 SPECIFIC AIMS A significant percentage of patients with primary FSGS are resistant to corticosteroids and other immunosuppressive medications. In view of the rising incidence of this disease and the grim prognosis for patients with resistant disease, it is imperative that new therapeutic approaches be evaluated in an efficient and systematic manner. This will enable accurate assessment of the risk-benefit ratio of novel therapies and guide the design of future Phase III randomized clinical trials. 