Gilteritinib has significant therapeutic effects on FLT3 mutation positive AML patients, but the discontinuation process needs to be standardized to avoid disease relapse or adverse reactions. During the treatment period, it is necessary to regularly evaluate the efficacy and safety. When discontinuing medication, the principle of gradual progression should be followed and residual lesions should be closely monitored.

Evaluation of treatment efficacy

1. Overall response rate: In the ADMIRAL trial, patients with FLT3-ITD mutations had a compound complete response rate (CRc) of 54% and a median overall survival of 9.3 months, significantly better than the chemotherapy group.

2. Molecular response: About 25% of patients can achieve zero FLT3-ITD allele burden, and the median recurrence free survival period for these patients can reach 17.8 months.

3. Drug resistance situation: About 30% of patients will develop acquired drug resistance, commonly caused by FLT3-F691L and other site mutations, which need to be monitored through regular genetic testing.

Precautions for discontinuation of medication

(1) Planned discontinuation criteria: Must meet the requirement of complete remission lasting for ≥ 6 months and negative peripheral blood/bone marrow FLT3-ITD test (sensitivity ≤ 10 ^ -4 ^).

(2) Gradual reduction plan: It is recommended to first reduce to half the dosage and maintain it for 2-4 weeks. After confirming that there are no signs of recurrence, completely stop the medication to avoid sudden cessation of medication causing kinase signal rebound.

(3) Emergency discontinuation indication: Immediate discontinuation is required when there is grade ≥ 3 non hematological toxicity, treatment-related pneumonia, or QTc interval>500ms.

Monitoring requirements after discontinuation of medication

1. Hematological monitoring: Blood routine tests will be conducted every 2 weeks for the first 3 months after discontinuation, and once a month until 1 year after discontinuation, with a focus on changes in the proportion of primitive cells.

2. Molecular monitoring: FLT3 mutation burden is detected by PCR or NGS every 1-2 months. If a positive result is found, further treatment should be considered.

3. Follow up of organ function: Due to potential cardiac toxicity, quarterly follow-up electrocardiograms and echocardiography are required within 6 months after discontinuation of medication.