ATRN-119 in Combination With Decitabine in Patients With TP53-Mutated AML or Higher-Risk MDS

Inclusion Criteria: * Diagnosis of AML or higher-risk MDS (HR-MDS) according to the World Health Organization (WHO) 5th Edition or International Consensus Classification (ICC) 2022 criteria. * HR-MDS is defined as: * IPSS-R (score \> 3.5) or IPSS-M (score \> 0.5) OR ii.≥ 10% bone marrow blasts * Dose Escalation ONLY - One of the following: * Previously untreated AML with ELN 2022 adverse-risk genetic features based on local testing, in patients who are ineligible for intensive induction chemotherapy (cytarabine plus an anthracycline) due to age, comorbidities, or performance status. * Previously untreated HR-MDS * Relapsed or refractory AML or HR-MDS meeting one or more of the following criteria: Failure to achieve CR, CRh, or CRi after ≥ 4 cycles of a hypomethylating agent (HMA); Failure to achieve CR, CRh, or CRi after ≥ 2 cycles of a HMA plus venetoclax; Overt disease progression during HMA-based therapy; First relapse with an initial remission duration \< 12 months; First relapse following failed salvage chemotherapy; Relapse after allogeneic hematopoietic cell transplant; Second or subsequent relapse * Dose Expansion ONLY - Both of the following: * AML or HR-MDS with a TP53 alteration, defined by the presence of any of the following features on local testing: Pathogenic or likely pathogenic TP53 mutation detected by molecular testing (with a minimum 2% VAF); Cytogenetic and/or FISH evidence of 17p deletion involving TP53 (with a minimum 2% cell involvemen…