Quizartinib is an FLT3 tyrosine kinase inhibitor primarily used to treat relapsed/refractory FLT3-ITD mutation positive acute myeloid leukemia (AML).

1 Indications

Quetzatinib is suitable for the treatment of relapsed/refractory FLT3-ITD mutation positive AML in adults. Before medication, molecular testing is required to confirm the FLT3-ITD mutation status, which accounts for approximately 25% -30% of AML patients. For patients without detected mutations, the use of this drug is not recommended.

2 Usage and Dosage

(1) Induction therapy (up to 2 cycles)

Initial dose: once daily, 35.4mg per dose, orally.

7+3 regimen: start administration on the 8th day; 5+2 regimen (second induction cycle): start administration on the 6th day.

Administer medication every week for 2 weeks (days 8-21 or 6-19).

(2) Consolidation therapy (up to 4 cycles)

Once a day, 35.4mg each time, administered on the 6th to 19th day.

(3) Maintenance treatment (up to 36 cycles)

Initial dose: once daily, 26.5mg each time, from day 1 to day 14.

If QTcF ≤ 450ms, increase to 53mg once daily from the 15th day onwards.

Administer daily continuously without any interval between cycles.

3 dose adjustments

(1) Adjustment due to adverse reactions: Based on the degree of QTcF prolongation, electrolyte abnormalities, non hematological toxicity, and decreased blood cells, dosage reduction, suspension of administration, or permanent discontinuation will be adopted. The specific adjustment gradient is 53mg → 35.4mg → 26.5mg → 17.7mg → suspension.

(2) When used in combination with potent CYP3A inhibitors:

The current dose is 53mg → adjusted to 26.5mg; 35.4mg → 17.7mg; 26.5mg → 17.7mg; if the current dose is 17.7mg, the administration will be suspended.

After discontinuing the potent CYP3A inhibitor for 5 half lives, restore the original dose.

4 Common Side Effects

The incidence of bone marrow suppression (anemia/thrombocytopenia/neutropenia) is>50%, and regular blood tests are required. The incidence of QT prolongation is 12% -18% and requires electrocardiographic monitoring. Other symptoms include nausea, fatigue, mucosal inflammation, etc., most of which are grade 1-2.

5 serious adverse reactions

Be alert to the risk of ventricular tachycardia caused by sharp twisting, especially when combined with other QT prolonging drugs. The risk of infection at level 3 or above is increased and is associated with neutropenia. Rare reports of interstitial lung disease/pneumonia require immediate assessment for respiratory distress.