INTERACTIONS Table 7: Effect of Other Drugs on VANFLYTA Strong CYP3A Inhibitors Clinical Impact VANFLYTA is a CYP3A substrate. Concomitant use of VANFLYTA with a strong CYP3A inhibitor increases quizartinib systemic exposure [see Clinical Pharmacology (12.3) ] , which may increase the risk of VANFLYTA adverse reactions. Prevention or Management Reduce the dosage of VANFLYTA [see Dosage and Administration (2.4) ]. Strong or Moderate CYP3A Inducers Clinical Impact Concomitant use of VANFLYTA with strong or moderate CYP3A inducers decreases quizartinib systemic exposure [see Clinical Pharmacology (12.3) ] , which may reduce VANFLYTA efficacy. Prevention or Management Avoid concomitant use of VANFLYTA with strong or moderate CYP3A inducers [see Clinical Pharmacology (12.3) ] . QT Interval Prolonging Drugs Clinical Impact VANFLYTA prolongs the QT/QTc interval. Coadministration of VANFLYTA with other drugs that prolong the QT interval may further increase the incidence of QT prolongation [see Warnings and Precautions (5.1) and Clinical Pharmacology (12.2) ] . Prevention or Management Monitor patients more frequently with ECG if coadministration of VANFLYTA with drugs known to prolong the QT interval is required. Examples of QT prolonging drugs include but are not limited to antifungal azoles, ondansetron, granisetron, azithromycin, pentamidine, doxycycline, moxifloxacin, atovaquone, prochlorperazine, and tacrolimus. Strong CYP3A Inhibitors: Reduce the VANFLYTA dose. ( 2.4 , 7 ) Strong or Moderate CYP3A Inducers: Avoid concomitant use. ( 7 , 12.3 )
VANFLYTA is contraindicated in patients with severe hypokalemia, severe hypomagnesemia, long QT syndrome, or in patients with a history of ventricular arrhythmias or torsades de pointes [see Warnings and Precautions (5.1) ]. Contraindicated in patients with severe hypokalemia, severe hypomagnesemia, long QT syndrome, or in patients with a history of ventricular arrhythmias or torsades de pointes. ( 4 , 5.1 )
AND PRECAUTIONS QT Prolongation, Torsades de Pointes, and Cardiac Arrest: Monitor electrocardiograms and levels of serum electrolytes. Reduce, interrupt, or permanently discontinue VANFLYTA as appropriate. ( 2.3 , 5.1 ) Embryo-Fetal Toxicity: VANFLYTA can cause fetal harm. Advise females of reproductive potential and males with female partners of reproductive potential of potential risk to a fetus and to use effective contraception. ( 5.3 , 8.1 , 8.3 )
5.1 QT Prolongation, Torsades de Pointes, and Cardiac Arrest VANFLYTA prolongs the QT interval in a dose- and concentration-dependent manner. The mechanism of QTc interval prolongation is via inhibition of the slow delayed rectifier potassium current, I Ks , as compared to all other medications that prolong the QTc interval, which is via the rapid delayed rectifier potassium current, I Kr . Therefore, the level of QTc prolongation with VANFLYTA that predicts the risk of cardiac arrhythmias is unclear. Inhibition of I Ks and I Kr may leave patients with limited reserve leading to a higher risk of QT prolongation and serious cardiac arrhythmias, including fatal outcomes <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.2) ]</span> . Torsades de pointes, ventricular fibrillation, cardiac arrest, and sudden death have occurred in patients treated with VANFLYTA. Of the 1,081 patients with AML treated with VANFLYTA in clinical trials, torsades de pointes occurred in approximately 0.2% of patients, cardiac arrest occurred in 0.6%, including 0.4% with a fatal outcome, and 0.1% of patients experienced ventricular fibrillation <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> . These severe cardiac arrhythmias occurred predominantly during the induction phase. Of the 265 patients with newly diagnosed FLT3-ITD-positive AML treated with VANFLYTA in combination with chemotherapy in the clinical trial, 2.3% were found to have a QTcF greater than 500 ms and 10% of patients had an increase from baseline QTcF greater than 60 ms. The clinical trial excluded patients with a QTcF ≥450 ms or other factors that increased the risk of QT prolongation or arrhythmic events (e.g., NYHA Class III or IV congestive heart failure, hypokalemia, family history of long QT interval syndrome). Therefore, avoid use in patients who are at significant risk of developing torsades de pointes, including uncontrolled or significant cardiac disease, recent myocardial infarction, heart failure, unstable angina, bradyarrhythmias, tachyarrhythmias, uncontrolled hypertension, high-degree atrioventricular block, severe aortic stenosis, or uncontrolled hypothyroidism. Do not initiate treatment with VANFLYTA if the QTcF interval is greater than 450 ms. Do not use VANFLYTA in patients with severe hypokalemia, severe hypomagnesemia, long QT syndrome, or in patients with a history of ventricular arrhythmias or torsades de pointes <span class="opacity-50 text-xs">[see Contraindications (4) ]</span> . Perform an ECG and correct electrolyte abnormalities prior to initiation of treatment with VANFLYTA. During induction and consolidation, perform an ECG prior to initiation and then once weekly during VANFLYTA treatment or more frequently as clinically indicated. During maintenance, perform ECGs prior to initiation, once weekly for at least the first month following dose initiation and escalation, and as clinically indicated thereafter. Do not escalate the dose if QTcF is greater than 450 ms <span class="opacity-50 text-xs">[see Dosage and Administration (2.3) ]</span> . Perform ECG monitoring of the QT interval more frequently in patients who are at significant risk of developing QT interval prolongation and torsades de pointes, or following dose escalation. Monitor and correct hypokalemia and hypomagnesemia prior to and during treatment with VANFLYTA. Maintain electrolytes in the normal range. Monitor electrolytes and ECGs more frequently in patients who experience diarrhea or vomiting. Monitor patients more frequently with ECGs if coadministration of VANFLYTA with drugs known to prolong the QT interval is required <span class="opacity-50 text-xs">[see Drug Interactions (7) ]</span> . Reduce the VANFLYTA dose when used concomitantly with strong CYP3A inhibitors, as they may increase quizartinib exposure <span class="opacity-50 text-xs">[see Dosage and Administration (2.4) ]</span> . Reduce VANFLYTA if QTc increases to greater than 480 ms and less than 500 ms. Interrupt and reduce VANFLYTA if QTc increases to greater than 500 ms. Permanently discontinue VANFLYTA in patients who develop recurrent QTc greater than 500 ms or QTc interval prolongation with signs or symptoms of life-threatening arrhythmia <span class="opacity-50 text-xs">[see Dosage and Administration (2.3) ]</span> . VANFLYTA is available only through a restricted program under a REMS <span class="opacity-50 text-xs">[see Warnings and Precautions (5.2) ]</span> .
5.2 VANFLYTA REMS VANFLYTA is available only through a restricted distribution program under a REMS called the VANFLYTA REMS because of the serious risk of QT prolongation, torsades de pointes, and cardiac arrest <span class="opacity-50 text-xs">[see Warnings and Precautions (5.1) ]</span> . Notable requirements of the VANFLYTA REMS include the following: Prescribers must be certified in the VANFLYTA REMS by enrolling and completing training. Prescribers must counsel patients receiving VANFLYTA about the risk of QT prolongation, torsades de pointes, and cardiac arrest, and provide patients with a Patient Wallet Card. Pharmacies that dispense VANFLYTA must be certified with the VANFLYTA REMS and must verify prescribers are certified through the VANFLYTA REMS. Further information about the VANFLYTA REMS is available at www.VANFLYTAREMS.com or by telephone at 1-855-212-6670.
5.3 Embryo-Fetal Toxicity Based on findings in animals and its mechanism of action, VANFLYTA can cause fetal harm when administered to a pregnant woman. In animal reproduction studies, administration of quizartinib to pregnant rats during organogenesis at exposures 3 times the maximum recommended human dose (MRHD) of 53 mg/day caused structural abnormalities and alterations to growth. Advise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment with VANFLYTA and for 7 months after the last dose. Advise males with female partners of reproductive potential to use effective contraception during treatment with VANFLYTA and for 4 months after the last dose <span class="opacity-50 text-xs">[see Use in Specific Populations (8.1 , 8.3) ]</span> .