Efficacy and Safety of Dupilumab in Immune Checkpoint Inhibitor Induced Bullous Pemphigoid: A Spanish Multicentric Case Series.

Immune checkpoint inhibitors (ICIs) have signifi-cantly improved oncologiconcological outcomes. However, ICIs can elicit immune-mediated adverse effects that may require treatment discontinuation and potentially affect cancer prognosis. Bullous pemphigoid (BP) can be induced by ICIs in up to 1 % of treated patients. Conventional treatments for BP (topical and systemic glucocorticoids as well as other classical immunosuppressants) associate substantial toxicities and may impair antitumour responses. Dupilumab, a monoclonal antibody that blocks IL-4/IL-13 signalling, represents a promising alternative, offering effective disease control with an improved safety profile. In this study, we assessed the efficacy and safety of dupilumab for the treatment of ICI-induced BP (ICI-BP) in a real-world multicentre case series of 19 patients, an underreported clinical setting. The median time to ICI-BP development from ICI initiation was 390 days (IQR 295). Overall, 18 patients (94.74%) achieved a clinical response, of whom 16 (84.21%) attained complete remission. Disease stabilization was observed in one1 patient. Among 17 patients receiving systemic corticosteroids prior to dupilumab, 14 (82.35%) discontinued them afterwards. Additionally, 11 patients (61.11 %; n=18) were able to continue or reintroduce ICI after dupilumab initiation. Dupilumab was well tolerated, with 18 patients (94.74%) experiencing no significant adverse events and only one case of suspected psoriasiform toxicity.