Real‐World Experience With Single Ultra‐Low Dose Rituximab for Remission Induction in Pemphigus

Standard-dose rituximab (SDRTX) is the established treatment for pemphigus, but optimization of cost-effectiveness and safety remains desirable. We retrospectively evaluated the efficacy of a single ultra-low dose RTX infusion (ULRTX; 100 or 200 mg) for remission induction in 12 patients with mild-to-severe pemphigus (median baseline Pemphigus Disease Area Index [PDAI] 29.5). 9 patients (75%) achieved complete remission on minimal therapy (CRMT), and among them 5 (41.7%) subsequently achieved complete remission off therapy (CROT), with a median time to CRMT and CROT of 24 weeks and 61 weeks, respectively. Significant corticosteroid sparing was achieved; 9 of 10 evaluable patients tapered prednisolone to ≤ 5 mg/day within 6 months. Despite the reduced dose of RTX, an overall decline in serum anti-desmoglein 1 and 3 IgG titers and effective peripheral B-cell depletion (≤ 1%) occurred in evaluable patients. However, early B-cell repopulation was observed in one patient who experienced an early relapse. Compared with the standard-dose group (n = 8), the ULRTX group demonstrated a favorable safety profile with significantly fewer drug-related adverse events (0% vs. 37.5%, p = 0.049), while maintaining effective clinical remission. Single-dose ULRTX appears to be a cost-efficient and biologically effective induction strategy, supporting a personalized, immunologically guided, on-demand treatment approach.