#5801 EXTENDED LOW DOSE RITUXIMAB REGIMEN FOR THE TREATMENT OF ADULT PATIENTS WITH STEROID-DEPENDENT AND FREQUENTLY RELAPSING MINIMAL CHANGE DISEASE

Abstract

Abstract Background and Aims Patients with frequently relapsing and steroid-dependent minimal change disease (MCD) imply a therapeutic challenge for nephrologists. The use of steroid sparing agents such as cyclosporine, rituximab and mycophenolate, allows minimization of steroids exposure among these patients. In children and adults, Rituximab has demonstrated safety and efficacy in some studies although there is no established treatment regimen. This study aims to demonstrate that a low dose extended regimen of rituximab is an effective alternative for preventing relapses among these patients. Method This is a single-centre retrospective descriptive study of a case series of adult MCD patients from Ramón y Cajal’ Hospital in Madrid, Spain. Since 2019, patients with steroids-dependent or frequently relapsing MCD were treated with a low dose extended protocol of Rituximab as follows; 500 mg of rituximab once remission is achieved with steroid therapy, and four additional doses at month +6, +18 and +30 during the follow-up. Relapse free survival was analyzed after rituximab therapy. Results Eight patients with a median age of 42 years (22–70 years) who received at least one dose of intravenous rituximab were included. Four of the patients (50%) had previously received additional immunosuppressive regimens (including cyclophosphamide, chlorambucil cyclosporine, mycophenolate or ACTH). Two of them (25%) had frequent relapses and the remaining six (75%) had steroid-dependent behaviour. After a median of 2 years (IQR, 1,4-3,3) of follow-up, 6 out of 8 (75%) patients stayed under remission, experiencing the remaining two one relapse at one month and at one year, respectively, after the first rituximab dose. Comparing relapses during the two years-period before and after rituximab use, the median relapse rate per patient dropped from 2.8 (IQR, 2-4) to 0.5 (IQR, 0-1; P = 0.001) (Fig. 1). No patient experienced rituximab related side effects nor infections during the study period. Conclusion In MCD patients, the administration of rituximab in an extended low-dose regimen as corticosteroid-sparing therapy appears to be safe and effective in most of the patients for preventing relapses. This regimen allows minimization exposure to rituximab as well as disease remission during a longer period of time.