A Study of Venetoclax in Combination With Conventional Chemotherapy in Pediatric Patients With Acute Myeloid Leukemia

This is a phase 2 study to test the hypothesis that venetoclax in combination with standard chemotherapy will be tolerable and active in pediatric patients with newly diagnosed acute myeloid leukemia (AML).

Primary Objectives:

* Establish the tolerability adding venetoclax to standard chemotherapy in pediatric patients with AML
* Estimate the proportion of patients who become minimal residual disease (MRD) negative by flow cytometry after one course of venetoclax-based induction therapy

Secondary Objectives:

- Estimate the rates of complete remission (CR), event-free survival (EFS), and overall survival (OS) in pediatric patients who receive venetoclax-based chemotherapy

Treatment will be based on genetic characteristics and response to therapy. Venetoclax will be given with each course of therapy. Low-risk patients will receive four courses of chemotherapy and intermediate-risk patients will receive five courses. High-risk patients who do not have a suitable stem cell donor or who decline HCT will receive five courses of chemotherapy. The definition of suitable stem cell donor and the conditioning regimens used for HCT will be determined by local institutional protocols or guidelines.

Intervention:

Low Risk

Induction 1: Venetoclax orally (PO) once daily (QD) on days -2 to 11, cytarabine intravenously (IV) over 30 minutes every 12 hours on days 1-8, daunorubicin hydrochloride IV over 1 hour QD on days 1, 3, and 5, etoposide IV over one hour QD on days 1-5, and gemtuzumab ozogamicin IV over 2 hours on day 6.

Induction 2: Venetoclax PO QD on days 1-14, cytarabine IV over 30 minutes every 12 hours on days 1-8, daunorubicin hydrochloride IV over 1 hour QD on days 1, 3, and 5, and etoposide IV over 1 hour QD on days 1-5.

Intensification: Venetoclax PO QD on days 1-7, cytarabine IV over 1-2 hours every 12 hours on days 1-4, and mitoxantrone hydrochloride IV over 1 hour QD on days 2-4 during intensification 1 and then venetoclax PO QD on days 1-7 and high-dose cytarabine IV over 3 hours every 12 hours on days 1, 3, and 5 during intensification 2. Patients with FLT3 activation receive gilteritinib PO QD on days 8-28 during intensification 1 and 2.

Intermediate Risk

Induction 1: Venetoclax orally (PO) once daily (QD) on days -2 to 11, cytarabine intravenously (IV) over 30 minutes every 12 hours on days 1-8, daunorubicin hydrochloride IV over 1 hour QD on days 1, 3, and 5, etoposide IV over one hour QD on days 1-5, and gemtuzumab ozogamicin IV over 2 hours on day 6.

Induction 2: Venetoclax PO QD on days 1-14, fludarabine phosphate IV over 30 minutes QD on days 1-5, cytarabine IV over 3 hours QD starting 4 hours after each dose of fludarabine on days 1-5, idarubicin hydrochloride IV over 15 minutes QD on days 3-5. Patients with FLT3 activation receive gilteritinib PO QD on days 8-28.

Intensification: Venetoclax PO QD on days 1-7, cytarabine IV over 1-2 hours every 12 hours on days 1-4, and mitoxantrone hydrochloride IV over 1 hour QD on days 2-4 during intensification 1, venetoclax PO QD on days 1-7 and high-dose cytarabine IV over 3 hours every 12 hours on days 1, 3, and 5 during intensification 2, and then venetoclax PO QD on days 1-7, cytarabine IV over 1-2 hours every 12 hours on days 1-5, and etoposide IV over 1 hour QD on days 1-5 during intensification 3. Patients with FLT3 activation receive gilteritinib PO QD on days 8-28 during intensification 1-3.

High Risk

Induction 1: Venetoclax orally (PO) once daily (QD) on days -2 to 11, cytarabine intravenously (IV) over 30 minutes every 12 hours on days 1-8, daunorubicin hydrochloride IV over 1 hour QD on days 1, 3, and 5, etoposide IV over one hour QD on days 1-5, and gemtuzumab ozogamicin IV over 2 hours on day 6.

Induction 2: Venetoclax PO QD on days 1-14, fludarabine phosphate IV over 30 minutes QD on days 1-5, cytarabine IV over 3 hours QD starting 4 hours after each dose of fludarabine on days 1-5, idarubicin hydrochloride IV over 15 minutes QD on days 3-5. Patients with FLT3 activation receive gilteritinib PO QD on days 8-28.

Intensification: Patients with MRD \< 0.1% proceed directly to HCT if donor is available. If a donor is not yet available, patients with MRD \< 0.1% may receive ventoclax PO QD on days 1-21 and azacitidine IV over 30 minutes QD on days 1-5 or venetoclax PO QD on days 1-7, cytarabine IV over 1-2 hours every 12 hours on days 1-5, and etoposide IV over 1 hour QD on days 1-5. Patients with MRD 0.1% to \< 1% may receive ventoclax PO QD on days 1-21 and azacitidine IV over 30 minutes QD on days 1-5 or venetoclax PO QD on days 1-7, cytarabine IV over 1-2 hours every 12 hours on days 1-5, and etoposide IV over 1 hour QD on days 1-5. Patients with MRD \>= 1% may receive venetoclax PO QD on days 1-10, azacitidine IV over 30 minutes QD on days 1-5, and high-dose cytarabine IV over 3 hours every 12 hours on days 6, 8, and 10. Patients with FLT3 activation receive gilteritinib PO QD on days 8-28.

Eligibility Criteria:
Inclusion Criteria:

* Diagnosis of AML fulfilling the criteria of the WHO classification of myeloid neoplasms or \< 20% marrow myeloblasts and evidence of a clonal de novo AML genetic abnormality or myeloid sarcoma or primary myelodysplastic syndrome (MDS) with ≥ 10% blasts or a complete blood count with the presence of at least 1,000 blasts/μL (e.g., a WBC count ≥ 10,000/μL with ≥ 10% blasts or a WBC count ≥ 5,000/μL with ≥ 20% blasts
* Age \> 28 days and \< 22 years
* No prior therapy for this malignancy except for one dose of intrathecal therapy and hydroxyurea or low-dose cytarabine (≤ 200 mg/m\^2 per day for ≤ 7 days)
* Female patients of childbearing potential must have a negative pregnancy test within 2 weeks prior to enrollment
* Male and female participants of reproductive potential must agree to use an effective contraceptive method during the study and for 6 months after study treatment
* Written informed consent from the patient and/or parent/legal guardian
* Direct bilirubin ≤ 1.5 x institutional upper limit of normal

Exclusion Criteria:

* Patients with treatment-related AML, Down syndrome, acute promyelocytic leukemia, chronic myeloid leukemia in blast crisis, juvenile myelomonocytic leukemia, Fanconi anemia, Kostmann syndrome, Shwachman syndrome, or other bone marrow failure syndromes are not eligible
* Uncontrolled systemic fungal, bacterial, or viral infection or significant concurrent disease that would compromise patient safety or compliance, study participation, follow up, or interpretation of study results
* Prior exposure to any dose of anthracycline or anthracenedione
* Patients may not receive strong or moderate CYP3A inducers, such as rifampin, within 3 days of enrollment
* Patients may not receive moderate or strong CYP3A inhibitors (e.g., ketoconazole, itraconazole, voriconazole, posaconazole) within 3 days of enrollment.