Stage IIB Mycosis Fungoides and Sezary Syndrome AJCC v8

This phase II trial studies the effect of extracorporeal photopheresis (ECP) and mogamulizumab in treating patients with erythrodermic cutaneous T cell lymphoma (CTCL), a type of skin lymphoma. CTCL is a rare type of cancer that begins in the white blood cells called T cells. Erythrodermic is a widespread red rash that may cover most of the body. ECP is a medical treatment that removes blood with a machine, isolates white blood cells and exposes them to ultra violet light, then returns the cells to the body. Mogamulizumab is a monoclonal antibody that may interfere with the ability of cancer cells to grow and spread. Giving mogamulizumab with ECP may work together to kill the tumor cells directly (with mogamulizumab) and boost immune response to cancer (with ECP).

This study is being done to assess mogamulizumab-associated rash in patients diagnosed with mycosis fungoides or sezary syndrome and treated with standard of care mogamulizumab. One of the most common side effects of mogamulizumab is a rash, currently named mogamulizumab-associated rash (MAR) which can look like MF or SS. However, mogamulizumab-associated rash (MAR) does not indicate failure of mogamulizumab, and may be a sign that the drug is working. If not properly evaluated, mogamulizumab-associated rash (MAR) could be misinterpreted as worsening of mycosis fungoides/sezary syndrome, which could lead doctors to recommend stopping mogamulizumab treatment early. The information learned by doing this research study may help tell the difference between mogamulizumab-associated rash (MAR) (sometimes also called "drug eruption") and worsening of the disease. It may also help to uncover information about the cause of mogamulizumab-associated rash (MAR).