Evaluating the Treatment Patterns of Chlormethine/Mechlorethamine Gel in Patients With Stage I-IIA Mycosis Fungoides: By-time Reanalysis of a Randomized Controlled Phase 2 Study.

BACKGROUND

The pivotal 201 Study investigated chlormethine/mechlorethamine gel treatment for patients with early stage disease mycosis fungoides and demonstrated the treatment was not inferior to chlormethine ointment. However, overall response rates do not provide information about response patterns. The study objective was to assess the value of by-time analysis of clinical response data in visualizing response over time.

METHODS

This post hoc analysis re-evaluated chlormethine efficacy using a by-time approach that investigated the trend to treatment response and permitted assessment of response, both monthly between 1 and 6 months, and once every 2 months between 7 and 12 months, over the course of 1 year. In addition, very good partial response was redefined as a ≥ 75% response.

RESULTS

By-time analyses of Composite Assessment of Index Lesion Severity (CAILS) and modified severity-weighted assessment tool (mSWAT) showed response rates at 1 month (respectively, 8.5% and 5.9%) that increased over time to peak at 10 months (78.9% and 54.4%). Early, intermittent, and late response patterns were observed. In total, 32.5% of patients experienced very good partial response over 2 consecutive visits, indicating that ∼ 33% of patients could expect to have very good to complete response within 1 year.

CONCLUSION

By-time analysis for clinical response provides complementary information to traditional overall response rate data regarding response peak time and changes over time.