This study will evaluate the impact of rapid acceleration in the heart rate on the QT prolongation of quizartinib.

This is a QT assessment study of quizartinib when given as a single oral dose of 90 mg in 70 healthy subjects.

Key Inclusion Criteria:

1. Male and female subjects 18 to 55 years of age (inclusive), with a BMI of 18 kg/m2 to 32 kg/m2 (inclusive) with a minimum body weight of 40 kg at Screening.
2. Has vital signs (measured after subject has been supine for at least 5 minutes) at Screening within the following ranges: heart rate: 50-100 beats per minute (bpm); systolic blood pressure (BP): 90-145 mmHg; diastolic BP: 50-95 mmHg. Out-of-range vital signs may be repeated once.
3. Liver function test results (alanine aminotransferase [ALT], aspartate aminotransferase [AST], and total bilirubin [TBil]) must be equal to or below the upper limit of normal.
4. Hemoglobin levels must ≥11.5 g/dL for female subjects and ≥12.5 g/dL for male subjects.
5. In females, documented surgical sterilization (ie, documented hysterectomy, bilateral tubal ligation, or bilateral salpingo-oophorectomy, Essure® with hysterosalpingogram [documentation to confirm tubal occlusion 12 weeks after procedure]), postmenopausal status for at least 1 year (follicle stimulating hormone [FSH] > 40 mIU/mL serum and estradiol <40 pg/mL [<147 pmol/L] at Screening), or agreement to have a sterile male partner, or agreement to use 1 of the protocol-approved means of contraception from Screening until 7 months after the dose of quizartinib.
6. In males, documented surgical sterilization, or sexual abstinence, or agreement to use 1 of the protocol-approved means of contraception from Screening until 4 months after the single dose of quizartinib.

Key Exclusion Criteria:

1. Any serious and/or unstable pre-existing medical, psychiatric disorder, or other conditions (including lab abnormality) that could interfere with subject's safety, obtaining informed consent, compliance to the study procedures, or the validity of the study results.
2. In the opinion of the investigator, history of a clinically significant illness within 4 weeks prior to administration of quizartinib.
3. History or presence of an abnormal ECG, which, in the investigator's opinion, is clinically significant and/or a QT interval corrected for heart rate using Fridericia's formula (QTcF) >450 milliseconds (ms) at Screening
4. Females who are pregnant or breastfeeding
5. Laboratory results (serum chemistry, hematology, and urinalysis) outside the normal range, if considered clinically significant by the investigator. Estimated creatinine clearance (CrCl) < 90 mL/min (calculated by Cockcroft-Gault equation) at Screening.

This is a single-blinded study where only the participants will be blinded to the treatment being administered.