A global multicenter, randomized, double-blind, placebo-controlled, pivotal phase III study. To evaluate overall survival (OS) of Lisaftoclax (APG-2575) combined with azacitidine (AZA) vs. placebo combined with azacitidine in newly diagnosed patients with HR-MDS.

This study intends to enroll patients with HR-MDS to receive the therapy of Lisaftoclax (APG-2575) combined with azacitidine (AZA) or placebo combined with azacitidine.

Inclusion Criteria:

1. Newly diagnosed higher-risk MDS.
2. ECOG score of ≤2.
3. Expected survival ≥ 3 months.
4. Adequate organ function.
5. Female subjects of potential childbearing potential have a negative urine or serum pregnancy test before dosing. Subjects of childbearing potential as well as their partners voluntarily use contraception deemed effective by the investigator during the treatment period and for at least six months after the last dose of study drug.
6. Able to understand and voluntarily sign a written informed consent form, which must be signed prior to the performance of any trial-specified study procedures.
7. Subjects are able to complete study procedures and follow-up examinations.

Exclusion Criteria:

1. Concomitant other malignancies or prior malignancies with disease-free intervals of less than 1 year at the time of signing the informed consent.
2. Have undergone hematopoietic stem cell transplantation.
3. Uncontrolled active infection
4. Use of moderately potent inducers and moderately potent inhibitors of CYP3A4 within 14 days prior to the first dose of study drug.
5. MDS or other conditions that cannot be administered enterally.
6. Any condition that the subject is deemed to be inappropriate to participate in this study after evaluation by the investigator.