Quizartinib

VANFLYTA

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Pronunciation: kwiz-AR-ti-nib (van-FLIT-a)

Quizartinib ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Quizartinib ballicule

What it isAn oral FLT3 inhibitor added to chemotherapy for newly diagnosed FLT3-ITD-positive AML.

Why this oneIt is highly selective for the FLT3-ITD driver, extending survival when layered onto standard induction and continued as maintenance.

What limits itQT prolongation is its signature hazard, managed under a REMS with ECG-gated dose escalation, and strong CYP3A inhibitors force dose reduction.

Quizartinib molecular structure (skeletal formula) — Molecular structure: Quizartinib

FDA label

Read the full label on DailyMed ↗

BOXED WARNING QT prolongation, torsades de pointes, and cardiac arrest: do not use with severe hypokalemia/hypomagnesemia or long QT syndrome; do not initiate or escalate if QTcF >450 ms; ECGs at baseline, weekly during induction/consolidation and first month of maintenance; available only through VANFLYTA REMS.

FDA dosing	Population	Start	Target	Max
Newly diagnosed FLT3-ITD-positive AML — induction (with cytarabine + anthracycline)	Adults	35.4 mg QD, Days 8-21 of each 28-day cycle (7+3; Days 6-19 for 5+2)	35.4 mg QD, up to 2 cycles	35.4 mg QD
Newly diagnosed FLT3-ITD-positive AML — consolidation (with high-dose cytarabine)	Adults	35.4 mg QD, Days 6-19 of each 28-day cycle	35.4 mg QD, up to 4 cycles	35.4 mg QD
Newly diagnosed FLT3-ITD-positive AML — maintenance (monotherapy)	Adults; start after consolidation once ANC >500/mm3 and platelets >50,000/mm3	26.5 mg QD Days 1-14 of first cycle (if QTcF ≤450 ms)	53 mg QD from Day 15 if QTcF ≤450 ms; keep 26.5 mg QD if QTcF >500 ms occurred during induction/consolidation	53 mg QD, up to 36 cycles

Titration Maintenance: increase 26.5 mg QD to 53 mg QD on Day 15 of the first cycle only if QTcF ≤450 ms

Renal No adjustment needed for mild-moderate impairment (CLcr 30-89 mL/min); severe (CLcr <30) not studied

Hepatic No adjustment needed for mild-moderate impairment (Child-Pugh A or B); severe (C) not studied

Initiate/escalate only if QTcF ≤450 ms; QTcF 481-500 ms: reduce dose; >500 ms: interrupt then resume reduced; recurrent >500 ms or torsades/life-threatening arrhythmia: permanently discontinue

Instructions

Select patients by FDA-approved FLT3-ITD mutation test
Swallow tablets whole; do not cut, crush, or chew
With or without food, same time each day
If dose vomited, do not replace; wait for next scheduled dose
Missed dose: take same day, then resume schedule; never two doses in one day
Stop 7 days before start of HSCT conditioning regimen
With strong CYP3A inhibitors reduce dose: 53→26.5 mg, 35.4→17.7 mg, 26.5→17.7 mg QD (interrupt if on 17.7 mg); resume prior dose 5 half-lives after inhibitor stopped

Available strengths

tab 17.7, 26.5 mg

Contraindications

Severe hypokalemia
Severe hypomagnesemia
Long QT syndrome
History of ventricular arrhythmias or torsades de pointes

Cautions

QT prolongation, torsades de pointes, cardiac arrest (boxed; REMS-restricted); correct K/Mg before and during treatment; monitor ECGs and electrolytes, more often with diarrhea/vomiting or QT-prolonging drugs
Avoid in patients at significant risk of torsades: uncontrolled/significant cardiac disease, recent MI, heart failure, unstable angina, brady/tachyarrhythmias, uncontrolled hypertension, high-degree AV block, severe aortic stenosis, uncontrolled hypothyroidism
Embryo-fetal toxicity: verify pregnancy status within 7 days before start; effective contraception during treatment and 7 months (females) / 4 months (males) after last dose
May impair male and female fertility (reversible)

Adverse reactions

Lymphocytes decreased, potassium decreased, albumin decreased, phosphorus decreased, ALP increased, magnesium decreased
Febrile neutropenia (44%), neutropenia, thrombocytopenia, anemia
Diarrhea (42%), mucositis, nausea, abdominal pain, vomiting
Sepsis (serious; most common cause of discontinuation)
Headache, CPK increased, upper respiratory tract infection
ECG QT prolonged (dose reduction in 4%)
Fatal adverse reactions in 10% (sepsis 5%)

Pregnancy Can cause embryo-fetal harm (animal structural abnormalities and growth alterations at ~3x MRHD exposure); no human data

Lactation Do not breastfeed during treatment and for 1 month after last dose

Cost

Quizartinib (VANFLYTA)

Strength		#/mo	generic $/mo	CostPlus
17.7 mg	tab	30 qd		not offered
26.5 mg	tab	30 qd		not offered

NADAC is a voluntary CMS survey of what retail community pharmacies pay for the drugs they stock. Quizartinib is dispensed outside retail pharmacies, so it rarely appears on surveyed invoices.

⚠ BOXED WARNINGS

QT prolongation and torsades de pointes
Cardiac arrest

Classes and tags

Clinical profile

QT / Torsades3 / 4

Direct muscarinic antagonism0 / 4

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