[Efficacy and safety of vemurafenib in the treatment of BRAF(V600E)-mutated Erdheim-Chester disease].

Objective: To evaluate the safety and efficacy of vemurafenib in the treatment of BRAF(V600E)-mutated Erdheim-Chester disease (ECD) . Methods: We retrospectively analyzed the clinical data, response rate, adverse events and survival of 12 patients with ECD treated with vemurafenib from March 2015 to October 2020 in Peking Union Medical College Hospital. Results: Of 12 patients [7 males and 5 females, median age = 51.5 (range, 32-66) years old], the median number of organs involved was 6 (range, 4-8) , and the median treatment duration of vemurafenib was 11 (3-60) months. All patients had improvement of clinical symptoms, of which 2 cases were completely relieved, and 10 cases were partially relieved. Seven patients evaluated by (18)F-FDG-positron emission tomography/computed tomography achieved a metabolic response, including 2 patients with a complete metabolic response and 5 patients with a partial metabolic response. The common adverse events in the overall cohort were grade 1 to 2 (Common Terminology Criteria for Adverse Events 5.0) , including skin rash (58.3%) , arthralgia (25.0%) , and digestive tract reactions (16.7%) . The median follow-up time was 13.5 (3-60) months. One patient with central nervous system involvement died due to a cerebrovascular event, and one patient relapsed 10 months after drug withdrawal. The estimated 2-year overall survival rate and 2-year progression free survival rate were 88.89% and 66.67%, respectively. Conclusions: Vemurafenib is safe and effective in the treatment of BRAF(V600E)-mutated ECD.