New systemic treatment options in mycosis fungoides and Sézary syndrome

Cutaneous T cell lymphomas (CTCL) are a heterogeneous group of rare non-Hodgkin lymphomas. The most common type of CTCL is Mycosis fungoides (MF). Much less common but clinically and histopathologically related to MF is Sézary syndrome (SS). CTCL are incurable and associated with a reduced quality of life. While early stage MF has a good prognosis and is usually treated with skin directed therapies, advanced-stages require systemic therapies, including retinoids, interferon, cytotoxic chemotherapeutic drugs, low-dose methotrexate, histone deacetylase inhibitors and alemtuzumab. However, relapses are frequent and long-term remissions are achieved only in few cases, e.g. with allogenic stem cell transplantation. In recent years, new therapeutic options have evolved by the approval of brentuximab vedotin and mogamulizumab. Both recently approved therapies demonstrated superiority with regard to overall response rate and progression free survival over traditional systemic therapies. Other promising treatments such as lacutamab and PD-1/L-1 inhibitors are in the pipeline, and more therapeutic agents are currently investigated in clinical trials.