Astellas' Xospata comes up short again in bid to expand leukemia use

After gaining approval for Xospata to treat acute myeloid leukemia (AML) in 2018, Astellas has had difficulty expanding its label.

On Thursday, the company said (PDF) that a trial evaluating Xospata (gilteritinib) as a maintenance therapy following allogenic hematopoietic stem cell transplantation (HSCT) had failed. Patients in the study had FLT3 internal tandem duplication (ITD) mutated AML .

It is the second time Xospata has come up short. A 2020 study of Xospata in combination with Bristol Myers Squibb’s Vidaza (azacytidine) showed that it failed to outdo Vidaza alone in newly diagnosed FLT3 mutation-positive AML patients who were ineligible for intensive induction chemotherapy.

In the more recent phase 3 MORPHO study, which included 356 patients who were in remission after induction therapy, Xospata did not achieve its primary goal of showing a relapse-free survival benefit over placebo over a period of two years.

Astellas says it will undergo a full examination of the data and will show findings in the future.

The news comes a month after the company named Naoki Okamura as its next CEO, replacing five-year helmsman Kenji Yasukawa.

AML is an aggressive cancer of the bone marrow and blood. Roughly a third of newly diagnosed AML patients have an alteration of the FLT3 gene. Those with FLT3-ITD mutations have a lower chance to survive and are at a higher risk for getting the disease more than once.

In the Xospata-Vidaza combo phase 3 trial, dubbed LACEWING, investigators halted it after four years and four months when they determined Xospata couldn’t prolong overall survival. A comprehensive review of data however showed that patients who received the combo had higher complete composite remission rates than those in the Vidaza arm.

Daiichi Sankyo has an FLT3 inhibitor in the works, quizartinib, which has been jumping through regulatory hoops for several years. In October, the FDA granted a priority review to quizartinib's application in newly diagnosed FLT3-ITD­-positive AML, with a decision expected by April 23. A phase 3 trial showed the addition of the Daiichi drug led to a 22.4% reduction in the risk of death compared to standard chemotherapy alone in these patients.