リツキシマブによる難治性微小変化型糸球体腎炎の寛解維持療法：寛解維持期における長期予後

Minimal change disease (MCD) has a high recurrence rate, with refractory MCD frequently requiring long-term corticosteroid therapy or combination regimens with other immunosuppressive agents. Rituximab (RTX) has been confirmed to be an effective treatment for refractory MCD. However, its role in remission maintenance remains uncertain. This study aimed to assess RTX dosing strategies, infusion intervals, and relapse predictors during the remission maintenance phase of refractory MCD. We conducted a retrospective analysis of 14 patients with refractory MCD who had achieved complete remission with corticosteroids or conventional immunosuppressants and subsequently received RTX during the maintenance phase. The mean follow-up period was 31.1 ± 9.6 months. RTX was administered intravenously at a dose of 375 mg/m2 body surface area or 1000 mg every infusion. Based on their laboratory results, RTX therapy was administered in the patients intermittently. Patients who experienced recurrence were withdrawn from the study for further observation and management. Patients were treated with RTX at 375 mg/m2 body surface area or 1000 mg with each infusion in the remission maintenance phase. The mean intervals from the first to second and from the second to third infusions were 7.9 ± 2.1 months and 11.8 ± 2.8 months, respectively. Eight patients remained in remission and 6 patients experienced a relapse. Steroids or immunosuppressants were discontinued in 12 patients, while a dose reduction was achieved in 2 others. The relapse frequency significantly decreased from 1.87 (0.43-2.69) to 0 (0.00-1.33; P < .05). Recurrence was negatively associated with additional annual RTX therapy (P < .05). Serious side effects were not found. RTX is associated with reduced relapse frequency and earlier discontinuation of corticosteroids and immunosuppressants in refractory MCD patients during remission maintenance. Additional annual RTX administration represents an effective strategy for decreasing disease recurrence. Our findings suggest potential benefit of early administration. While findings are promising, larger controlled studies are necessary to establish optimal dosing intervals and long-term efficacy.