title: 2-Chlorodeoxyadenosine therapy for disseminated Langerhans cell histiocytosis.
abstract: OBJECTIVE
  To evaluate the efficacy of 2-chlorodeoxyadenosine (2-CDA), a purine nucleoside analogue, in treating disseminated Langerhans cell histiocytosis (LCH).
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Hematology and Internal Medicine, Mayo Clinic, 200 First St SW, Rochester, Minn 55905, USA.
authors.forename: Animesh
authors.initials: A
authors.lastname: Pardanani
authors.forename: Robert L
authors.initials: RL
authors.lastname: Phyliky
authors.forename: Chin-Yang
authors.initials: CY
authors.lastname: Li
authors.forename: Ayalew
authors.initials: A
authors.lastname: Tefferi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001853:Bone Marrow / Q000187:drug effects; D001927:Brain Diseases / Q000188:drug therapy / Q000209:etiology; D017338:Cladribine / Q000627:therapeutic use*; D005260:Female; D006562:Herpes Zoster / Q000139:chemically induced; D006646:Histiocytosis, Langerhans-Cell / Q000150:complications / Q000188:drug therapy*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D007166:Immunosuppressive Agents; D017338:Cladribine