Phase I study of quizartinib administered daily to patients with relapsed or refractory acute myeloid leukemia irrespective of FMS-like tyrosine kinase 3-internal tandem duplication status

J Clin Oncol. 2013 Oct 10;31(29):3681-7. doi: 10.1200/JCO.2013.48.8783. Epub 2013 Sep 3.


Purpose: FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutations in acute myeloid leukemia (AML) are associated with early relapse and poor survival. Quizartinib potently and selectively inhibits FLT3 kinase activity in preclinical AML models.

Patients and methods: Quizartinib was administered orally at escalating doses of 12 to 450 mg/day to 76 patients (median age, 60 years; range, 23 to 86 years; with a median of three prior therapies [range, 0 to 12 therapies]), enrolled irrespective of FLT3-ITD mutation status in a phase I, first-in-human study in relapsed or refractory AML.

Results: Responses occurred in 23 (30%) of 76 patients, including 10 (13%) complete remissions (CR) of any type (two CRs, three CRs with incomplete platelet recovery [CRp], five CRs with incomplete hematologic recovery [CRi]) and 13 (17%) with partial remissions (PRs). Of 17 FLT3-ITD-positive patients, nine responded (53%; one CR, one CRp, two CRis, five PRs); of 37 FLT3-ITD-negative patients, five responded (14%; two CRps, three PRs); of 22 with FLT3-ITD-indeterminate/not tested status, nine responded (41%; one CR, three CRis, five PRs). Median duration of response was 13.3 weeks; median survival was 14.0 weeks. The most common drug-related adverse events (> 10% incidence) were nausea (16%), prolonged QT interval (12%), vomiting (11%), and dysgeusia (11%); most were ≤ grade 2. The maximum-tolerated dose was 200 mg/day, and the dose-limiting toxicity was grade 3 QT prolongation. FLT3-ITD phosphorylation was completely inhibited in an in vitro plasma inhibitory assay.

Conclusion: Quizartinib has clinical activity in patients with relapsed/refractory AML, particularly those with FLT3-ITD, and is associated with an acceptable toxicity profile.

Trial registration: NCT00462761.

Publication types

  • Clinical Trial, Phase I
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Benzothiazoles / adverse effects
  • Benzothiazoles / therapeutic use*
  • Electrocardiography / drug effects
  • Female
  • Humans
  • Leukemia, Myeloid, Acute / drug therapy*
  • Leukemia, Myeloid, Acute / genetics
  • Leukemia, Myeloid, Acute / mortality
  • Male
  • Middle Aged
  • Mutation
  • Phenylurea Compounds / adverse effects
  • Phenylurea Compounds / therapeutic use*
  • Protein Kinase Inhibitors / therapeutic use*
  • Recurrence
  • Tandem Repeat Sequences*
  • fms-Like Tyrosine Kinase 3 / antagonists & inhibitors*
  • fms-Like Tyrosine Kinase 3 / genetics


  • Benzothiazoles
  • Phenylurea Compounds
  • Protein Kinase Inhibitors
  • quizartinib
  • FLT3 protein, human
  • fms-Like Tyrosine Kinase 3

Associated data