Rituximab for the second- and third-line therapy of idiopathic membranous nephropathy: a prospective single center...

Idiopathic membranous nephropathy (MN) is a major cause of nephrotic syndrome. Conventional treatment strategies induce remission but the relapse rates are high. Different doses of rituximab (RTX) appeared effective in reducing proteinuria in MN but long-term follow-up data are rare.

Since 2006, a total of 14 patients (median age 51 (26 - 69) years, 4 women, 10 men) with biopsy-proven MN (1 - 4 relapses, MN since 4 (1 - 13) years) were treated with RTX (4 doses of RTX 375 mg/m2 on Days 0, 30, 60, 90). All patients had prior immunosuppressive therapy with Cyclosporin A, 7 with alkylating agents. In 11 patients, an additional renal biopsy was performed 2 (1 - 10) months before RTX.

Three months after the last RTX infusion, proteinuria decreased from a baseline of 5.5 (2.9 - 11.9) g/24 h to 1.8 (0.03 - 8.7) g/24 h (p = 0.012). Creatinine clearance remained stable (53 (29 - 160) ml/min at 3 months vs. 44 (29 - 159) at baseline). Until now, patients could be followed for a median of 3 (1 - 6) years. After 1 year, 21.4% (n = 3) had a complete response, 50.0% (n = 7) partial response. Two relapses occurred after 1 and 3.5 years. The presence of glomerulosclerosis before RTX was associated with a poorer outcome.

The 4 × 4-weekly infusion of RTX is a reasonable option for the second- and third line therapy of MN providing a better safety profile compared to other immunosuppressive treatments of MN.