Ulixertinib in People With Histiocytic Neoplasms

Histologically confirmed histiocytic neoplasm or histologic findings consistent with histiocytic neoplasm with confirmatory radiologic or molecular findings. Pathologic examination can be performed at any of the enrolling institutions. This qualification is made because it is well known that biopsies of histiocytic neoplasms are variable and do not always demonstrate "typical" morphologic appearance with all of the classically described elements. As a result, histiocytic neoplasms are not exclusively pathologic diagnoses-rather, they are interpretations of histologic findings in a clinical and radiologic context. These criteria were applied in NCT02649972 and will be applied in this trial

Identified mutation in MAPK pathway genes, including but not limited to ARAF, BRAF, RAF1, NRAS, KRAS, MAP2K1, MAP2K2, and NF1 (for primary cohort; no mutation needed for exploratory cohort). Tumor mutation may be identified by tumor sequencing or cfDNA-based sequencing. Concordance between cfDNA and tumor sequencing for BRAFV600E and non-BRAF mutations in histiocytic neoplasms has been documented by our group and others

Measurable disease according to PRC, confirmed by an investigator radiologist

Age (a) ≥18 years prior to interim safety and efficacy analyses or (b) ≥12 years following the interim safety and efficacy analyses