Common Side Effects of Quizartinib and Management Strategies

Common Side Effects of Quizartinib and Management Strategies

(1) Common side effects of quizartinib involve multiple systems, with higher incidences including: leukopenia (which may increase infection risk), febrile neutropenia, thrombocytopenia (bleeding predisposition), and anemia (fatigue, shortness of breath).

(2) Gastrointestinal reactions are also very common, such as nausea, vomiting, diarrhea, oral mucositis, and abdominal pain; additionally, elevated liver function tests and electrolyte disturbances (e.g., potassium, magnesium, phosphorus abnormalities) may occur.

(3) Other side effects include: headache, upper respiratory tract infections, sepsis (severe systemic infection), fungal or herpesvirus infections, epistaxis, insomnia, electrocardiogram abnormalities (QT prolongation), dyspepsia, and ocular irritation.

(4) Physicians will regularly monitor blood counts, liver and renal function, and electrocardiograms throughout the treatment course. If severe adverse reactions occur, the physician may temporarily interrupt therapy, reduce the dose, or permanently discontinue the drug. In addition, this medication may affect fertility in both males and females; if you have plans for reproduction, please discuss fertility preservation options with your doctor in advance.

What Is Acute Myeloid Leukemia (AML)?

(1) Acute myeloid leukemia (AML) is a malignant hematologic neoplasm originating from hematopoietic stem cells in the bone marrow. Under normal conditions, hematopoietic stem cells differentiate into mature red blood cells, white blood cells, and platelets; however, in AML patients, these cells acquire genetic mutations, leading to arrested development and massive proliferation of immature leukemic blasts.

(2) These abnormal cells crowd out normal hematopoietic space, reducing healthy blood cell counts, thereby causing anemia, infections, and bleeding tendency. AML is the most common acute leukemia in adults, but it remains a rare cancer overall, accounting for approximately 1% of all cancers.

(3) Unlike solid tumors, leukemia is a "liquid tumor" with malignant cells circulating throughout the body via the bloodstream; therefore, treatment generally requires systemic chemotherapy and targeted therapy. AML diagnosis relies on bone marrow aspiration and cytogenetic analysis to identify specific mutation types, which is crucial for selecting precise treatment regimens.

What Is the Mechanism of Action of Quizartinib?

(1) The FLT3 gene encodes a receptor tyrosine kinase involved in hematopoietic cell growth and differentiation. When an internal tandem duplication (ITD) mutation occurs in this gene, the receptor becomes constitutively activated, leading to uncontrolled proliferation of leukemic cells, and such patients experience faster disease progression, higher relapse risk, and relatively poorer prognosis.

(2) FLT3‑ITD is the most common mutation type in AML, present in approximately 25%–30% of newly diagnosed AML patients. This mutation may be present at initial diagnosis or emerge during the disease course. Therefore, prompt FLT3 mutation testing immediately after diagnosis is the cornerstone for developing individualized treatment strategies.

(3) Quizartinib, as a second‑generation FLT3 inhibitor, selectively binds to and inhibits the ITD‑mutant kinase, thereby blocking cancer cell growth signals and inducing apoptosis of leukemic cells. Compared with conventional chemotherapy, combination with quizartinib significantly prolongs relapse‑free survival and overall survival.

(4) Knowing your mutation status can help you and your physician select the most appropriate medication and avoid ineffective therapy.