Inclusion Criteria:
1. Diagnosis of MDS according to World Health Organization (WHO) classification that meets Revised International Prognostic Scoring System (IPSS-R) classification of very low, low, or intermediate risk disease（IPSS-R ≤ 3.5）.
2. \< 5% blasts in bone marrow and \< 1% blasts in peripheral blood.
3. Each cohort is defined as:
Cohort 1： In NTD participants, having received no red blood cell (RBC) transfusions within 16 weeks Hgb concentration between 60 and 100g/L.
Cohort 2： In LTB participants, having received an average of \< 4 units of RBC transfused within 8 weeks (i.e., total blood transfused over 16 weeks/2) Hgb concentration between 60 and 100 g/L.
In HTB participants, having received an average of ≥ 4 units of RBC transfused within 8 weeks (i.e., total blood transfused over 16 weeks/2) Hgb concentration between 60 and 100 g/L.
4. Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2 (if related to anemia.
5. Females of child-bearing potential and sexually active males must agree to use effective methods of contraception.
Exclusion Criteria:
1. Chromosome 5q deletion, del (5q).
2. Anemia caused by other reasons, such as iron deficiency anemia, megaloblastic anemia, aplastic anemia, renal anemia or blood loss.
3. Diagnosis of secondary MDS (i.e., MDS known to have arisen as the result of chemical injury or treatment with chemotherapy and/or radiation for other diseases).
4. Prior treatment with azacitidine, decitabine, lenalidomide, luspatercept, or sotatercept.
5. Treatment within 4 weeks prior to C1D1 with:
1\) Erythropoiesis stimulating agent (ESA) OR 2) Granulocyte colony-stimulating factor (G-CSF) OR 3) Granulocyte-macrophage colony-stimulating factor (GM-CSF) 6. Iron chelation therapy if initiated within 8 weeks prior to C1D1. 7. Vitamin B12 therapy if initiated within 8 weeks prior to C1D1. 8. Treatment with another investigational drug or device or approved therapy for investigational use \< or = 4 weeks prior to C1D1, or if the half-life of the previous product is known, within 5 times the half-life prior to C1D1, whichever is longer.
9\. Peripheral blood white blood cell count \>13.0 x 10\*9/L. 10. Neutrophil count \< 1.0 x 10\*9/L. 11. Platelet count \> 450 x 10\*9/L or \< 30 x 10\*9/L. 12. Transferrin saturation \< 15%. 13. Ferritin \< 15 μg/L. 14. Folate \< 4.5 nmol/L (\< 2.0 ng/mL). 15. Vitamin B12 \< 148 pmol/L (\< 200 pg/mL). 16. Estimated glomerular filtration rate (GFR) \< 40 mL/min/1.73 m2 (as determined by the Chronic Kidney Disease Epidemiology Collaboration \[CKD-EPI\].
17\. Pregnant or lactating females
