Abstract
Abstract Background The interest of omalizumab in bullous pemphigoid (BP) in the event of resistance or contraindication to conventional therapies is currently based on limited evidence. Objectives To assess the effectiveness and safety of omalizumab in BP and to identify predictive factors of response to treatment. Methods We conducted a French national multicentre retrospective study including patients with a confirmed diagnosis of BP treated with omalizumab after failure of one or several treatment lines. We excluded clinically atypical BP patients, as per Vaillant’s criteria. The criteria for clinical response to omalizumab were defined according to the 2012 international consensus conference. Anti-BP180-NC16A IgE ELISA was performed on sera collected before initiating omalizumab, when available. Results Between 2014 and 2021, 100 patients treated in 18 expert departments were included. Median age at diagnosis was 77 years [20–98]. Complete remission (CR) was achieved in 77% of patients, and partial remission in additional 9%. CR was maintained “off therapy” in 11.7%, “on minimal therapy” in 57.1%, and “on non-minimal therapy” in 31.2%. Median time to CR was 3 months [2.2–24.5]. Relapse rate was 14% with a median follow-up time of 12 months [6–73]. Adverse events occurred in 4 patients. CR was more frequently observed in patients with increased serum baseline level of anti-BP180-NC16A IgE (74.6% versus 41.2%; p = 0.011). Conversely, urticarial lesions, blood total IgE concentration or eosinophil count were not predictive of CR. Patients with omalizumab dosage >300 mg/4wks showed a similar final outcome, but control of disease activity (10 [5–30] versus 15 [10–60] days; p < 0.0001) and CR (2.4 [2.2–8.2] versus 3.9 [2.3–24.5] months; p = 0.0006) were achieved significantly faster. Conclusion We report the largest series to date of BPs treated by omalizumab and confirm its effectiveness and safety in this indication. Serum baseline level of anti-BP180-NC16A IgE may predict response to treatment.