Japan’s Astellas Pharma has won EU approval for Xospata, a drug to treat acute myeloid leukaemia associated with a mutation in the FLT3 gene, keeping it ahead of rival Daiichi Sankyo.
The approval comes after an accelerated review of Xospata (gilteritinib) as a monotherapy for relapsed/refractory FLT3-positive AML, and just a few days after the EMA’s main advisory committee rejected Daiichi Sankyo’s marketing application for quizartinib in the same indication.
The EU regulator has given a green light for the use of Xospata in patients with two of the most common FLT3 mutations – internal tandem duplication (ITD) and tyrosine kinase domain (TKD).
All told, between 20 and 30% of people with AML have FLT3 mutations, which are associated with poorer outcomes, including a higher relapse rate, faster progression and shorter overall survival times.
Xospata has already been approved for this indication in Japan and the US, based on the results of the ADMIRAL study which compared Xospata to salvage chemotherapy. The results of that study showed Xospata extended overall survival (OS) to 9.3 months from 5.6 months in the control group.
After one year, 37% of patients taking Astellas’ drug were still alive, versus 17% of those in the chemotherapy arm.
Xospata is the first FLT3 inhibitor to be approved for use in relapsed or refractory AML with a FLT3 inhibitor mutation. It is however the second drug in the class to be approved for marketing after Novartis’ Rydapt (midostaurin), which was cleared for newly-diagnosed FLT3-positive AML in the US and Europe 2017.
First-line use will be the big battleground for the drugs, and Astellas already has phase 3 trials in previously-untreated FLT3-positive AML on the go, including a head-to-head study with Rydapt.
Meanwhile, Daiichi Sankyo has said it will concentrate on first-line use of quizartinib after being turned down by regulators in Europe and the US, and says it recently completed enrolment in a phase 3 trial – QuANTUM-First – which is testing its drug in combination with chemo in the front-line setting.
There are differences between the two drugs, as quizartinib only targets the ITD mutation, not TKD, although Daiichi Sankyo claims it has greater potency against the former.
There’s more potential competition on the way too from Arog Pharma, which has a FT3 inhibitor called crenolanib in phase 3 testing for first-line use alongside chemotherapy, including a comparative trial with Rydapt.
Astellas has already started to see the first revenues from Xospata, with the drug bringing in 2.5bn yen ($22m) in the first quarter. The company has forecast that full-year revenues from Xospata will reach around $140m, and hasn’t changed that prediction following the EU approval.