Astellas scores first US blood cancer approval with Xospata

Xospata (gilteritinib) has been approved in adults who have relapsed or refractory AML where an FDA-approved test has detected an FLT3 mutation.

The oral drug is the only FLT3-targeting drug to be approved by the FDA for this population.

The FLT3 mutation is expressed in about 30% of AML patients and is associated with a worse prognosis, higher relapse rate, faster progression and shorter overall survival.

Xospata has demonstrated inhibitory activity against two different mutations, FLT3 internal tandem duplication (ITD) and FLT3 tyrosine kinase domain (TKD).

The TKD mutations impact around 7% of AML patients, and although the impact of these mutations is less clear, they have been associated with treatment resistance.

Astellas is pricing the drug at $22,500 for a 30-day course of treatments, according to media reports.

Richard Pazdur, acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, said: “Approximately 25 to 30% of patients with AML have a mutation in the FLT3 gene. These mutations are associated with a particularly aggressive form of the disease and a higher risk of relapse.

“Xospata targets this gene and is the first drug to be approved that can be used alone in treating patients with AML having a FLT3 mutation who have relapsed or who don’t respond to initial treatment.”

Steven Benner, senior vice president and global therapeutic area head, Oncology Development, at Astellas, said: “Xospata offers new hope to patients for whom the treatment path forward is unclear.

“For the first time, people with relapsed or refractory FLT3 mutation-positive AML have an FDA approved FLT3 -targeting treatment available to them. The approval of Xospata is also a proud, landmark moment for our oncology program and marks the first approval of a medicine that will be the cornerstone of our new presence in blood cancers.”

However competition is looming in AML patients with FLT3 mutations – Japanese drugmaker Daiichi Sankyo’s FLT3 inhibitor quizartinib won an FDA priority review in an overlapping indication.

With the FDA due to make a decision on 25 May next year because of the faster six-month review period.

Daiichi’s drug, quizartinib, targets a slightly different mutation, known as FLT3-ITD, and the FDA is reviewing trial data submitted by the Japanese pharma last month.