The purpose of this study is to evaluate the safety and tolerability of Palbociclib in combination with investigational (experimental) drug, CPX-351 and evaluate the efficacy of Palbociclib in combination with chemotherapy as measured by overall response rate (ORR), i.e. complete response (CR) and CR with incomplete blood count recovery (CRi) by 2003 IWG criteria.

The objectives of this study are to evaluate the safety and tolerability of Palbociclibin combination with CPX-351, and to evaluate the efficacy of Palbociclibin combination with chemotherapy as measured by overall response rate (ORR), i.e. complete response (CR) and CR with incomplete blood count recovery (CRi) by IWG criteria.

CPX-351 is an investigational drug that works as formulation of a fixed combination of the antineoplastic (acting to prevent, inhibit or halt the development of a neoplasm (a tumor)) drugs cytarabine and daunorubicin.

Palbociclibis an investigational drug that works to induce early G1 arrest by inhibiting CDK4/6, which are two types of CDKs that are overexpressed in AML cell cancer lines.

CPX-351 and Palbociclib is experimental because it is not approved by the Food and Drug Administration (FDA).

This is a single arm, open label study of the combination of Palbociclib with CPX-351 in adults with AML. The trial consists of two components: phase I to evaluate the safety with dose escalation of Palbociclib in combination with CPX-351 and phase II to evaluate the overall response rate of the combination in the targeted participant population.

Inclusion Criteria:

• Newly diagnosed acute myeloid leukemia according to 2016 WHO criteria(excluding APL [AML-M3]).
• Eastern Cooperative Oncology Group (ECOG) Performance Status <2
• Subjects must have normal organ function as defined below:
• Total bilirubin <2 times upper limit of normal ((≤ 3 x ULN if considered to be due to leukemic involvement or Gilbert's syndrome) or if higher than 2 times upper limit of normal with approval from the PI
• Serum Creatinine <2 x ULNor if higher than 2 times upper limit of normal with approval from the PI
• Left ventricular ejection fraction of ≥45%
• Patients with secondary AML arising out of MDS (all subtypes under WHO classification), chronic myelomonocytic leukemia (CMML) and therapy-related AML are eligible.
• Women of childbearing potential should be advised to avoid becoming pregnant and men should be advised to not father a child while receiving treatment. All men and women of childbearing potential must use acceptable methods of birth control throughout the study
• Subjects must have the ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria:

• Prior treatment with CPX-351, Palbociclib or other cell cycle inhibitors.
• Any serious medical condition, laboratory abnormality, or psychiatric illness that, in the view of the treating physician, would place the participant at an unacceptable risk if he or she were to participate in the study or would prevent that person from giving informed consent.
• Any active malignancy (unrelated, non-hematological malignancy) diagnosed within the past 6 months of starting the study drug (other than curatively treated carcinoma-in-situ of the cervix or non-melanoma skin cancer).
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to CPX-351, Palbociclib or other cell cycle inhibitors.
• Subjects with uncontrolled intercurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, uncontrolled cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
• Known history of HIV or active hepatitis B or C.
• No major surgery within 2 weeks prior to study enrollment.
• Pregnancy or breast feeding
• Male and female patients who are fertile who do not agree to use an effective barrier methods of birth control (i.e. abstinence) to avoid pregnancy while receiving study treatment.
• Acute promyelocytic leukemia (APL)

All adverse events were collected through 30 days after the final dose of study drug, up to 100 days, all cause mortality was assessed through 2 years from end of treatment