This salvage approach was designed as a non-randomized phase II study, aiming to evaluate the activity of cladribine (2-chlorodeoxyadenosine; 2-CdA) in patients with risk organ involvement (RO+), whose disease progressed after combination therapy with prednisolone, vinblastine and etoposide and in patients without risk organ involvement (RO-) with multiple disease reactivations (≥ 2 episodes).1 2-CdA was given as a 5-day course at a dose of 5 mg/m2/day, repeated every 3-4 weeks for 2-6 courses depending on response. Forty-six RO+ and 37 RO- patients were evaluable. 2-CdA as monotherapy was significantly more effective in RO- patients with a response in 62% compared to 22% in RO+ patients. Two-year predicted survival was 48% for RO+ and 97% for RO- patients. Thus, 2-CdA as a single drug was not sufficient to change the fate of the patients with most severe disease.
1. Weitzman S, Braier J, Donadieu J, Egeler RM, Grois N, Ladisch S, et al. 2'-Chlorodeoxyadenosine (2-CdA) as salvage therapy for Langerhans cell histiocytosis (LCH). results of the LCH-S-98 protocol of the histiocyte society. Pediatr Blood Cancer, 2009, 53(7):1271-6.