Abstract #3926: A Phase II Study of Tosedostat (TST) in Combination with Either Cytarabine or Decitabine in Newly Diagnosed Older Patients with Acute Myeloid Leukemia (AML) or High-Risk Myelodysplastic Syndrome (MDS).The Phase 2 randomized, open-label trial enrolled patients 60 years of age or older with untreated AML or high-risk MDS to receive tosedostat 120 mg orally, once daily on days 1–21 with five days of either cytarabine 1 g/m 2/day IV or decitabine 20 mg/m 2/day IV delivered every 35 days. Patients received up to three cycles of therapy if they had at least stable disease following the initial course, and patients that achieved a CR/CRi were eligible to receive up to two additional cycles. The primary endpoint of the trial was to determine the CR rate and four-month survival. Secondary endpoints were to assess safety and tolerability of tosedostat with either cytarabine or decitabine, to estimate rates of disease-free survival and one-year overall survival. A total of 26 patients have been treated, with 13 receiving tosedostat/cytarabine and 13 receiving tosedostat/decitabine. Nineteen patients (73 percent) had AML and seven (27 percent) had high-risk MDS. The poster is available at www.celltherapeutics.com. About Acute Myeloid Leukemia (AML) and Myelodysplastic Syndrome (MDS) Approximately 14,590 new cases of AML are expected to be diagnosed in the United States in 2013. 1 As of January 2008, an estimated 30,993 people were living with (or were in remission from) AML. 2 Although AML can occur at any age, adults aged 60 years and older are more likely to develop the disease than younger people. AML is a cancer characterized by the rapid growth of abnormal white blood cells that accumulate in the bone marrow and interfere with the production of normal blood cells. AML may develop from the progression of other diseases, such as MDS, a blood cancer that also affects the bone marrow leading to a decrease in circulating red blood cells. AML is the most common acute leukemia affecting adults, and its incidence increases with age. The symptoms of AML are caused by the replacement of normal bone marrow with leukemic cells, which causes a drop in red blood cells, platelets and normal white blood cells, leading to infections and bleeding. AML progresses rapidly and is typically fatal within weeks or months if left untreated. Although a substantial proportion of younger individuals who develop AML can be cured, AML in the elderly typically responds poorly to standard therapy with few complete remissions.