FDA Approves Xospata and Companion Diagnostic Test for Leukemia Treatment

The Food and Drug Administration (FDA) approved Xospata (gilteritinib), the first ever treatment of adults with relapsed or refractory acute myeloid leukemia (AML) who have a FLT3 mutation that is detected by an FDA-approved test, according to the agency.

“Today’s approval brings a new, highly-effective, and well-tolerated treatment option to the clinic for a group of truly high-risk patients who, until today, had no specific therapies available beyond chemotherapy to treat their disease,” Alexander Perl, M.D., MS, an associate professor of Hematology-Oncology in the Perelman School of Medicine at the University of Pennsylvania and the Abramson Cancer Center, said in a press release.

The companion diagnostic — LeukoStrat CDx FLT3 Mutation Assay – was also granted an expanded indication to detect the FLT3 mutation in this patient population.

Xospata’s approval was based on the randomized phase 3 ADMIRAL trial, led by Perl, which included 138 adult patients with relapsed or refractory AML who had FLT3 ITD, D835 or I836 mutations, as determined by the assay. The drug was given orally at 120 mg per day until unacceptable side effects occurred or there was a lack of clinical benefit.

At a median follow-up of 4.6 months, 29 patients experienced a complete response or complete response with partial hematologic recovery (21 percent).

There were also 106 patients involved in the study who were dependent on red blood cell and/or platelet infusions at the start of the trial. Thirty-three of them (31.1 percent) became independent on transfusions during any 56-day baseline period. For the others who were not dependent on transfusions at baseline, 17 (53.1 percent) remained transfusion-independent during any 56-day post-baseline period.

Common side effects with Xospata include myalgia/arthralgia, transaminase increase, fatigue/malaise, fever, noninfectious diarrhea, dyspnea, edema, rash, pneumonia, nausea, stomatitis, cough, headache, hypotension, dizziness and vomiting.

The ADMIRAL trial itself is still ongoing, and detailed response and overall survival data are expected to be made public in the coming year, the release said.

“Although we’re waiting for the final analysis of ADMIRAL, the available data with (Xospata) show fewer and milder side effects than typically is seen with traditional chemotherapy,” Perl said, adding that the agent is given in an outpatient setting, making it easier for patients to receive treatment.

“Often, salvage therapy is used to stabilize aggressive leukemia before a patient receives a bone marrow transplant that we hope can be curative,” he added. “Having a low-toxicity but highly-active drug like (Xospata) means that relapsed or refractory patients not only are more likely to undergo transplant, but also they remain stronger at the time of transplant and are better able to withstand the surgery and recovery.”