MiRisten for the Treatment of Relapsed or Refractory Acute Myeloid Leukemia

Inclusion Criteria:

* Documented informed consent of the participant and/or legally authorized representative.
* Agreement to allow the use of archival tissue from diagnostic tumor biopsies

  * If unavailable, exceptions may be granted with study principal investigator (PI) approval.
* ≥ 18 years.
* Eastern Cooperative Oncology Group (ECOG) ≤ 2.
* Patients with histologically confirmed AML, according to International Consensus Classification (ICC) or World Health Organization (WHO) criteria, with relapsed or refractory (R/R) disease who have failed treatment with, or are ineligible for, available therapies known to be active for treatment of AML.

  * Patients with extramedullary disease may be included if they also have concurrent marrow disease.
* Fully recovered from the acute toxic effects (except alopecia) to ≤ grade 1 to prior anti-cancer therapy.
* Life expectancy of ≥ 3 months.
* Total bilirubin ≤ 1.5 x upper limit of normal (ULN) (performed within 28 days prior to day 1 of protocol therapy unless otherwise stated).
* Aspartate aminotransferase (AST) ≤ 3 x ULN (performed within 28 days prior to day 1 of protocol therapy unless otherwise stated).
* Alanine aminotransferase (ALT) ≤ 3 x ULN (performed within 28 days prior to day 1 of protocol therapy unless otherwise stated).
* Creatinine clearance of ≥ 60 mL/min per 24-hour urine test or the Cockcroft-Gault formula (performed within 28 days prior to day 1 of protocol therapy unless otherwise stated).
* International normalized ratio (INR) or prothrombin (PT) ≤ 1.5 x ULN (performed within 28 days prior to day 1 of protocol therapy unless otherwise stated).
* Activated partial thromboplastin time (aPTT) ≤ 1.5 x ULN (performed within 28 days prior to day 1 of protocol therapy unless otherwise stated).
* Left ventricular ejection fraction (LVEF) ≥ 45% (performed within 28 days prior to day 1 of protocol therapy unless otherwise stated).
* Corrected QT interval (QTcF) ≤ 480 ms based on Fridericia's formula

  * Note: To be performed within 28 days prior to day 1 of protocol therapy.
* Women of childbearing potential (WOCBP): negative urine or serum pregnancy test (performed within 28 days prior to day 1 of protocol therapy unless otherwise stated).

  * If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required.
* Agreement by females and males of childbearing potential to use an effective method of birth control or abstain from heterosexual activity for the course of the study through at least 3 months after the last dose of protocol therapy.

  * Childbearing potential defined as not being surgically sterilized (men and women) or have not been free from menses for \> 1 year (women only).

Exclusion Criteria:

* Allogeneic hematopoietic stem cell transplant within 3 months prior to day 1 of protocol therapy. Patients must be off calcineurin inhibitors for at least 2 weeks prior to day 1 of protocol therapy.
* Chemotherapy, radiation therapy, biological therapy, immunotherapy within 14 days prior to day 1 of protocol therapy, with the exception of hydroxyurea.
* Strong and moderate CYP3A4 inducers and strong CYP3A inhibitors (with the exception of azole antifungals) within 7 days prior to day 1 of protocol therapy.
* Foods/supplements that are strong inhibitors or strong or moderate inducers of CYP3A (such as St. John's wort) within 3 days prior to initiation of and during study treatment.
* Systemic steroid therapy \> 10 mg/day (≤ 10mg/day prednisone equivalent ok) or any other form of immunosuppressive medication within 14 days. Inhaled or topical steroids, and adrenal replacement steroid doses ≤10 mg daily prednisone equivalent, are permitted. Steroids given for study drug infusion reaction prophylaxis or infusion reactions should not count towards this maximum.
* Must not have received or planning to receive live vaccine while being on study or 28 days before and after completion of treatment.
* Acute promyelocytic leukemia (APL).
* History of allergic or infusion reactions attributed to compounds of similar chemical or biologic composition to study agent.
* Inability to tolerate dexamethasone at the doses prescribed in this protocol.
* Unstable cardiac disease as defined by the following:

  * Unstable angina
  * Uncontrolled atrial fibrillation or hypertension
  * Acute coronary syndrome and/or revascularization (e.g., coronary artery bypass graft, stent) within 6 months of first dose of study drug.
* Clinically significant uncontrolled illness.
* Uncontrolled active infection.
* Other active malignancy. Patients with a prior or concurrent malignancy whose natural history or treatment have the potential to interfere with the safety or efficacy assessment of the investigational regimen are not eligible for this trial. Low grade indolent malignancies may be allowed if not actively undergoing treatment (such as non-melanoma skin cancers, low grade prostate cancer and others per the PI discretion).
* Females only: Pregnant or breastfeeding.
* Any other condition that would, in the investigator's judgment, contraindicate the patient's participation in the clinical study due to safety concerns with clinical study procedures.
* Prospective participants who, in the opinion of the investigator, may not be able to comply with all study procedures (including compliance issues).