Daiichi Sankyo Company, Limited announces that the pivotal QuANTUM-R phase 3 study of single agent quizartinib met its primary endpoint of significantly prolonging overall survival compared to salvage chemotherapy in patients with relapsed/refractory acute myeloid leukaemia (AML) with FLT3-ITD mutations after first-line treatment with or without haematopoietic stem cell transplantation (HSCT). Safety appears consistent with that observed at similar doses in the quizartinib programme.

“Single agent quizartinib is the first FLT3 inhibitor to show a significant improvement in overall survival compared to cytotoxic chemotherapy in a randomised phase 3 study of patients with relapsed/refractory AML with FLT3-ITD mutations, a very aggressive form of the disease with limited treatment options,” said Antoine Yver, MD, MSc, executive vice president and global head, oncology research and development, Daiichi Sankyo. “We sincerely thank all of the investigators and patients who participated in this study and will share the results of the QuANTUM-R study at an upcoming medical meeting. We look forward to working with regulatory authorities worldwide to potentially bring quizartinib to patients as quickly as possible.”

QuANTUM-R is a pivotal, global, phase 3, open-label randomised study that enrolled 367 patients with FLT3-ITD-mutated AML who were refractory to or in relapse (with duration of remission of six months or less) following standard first-line AML therapy with or without HSCT. Patients were randomised in a 2:1 ratio to receive either single agent oral quizartinib or salvage chemotherapy. The primary objective of the study was to determine whether single agent quizartinib prolonged overall survival compared to salvage chemotherapy.  

Daiichi Sankyo intends to initiate regulatory submissions worldwide for quizartinib on the basis of the QuANTUM-R results. The topline results of QuANTUM-R will be presented at an upcoming scientific conference.

Quizartinib, the lead investigational agent in the AML Franchise of the Daiichi Sankyo Cancer Enterprise, is an oral selective FLT3 inhibitor currently in phase 3 development for relapsed/refractory (QuANTUM-R) and newly-diagnosed (QuANTUM-First) AML with FLT3-ITD mutations globally, and phase 2 development for relapsed/refractory AML with FLT3-ITD mutations in Japan.

Quizartinib has been granted Fast Track designation by the US Food and Drug Administration (FDA) for the treatment of relapsed/refractory AML. Quizartinib also has been granted Orphan Drug designation by the FDA and European Medicines Agency (EMA) for the treatment of AML. Quizartinib is an investigational agent that is not approved for any indication in any country. Safety and efficacy have not been established.

AML is an aggressive blood and bone marrow cancer that causes uncontrolled growth and accumulation of malignant white blood cells that fail to function normally and interfere with the production of normal blood cells.1 The five-year survival rate of AML reported from 2005 to 2011 was approximately 26 per cent, which was the lowest of all leukaemias.

FLT3 gene mutations are one of the most common genetic abnormalities in AML. The FLT3-ITD mutation is the most common FLT3 mutation, affecting approximately one in four patients with AML. Patients with FLT3-ITD-mutated AML have a worse overall prognosis, including an increased incidence of relapse, an increased risk of death following relapse and a higher likelihood of relapse following HSCT as compared to those without this mutation.