REACH: Study to Determine the Aetiology of Chlormethine Gel Induced-skin Drug Reaction in Early Stage Mycosis Fungoides Cutaneous T Cell Lymphoma (MF-CTCL)

Study to Determine the Aetiology of Chlormethine Gel Induced-skin Drug Reaction in Early Stage Mycosis Fungoides Cutaneous T Cell Lymphoma (MF-CTCL)

Adult patients with early stage MF-CTCL (stage IA-IB) will be eligible for this study. A total of 100 early stage MF-CTCL patients diagnosed in the past year will be enrolled.

Treatment with CL gel will be applied once daily to all skin areas affected by MF-CTCL and, for 8 weeks, one selected skin area unaffected by MF-CTCL (0.5% body surface area) until treatment response (complete response), study treatment duration completed (56 weeks), progression, or another withdrawal criterion is met.

Depending on the type of skin drug-related reaction (if any) occurring after application of CL gel, this study will categorize patients into three different groups corresponding to three different treatment patterns:

• Group A: Patients with no skin drug reaction with CL gel application
• Group B: Patients developing a skin drug reaction of any grade with CL gel application, not due to allergic reaction to CL gel, will continue treatment at reduced application frequency
• Group C: Patients from Group B unable to tolerate reduced CL gel application frequency will apply a potent topical steroid twice daily in addition to CL gel applied every other day

Inclusion Criteria:

• Diagnosis of MF-CTCL stage IA or IB at enrolment as per ISCL/EORTC revision to the MF and Sézary syndrome classification and MF stage should have never met the criteria for stage IIA or higher in the patient medical history
• Lesions cover less than 80% of BSA
• Age ≥ 18
• ECOG/WHO performance status 0-2

Exclusion Criteria:

• Previous treatment with CL gel
• Concurrent or planned local or systemic anti-CTCL therapy
• Prior treatment with antihistamines or narrow band UV-B or PUVA therapy one week before enrolment, or systemic corticosteroids or radiotherapy in the last 4 weeks before enrolment
• Prior treatment with topical steroids in the patch test area (upper back) one week before enrolment