OBJECTIVES: Mycosis fungoides (MF) and Sézary syndrome (SS) are cutaneous T-cell lymphomas (CTCLs) associated with a wide range of symptoms, including severe pruritis and other morbidities. In the phase 3 MAVORIC trial (NCT01728805), mogamulizumab, a first-in-class defucosylated humanized IgG1-kappa monoclonal antibody that selectively binds to C-C chemokine receptor 4, significantly improved progression-free survival compared to vorinostat in patients with relapsed or refractory MF or SS and health-related quality of life (HRQoL). The objectives of the PROSPER study (NCT05455931) are to evaluate patient-reported changes in key patient-reported symptoms of disease, fatigue, and HRQoL following initiation of mogamulizumab treatment. Changes in caregiver HRQoL and real-world treatment patterns will also be assessed.

METHODS: PROSPER is an international, observational, prospective, mixed-methods multicenter study recruiting 80 patients aged ≥18 years with a confirmed diagnosis of MF or SS who are scheduled to start mogamulizumab. Up to 25 primary caregivers of patients will also be invited to participate. All patients will complete a bespoke symptom diary as well as the Brief Fatigue Inventory (BFI) and CTCL QoL questionnaires, with voluntary participation in one-on-one interviews and photographs of significant lesions prior to mogamulizumab initiation and at regular intervals throughout the study for a follow-up period of up to 50 weeks. Patient medical data will be entered into an electronic data capture system. Caregivers will complete the CareGiver Oncology Quality of Life questionnaire (CarGoQoL). The study period is from November 2022 to the end of 2024.

RESULTS: As a trial-in-progress, data are not yet available.

CONCLUSIONS: The PROSPER study will provide novel patient insights into the impact of mogamulizumab treatment on symptoms and HRQoL of patients with MF and SS as well as their caregivers in the real-world clinical practice setting.