A Phase 2 Multicenter Study of TL-895 in Subjects withMyelofibrosis, Indolent Systemic Mastocytosis, MonoclonalMast Cell Activation Syndrome, or Non-Monoclonal Mast CellActivation Syndrome

The purpose of this study is to evaluate whether the investigational drug TL-895, which has not been approved by the U.S. Food and Drug Administration (FDA), can help improve symptoms in people with indolent systemic mastocytosis (ISM). TL-895 is being studied alone, in combination with avapritinib, and in comparison with either placebo or avapritinib. Avapritinib is an approved drug that is already used to treat certain types of systemic mastocytosis. A placebo is a treatment with no active therapeutic effect, used to compare against an investigational drug. The main goals of the study are to assess the safety and tolerability of TL‑895 and to identify the recommended dosing regimen when it is taken alone or together with avapritinib. Overall, the study aims to determine whether TL‑895 could become a helpful future treatment option for patients with ISM.

Are you Eligible? (Inclusion Criteria)

• confirmed diagnosis of Indolent Systemic Mastocytosis (ISM) or Bone Marrow Mastocytosis (BMM) - 18 years of age who can provide informed consent - cannot have diagnosis of another myeloid disorder