PDL241

**PDL241** is a humanized IgG1 monoclonal antibody targeting **CD319** (also known as SLAMF7 or CS1), a cell surface marker highly expressed on plasmablasts and plasma cells in rheumatoid arthritis (RA) synovium but absent on naïve B cells. It inhibits immunoglobulin production (e.g., IgM) in a Fc-dependent manner primarily through natural killer (NK) cell-mediated depletion of CD319-positive plasmablasts and plasma cells, without affecting B cells, offering a therapeutic approach to target CD20-negative late-stage B cell populations resistant to anti-CD20 therapies like rituximab. Preclinical studies demonstrated efficacy in human PBMC cultures, a human PBMC transfer NSG mouse model, and a collagen-induced arthritis (CIA) model in rhesus monkeys, reducing anti-collagen antibodies, joint swelling, bone remodeling markers, and histopathology, though limited by anti-drug antibodies after multiple doses.[1][3][7][8][10]

Other names

PDL-241PDL241PDL 241