Sibeprenlimab (formerly VIS649) is an investigational humanized IgG2 monoclonal antibody that reduces the production of Gd-IgA1 by binding to a specific signaling molecule called APRIL (short for “A Proliferation-Inducing Ligand”), which is believed to be a driver of IgA and Gd-IgA1 production. By binding and neutralizing APRIL, Sibeprenlimab may reduce the amount of IgA, and Gd-IgA1. Lower levels of Gd-IgA1 may then result in reduced auto-antibody production, which in turn may result in fewer immune complexes, decreased immune complex deposits in the kidney, and reduced kidney inflammation. By reducing the production of Gd-IgA1, Sibeprenlimab is believed to prevent further kidney damage and the progression to end stage kidney disease.

Sibeprenlimab is an investigational drug only and has not been approved by the U.S. FDA or any other regulatory agencies. Sibeprenlimab (VIS649) is a study drug that is in clinical studies and efficacy and safety have not been established. There is no guarantee that Sibeprenlimab (VIS649) will become available for use outside of a clinical study.