The US Food and Drug Administration (FDA) granted a Breakthrough Therapy designation to quizartinib for the treatment of adult patients with relapsed/refractory (R/R) FLT3-internal tandem duplication (FLT3-ITD)–positive acute myeloid leukemia (AML), according to a press release.1
A FLT3-ITD mutation, which is characteristic of a highly aggressive form of AML, is found in approximately a quarter of patients with leukemia and is associated with a poor prognosis. Quizartinib — an investigational FLT3 inhibitor — is the first agent in its class to demonstrate improved overall survival (OS).
The FDA granted a Breakthrough Therapy designation to the investigational medication based on the results of the QuaNTUM-R (ClinicalTrials.gov Identifier: NCT02039726) phase 3 study.2 For this study, investigators randomly assigned 367 patients with R/R FLT-ITD mutated AML to oral quizartinib or various prespecified investigator’s choice salvage chemotherapy (SC) arms. Study participants had achieved a complete response with standard AML therapy alone or with hematopoietic stem cell transplant, but had relapsed after 6 months or less following treatment completion.
After a median follow-up of 102.4 weeks, results showed that the median OS was 27 weeks (95% CI, 23.1-31.13) among patients in the quizartinib arm compared with 20.4 weeks (95% CI, 17.3-23.7) among patients in the SC arms. The estimated 52-week survival probability was 27% and 20% for patients in the quizartinib arm and SC arms, respectively. The hazard ratio for OS of quizartinib relative to SC was 0.76 (95% CI, 0.58-0.98; P = .0177).
The rate of treatment-related adverse events (AE) was similar between the 2 study arms. The AE profile of quizartinib remained consistent with those included in previous reports.
- FDA Grants Breakthrough Therapy Designation to Daiichi Sankyo’s FLT3 Inhibitor Quizartinib for Relapsed/Refractory FLT3-ITD AML [press release]. Tokyo, Japan; Basking Ridge, NJ; and Munich, Germany: Daiichi Sankyo Company; August 1, 2018. https://www.daiichisankyo.com/media_investors/media_relations/press_releases/detail/006896.html. Accessed August 1, 2018.
- Cortes J, Khaled S, Martinelli G, et al. Quizartinib significantly prolongs overall survival in patients with FLT3-internal tandem duplication-mutated (MUT) relapsed/refractory AML in the phase 3, randomized, controlled QUANTUM-R trial. Oral presentation at: The 23rd Annual Congress of the European Hematology Association; June 2018; Stockholm, Sweden.