What is the starting dose and adjustment method of fotantinib/fotantinib?

Fostamatinib is an oral splenic tyrosine kinase (SYK) inhibitor, primarily used to treat adult patients with chronic immune thrombocytopenia (ITP) who have had an inadequate response to previous treatments. The recommended initial dose is 100 mg twice daily. After initiation of treatment, if the patient's platelet count does not reach at least 50 × 10^9/L within one month and the patient is able to tolerate the drug, the dose may be increased to 150 mg twice daily. During treatment, the lowest effective dose should be used to maintain platelet counts within a safe range to reduce the risk of bleeding.

Patients' blood pressure needs to be monitored closely while taking fotantinib because the drug may cause hypertension. If the patient develops stage 1 hypertension (systolic blood pressure 130–139 mmHg or diastolic blood pressure 80–89 mmHg), the dose of antihypertensive drugs should be started or increased and adjusted to the blood pressure control target within 8 weeks; if blood pressure cannot be controlled, it is recommended to reduce the fotantinib dose to the next lower daily dose. For stage 2 hypertension (systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg), the dose of antihypertensive drugs should be started or increased immediately and adjusted to the blood pressure control target within 4 weeks; if blood pressure is still not controlled, fotantinib treatment may need to be interrupted or stopped.

In addition, fotantinib may cause other adverse reactions, such as diarrhea, nausea, dizziness, elevated liver enzymes, respiratory infections, rash, abdominal pain, fatigue, chest pain, and neutropenia. Therefore, the patient's liver function, blood routine and other indicators should be regularly monitored during treatment in order to detect and deal with possible adverse reactions in a timely manner.

If a patient's platelet count fails to reach a level sufficient to avoid clinically relevant bleeding after 12 weeks of treatment, it is recommended to discontinue fotantinib treatment. During treatment, the dosage should be flexibly adjusted according to the patient's individual response and tolerance to achieve the best therapeutic effect and minimal adverse reactions.

Reference materials:https://go.drugbank.com/drugs/DB12010