Mogamulizumab-kpkc Receives FDA Approval for Mycosis Fungoides and Sézary Syndrome Treatment

On 8 August 2018, the US Food and Drug Administration (FDA), for adults with relapsed or refractory mycosis fungoides (MF) or Sézary syndrome (SS) after at least one prior line of systemic treatment, approved mogamulizumab-kpkc(brand name Poteligeo).

What Are Mycosis Fungoides and Sézary Syndrome?

Mycosis fungoides and Sézary syndrome are rare tumorsclassified as non-Hodgkin lymphomas.

Mycosis fungoides arises from cells called lymphocytes, circulating in the blood and functioning in our immune system, departing from their normal functions and accumulating in the skin. Because of its origin, it is considered a lymphoma group disease, but its course differs substantially from lymphomas of internal organs and lymph nodes; in many patients it causes only a chronic skin problem.

Mycosis fungoides was first described in 1806 by French dermatologist Jean-Louis-Marc Alibert. The name is actually misleading, meaning "fungus-like disease". Yet it is not a fungal infection but a non-Hodgkin lymphoma. Dr. Alibert chose the name because the skin tumors in a severe case had a mushroom-like appearance.

Mycosis fungoides (MF) is the most common cutaneous lymphoma. Most patients are detected early, when skin-directed treatments can produce high response rates and prolonged disease-free survival. Sézary syndrome is the advanced stage and leukemic variant of mycosis fungoides; although less common, it is more treatment-resistant and has a shorter life expectancy.

MF's cause is unclear, and most cases are hereditary not in nature. Most patients are older than 20, and it is more common in men. Treatments include ultraviolet light, topical corticosteroids, chemotherapy and radiotherapy.

Details of the Trial Leading to FDA Approval of Mogamulizumab-kpkc for Mycosis Fungoides and Sézary Syndrome

Mogamulizumab-kpkc targets the CC chemokine receptor type 4 (CCR4) and is a monoclonal antibody. Its FDA approval was supported by a trial in patients who had received a median of 3 previous treatments, totaling 372 participants, a randomized, open-label, multicenter clinical trial as supporting evidence. Of patients, %44 had Sézary syndrome. Patients were randomized to two arms: one received mogamulizumab-kpkc, the other vorinostat.

• Progression-free survival (the time treatment keeps disease controlled) was statistically significantly longer in the mogamulizumab-kpkc arm (7.6 versus 3.1 months).
• Mogamulizumab-kpkc reduced progression (disease worsening) risk by %47 compared with vorinostat.
• Overall response rates were % 28 and % 5, respectively.

Common, occurring in at least 20 percent of patients, adverse effectswere rash, infusion-related allergic reactions, fatigue, diarrhea, musculoskeletal pain and upper respiratory infection. Severe (grade 3 and above) adverse effects occurred in % 36, most often due to infection (% 16 of all patients).

The recommended mogamulizumab-kpkc dose is administered as an intravenous infusion over at least 60 minutes at 1 mg / kg. It is given in the first 28-day cycle on days 1, 8, 15 and 22, then in subsequent 28-day cycles on days 1 and 15 until progression or unacceptable adverse effects.