Atacicept is a recombinant fusion protein containing the soluble TACI receptor that binds to the cytokines BLyS and APRIL. These cytokines are members of the tumor necrosis factor family, which promote B-cell survival and stimulate the formation of autoantibodies involved in certain autoimmune diseases such as IgA nephropathy (IgAN). IgAN is one of the most common kidney diseases. The start of a Phase IIb study on IgAN is planned for Q2 2021.