An Efficacy and Safety Study of Decitabine in Participants With Myelodysplastic Syndrome (MDS)

The purpose of this study is to evaluate the response rate of decitabine in previously treated and untreated Taiwanese participants with Myelodysplastic Syndrome (MDS - a disease associated with decreased production of blood cells, blood cells are produced but do not mature normally).

This is an open-label (a medical research study in which participants and researchers are told which treatments the participants are receiving, "unblinded"), multi-center (when more than 1 hospital or medical school team work on a medical research study), single-arm study of decitabine. The study will consist of 5 phases: Pre-treatment phase (before 30 days of first dose), Treatment phase (consist of 8 cycles, each cycle of 28 days), End-of-treatment phase (consist of 30-42 days after the last dose of cycle 8, or at time of discontinuation), Extension phase (1 cycle of 4 weeks) and Post-study phase or follow-up phase (every 2 months until 1 year, lost to follow-up or death). Participants who achieve a complete remission (when a medical problem gets better or goes away at least for a while) will be treated for at least 2 more cycles after first documentation of complete response (CR), after which treatment can be discontinued. Decitabine in a dose of 20 milligram per square meter (mg per m\^2) will be administered intravenously over 1 hour infusion, 1 hour, once daily for 5 consecutive days of a 28 days cycle up to 8 cycles or continued until disease progression or unacceptable toxicity. The primary objective is to evaluate the best response rate (complete response and partial response). Participants' safety will be monitored throughout the study.

Eligibility Criteria:
Inclusion Criteria:

* Participants with documented pathological (bone marrow, no longer than 30 days before first dosing in study) evidence of Myelodysplastic syndromes (MDS) or of chronic myelomonocytic leukemia (CMML) by World health organisation classification
* Participants with international prognostic scoring system (IPSS) score equal to 0.5 or more (only for participants for whom IPSS is applicable)
* Participants with an Eastern oncology cooperative group (ECOG) performance status of 0-2
* Participants with adequate hepatic (liver) and renal (kidney) function as measured by pre-treatment laboratory criteria within 21 days of starting treatment with decitabine
* Participants must have recovered from toxic effects of previous therapy and not receiving any chemotherapy for a minimum of 4 weeks (6 weeks if the participants has been treated with a nitrosoureas) before to the first dose of study drug

Exclusion Criteria:

* Participants with a diagnosis of acute myeloid leukemia (AML) (greater than 30 percent bone marrow blasts)
* Participants with AML with multilineage dysplasia (abnormal development or cell growth) following MDS (20-30 percent bone marrow blasts) can be enrolled. For these latter participants an observation period of 1 month is necessary to exclude those participants with rapid progression to full blown AML
* Participants with previous treatment with azacitadine or decitabine or hematopoietic stem cell transplantation less than 1 year prior to study enrollment
* Participants with past history of malignancy and received any treatment for this before malignancy within the last 3 years, except for superficial bladder cancer, basal cell or squamous cell carcinoma of the skin, cervical intraepithelial neoplasia (CIN) or prostate intraepithelial neoplasia (PIN)
* Participants with known hepatitis B (surface antigen-positive) or active hepatitis C infection