P139 Real-world longitudinal rituximab use in pemphigus and pemphigoid: outcomes from a UK tertiary centre

Abstract

Autoimmune bullous disorders including pemphigus and pemphigoid are associated with significant morbidity and mortality. Rituximab is recognized as first-line therapy for pemphigus in European and US guidelines, while UK commissioning criteria limit its use to refractory disease after failure of two systemic therapies. We retrospectively reviewed 20 patients prescribed rituximab for immunobullous disease at our tertiary centre over a 10-year period. The patients included 17 with pemphigus vulgaris, 1 with pemphigus foliaceus and 2 with mucous membrane pemphigoid. The diagnoses were confirmed by histopathology, immunofluorescence and/or serology. Their median age onset was 36 years [interquartile range (IQR) 25–49, range 16–75], 70% were female and there was a predominance of South Asian/Middle Eastern ancestry (n = 14), consistent with recognized epidemiology. Oral mucosal involvement was a prominent presenting feature, with 12 patients referred via oral medicine. Patients trialled a median of three systemic therapies prior to rituximab (IQR 3–4, range 2–7). All 20 patients (100%) trialled prednisolone, 19 mycophenolate and 19 azathioprine. Tetracyclines (n = 6) and dapsone (n = 4) were used in smaller subsets. Rituximab was initially administered as paired 1-g infusions 14 days apart; eight patients subsequently received single 500-mg infusions as maintenance. The patients received a median of three rituximab cycles (IQR 2–5, range 1–15). Treatment intervals ranged from 6 to 60 months depending on clinical activity. Desmoglein antibody titres (n = 12) were used to assess disease activity and supported treatment decisions. Prednisolone and/or concomitant immunosuppression reduction was observed following rituximab, with improvement in clinical and biochemical activity. The lower dose of rituximab 500 mg was used for maintenance of patients facilitating discontinuation of other systemics. Nine patients developed adrenal insufficiency and one patient died from sepsis following rituximab therapy. This real-world tertiary cohort highlights the complexities of rituximab use in these chronic and relapsing conditions. Lower-dose maintenance therapy and use of antibody titres can help to guide further use of rituximab therapy, reducing side effects. Earlier access to rituximab therapy may facilitate earlier clinical response and reduce overall morbidity.