SEATTLE, Dec. 10, 2013 /PRNewswire/ -- Cell Therapeutics, Inc. (CTI) (NASDAQ and MTA: CTIC) today announced promising interim results from an investigator-initiated Phase 2 clinical trial of tosedostat in combination with cytarabine or decitabine in newly diagnosed older patients with acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (MDS). Tosedostat is a first-in-class selective inhibitor of aminopeptidases, which are required by tumor cells to provide amino acids necessary for growth and tumor cell survival. Tosedostat is administered orally and has been previously shown to induce complete remissions as monotherapy in relapsed or refractory AML. Researchers presented the findings from this combination study today for the first time at the 55 th American Society of Hematology (ASH) Annual Meeting and Exposition held December 7–10 in New Orleans, La.
"Treatment outcomes for older patients with newly diagnosed AML remain poor," said John Pagel, M.D., Ph.D., Associate Member, Clinical Research Division, Fred Hutchinson Cancer Research Center; Associate Professor, Medical Oncology Division, University of Washington School of Medicine; and Principal Investigator in the tosedostat first-line AML/MDS trial. "This is the first time that tosedostat has been given in a front-line setting in combination with low intensity therapy. The complete response rates and median survival observed in previously untreated older patients with AML is promising and appears to be worthy of further clinical investigation."
The Phase 2 trial was designed to test the efficacy of tosedostat in combination with low intensity therapy for older patients with previously untreated AML or high-risk MDS not considered candidates for standard intensive therapy. This presentation reported on the results of 26 patients (median age was 69) enrolled in the first dose cohort. Patients were randomized to treatment with tosedostat in combination with either cytarabine or decitabine. Fourteen out of 26 (54 percent) patients in this cohort had either a complete response (CR; n=10, 39 percent) or complete response with incomplete blood count recovery (CRi; n=4, 15 percent). The percentage of complete responses was comparable between arms. Seven (50 percent) of the 14 CR/CRi were achieved in patients with poor-risk cytogenetic features. Importantly, 10 of the 26 patients subsequently went on to receive hematopoietic stem cell transplant. The study achieved its primary objective with 21 (82 percent) patients alive at four months. Median overall survival was encouraging at approximately 12 months for both study arms. Tosedostat combination therapy was well tolerated and predominantly administered as an outpatient therapy. The primary side effects of the combination therapy, the majority of which were associated with the cytarabine arm, included febrile neutropenia (50 percent), pulmonary infections (31 percent) and sepsis (19 percent). Clinically significant non-hematological toxicities were uncommon and predominantly low grade.