Mogamulizumab as Bridge to Thiotepa‐Based Allogeneic Haematopoietic Stem Cell Transplantation in Sézary Syndrome: A Single‐Centre Experience

Introduction Sézary syndrome (SS) is an aggressive cutaneous T‐cell lymphoma for which allogeneic haematopoietic stem cell transplantation (allo‐HSCT) represents the only potentially curative treatment. Methods We report a single‐centre series of three consecutive SS patients treated with mogamulizumab as bridging therapy to allo‐HSCT using thiotepa‐based reduced‐intensity conditioning. Results Mogamulizumab induced rapid clearance of circulating Sézary cells and significant clinical improvement. All patients achieved early and stable full donor chimerism and complete remission. Post‐transplant GVHD occurred but was manageable with standard therapy. Conclusion Early use of mogamulizumab may provide effective disease control and facilitate successful allo‐HSCT in SS. Trial Registration The authors have confirmed clinical trial registration is not needed for this submission.