Immune‐related adverse events with mogamulizumab in cutaneous T‐cell lymphoma: A multicentre study
David Neubauer, Pascale Palassin, Caroline Ram‐Wolff, Adèle De Masson, Jeremie Delaleu, Diane Kottler, Florent Amatore, Henri Adamski, Claudia Bejar, Raphaël Janela‐Lapert, Emmanuella Guenova, Pauline Bernard, Coralie Lheure, Laurent Machet, Laura Troin, Gaëlle Quereux, Anne Pham‐Ledard, Sarah Faiz, Florent Grange, Yannick Le Corre, Arjen Nikkels, Stéphane Barete, Lorena Manea, Emmanuelle Amazan, Alexandre Tj Maria, Lionel Moulis, Olivier Dereure, Quentin Samaran,Abstract
Background
Mogamulizumab, an anti‐CCR4 monoclonal antibody used in advanced mycosis fungoides (MF) and Sezary syndrome (SS), also depletes regulatory T cells, potentially leading to immune‐related adverse events (irAEs). Unlike mogamulizumab‐associated rash (MAR), other irAEs remain poorly documented to date.
Objectives
To estimate the prevalence of mogamulizumab‐associated irAEs (excluding MAR), characterize their clinical profile and assess management strategies and outcome.
Methods
A retrospective nationwide multicentre survey was conducted using the French Study Group on Cutaneous Lymphomas (GFELC) database with standardized questionnaires collecting demographic, clinical and therapeutic data. An exploratory pharmacovigilance analysis was also performed using the WHO pharmacovigilance database, VigiBase.
Results
Among 403 treated patients from 19 participating centres, 34 patients (8.4%) experienced at least one irAE (41 events overall, event rate 10.2%). The most frequent irAEs involved the endocrine system, skin, and liver. Severe (grade ≥3) or serious irAEs occurred in about one‐third of cases, resulting in permanent treatment discontinuation in 29%. Most events occurred after several months of treatment, often in patients experiencing objective responses. In VigiBase (2464 reports), reported irAEs were most frequently digestive, musculoskeletal, cutaneous, and hepatic.
Conclusions
In this large retrospective series, a minority of patients developed irAEs during mogamulizumab treatment, although a substantial proportion were rated as severe and led to permanent treatment discontinuation. These findings highlight the need for systematic detection, as with immune checkpoint inhibitors, early recognition and prolonged monitoring, as irAEs may occur late during treatment. Prospective studies are warranted to refine epidemiological data along with diagnostic and therapeutic strategies.