Real-life experience with chlormethine gel: moving beyond clinical trial data

Background

Data on real-life experience with the novel 0.016% chlormethine gel approved (FDA and EMA) for topical treatment of mycosis fungoides (MF) is strikingly sparse.

Objective

To assess the efficacy and safety of chlormethine gel in early-stage MF patients in a real-life setting.

Methods

Data on early-stage MF patients treated with chlormethine gel during 2016-2019 was retrospectively collected from the records of the MF Clinic of Rabin Medical Center. All patients had at least one follow-up visit after initiation of treatment, and in each patient the best response was assessed.

Results

Overall, 66 early-stage MF patients received chlormethine gel: 51 male (77%), mean age 57 years (range 24-83), 37 had stage IA, 27-stage IB, 2 stage IIA, and 7- folliculotropic MF. Regional application of chlormethine gel was given to 57 patients (86%), and total body application- to 9 (14%), as monotherapy (most of the time)- in 48 patients (73%), in combination with topical corticosteroids- in 13 (20%), and in combination with systemic treatment- in 5 (7%), for and an average duration of 342 days (7-1096). Overall response rate (≥50% clearance from baseline) was 59% (39/66), and only 2 patients achieved complete response (100% clearance).

Cutaneous side effects (SE) were seen in 32 patients (48%) that were mild in the vast majority of the patients. Dermatitis, specifically irritation, and localized pruritus were the most frequently observed SEs and were manageable by a reduction in application frequency and/ or application of topical steroids, or temporary treatment interruption. Eight patients had unmasking effect, and 7- hyperpigmentation at application site. Treatment withdrawals for S/Es occurred in 12 patients, and in 6 during the first month.

Conclusion

Our single-center experience showed that topical chlormethine gel improves the skin lesions of early- stage MF, with cutaneous S/Es that are manageable. However, complete response is rarely achieved.