AbstractBackgroundChlormethine gel is a skin‐directed therapy used for patients with mycosis fungoides (MF) that showed a favourable risk/benefit profile in a randomized clinical trial. Currently, data on chlormethine gel use in real‐world settings are limited.ObjectivesThe aim of this study was to assess safety and efficacy of chlormethine gel treatment in patients treated during daily clinical practice and investigate associations between response and disease stage, lesion type, mono‐ or combination therapy, and occurrence of dermatitis.MethodsClinical data from patients using chlormethine gel from three sites in Greece were analysed. Efficacy was assessed through modified Severity‐Weighted Assessment Tool (mSWAT) scores. Safety assessments included analysis of the occurrence and severity of dermatitis. The Skindex‐29 questionnaire was used for quality‐of‐life assessments.ResultsFifty‐eight patients were included. The overall response rate (ORR) increased from 37.9% at month 1 to 80.8% at month 9. For 64.2% of patients, response was maintained for at least 4 months (ORR4). At month 3, a higher ORR was seen for patients with patches (69.7%) than patients with plaques/tumours (both 15.2%). A higher ORR4 was observed for patients with early‐ vs late‐stage disease (71.4% vs. 36.4%) and patients on mono‐ vs combination therapy (75% vs. 47.6%). Dermatitis was observed in the majority of patients (72.4%), but the presence or severity of dermatitis was not directly correlated with treatment response. Both mSWAT and Skindex‐29 scores decreased significantly during treatment, and changes in these scores from baseline to month 6 showed a positive correlation (r = 0.55, P = 0.026).ConclusionsChlormethine gel was effective for the treatment of skin lesions in patients with early‐ and late‐stage MF in clinical practice. Response rates increased over time, indicating that continued treatment with the gel is important. Dermatitis may be managed by reducing the treatment frequency; the occurrence of dermatitis did not affect the response to treatment.