Pharmacological introduction to the FLT3 inhibitor Quizartinib

Quizartinib (Quizartinib) is a selective second-generation FLT3 inhibitor, which belongs to the tyrosine kinase inhibitor (TKI) class of anti-cancer drugs. It is mainly used to treat acute myeloid leukemia (AML) carrying FLT3-ITD mutations. Its core pharmacological mechanism lies in specifically inhibiting the activity of FLT3 receptor tyrosine kinase, thereby blocking the abnormal signaling chain of leukemia cells. FLT3 is an important regulatory protein for the proliferation and differentiation of hematopoietic stem cells. When it is mutated (especially the ITD mutation), it will lead to continued activation of the cells, leading to canceration. By binding to the ATP binding site of FLT3, Quizartinib effectively inhibits the overactivity of signaling pathways, promotes apoptosis of abnormal cells, and prevents their spread.

Pharmacological studies have shown that quizartinib not only selectively inhibitsFLT3, but also has certain inhibitory effects on other tyrosine kinases such as KIT and PDGFR, which gives it a multi-target advantage in controlling the growth of tumor cells. At the same time, its molecular structure optimization improves the bioavailability and metabolic stability of the drug and reduces the risk of drug-drug interactions. Quizartinib is rapidly absorbed orally and has a long half-life, allowing it to be taken once a day, making it convenient for clinical use.

The biggest difference between Quizartinib and the first generationFLT3 inhibitors is its higher selectivity and lower off-target effects. Early drugs such as sorafenib and midostaurin often caused high toxicity due to broad-spectrum inhibition, while quizartinib balances efficacy and safety by precisely targeting FLT3-ITD mutated cells. In addition, it is more sensitive to drug-resistant mutations and can restore drug response in some relapsed cases.

In terms of pharmacokinetics in vivo, quizartinib is mainly metabolized by CYP3A4, and the activity of metabolites is low, which reduces the risk of drug accumulation. After taking the drug, the plasma concentration in the patient's body is stable and the sustained inhibitory effect can be maintained. The drug can be used in combination with chemotherapy or other targeted drugs to improve response rates and delay the development of drug resistance.

Reference materials:https://go.drugbank.com/drugs/DB12874