Dermatological adverse events during hematological and oncological therapies (Bruton’s tyrosine kinase inhibitors and mogamulizumab): an Italian retrospective multicenter study

Background: Bruton's Tyrosine Kinase Inhibitors (BTKIs) and mogamulizumab have revolutionized the treatment of hematologic malignancies, yet they are frequently associated with dermatologic adverse events (dAEs) that can impact patient quality of life and adherence. The aim is to evaluate the incidence, clinical features, and management of dAEs associated with BTKIs and mogamulizumab across multiple Italian dermatology centers. Methods: We conducted a retrospective, multicenter study involving 80 patients treated with BTKIs or mogamulizumab from January to December 2024. Patients were stratified into three cohorts: mogamulizumab (MOG), ibrutinib (IBR), and other BTKIs. dAEs were assessed for type, location, severity (CTCAE v5.0), duration, and treatment outcomes. Results: Eczema-like rashes were most frequent in BTKI-treated patients (43.2% in IBR; 22.2% in other BTKIs), while mogamulizumab was primarily associated with morbilliform rashes (36%). The mean duration of dAEs was under six months across all cohorts, with most cases graded as mild. Topical corticosteroids and emollients were the mainstay of treatment. Remission rates were 64% (MOG), 89.2% (IBR), and 83.3% (other BTKIs), with few cases of progression. Conclusions: dAEs are common but manageable side effects of BTKIs and mogamulizumab. Dermatologic surveillance and early treatment are crucial for optimizing patient outcomes. Multidisciplinary collaboration is essential to prevent misdiagnosis and treatment interruptions, especially in cases of mogamulizumab-associated rash.