C3 and lupus nephritis: APL-2, also known as pegcetacoplan, is a small peptide targeted at C3 and C3b (clinical trial code: NCT03453619) that was trialed for C3 glomerulopathy, IgA nephropathy, primary MN, and lupus nephritis; however, development for the latter two indications was curtailed as the company prioritized development of the drug for C3 glomerulopathy.