US researchers at the University of Pennsylvania’s Perelman School of Medicine and Abramson Cancer Centre have reported positive data from a Phase I/II clinical trial of Astellas Pharmaceuticals’ new drug gilteritinib in patients with acute myeloid leukaemia (AML).
Gilteritinib is an inhibitor of FMS-like tyrosine kinase 3 (FLT3) gene, which the mutation of is considered to be a predictor of AML relapse and short survival.
Results from the Phase I/II trial indicated that the response to the drug was more sustained in relapsed patients with a FLT3 mutation.
The trial investigated increasing doses of the initial 80mg of gilteritinib in 252 relapsed AML patients who were not responding to chemotherapy.
Findings showed that the evaluated doses demonstrated potent inhibition of the mutation, increased response rates and prolonged survival.
Of the total subjects, 100 received a 200mg dose and 67 were administered with 120mg dose.
In the trial, 191 volunteers had a FLT3 mutation, with 49% showing a response compared with the response of 12% who did not carry the mutation.
Abramson Cancer Centre Hematology Oncology assistant professor Alexander Perl said: “The fact that the response rate tracked with the degree of FLT3 inhibition and was so much lower among patients who did not have an FLT3 mutation gives us confidence that this drug is hitting its target.”
It was further observed that the clinical response rates during the trial were same in case of patients with FLT3 internal tandem duplication (FLT3-ITD) alone, and those with FLT3-ITD, as well as D835 mutation, which is an alternate mutant form of FLT3.
The drug was also found to be well-tolerated with mild diarrhoea, fatigue, and abnormal liver enzyme tests being its side-effects.