MEK inhibitors are effective in Erdheim–Chester disease regardless of MAPK pathway mutations

In the last decade, targeted treatments such as BRAF inhibitors (BRAFi) and MEKi have revolutionized the management of patients with ECD. While BRAFi are considered to be effective only in patients harboring the BRAFV600E mutation, responses to MEKi have been reported regardless of the underlying mutation. We herein present data on MEKi efficacy from a cohort of ECD patients treated at two referral centers, one in France (Pitié-Salpêtrière Hospital, Paris) and one in Italy (Meyer Children’s Hospital IRCCS, Florence). The MAPK-ERK pathway mutation status was determined in all patients using NGS, following the latest consensus recommendations on ECD