Efficacy and safety of Dabrafenib in Erdheim-Chester disease

This study evaluates the efficacy and safety of dabrafenib in BRAF^V600E mutant Erdheim-Chester disease (ECD). This retrospective study reviewed patients who received dabrafenib treatment for at least one month at Peking Union Medical College Hospital and the Cancer Hospital of the Chinese Academy of Medical Sciences from December 2021 to February 2025. All patients received dabrafenib 75 ~ 150 mg twice daily. Treatment response was assessed through radiological examinations, and the objective response rate (ORR) was evaluated. A total of 20 ECD patients with BRAF^V600E mutation were included in the present study (7 women and 13 men; median age, 51.5 years; age range, 9-72 years). The most affected organs were bones (n = 16, 80.0%), lungs (n = 11, 55.0%), perirenal infiltration (n = 10, 50.0%), and central nervous system (n = 9, 45.0%). The ORR was 100.0% (95% CI, 80.5-100.0%) among the evaluable 17 patients, with 5 (29.4%) achieving complete response and 12 (70.6%) partial response. The median follow-up duration was 19.5 months. No disease progression or death occurred. Six patients (30.0%) discontinued dabrafenib, due to financial constraints (n = 3), adverse events (n = 1), patient preference (n = 1), and insufficient symptomatic improvement despite radiologic response (n = 1). The 18-month event-free survival (EFS) and overall survival (OS) rates were 68.7% (95% CI, 50.7%-93.3%) and 100.0%, respectively. The most common adverse events (AEs) in the overall cohort included arthralgia (n = 7, 35.0%), fever (n = 6, 30.0%), and rash (n = 4, 20.0%), with no grade 3-4 AEs observed. Dabrafenib demonstrates promising efficacy and acceptable safety in ECD patients with BRAF^V600E mutation.