Sibeprenlimab (VIS649) is a humanized IgG2 monoclonal antibody which inhibits a proliferation-inducing ligand (APRIL). Sibeprenlimab suppresses pathogenic immunoglobulins (IgA and IgM), while preserving antibody responses to mRNA-based vaccines against SARS-COV-2. Sibeprenlimab reduces urinary protein-to-creatinine ratio (UPCR) and glomerular filtration rate (GFR). Sibeprenlimab is promising for the research of IgA nephropathy (IgAN).