More recently, a clinical trial carried out by the Spanish Network on Mastocytosis (REMA) showed response to imatinib in 5/10 patients with SM lacking exon 17 KIT mutations, which included three WDSM patients with the K509I KIT mutation, one patient with wild-type KIT SM-chronic eosinophilic leukemia who had no PDGFR rearrangements and 1 patient with wild-type KIT WDSM (Alvarez-Twose et al., 2017). The gene discussed is KIT; the disease is Chronic Eosinophilic Leukemia, Not Otherwise Specified.