Efficacy, safety, and B-cell depletion capacity of three rituximab dosing regimens in the treatment of moderate-to-severe pemphigus vulgaris and pemphigus foliaceus: a 52-week clinical trial

Rituximab (RTX) is effective for pemphigus, but optimal dosing remains uncertain. Compare efficacy, safety, and B-cell depletion of three RTX regimens over 52 weeks. In an open-label trial (May 2023-October 2024), 52 pemphigus vulgaris and pemphigus foliaceus patients received ultralow-(ULRTX; 100mg), low-(LRTX; 500mg), and standard-dose RTX (SDRTX; 1000 mg) at weeks 0 and 2, with supplemental doses guided by CD20+B-cell reconstitution. All received concomitant glucocorticoids. time to disease control, complete remission (CR), CR off therapy (CROT), CR on minimal therapy (CRMT). pemphigus disease area index (PDAI) changes, glucocorticoid use, relapse rates, and autoantibody seroconversion. All achieved disease control (median days: ULRTX=15.5, LRTX=14.0, SDRTX=13.0; P=0.02). CD20+B-cell depletion occurred universally by week 2, with faster reconstitution in ULRTX by 26 weeks. CR rates: 92.3% (ULRTX) vs 100% (LRTX/SDRTX); CROT/CRMT showed no intergroup differences. Median PDAI reduction, cumulative glucocorticoid doses, relapse rates and autoantibody seroconversion were comparable. No significant difference was found in adverse events (AEs). ULRTX demonstrated cost advantages. Single-center, non-randomized design, small sample. All regimens demonstrated comparable efficacy and B-cell depletion. ULRTX, despite a marginally longer time to disease, had the lowest AEs and cost, supporting its utility in pemphigus management.