Alternating Regimen of VA and Low-dose CHA in the Treatment of Unfit Newly Diagnosed AML

Inclusion Criteria: * Understand the research and sign a written informed consent form; * Be newly diagnosed with AML according to WHO 2022 criteria without prior treatment; * or unwilling to undergo IC. Ineligibility for IC is defined as meeting any of the following criteria: * Age ≥ 60 years * Age 18-59 years but ineligible for intensive chemotherapy (IC) , meet ≥1 of the following: * Eastern Cooperative Oncology Group (ECOG) performance status ≥2 at screening; * Severe heart failure (congestive heart failure requiring treatment or myocardial infarction history with ejection fraction ≤50%); * Severe pulmonary dysfunction (DLCO ≤65%, FEV1 ≤65%, dyspnea at rest, or oxygen dependence); * Severe renal insufficiency requiring dialysis; * Child-Pugh B or C cirrhosis, or hepatic impairment with total bilirubin \>1.5×ULN; * Mental illness requiring inpatient psychiatric treatment; * Any comorbidity deemed by physician to contraindicate IC. Exclusion Criteria: * Diagnosis of: AML arising from chronic myeloid leukemia (CML); myeloid sarcoma; acute promyelocytic leukemia (APL) or presence of FLT3-ITD mutations; * Active malignancies (except adequately treated carcinoma in situ or basal cell carcinoma) within 2 years prior to Cycle 1 Day 1 (C1D1); * Major surgery or systemic anticancer therapy within 28 days before C1D1; * Known hypersensitivity to: Active pharmaceutical ingredients: cladribine, homoharringtonine, cytarabine, venetoclax, azacitidine; Any excipients in study drug formulations; * GI conditions impairing oral drug absorption: Dysphagia; short-gut syndrome; gastroparesis or related disorders; * Uncontrolled active infection; * Controlled infection permitted if: Afebrile (\<38°C) and hemodynamically stable (SBP \>90 mmHg, HR \<100 bpm) for ≥72 hours pre-C1D1; on non-interacting antimicrobial regimen; active HBV/HCV infection (Chronic carriers require PI approval with viral load monitoring); HIV-positive patients receiving HAART; * Pregnancy/lactation or refusal of contraception: Negative serum β-hCG within 24h pre-C1D1; * Psychiatric disorders or social circumstances compromising protocol compliance; * Prior AML-directed therapy except: cytoreduction for hyperleukocytosis per institutional guidelines (hydroxyurea, leukapheresis); supportive growth factors;