BACKGROUND: We investigated the efficacy of oral mizoribine pulse therapy (mizoribine-pulse) for cyclosporin (CyA)-dependent, steroid-resistant nephrotic syndrome (SRNS) and frequently relapsing, steroid-dependent nephrotic syndrome (FR-SDNS). METHODS: One child with CyA-dependent SRNS and eight children with CyA-dependent FR-SDNS were treated with mizoribine-pulse (daily dose: 10 mg/kg; maximum total dose 500 mg). We compared clinical manifestations before and after mizoribine-pulse, and studied the changes in serum mizoribine concentration in each patient on days when mizoribine was administered. RESULTS: Four patients had no subsequent relapses (responders). Two of the four responders discontinued prednisolone and CyA, the other two discontinued CyA. Although each of the five other patients (non-responders) experienced single subsequent relapses, the dosages of prednisolone and CyA after mizoribine-pulse were decreased significantly compared with before mizoribine-pulse. The peak blood concentration of mizoribine in the responders was higher than in the non-responders (3.6+/-0.9 vs 1.8+/-0.4 microg/ml). CONCLUSIONS: Mizoribine-pulse may be effective for some patients with CyA-dependent SRNS and FR-SDNS.
BACKGROUND: We investigated the efficacy of oral mizoribine pulse therapy (mizoribine-pulse) for cyclosporin (CyA)-dependent, steroid-resistant nephrotic syndrome (SRNS) and frequently relapsing, steroid-dependent nephrotic syndrome (FR-SDNS). METHODS: One child with CyA-dependent SRNS and eight children with CyA-dependent FR-SDNS were treated with mizoribine-pulse (daily dose: 10 mg/kg; maximum total dose 500 mg). We compared clinical manifestations before and after mizoribine-pulse, and studied the changes in serum mizoribine concentration in each patient on days when mizoribine was administered. RESULTS: Four patients had no subsequent relapses (responders). Two of the four responders discontinued prednisolone and CyA, the other two discontinued CyA. Although each of the five other patients (non-responders) experienced single subsequent relapses, the dosages of prednisolone and CyA after mizoribine-pulse were decreased significantly compared with before mizoribine-pulse. The peak blood concentration of mizoribine in the responders was higher than in the non-responders (3.6+/-0.9 vs 1.8+/-0.4 microg/ml). CONCLUSIONS:Mizoribine-pulse may be effective for some patients with CyA-dependent SRNS and FR-SDNS.