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.

Inclusion Criteria:

• Adults, age 18-75 years
• Diagnosis of one of the following glomerular kidney diseases: diabetic nephropathy; primary focal segmental glomerulosclerosis; treatment resistant-minimal change disease; primary IgA nephropathy; primary membranous nephropathy
• eGFR greater than or equal to 30 mL/min/1.73 m2

Exclusion Criteria:

• Currently pregnant or planning to become pregnant
• History of organ transplantation
• History of alcohol or substance use disorder
• Acute dialysis or acute kidney injury within 6 months of Screening
• Any prior or current medical condition that, in the judgment of the Investigator, would prevent the subject from safely participating in and/or completing all study requirements