Effect of cytotoxic drugs in frequently relapsing nephrotic syndrome with and without steroid dependence.

In a prospective, controlled study, 50 children with frequently relapsing nephrotic syndrome who had steroid toxicity were treated for eight weeks with either cyclophosphamide (2 mg per kilogram of body weight per day) or chlorambucil (0.15 mg per kilogram per day), in combination with prednisone in tapering doses. Of the 34 children shows relapses had tended to occur after the prednisone dosage had been reduced or immediately after the drug was discontinued (the steroid-dependent group), 22 also had early relapses after cytotoxic-drug treatment. In contrast, cytotoxic drug treatment produced long-lasting remissions in 12 of the 16 children whose relapses usually occurred after prednisone treatment had been interrupted for more than 14 days (the non-steroid-dependent group). The difference in response between the two groups was highly significant (P less than 0.001). We conclude that patients with frequent relapses without steroid dependence can be treated successfully with an eight-week course of cytotoxic drugs, whereas those with steroid-dependent nephrotic syndrome do not profit from cytotoxic drugs in the low doses used.