This is a Phase II, open-label pilot study to determine if the use of Rituximab reduces proteinuria over a 12 month period and is there preservation of kidney function with the use of this study drug. Each patient will be treated with 2 intravenous infusions of rituximab 1000 mg, two weeks apart for a total of 2 doses. Each patient will be retreated with identical 2 intravenous infusions of rituximab, two weeks apart at 6 months after the first infusion, irrespective of cluster of differentiation (CD) 20+ cell counts. Thus, each participant will receive 4 infusions of rituximab.
This pilot study is being done to see if the study medication, Rituximab, preserves kidney function after 12 months of taking the drug.