Rituximab: effective treatment for severe steroid-dependent minimal change nephrotic syndrome?

Sir, Minimal change disease (MCNS) accounts for 70–90% of the cases of idiopathic nephrotic syndrome in children. Most patients respond to steroid therapy. However, the relapse rate is high and ∼50% of patients are steroid-dependent or frequent-relapsers [ 1 ]. These patients are often treated with other immunosuppressive agents, such as cyclophosphamide or ciclosporin (CsA). Ultimately ∼75% of these patients will develop a long-lasting remission. However, 25% of patients will experience a relapsing course of the disease and many of them need immunosuppressive maintenance therapy [ 2 ]. New therapeutic strategies are desirable. We report the results of treatment with rituximab, a monoclonal anti CD-20 antibody, in a 20-year-old Caucasian female with steroid-dependent MCNS. The patient presented at the age of 2 years with an idiopathic nephrotic syndrome. Treatment with high-dose prednisone resulted in a remission of proteinuria, but the nephrotic syndrome recurred immediately after tapering of the prednisone dose. Frequent relapses necessitated repeated courses of prednisone therapy over the following two years. A renal biopsy was performed at the age of 4 years and showed MCNS. Treatment with cyclophosphamide was started and resulted in a remission which lasted for 18 months. Despite prednisone maintenance therapy, multiple relapses occurred over the next 4 years. Therefore treatment with ciclosporin (CsA) was started. At the age of 11 years, relapses necessitated a higher dose of steroids. The clinical course was complicated by a herpes zoster infection and osteoporosis. The treatment regimen was changed in an attempt to decrease the amount of prednisone. At the age of 18, the nephrotic syndrome was under control with the use of low-dose prednisone (5 mg every other day) in combination with mycophenolate mofetil (MMF 1000 mg bid) and tacrolimus (target through level 5–10 mg/l). Over the next year, the patient again developed relapses, necessitating higher doses of prednisone. In time, the steroid-dependency increased and finally she responded only to very high-dose prednisone (60 mg qd), with an immediate relapse during tapering ( Figure 1 ). Ultimately she remained nephrotic while using prednisone (20 mg qd), MMF (1000 mg bid) and tacrolimus (15 mg bid to attain a target through level of 8–12 mg/l). Laboratory values while on triple therapy were: serum albumin 12 g/l, serum creatinine 67 µmol/l and proteinuria averaged 10 g/day. This situation lasted for more than 12 months and became unacceptable. Therefore we decided to treat our patient with rituximab. She was given two doses of 1000 mg i.v. with a 2-week interval. MMF was stopped. Within 2 weeks there was a remarkable decrease in proteinuria (2–3 g/day) as well as an increase of serum albumin (21 g/l). Tacrolimus and prednisone were tapered ( Figure 1 ).