Close to 4 years ago, Daiichi Sankyo swooped in to buy little San Diego-based Ambit Biosciences for up to $410 million — $315 million of that in cash — to lay its hands on a leukemia drug called quizartinib.
Over the weekend, investigators rolled out the late-stage data that the Japanese company plans to take to regulators at the FDA. The results are statistically significant but unspectacular, with 27% of the patients suffering from treatment-resistant acute myeloid leukemia with FLT3-ITD mutations in the drug arm making it to 52 weeks compared to 20% of the chemo patients in the control arm.
The hazard ratio was 0.76, with a 24% drop in risk of death. The p-value on that was positive: 0.0177.
For Jorge Cortes at MD Anderson, who led the study, the data offer a compelling case for Daiichi’s drug as the only single agent to prove efficacy in this specific FLT3-ITD group.
“For 50 years, since the standard of therapy was introduced, nothing has changed since then,” Cortes tells me. “You could say a few weeks isn’t much,” but he sees this as a landmark success that will change that long-running standard of care.
“I see this as very significant,” he adds, citing the progress with an oral, single agent in a salvage setting with refractory patients. “Any benefit for these patients is very welcome.”
That’s all true, but it’s worth noting that Novartis’ Rydapt (midostaurin) was approved a year ago in combination with chemo for frontline cases of AML with FLT3 mutations (including ITD) while Nexavar recently demonstrated efficacy with chemo in the same specific patient population.
Daiichi is clearly interested in seeing how this drug can do with chemo as well, with at least two combo studies ongoing, according to clinicaltrials.gov. One of the study descriptions notes the “transient” nature of the second-gen drugs in the field. There’s also an early-stage study that was filed on the site a few days ago calling for a combination of Daiichi’s MDM2 Inhibitor DS-3032 with quizartinib.
That chemo combo approach may well prove effective in the frontline setting, says the investigator. And the MDM2 approach could significantly expand the population of AML patients they can help.
The next stop for quizartinib: Regulators.
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