• The purpose of this research study is to determine if tipifarnib leads to a complete response for in patients with high-risk Myelodysplastic Syndrome (MDS).
  

• Efficacy will be assessed by evaluation of bone marrow and hematologic laboratory tests. Safety will be assessed by evaluation of adverse events and clinical laboratory tests.
  

Treatment with tipifarnib will be given during one or more periods of time called cycle(s). Each cycle will be 28 days long and patients will take tipifarnib for the first 21 days of each cycle. No medication will be taken during the last 7 days of each cycle. On day 1 and 15 of each cycle, patients will be asked about any side effects that have occurred since their last visit. Blood will drawn for routine testing to evaluate any possible effects of tipifarnib on white blood cells or on specific elements, that can be measured in the blood. The study doctor will decide if any bone marrow aspirates or biopsies should be taken. Tipifarnib will be given until the patient's disease worsens or they develop unacceptable side effects or until they withdraw consent to receive tipifarnib. When tipifarnib treatment is ended or if the patient leaves the study early, they will be asked to come in for a final visit. The study doctor will decide if any blood draws, bone marrow aspirates or biopsies need to be taken.

Tipifarnib is 300 mg administered orally as three 100 mg tablets twice daily for the first 21 days in each 28-day cycle. Tipifarnib will be administered until the patient discontinues treatment due to disease progression or unacceptable toxicity.