins enhances impurity clearance. • The proposed process architectures robustly achieve up to 99.9 % monomer purity. • Proteomic analysis demonstrates reduction from >2600 to ~30 HCPs in the polished pools. • The combination of LigaGuard and Protein A resin remove cathepsins, chromatin, and lipases. • Platform met regulatory impurity thresholds while achieving high yield and productivity.