Analysis of outcome for patients with mass lesions of the central nervous system due to langerhans cell histiocytosis treated with 2-chlorodeoxyadenosine

Purpose. To assess the activity and tolerability of 2-chlorodeoxyadenosine (2-CDA) in treating mass lesions of the central nervous system (CNS) due to Langerhans cell histiocytosis (LCH). Patients and Methods. The records of eight children and four adults with CNS LCH who were treated with 2-CDA were reviewed. The pattern of CNS disease included involvement of the hypothalamic-pituitary axis, gadolinium enhancing parenchymal as well as dural and choroid plexus based mass lesions, and atrophy. 2-CDA (5-13 mg/m(2)/day) was given on 3-5 consecutive days and repeated every 28 weeks for a period ranging from 3 to 12 months. Results. Eight patients demonstrated a complete radiographic response to 2-CDA with resolution of all enhancing mass lesions and four patients showed a sustained, partial radiographic response. One patient died from a non-treatment related cause without evidence of LCH on autopsy. With a follow-up ranging from 2 to 10 years after completion of therapy, the I I surviving patients remain in continuous remission or are progression free. Prolonged bone marrow suppression was the most common toxicity (four patients). Permanent sequelae of CNS LCH, such as panhypopituitarism, diabetes insipidus 00 and neurocognitive dysfunction, were not found to be reversible with 2-CDA therapy. Conclusions. 2-CDA is an active agent in patients with CNS LCH, with the possible exception of neurodegenerative disease, and should be further evaluated in a prospective multi-center clinical trial for LCH patients with enhancing mass lesions of the CNS.