This is an adaptive prospective, multi-center, randomized, double-blind, placebo-controlled study to evaluate the safety, efficacy, pharmacokinetics, and pharmacodynamics of WAL0921 in subjects with glomerular kidney disease and proteinuria, including diabetic nephropathy and rare glomerular kidney diseases (primary focal segmental glomerulosclerosis \[FSGS\], treatment-resistant minimal change disease \[TR MCD\], primary immunoglobulin A nephropathy \[IgAN\], and primary membranous nephropathy \[PMN\]). Subjects in this study will be randomized to receive the investigational drug WAL0921 or placebo as an intravenous infusion once every 2 weeks for 7 total infusions. All subjects will be followed for 24 weeks after their last infusion.