Clofarabine in refractory Langerhans cell histiocytosis.

Patients with multi-system Langerhans cell histiocytosis (LCH) who progress on frontline therapy have a dismal outcome. Responses to cladribine have been reported in relapsed LCH, but there are no well defined salvage regimens for LCH is refractory to therapy. The next generation deoxyadenosine analog, clofarabine, has demonstrated activity in patients with leukemia that is refractory to salvage regimens, including other nucleotide congeners; however, no experience exist on the use of clofarabine in LCH. In this report we describe significant single agent activity of clofarabine in disseminated LCH refractory to salvage regimens, including cladribine.