QuANTUM-R: Quizartinib vs Salvage Chemotherapy in Relapsed or Refractory FLT3-ITD–Positive AML
In the phase III QuANTUM-R trial reported in The Lancet Oncology, Cortes et al found that the FLT3 inhibitor quizartinib produced a modest but significant improvement in overall survival vs salvage chemotherapy in relapsed or refractory FLT3 internal tandem duplication (FLT3-ITD)-positive acute myeloid leukemia (AML).
Study Details
In the open-label trial, 367 patients from 152 sites in 19 countries who had received standard therapy with or without allogeneic hematopoietic stem cell transplantation were randomly assigned 2:1 between May 2014 and September 2017 to receive quizartinib 60 mg once daily (n = 245) or salvage chemotherapy (n = 122). Investigator’s choice of chemotherapy consisted of: low-dose cytarabine; mitoxantrone, etoposide, and cytarabine; or granulocyte colony-stimulating factor, fludarabine, cytarabine, and idarubicin.
The primary endpoint was overall survival in the intention-to-treat population.
Overall Survival
Median follow-up was 23.5 months. Median overall survival was 6.2 months (95% confidence interval [CI] = 5.3–7.2 months) in the quizartinib group vs 4.7 months (95% CI = 4.0–5.5 months) in the salvage chemotherapy group (hazard ratio = 0.76, P = .02). Estimated 12-month survival was 27% vs 20%.
Adverse Events
The most common nonhematologic grade ≥ 3 adverse events were sepsis or septic shock (19% in quizartinib group vs 19% in chemotherapy group), pneumonia (12% vs 9%), and hypokalemia (12% vs 9%). The most frequent treatment-related serious adverse events were febrile neutropenia (7%), sepsis or septic shock (5%), QT prolongation (2%), and nausea (2%) in the quizartinib group, and febrile neutropenia (5%), sepsis or septic shock (4%), pneumonia (2%), and pyrexia (2%) in the chemotherapy group. Grade 3 QT prolongation occurred in 3% and 4% of the quizartinib group on central and investigator assessment, respectively. Adverse events led to death in 13% of the quizartinib group and 10% of the chemotherapy group.
The investigators concluded, “Treatment with quizartinib had a survival benefit vs salvage chemotherapy and had a manageable safety profile in patients with rapidly proliferative disease and very poor prognosis. Quizartinib could be considered a new standard of care. Given that there are only a few available treatment options, this study highlights the value of targeting the FLT3-ITD driver mutation with a highly potent and selective FLT3 inhibitor.”
Jorge Cortes, MD, of the Leukemia Department, The University of Texas MD Anderson Cancer Center, is the corresponding author for The Lancet Oncology article.
Disclosure: The study was funded by Daiichi Sankyo. For full disclosures of the study authors, visit thelancet.com.
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