QUANTUM-R: Transfusion independence in patients with FLT3-ITD-mutated R/R AML treated with quizartinib or salvage chemotherapy

Dr Mark Levis - Johns Hopkins Medicine, Baltimore, USA

This is a post-hoc analysis of QUANTUM-R as essentially all of these are since the primary data for that trial has actually already been published. QUANTUM-R was a randomised study of patients with FLT3-ITD AML who were relapsed or refractory and those patients were randomised to receive either conventional salvage chemotherapy or single agent quizartinib which is a very potent selective FLT3 inhibitor. The trial was positive in that there was an overall survival benefit for patients randomised to receive quizartinib but there were a number of other issues that we wanted to drill down on. One of the ones was transfusion independence.

So as an approval endpoint, or a regulatory endpoint, it has come to the attention of a number of us in the field that in fact a demonstration that your drug can improve quality of life by decreasing the dependence of our patients on having to come to the clinic and get blood transfusions is important. In fact, even apart from a benefit in overall survival, a regulatory agency will look kindly upon the fact that we are improving our patients’ quality of lives.

So it turns out in QUANTUM-R in patients randomised to receive quizartinib there was an improvement in transfusion independence. So the study measured patients, defined transfusion independence and set it at baseline and then asked during a sixty day window of treatment did they at any point become transfusion independent. In fact, 22% of patients on that quizartinib arm became transfusion independent. This compares with other FLT3 inhibitors or other targeted agents, it gets it into that same ballpark.

So while this is just one of the parameters that we have been looking at post-hoc this was an important one because, okay, many of our agents – do they result in a cure? Not necessarily. They are prolonging survival but are they also changing the nature of what the patient is going through? Quizartinib is an oral agent that you take and you’re at home; chemo you take in-patient at the hospital. Not only are you at home, you’re not needing transfusions as often. So that is the point of the abstract.