Infigratinib is a kinase inhibitor targeting FGFR1-3, indicated for the treatment of patients with locally advanced or metastatic cholangiocarcinoma harboring FGFR2 gene fusions or rearrangements. As an accelerated approval drug, its use must strictly comply with medication standards, and adverse reactions should be closely monitored.
Precautions for Infigratinib Use
Confirmation by Genetic Testing
Before using infigratinib, the presence of FGFR2 fusions or rearrangements in the tumor must be confirmed by an FDA-approved testing method.
Common partner genes include BICC1, etc., and non-fusion rearrangements may also be eligible for treatment.
Unvalidated test results may lead to ineffective treatment.
Baseline Examination Items
Ophthalmic evaluation: Including optical coherence tomography (OCT) examination to screen for the risk of retinal pigment epithelial detachment (RPED).
Laboratory tests: Serum phosphorus, renal function (creatinine clearance), liver function (bilirubin/AST), and electrolytes (calcium/sodium/potassium).
Pregnancy test: Women of childbearing age need to confirm they are not pregnant.
Adjustments for Special Populations
Renal impairment: For patients with mild to moderate renal impairment, reduce the dose to 100mg per day.
Hepatic impairment: For patients with mild hepatic impairment, reduce the dose to 100mg per day; for moderate hepatic impairment, reduce to 75mg per day.
Vomiting or missed dose: If a dose is missed by more than 4 hours or vomiting occurs, skip the missed dose and continue with the original schedule the next day.
Management of Drug Interactions
CYP3A inhibitors/inducers: Avoid combined use with strong/moderate-acting drugs (e.g., itraconazole, rifampicin).
Gastric acid modifiers: Proton pump inhibitors (PPIs) must be completely avoided.
H2 receptor antagonists: Administration should be separated by an interval of 2 hours.
Antacids: Administration should be separated by an interval of 2 hours.
Monitoring During Infigratinib Treatment
Monitoring of Ophthalmic Toxicity
RPED risk: Conduct regular OCT examinations at 1 month, 3 months after medication initiation, and every 3 months thereafter.
Symptom warning: Seek medical attention immediately if sudden blurred vision or metamorphopsia occurs.
Dry eye management: Use artificial tears or lubricating eye gel to relieve symptoms.
Hyperphosphatemia and Soft Tissue Calcification
Monitoring frequency: Measure serum phosphorus weekly in the early stage of treatment, and appropriately extend the interval after the condition stabilizes.
Intervention thresholds:
Serum phosphorus >5.5mg/dL: Initiate phosphorus-lowering treatment.
Serum phosphorus >7.5mg/dL: Suspend medication and intensify phosphorus-lowering measures.
Symptom recognition: Muscle spasms and perioral numbness indicate the need for emergency treatment.
Management of Other Common Adverse Reactions
Skin/nail toxicity: Hand-foot syndrome (33%) and alopecia (38%) can be relieved with moisturizers.
Gastrointestinal reactions: For stomatitis (56%), alcohol-free mouthwash is recommended; for diarrhea (24%), prevent dehydration.
Hepatic impairment: Elevated ALT (51%) requires evaluation of whether dose reduction is necessary.
