Temporal outcomes and biomarkers of rituximab treatment response in pemphigus: Validation of a historical control dataset.

Rituximab and corticosteroids remain the only clinically approved therapies for pemphigus vulgaris, although novel therapeutics are entering clinical development. A historical control dataset previously described clinical and serologic outcomes after rituximab therapy in pemphigus vulgaris, but whether these data are representative of other patient cohorts is currently unclear. A contemporary pemphigus vulgaris cohort (n = 97) was compared with the historical cohort (n = 107) to assess clinical outcomes as well as desmoglein 3 ELISA predictive performance for achieving complete remission off oral immunosuppressive therapy. A total of 41.2% of patients achieved complete remission off oral immunosuppressive therapy after the first rituximab cycle, with a maximum complete remission off oral immunosuppressive therapy prevalence of 52.8% at month 36, including multiple rituximab cycles. Despite differences in baseline characteristics and treatments (particularly rituximab dosing), the temporal patterns of remission, relapse, and retreatment were broadly similar across cohorts. A desmoglein 3 ELISA index value ≤ 130 RU/ml and > 90.7% titer reduction between months 3 and 9 demonstrated 90% specificity and 88% sensitivity for future achievement of complete remission off oral immunosuppressive therapy, with negative predictive values of 85% and 92%, respectively, suggesting that low and/or rapid large drops in autoantibody titers after rituximab may predict an absence of disease activity. These data describe the temporal outcomes of rituximab therapy in pemphigus vulgaris and validate the historical control dataset for future comparative effectiveness research and biomarker-driven management.