AACR: Astellas pads Xospata's AML lead with chemo-beating survival data

ATLANTA—Astellas is looking to snap up share with its newly approved Xospata before a direct competitor hits the acute myeloid leukemia scene, and positive new survival data could help speed that process along.

Monday at the American Association for Cancer Research annual meeting, the Japanese drugmaker rolled out phase 3 data showing that the drug could significantly prolong the lives of relapsed or refractory AML patients with an FLT3 mutation. Xospata patients lived a median 9.3 months after therapy, compared with 5.6 months for those receiving salvage chemo.

At the one-year mark, 37% of patients in the experimental arm of the study, dubbed Admiral, were still alive, while just 17% of chemo patients reached that mark.

“The positive overall survival data really underscores Xospata’s role as an important treatment option for patients,” Andrew Krivoshik, M.D., Astellas' vice president of medical science for oncology, said.

He also pointed to the fact that Xospata was not associated with a higher rate of serious side effects than chemo during the first 30 days of treatment.

RELATED: Astellas’ Xospata wins FDA nod in AML, with Daiichi competition looming

Astellas snagged an FDA green light for Xospata back in late November as part of a busy spree for the FDA, which approved three AML drugs that week. Xospata, though, was the only one it cleared for patients with the FLT3 mutation, and the drug is currently the only one on the market specifically approved for FLT3-mutated patients who've either failed to respond to treatment or relapsed; Novartis’ Rydapt bears a FLT3 indication, but only for newly diagnosed patients.

Xospata’s solo status may not last, though. Fellow Japanese drugmaker Daiichi Sankyo’s FLT3 inhibitor, quizartinib, is waiting in the wings after grabbing an FDA priority review tag that sets it up for a May 25 verdict. If approved, Daiichi’s drug will only be eligible to treat FLT3-ITD patients, a subset of Xospata’s patient pool. But with the FLT3-ITD mutation affecting about 25% of all AML patients, it’s a large subset.

Meanwhile, though, Astellas is examining Xospata in multiple other phase 3 trials, including those in newly diagnosed AML patients and in the post-chemo maintenance setting.

“As we bring Xospata forward from a clinical trial perspective,” the new Admiral overall survival readout “is one of many data points that will help determine how best to use Xospata in the treatment paradigm for AML,” Krivoshik said.