Daiichi Sankyo’s challenger to Novartis’ Rydapt looks like it may get another shot at FDA approval, with quizartinib posting positive survival data from a phase 3 trial.
The blood cancer drug has a checkered history with the regulator, having had its approval turned down in 2019. But data from the global Quantum First trial showed that the med, combined with chemotherapy and then continued as a single agent, demonstrated a statistically significant improvement in overall survival in adult patients aged 18-75 years with newly acute myeloid leukemia (AML) with the FLT3-ITD mutation.
A quarter of all cases of AML involve FLT3, and Daiichi Sankyo has already been beaten to the market by Novartis’ Rydapt and Astellas’ Xospata, which both target this gene mutation.
But new data, presented Saturday at the European Hematology Association Congress, suggests Daiichi Sankyois closer to potentially getting its asset on to the market. The readout showed that quizartinib resulted in a 22.4% reduction in the risk of death compared to standard chemotherapy alone. After a median follow-up of 39 months, overall survival was more than double at 31.9 months for patients receiving quizartinib compared to 15.1 months for patients receiving chemo alone.
The safety of quizartinib was generally manageable, Daiichi Sankyo said, with no new safety signals observed. The rates of emergent adverse events (TEAEs) at grade 3 or higher were similar for both the quizartinib and chemo only study groups, with the most common TEAEs at these levels including febrile neutropenia, neutropenia, hypokalemia and pneumonia.
When it came to fatalities, however, the rate of TEAEs associated with death were 11.3% for quizartinib, compared to 9.7% for chemotherapy. The main cause of these fatalities was infections, the company said.
Quizartinib is already approved in Japan, and Daiichi Sankyo’s global head of R&D Ken Takeshita, M.D., said the survival results meant the company has now initiated regulatory filings with other regulators around the world.
"There is great interest in the increased use of targeted therapies to improve outcomes for patients with AML, particularly those with the FLT3-ITD subtype, which is one of the most common, aggressive and difficult-to-treat," said Harry Erba, M.D., PhD, an instructor at the Duke Cancer Institute's Division of Hematologic Malignancies and Cellular Therapy, in a statement accompanying the results.
Daiichi Sankyo picked up quizartinib as part of its $410 million acquisition of San Diego-based Ambit Biosciences in 2014. Ambit had previously been working with Daiichi’s compatriot Astellas under a $40 million pact inked in 2009 around quizartinib and other FLT3 inhibitors.