Chlormethine gel effectiveness as second-line treatment in mycosis fungoides: a single-centre retrospective study

Chlormethine gel is a promising treatment for early-stage mycosis fungoides (MF) with strong efficacy and manageable side effects. This study evaluates its effectiveness as a second-line treatment in patients unresponsive to prior skin-directed therapies (SDTs) or combined systemic treatments, hypothesising significant therapeutic benefits with manageable adverse reactions.

A retrospective observational study was conducted from April 2021 to December 2022, including adult patients with histologically confirmed MF who had not responded to at least one prior SDT. Patients received daily chlormethine gel applications, and responses were evaluated at 3, 6, and 12 months using the Modified Severity-Weighted Assessment Tool (mSWAT). Statistical analyses were performed using SPSS ver 26 (IBM), including one-way ANOVA and univariate regression.

The study included 21 patients (12 males, 9 females; mean age 61 years). 81% had early-stage MF, and 19% had advanced-stage disease. Chlormethine gel showed a 90% response rate, with 33.3% achieving complete response (CR) and 57.1% partial response (PR). Adverse reactions were primarily contact or irritative dermatitis, which were manageable and did not significantly affect outcomes. Median mSWAT scores significantly reduced from baseline at 3, 6, and 12 months (P = 0.002).

Chlormethine gel appeared to be efficacious and safe as a second-line treatment for MF, including in advanced stages. Despite limitations like small sample size and retrospective design, these findings highlight its potential in combination therapies and the importance of continued treatment for optimal outcomes. Future research should confirm these results in larger, prospective studies.