Quizartinib is an oral kinase inhibitor primarily indicated for the treatment of newly diagnosed FLT3-ITD-positive acute myeloid leukemia (AML). As a targeted therapy, it offers therapeutic efficacy alongside potential risks.

Side Effects of Quizartinib

Abnormal Laboratory Parameters

Hematological system: Lymphopenia (60%), neutropenia (29%), thrombocytopenia (18%), anemia (11%).

Electrolyte disorders: Hypokalemia (decreased blood potassium, 57%), hypomagnesemia (decreased blood magnesium, 44%), hypocalcemia (decreased blood calcium, 33%), hypophosphatemia (decreased blood phosphorus, 51%).

Other parameters: Hypoalbuminemia (decreased albumin, 55%), elevated alkaline phosphatase (51%), elevated creatine kinase (26%).

Clinical Symptoms and Infections

Gastrointestinal reactions: Diarrhea (42%), mucositis (38%), nausea (34%), abdominal pain (30%), vomiting (25%).

Infection-related events: Febrile neutropenia (44%), sepsis (30%), upper respiratory tract infection (21%), fungal infection (16%).

Severe Side Effects of Quizartinib

Cardiotoxicity Risk

QT interval prolongation: 14% of patients experience QTcF prolongation on electrocardiogram (ECG), with 3% being severe (QTcF > 500 ms).

Severe arrhythmias: Including torsades de pointes (0.2%), cardiac arrest (0.6%, with 0.4% being fatal), and ventricular fibrillation (0.1%).

Risk factors: Hypokalemia, hypomagnesemia, and concurrent use of QT-prolonging drugs.

Preventive measures: Regular ECG monitoring and electrolyte testing before and during treatment.

Other Life-Threatening Reactions

Differentiation syndrome (incidence of 5% in relapsed/refractory AML): Manifested by dyspnea, fever, edema, etc., requiring immediate intervention.

Risks in Special Populations

Pregnancy toxicity: Animal studies have shown that Quizartinib can cause fetal structural abnormalities and growth restriction; strict contraception is required.

Precautions for Quizartinib

Pre-Treatment Screening and Monitoring

Genetic testing: Only applicable to patients with positive FLT3-ITD mutation.

Baseline cardiac assessment: Treatment can only be initiated if QTcF ≤ 450 ms.

Hepatic and renal function: No dose adjustment is required for patients with mild to moderate impairment; the safety in patients with severe impairment is unknown.

Management of Drug Interactions

Strong CYP3A inhibitors (e.g., ketoconazole): The dose of Quizartinib needs to be reduced to avoid increased drug exposure.

QT-prolonging drugs (e.g., azole antifungals, ondansetron): Enhanced ECG monitoring is required when used concomitantly.