Clofarabine salvage therapy for refractory high-risk langerhans cell histiocytosis.

Pediatric patients with refractory multisystem Langerhans cell histiocytosis (LCH) have a poor prognosis despite aggressive chemotherapy. Salvage therapy with cytarabine and cladribine has shown promise as an effective treatment but is associated with significant toxicity. A previous report described two patients with refractory LCH who had a rapid response to single-agent clofarabine with minimal toxicity. In this report, we describe four children with refractory, risk-organ-positive LCH who were treated with clofarabine and provide follow-up for the two previously reported cases. The results support development of a formal trial evaluating clofarabine as front-line salvage for refractory LCH.