Xospata (gilteritinib) has been conditionally approved in China to treat adults who have relapsed or refractory acute myeloid leukemia (AML) with mutations in the FLT3 gene.

The therapy’s conditional approval by the Chinese National Medical Products Administration (NMPA) followed an expedited regulatory pathway, as the therapy was previously granted priority review and added to the NMPA’s list of new treatments from overseas that are urgently needed in a clinical setting.

With this approval, Xospata has now become the first and only targeted therapy to be approved in China for this indication.

“Patients with relapsed or refractory AML with a FLT3 mutation are in urgent need of new treatment options,” Ma Ju, PhD, director of the Harbin Institute of Hematology in China, said in a press release.

“As the first approved targeted therapy agent to treat relapsed or refractory AML with a FLT3 mutation in China, gilteritinib, which was approved under an expedited pathway, has enabled patients in China to have rapid access to a novel treatment option,” Ju said.

FLT3 is a protein that normally controls the survival and proliferation of blood stem cells and is activated only in specific instances while interacting with another protein. However, certain mutations in the FLT3 gene may cause the protein to become overly active, promoting the growth of malignant cancer cells.

Developed by Astellas Pharma, Xospata is a FLT3 inhibitor that is designed to counteract the effects of two specific mutations — an internal tandem duplication and one in the protein’s tyrosine kinase domain — that are associated with a high risk of relapses and poor survival, and have consistently failed to be targeted by other FLT3 inhibitors.

“Having a FLT3 mutation has a highly negative impact on prognosis for people living with AML,” said Wang Jianxiang, MD, vice director of the Institute of Hematology at the Chinese Academy of Medical Sciences.

“The approval of gilteritinib provides an important new option for Chinese patients that have relapsed or refractory AML with a FLT3 mutation, backed by substantial safety and efficacy data,” he added.

Xospata’s conditional approval was supported by data from the Phase 3 ADMIRAL trial (NCT02421939), which compared the safety and efficacy of Xospata to that of chemotherapy in 371 AML patients with FLT3 mutations, whose disease either returned or progressed after first-line treatment.

Data from ADMIRAL showed Xospata prolonged the time patients lived from a median of 5.6 months on salvage chemo to 9.3 months, lowering the risk of death by 36%.

“There is an urgent unmet need among FLT3-mutated relapsed or refractory AML patients, whose median survival is currently less than six months with chemotherapy,” said Andrew Krivoshik, MD, PhD, senior vice president and global therapeutic area head of oncology development at Astellas Pharma.

“The expedited approval of gilteritinib is an important step in offering a new treatment option for doctors and patients in China,” he added. “We look forward to offering gilteritinib as part of our commitment to developing innovative solutions for patients with hard-to-treat cancers with limited treatment options.”

Xospata was also associated with better response rates compared to chemo, with 21.1% of patients on Xospata achieving a complete response (complete cancer elimination), compared with 10.5% of those on chemo.

Safety assessments based on data from 355 patients with relapsed or refractory AML, who received at least one dose of Xospata in the study, showed the most common side effects associated with treatment included high levels of liver enzymes (indicative of liver inflammation or damage), low platelet counts, and low white blood cell counts accompanied by fever. Differentiation syndrome — a serious immune reaction that can be triggered by certain anti-cancer therapies — was reported as a fatal side effect in one patient treated with Xospata.

The approval was also supported by pharmacological data from the Phase 3 COMMODORE trial (NCT03182244), which is currently assessing the safety and efficacy of Xospata in patients with relapsed or refractory AML in China and other countries.

Xospata has been approved in the U.S., Japan, and Europe for the same indication.