[Recurrent and Refractory Langerhans Cell Histiocytosis in Children Treated with the Combination of Cladribine and Cytarabine].

Objective: To observe the efficacy and prognosis of cladribine (2-CdA) combined with cytarabine (Ara-C) regimen in the treatment of relapsed refractory Langerhans cell histiocytosis (LCH) in children.
Methods: Nine patients with relapsed refractory LCH treated with the 2-CdA combined with Ara-C regimen in the Department of Hematology and Oncology of Wuhan Children's Hospital from July 2014 to February 2020 were retrospectively analyzed, and the efficacy and disease status were evaluated according to the Histiocyte Society Evaluation and Treatment Guidelines (2009) and the Disease Activity Score (DAS), the drug toxicity were evaluated according to the World Health Organization（WHO） grading criteria for chemotherapy. All patients were followed up for survival status and disease-related sequelae.
Results: Before the treatment combining 2-CdA and Ara-C, 7 of 9 patients were evaluated as active disease worse (ADW), and 2 as active disease stable (ADS) with a median disease activity score of 8 (4-15). Of 9 patients, 6 cases achieved non active disease (NAD) and 3 achieved active disease better (ADB) with a median disease activity score of 0 (0 to 5) after 2-6 courses of therapy. All 9 patients experienced WHO grade IV hematologic toxicity and 3 patients had hepatobiliary adverse effects (WHO grade I～II) after treatment. The median follow-up time was 31(1 to 50) months with all 9 patients survived, 3 of the 9 patients experienced sequelae to the disease with 2 combined liver cirrhosis as well as cholestatic hepatitis and 1 with oral desmopressin acetate tablets for diabetes insipidus.
Conclusion: 2-CdA combined with Ara-C is an effective regimen for the treatment of recurrent refractory LCH in children, and the main adverse effect is hematologic toxicity, which is mostly tolerated in children. Early treatment with this regimen may be considered for patients with multisystem LCH with risky organ involvement who have failed first-line therapy and for patients with relapse.