Astellas Pharma Inc.  announced that it submitted a new drug application (NDA) for marketing approval of generic  gilteritinib in Japan for the treatment of adult patients with FLT3 mutation-positive (FLT3mut+) relapsed or refractory acute myeloid leukemia (AML). Astellas also submitted a NDA for approval of gilteritinib in the same patient population to the US Food and Drug Administration (FDA) on March 29, 2018 following the submission in Japan. The applications for marketing approval for gilteritinib are based on data from the ongoing pivotal phase 3 ADMIRAL study investigating gilteritinib in adult patients with FLT3mut+ relapsed or refractory AML.

AML is a cancer that impacts the blood and bone marrow, and its incidence increases with age. In Japan, approximately 5,500 patients are diagnosed with AML each year. Gilteritinib is an investigational compound that has demonstrated inhibitory activity against both internal tandem duplication (ITD) and tyrosine kinase domain (TKD), FLT3 mutations that are seen in approximately one-third of patients with AML.

In October 2015, the Japanese Ministry of Health, Labor and Welfare (MHLW) announced the selection of gilteritinib as one of the first products designated for SAKIGAKE.

Gilteritinib was discovered through a research collaboration with Kotobuki Pharmaceutical Co., Ltd., and Astellas has exclusive global rights to develop, manufacture and potentially commercialize gilteritinib. Gilteritinib has been granted Orphan Drug  and Fast Track designation by the U.S. FDA, Orphan Drug Designation by the European Commission, and SAKIGAKE Designation and Orphan Drug Designation by the Japan Ministry of Health, Labor and Welfare.

The phase 3 ADMIRAL trial is an open-label, multicenter, randomized study of gilteritinib versus salvage chemotherapy in adult patients with FLT3 mutations who are refractory to or have relapsed after first-line AML therapy. The co-primary endpoints of the trial are OS (Overall Survival) and CR (complete remission) / CRh (CR with partial hematological recovery) rate and the study is still ongoing. The study enrolled 371 patients with FLT3 mutations present in bone marrow or whole blood, as determined by central lab. Subjects have been randomized in a 2:1 ratio to receive gilteritinib (120 mg) or salvage chemotherapy.