2-chlorodeoxyadenosine therapy for disseminated langerhans cell histiocytosis

Objective: To evaluate the efficacy of 2-chlorodeoxyadenosine (2-CDA), a purine nucleoside analogue, in treating disseminated Langerhans cell histiocytosis (LCH). Patients and Methods: We retrospectively reviewed the clinical records of 5 patients who were seen at our institution for histologically confirmed disseminated LCH, including 1 patient with central nervous system parenchymal involvement. These patients were treated consecutively with 2-CDA chemotherapy between December 1994 and January 2001. The patients ranged in age from 19 to 81 years, and the median pretreatment duration of disease was 23 months. Median follow-up after initiation of 2-CDA treatment was 33 months. 2-Chlorodeoxyadenosine was used as frontline therapy for 1 patient and as salvage therapy for the other patients. Patients generally received 0.7 mg/kg over 5 or 7 days; the median number of courses was 4. Results: Complete responses were achieved in 3 patients, including the patient with central nervous system disease, which, to our knowledge, has not been described previously. Two other patients achieved partial responses. The overall response rate was 100%. Toxic effects consisted mainly of myelosuppression; 1 patient developed dermatomal herpes zoster infection. Conclusion: Our experience confirms the reported efficacy of 2-CDA in the treatment of LCH; however, the optimal timing and schedule of therapy remain to be determined.