What are the precautions for Fostamatinib?

In the clinical study of Fostamatinib in the treatment of thrombocytopenia, warnings and precautions such as hypertension, hepatotoxicity, diarrhea, neutropenia, embryo-fetotoxicity appeared. Discontinue and resume at reduced dose upon recovery, or permanently discontinue based on severity.

1. Hypertension: Hypertension can occur when treated with fotantinib; 1% of patients develop hypertensive crisis. Patients with essential hypertension may be more susceptible to the hypertensive effects of tavalis. Monitor blood pressure every two weeks until stable and then monthly and adjust or initiate antihypertensive therapy to ensure blood pressure control is maintained during fotantinib treatment. If blood pressure remains elevated despite appropriate therapy, fotantinib may need to be interrupted, reduced, or discontinued.

2. Hepatotoxicity: Fotantinib can cause an increase in liver function tests (lft), mainly alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Laboratory testing showed that 9% of treated patients had maximum ALT/AST levels that were more than 3 times the upper limit of normal (ULN). In most patients, transaminases return to baseline levels within 2 to 6 weeks after dose adjustment. Monitor liver function tests monthly during treatment. If alanine aminotransferase or aspartate aminotransferase increases above 3*ULN, fotantinib should be interrupted, reduced, or discontinued to control hepatotoxicity.

3. Diarrhea:Monitor the patient for the development of diarrhea. Use supportive care measures to control diarrhea early after symptoms appear, including dietary changes, hydration, and/or antidiarrheal medications. If diarrhea becomes severe (Grade 3 or greater), interrupt, reduce the dose, or stop taking fotantinib.

4. Neutropenia: Among patients treated with fotantinib, approximately6% will develop neutropenia, and 1% of patients may have febrile neutropenia. Therefore, the medical team needs to regularly monitor the patient's absolute neutrophil count (ANC) and monitor for the occurrence of infection during treatment. Once the neutrophil count is found to have dropped to a dangerous level, doctors usually choose to interrupt, reduce the dose, or discontinue fotantinib depending on the patient's condition to control possible infection risks.

5. Embryonic-Fetal Toxicity: Based on findings from animal studies and its mechanism of action, fotantinib can cause fetal damage when given to pregnant women. In animal reproduction studies, administration of fotantinibto pregnant rats and rabbits during organogenesis resulted in adverse developmental outcomes, including embryonic-fetal death, altered growth, and structural abnormalities. Inform pregnant women of potential risks to the fetus. Advise females of reproductive potential to use effective contraception during treatment and for at least 1 month after the last dose.

In summary, during the treatment of thrombocytopenia with fotantinib, full attention must be paid to the monitoring and management of the above adverse reactions. By regularly assessing the patient's health status and adjusting treatment plans in a timely manner, the incidence of adverse reactions can be effectively reduced and the safety and effectiveness of treatment can be improved.

Reference materials:https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=21149cc3-049b-43e2-b141-c9499160556c