Duration of Therapeutic Regimens and Follow-up. The study treatment duration for a randomized patient depends on the level of response to treatment as follows: 26 weeks if neither a partial or complete remission occurs at the 26-week visit; 52 weeks if there is a partial or complete remission at 26 weeks but not at 52 weeks, and 78 weeks if partial or complete remissions are recorded at both the 26- and 52-week visits. For all patients low intensity follow-up for long-term assessment of renal function is maintained after termination of the therapeutic regimens until September, 2008.