A Phase 3 Clinical Study to Evaluate Lemzoparlimab for Injection in Combination With Azacitidine (AZA) Versus AZA Monotherapy in Treatment-naïve Patients With Higher-risk Myelodysplastic Syndrome (MDS)

Inclusion Criteria:

• Male or female, ≥ 18 years of age at the time of signing the ICF.

• Subjects with intermediate- and high-risk MDS who are confirmed by bone marrowaspiration or pathological biopsy according to the diagnostic criteria of WorldHealth Organization (WHO) 2016 or who are eligible for blasts in bone marrow andperipheral blood < 20% and have a score > 3.5 according to the revised InternationalPrognostic Scoring System (IPSS-R).

• Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 2.

• Subjects without any prior anti-tumor therapy for MDS, including demethylated drugs (eg, AZA, decitabine), chemotherapy, targeted therapy, or HSCT. The bloodtransfusion or use of hematopoietic growth factors and supplementation ofhematopoietic raw materials such as folic acid, vitamin B12 are permitted. Forpatients who ever took lenalidomide, thalidomide, antithymocyte globulin (ATG), orciclosporin before study entry, there should be a washout period of at least 28 daysprior to the first dose.

• Subjects who are eligible for HSCT and have no pre-scheduled HSCT at screening, orsubjects who are ineligible for HSCT and have no scheduled HSCT at screening

• Expected survival ≥ 12 weeks

• Subjects with adequate organ function and laboratory tests meet the followingrequirements

• Female subjects of childbearing potential or male subjects whose partner is a womanof childbearing potential are required to use effective contraception throughout thetreatment period and until 6 months after the treatment period.

• Subjects must be willing to provide available diagnostic evidence or undergo bonemarrow aspiration and biopsy before study treatment, and must be willing to undergobone marrow aspiration and biopsy after receiving study treatment.

• Subjects must give informed consent before starting the study and sign written ICFvoluntarily by themselves (or their legal representatives). Subjects or their legalrepresentatives should be able to communicate well with investigators and agree toadhere with the study protocol and complete the study

Exclusion Criteria:

• Patients who have transformed from MDS to AML, or have been diagnosed withtreatment-related MDS (t-MDS), or patients with myeloproliferative neoplasia (MPN)or myelodysplastic syndrome/myeloproliferative disorder (MDS/MPN) that meet WHO 2016criteria

• Previously received any anti-CD47 antibody or SIRPα antibody or the drugs targetingthe same target

• Subjects have received or plan to receive the allogeneic stem cell transplantationor organ transplantation during the study

• History of chronic hemolytic anemia due to other diseases or clinically significantpositive hemolysis-related test at screening (except positive hemolysis test due toMDS)

• Concurrent participation in another interventional clinical study, unless it is anobservational (non-interventional) clinical study or during the follow-up period ofan interventional study

• Subjects plan to receive other anti-tumor therapies, including but not limited tochemotherapy, biotherapy and immunotherapy, while participating in the study