Oral and Topical Janus Kinase Inhibitors in Patients With Cutaneous T‐Cell Lymphoma: A Real‐World Single‐Center Experience

The JAK/STAT pathway is implicated in the pathogenesis of cutaneous T-cell lymphoma (CTCL), with early studies suggesting that JAK inhibitors (JAKi) may be used for treating CTCL. Patients with CTCL may have other indications for JAKi use, but data on JAKi agents in CTCL is limited due to warnings against their use in malignancy. We retrospectively characterized the experience of our tertiary cancer center with JAKi in patients seen for CTCL between the years 2011 and 2024. We identified 26 CTCL patients who received a JAKi: 7 received a JAKi prior to their CTCL diagnosis (topical (n = 5) or oral (n = 2) for itchy rash or eczema), 6 received a JAKi as CTCL treatment, and 13 received a JAKi for other indications following a diagnosis of CTCL (oral ruxolitinib for graft versus host disease (GvHD) following allogeneic stem cell transplant (n = 9), oral ruxolitinib for hemophagocytic lymphohistiocytosis (n = 3), or topical ruxolitinib for alopecia areata (n = 1)). Of the six patients treated for CTCL with a JAKi, four received oral ruxolitinib and two received topical ruxolitinib. One patient treated orally has had a complete response for 3 years and another patient has had a diminishing lesion size for 1 year. One patient treated topically for skin-limited CTCL demonstrated plaque thinning. Of the nine patients treated for GvHD, five experienced CTCL relapse a median of 8 weeks following ruxolitinib exposure. This study provides initial insights into the real-world use of JAKi in patients with CTCL. Further studies, however, are required to characterize any association between JAKi use and CTCL development, as well as the safety of JAKi use in the context of pre-existing CTCL.