The goal of this clinical research study is to compare the effectiveness of 2 different doses
of the drug clofarabine that can be given on a weekly schedule for the treatment of
Myelodysplastic Syndrome (MDS). The safety of these two doses will also be compared.
Primary Objective: Compare the response rates of two dose schedules of clofarabine in MDS.
Secondary Objective: Compare response durations, survivals and side effects of the two
schedules.