This open-label, prospective, non-randomized, phase 2 trial, was based on the promising results of a previous pilot trial of the French LCH Study Group. The prescribed treatment consisted of at least two 5-day courses of cytarabine (Ara-C) 1g/m2/day plus cladribine (2-CdA) 9mg/m2/day, followed by maintenance therapy. The primary end-point of this salvage trial was the response rate after two Ara-C/2-CdA courses.8 Twenty-seven patients with MS-LCH, risk organ involvement and resistant to at least 1 course of steroids and vinblastine, were enrolled on this trial. The overall response rate after two courses was 92% (7% non-active disease and 85% active disease, better). The study achieved an excellent 5-year survival of 85%, but the toxicity of the regimen was very high (at least 2/4 deaths were due to treatment toxicity) and required highest level of supportive therapy.1
1. Donadieu J, Bernard F, van Noesel M, Barkaoui M, Bardet O, Mura R, et al. Cladribine and cytarabine in refractory multisystem Langerhans cell histiocytosis: results of an international phase 2 study. Blood, 2015, 126(12):1415-23.