Abstract
Erdheim-Chester disease (ECD), also known as non-Langerhans cell histiocytosis, is a multi-systemic disease with unclear pathogenesis. Based on a small number of case studies, pegylated interferon-α (PEG-IFN-α) has been used as the front-line treatment option. However, there are limited data regarding administration of ropegylated-interferon α-2b (ROPEG-IFN-α 2b) for ECD patients. Herein, we report two cases of severe ECD treated with two types of PEG-IFN-α. One patient with heart and skeleton involvement and BRAF V600E mutation was treated with weekly PEG-IFN-α 2a. Another patient with bone involvement and no BRAF V600E mutation was administered monthly ROPEG-IFN-α 2b. The two types of PEG-IFN-α showed excellent disease control, excellent survival outcomes, and manageable toxicities in ECD patients. These results suggest that ROPEG-IFN-α 2b could be used equivalently to PEG-IFN-α 2a for management of advanced ECD.