MSB2311

MSB2311 is a novel, humanized monoclonal antibody targeting programmed death-ligand 1 (PD-L1) with a unique pH-dependent binding property. This design enables the antibody to bind PD-L1 with high affinity at neutral pH and dissociate at lower pH, such as in acidic endosomal environments within tumor cells. The dissociation allows MSB2311 to be recycled via the neonatal Fc receptor pathway, reducing lysosomal degradation and increasing its concentration and duration of action in the tumor microenvironment. Mechanistically, it blocks PD-L1 from interacting with its receptor PD-1 on T cells, thereby enhancing anti-tumor immune responses. The antibody has been engineered (IgG1 subtype with N297A mutation) to abolish antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity activities. Developed for advanced solid tumors and lymphoma—especially those characterized by biomarkers such as high PD-L1 expression, Epstein-Barr Virus positivity, microsatellite instability-high/mismatch repair deficiency (MSI-H/dMMR), or high tumor mutation burden—MSB2311 has demonstrated manageable safety and promising antitumor activity in phase I clinical trials[1][2][3][4][5].