Abstract
BackgroundNon-Langerhans cell histiocytosis, including Erdheim–Chester disease (ECD), Rosai–Dorfman disease (RDD), indeterminate cell histiocytosis (ICH), and unclassified histiocytosis, is a rare disorder lacking a standard treatment strategy. We report our experience using intermediate-dose cytarabine as the first or subsequent therapy in non-Langerhans cell histiocytosis.ResultsNine ECD patients, 5 RDD patients, 1 ICH patient and 1 unclassified histiocytosis patient were enrolled. Intermediate-dose cytarabine therapy was administered as 0.5–1.0 g/m2 of intravenous cytarabine every 12 h for 3 days every 5 weeks. The median age at cytarabine initiation was 47.5 years (range 18–70 years). The median number of cycles of cytarabine administered was 5.5 (range 2–6). The overall response rate (ORR) was 87.5% in the overall cohort, including 12.5% with complete response and 75.0% with partial response. One patient experienced disease recurrence 19 months after cytarabine therapy. The median follow-up duration for the entire cohort was 15.5 months (range 6–68 months). The estimated 2-year progression-free survival and overall survival rates were 85.6% and 92.3%, respectively. The most common toxicity was haematological adverse events, including grade 4 neutropenia and grade 3–4 thrombocytopenia. No treatment-related deaths occurred.ConclusionsIntermediate-dose cytarabine is an efficient treatment option for non-Langerhans cell histiocytosis patients, especially for those with CNS involvement.
Highlights
Histiocytosis is a rare disorder characterized by the accumulation of macrophages, dendritic cells, or monocytederived cells in various tissues and organs [1]
We previously reported remarkable responses to intermediate-dose cytarabine in 3 patients with Erdheim–Chester disease (ECD) [7, 8] and 2 patients with Rosai–Dorfman disease (RDD) [9] with central nervous system (CNS) involvement
Patients A retrospective review was conducted among patients who were diagnosed with non-Langerhans cell histiocytosis (ECD, RDD, indeterminate cell histiocytosis (ICH) and unclassified histiocytosis) and had received intermediate-dose cytarabine for at least 2 cycles at Peking Union Medical College Hospital between October 2013 and August 2021
Summary
Histiocytosis is a rare disorder characterized by the accumulation of macrophages, dendritic cells, or monocytederived cells in various tissues and organs [1]. The discovery of the BRAFV600E mutation in approximately 50% of patients with LCH [2] and ECD [3] provided the first molecular therapeutic target in histiocytosis. For patients who lack BRAFV600 mutations but carry other MAPK-ERK pathway mutations, treatment with MEK inhibitors has shown clinical efficacy [5]. Recurrent driving mutations of the MAPK/ERK pathway are not universal in non-Langerhans cell histiocytosis [6], and recent biological and molecular advances in ECD have not been matched in other non-Langerhans disorders. For non-Langerhans cell histiocytosis types excluding ECD, the efficacy of targeted therapy has only been reported in isolated case reports. Non-Langerhans cell histiocytosis, including Erdheim–Chester disease (ECD), Rosai–Dorfman disease (RDD), indeterminate cell histiocytosis (ICH), and unclassified histiocytosis, is a rare disorder lacking a standard treat‐ ment strategy. We report our experience using intermediate-dose cytarabine as the first or subsequent therapy in non-Langerhans cell histiocytosis
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