Avapritinib With Decitabine in Patients With SM-AHN

Inclusion Criteria: * Diagnosis of SM-AHN defined by World Health Organization 2022 criteria. * ECOG 0-3 * Ability to understand and the willingness to sign a written informed consent. * Ability to adhere to study visit schedule and other protocol requirements. * Willing to receive blood products as deemed clinically necessary. * Adequate organ and marrow function as defined by the protocol. * Human immunodeficiency virus (HIV)-infected participants on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial. * For participants with evidence of chronic hepatitis B virus (HBV) infection, the HBV viral load must be undetectable on suppressive therapy, if indicated. * Participants with a history of hepatitis C virus (HCV) infection must have been treated and cured. For participants with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load. * Participants with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should undergo a clinical risk assessment of cardiac function using the New York Heart Association Functional Classification. To be eligible for this trial, participants should be class 2B or better. * Women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, for the duration of study participation, and for at least …