Objectives: Mycosis Fungoides (MF) and Sézary syndrome (SS) are the two most common subtypes of cutaneous T cell lymphomas. Given their low prevalence, real-world treatment patterns of existing and newly approved therapies for MF and SS remain unknown, especially during the COVID pandemic. This study examined treatment patterns among patients with MF or SS between 2018-2020 in the United States.

Methods: Patients in the Symphony Health Solutions database were classified into 6 groups: ≥1 MF diagnosis (no SS diagnosis) in 2018, 2019, and 2020, and ≥1 SS diagnosis in 2018, 2019, 2020, respectively. Utilization of treatments recommended by the current National Comprehensive Cancer Network guidelines was examined: skin-directed therapy (SDT; topical, local radiation, total skin electron beam therapy, or phototherapy), systemic therapy (extracorporeal photopheresis [ECP], parenteral, or oral), and bone marrow transplant (BMT).

Results: Overall(mean age; male), 10,527(62.9 years; 54.6%), 10,078(63.2 years; 54.3%) and 9,414(63.2 years; 53.9%) patients had ≥1 MF diagnosis and 869(66.3 years; 54.4%), 882(66.9 years; 54.8%) and 853(67.3 years; 55.6%) patients had ≥1 SS diagnosis in 2018, 2019 and 2020, respectively. From 2018-2020, 56.1-56.6% of MF (SDT 52.1-52.5%; systemics 12.1-13.5%; BMT 0.1-0.2%) and 64.6-68.8% of SS patients (SDT 48.9-52.9%; systemics 41.8-46.5%; BMT 0.8-1.5%) had ≥1 treatment claims. Among MF patients with any systemic therapies, bexarotene was the most common in 2018 (28.1%) and 2019 (27.5%), methotrexate in 2020 (27.2%), and mogamulizumab (2018 MF/SS approval) the 6^th most common in 2019 (6.8%) and 2020 (6.6%). Among SS patients with any systemic therapies, ECP was the most common in 2018 (40.8%) and 2019 (33.3%), and mogamulizumab in 2020 (29.2%).

Conclusions: Using claims from 2018-2020, approximately half of MF and SS patients had SDT each year, without major change during the COVID pandemic. Since 2018 in SS, there was an increasing systemic usage, with increasing mogamulizumab but decreasing ECP usage.