The primary objective is to evaluate the efficacy of the treatment in response rate terms. Otherwise this study wants to evaluate the safety of the treatment.

A total of up to 30 patients diagnosed of myelodysplastic syndrome red cell transfusion dependent with low or intermediate -1 risk will be included.

The patients will be evaluated at scheduled visits in up to three study periods: Pre-treatment, Treatment and Follow up.

The Pre-treatment includes Screening and baseline visits. After providing informed consent, patients will be evaluated for study eligibility.

During Treatment Period patients will be evaluated once a month although biochemistry and haematology parameters will be evaluated every 2 weeks.

If an erythroid response after 24 weeks is determined, a extension treatment will be carry out without disease progression.

Inclusion Criteria:

1. Must voluntary sign the informed consent.
2. Age ≥ 18 years.
3. Must be able to comply with the protocol requirements
4. Patient recently diagnosed with Myelodysplastic syndrome red cell transfusion dependent with low or intermediate -1 risk according IPSS criteria.
5. Red cell transfusion dependent anemia.
6. El patient has to be able to complain with the protocol visits.
7. Women and man must accept to use high efficacy anticonceptive methods

Exclusion Criteria:

1. Pregnancy or breast-feed women.

2. Patients previously received treatment with azacytidine .

3. Patients previously received treatment with erythropoietin agents.

4. Proliferative Chronic myelomonocytic Leukaemia (leukocytes ≥ 12000/mL).

5. Patient with a previous clinical history of another cancer (except for basocellular carcinoma or spinocellular carcinoma in situ of cervix or breast) except if the patient is free of symptoms during ≥ 3 years.

6. Cytotoxic chemotherapy or experimental agents usage for myelodysplastic syndrome treatment during 28 days.

7. Previous haematopoietic transplant.

8. Mielosupresion and antitumoral treatment during the previous 28 days.

9. The following laboratory data:

   Absolute neutrophil count < 1000 cel/ml (0.5x 109L) Platelet count < 50000/μL (25 x 109/L) Creatinine > 2.0 mg/dL (177 mmol/L) Aspartate transaminase (AST) or Alanine transaminase (ALT ) > 5 x the upper limit of normal. Total bilirubin: > 2 mg/dL

10. Patients with B12 vitamin, folic acid and ferrum deficiency.

11. Patient with positive VIH-1.

12. Any other organic or mental illness that could make impossible to sign the Inform consent or involve risk to the patient.

13. Patient has hypersensitivity previous to beta ,azacytidine, erythropoietin and/or mannitol.