Ambit initiates Phase 2 study of quizartinib in acute myeloid leukemia patients

Ambit Biosciences (Nasdaq: AMBI), a biopharmaceutical company focused on discovery and development of drugs targeting unmet needs in oncology, autoimmune and inflammatory disease, today announced the initiation of the Phase 2 cohort of the MD Anderson Cancer Center-sponsored Phase 1/2 study of quizartinib in combination with either 5-azacitidine or low dose cytarabine for previously untreated FLT3-ITD positive acute myeloid leukemia (AML) patients age 60 or older, or FLT3-ITD positive AML patients 18 years of age or older in first relapse.

The trial is being conducted under the principal direction of Jorge Cortes, M.D., of The University of Texas MD Anderson Cancer Center.  Dr. Cortes is also the principal investigator of the upcoming Phase 3 QUANTUM-R trial, the Company's randomized trial comparing quizartinib to standard chemotherapy in FLT3-ITD positive AML patients over the age of 18 who have relapsed from, or are refractory to, frontline chemotherapy, including those patients relapsing following a hematopoietic stem cell transplant (HSCT). 

"We are delighted to expand the clinical development of quizartinib to include a new combination of quizartinib with a hypomethylating agent, providing another therapeutic option for patients who would not typically receive standard chemotherapy," said Athena Countouriotis, chief medical officer at Ambit.

The Phase 2 cohort follows completion of the Phase 1 open-label, two-arm portion which included twelve total patients, six in each arm. Phase 1 included patients who were 18 years of age or older and who had relapsed AML or myelodysplastic syndrome (MDS) and were treated with quizartinib in combination with either 5-azacitidine or cytarabine. Up to a total of 64 patients are planned to be treated in this clinical trial.  The regimen was found to be generally well tolerated, and there were no early mortalities.  Despite limited follow up, evidence of anti-leukemia activity has been observed in a number of patients. Full results, including data from the Phase 2 cohort, are expected to be submitted to a medical conference in 2014.

"Older patients with AML or high-risk MDS are often intolerant or unresponsive to standard treatments," said Dr. Cortes. "We are exploring this combination with the goal to improve the outcome of these patients, particularly those with FLT3 mutations, that otherwise have a very poor prognosis. The early results are very encouraging and opening the phase 2 portion of the study is an important step to further define the magnitude of the clinical efficacy of this approach."