This phase II trial tests the safety, side effects, best dose and activity of tovorafenib (DAY101) in treating patients with Langerhans cell histiocytosis that is growing, spreading, or getting worse (progressive), has come back (relapsed) after previous treatment, or does not respond to therapy (refractory). Langerhans cell histiocytosis is a type of disease that occurs when the body makes too many immature Langerhans cells (a type of white blood cell). When these cells build up, they can form tumors in certain tissues and organs including bones, skin, lungs and pituitary gland and can damage them. This tumor is more common in children and young adults. DAY101 may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Using DAY101 may be effective in treating patients with relapsed or refractory Langerhans cell histiocytosis.
180 days- < 22 years (at time of study enrollment)
Patient must have a body surface area of ≥ 0.3 m²
Patients with progressive, relapsed, or recurrent LCH with measurable disease at study entry
Patients must have had histologic verification of LCH (from either original diagnosis or relapse/progression) at the time of study entry
LCH arising along with other hematologic malignancy (e.g. mixed LCH with acute lymphoblastic leukemia) or any history of non-histiocytic malignancy
Disease scenarios as below will be excluded
Skin-limited disease
Gastrointestinal (GI) tract involvement only (those that have disease that can be determined by endoscopic biopsies only)