A Phase 1, Open-label, Dose Finding Study of CC-95251 Alone and in Combination With Antineoplastic Agents in Subjects With Acute Myeloid Leukemia and Myelodysplastic Syndromes

Number of Participants With With Grade 3 or Higher Laboratory Abnormalities

时间窗: From signing informed consent to 56 days post last dose (Approximately 30 months)

Clinical laboratory values from laboratories will be graded according to CTCAE Version 5 for applicable tests programmatically. For laboratory values that fall outside of the grade criteria of CTCAE Version 5, a Grade of 0 will be assigned. In addition, normal ranges will be used to determine the categories of High, Low, and Normal for laboratory tests that have no severity grade.

Number of Participants With DLTs

时间窗: From Cycle 1 Day 1 to Cycle 1 Day 28 up to 42 post first dose of cycle 1 (upto 42 days)

A dose-limiting toxicity (DLT) is any treatment-related toxicity during Cycle 1 (Days 1-28, up to 42) not clearly due to illness or external causes. DLTs include: * Any Grade ≥3 non-hematologic toxicity, except specific reversible or manageable cases (e.g., IRR, nausea, diarrhea, fatigue, infection with leukemia, TLS, electrolyte imbalance, liver enzyme elevations, or rash). * Any confirmed Hy's law case (ALT/AST ≥3× ULN + bilirubin \>2× ULN without cholestasis). * Hematologic toxicities: Grade 4 neutropenia/thrombocytopenia persisting at Day 28 without active AML/MDS; febrile neutropenia or Grade ≥3 thrombocytopenia with severe bleeding and prolonged myelosuppression (\>42 days) without active leukemia. * Any adverse event requiring dose reduction in Cycle 1 unless clearly unrelated to the drug.

Number of Participants With Treatment Emergent Adverse Events

时间窗: From signing informed consent to 56 days post last dose (Approximately 30 months)

An AE is any noxious, unintended, or untoward medical occurrence that may appear or worsen in a participant during the course of a study. It may be a new intercurrent illness, a worsening concomitant illness, an injury, or any concomitant impairment of the subject's health, including laboratory test values, regardless of etiology. Any worsening (ie, any clinically significant adverse change in the frequency or intensity of a pre-existing condition) should be considered an AE.

Number of Participants With Clinically Significant ECG Abnormalities Presented as Adverse Events

时间窗: From screening to 56 days post last dose (Approximately 29 months)

A single ECG will be performed in Screening, Cycle 1 Day 1 and 15, and Day 1 of Cycles ≥ 2. Investigators will make immediate clinical decisions based on their interpretation of the ECG results and provide their overall assessment.

Number of ECOG Evaluations With Shift of ECOG Score of 3 or Greater.

时间窗: From screening to 56 days post last dose (Approximately 29 months)

ECOG Scale was used to assess performance status. Grades: 0: Fully active, able to carry on all pre-disease performance without estriction. 1: Restricted in physically strenuous activity but ambulatory, able to carry out work of light nature. 2: Ambulatory, capable of self-care, unable to carry out work activities. Up and about more than 50% waking hours. 3: Capable of limited self-care, confined to bed/chair more than 50% waking hours. 4: Completely disabled. Cannot carry on any self-care. Totally confined to bed/chair. 5: Dead. Baseline value was defined as the last non-missing value on or before the day that first dose of study drug is administered; if multiple values are present for the same date, the average of these values will be used as the baseline.

Number of Participants With Clinically Significant Changes in Vital Signs Presented as AEs

时间窗: From signing informed consent to 56 days post last dose (Approximately 30 months)

Vital sign measurements include: Weight (kg), Temperature (°C), Systolic Blood Pressure (mmHg), Diastolic Blood Pressure (mmHg), Pulse (beats/min), Respiration Rate (breaths/min).