What are the precautions for pemigatinib?

During the treatment with Pemigatinib (Pemigatinib), patients should pay attention to the occurrence of eye toxicity, hyperphosphatemia and soft tissue mineralization, embryo-fetal toxicity and other events. If any discomfort occurs, the patient should inform the doctor in time.

1. Eye toxicity: Pemetinib may cause retinal pigment epithelial detachment (RPED), dry eye disease, etc., which may cause symptoms such as blurred vision, visual floaters or light perception. Patients need a comprehensive eye examination, including OCT examination before starting pemetinib, every 2 months for the first 6 months, and every 3 months during treatment. For visual symptoms that occur, patients should receive immediate ophthalmic evaluation, follow-up visits every 3 weeks, and treatment with ocular analgesics as needed until symptoms resolve or pemetinib is discontinued.

2. Hyperphosphatemia and soft tissue mineralization: Pemetinib may cause hyperphosphatemia, leading to soft tissue mineralization, skin calcification, calcinosis and non-uremic calcium allergy. The increase in phosphate levels is the pharmacodynamic effect of pemetazole. Monitor for hyperphosphatemia and initiate a low-phosphate diet when serum phosphate level>5.5 mg/dL. In patients with serum phosphate levels >7 mg/dL, phosphate-lowering therapy should be initiated and pemetinib should be withheld, dose reduced, or permanently discontinued depending on the duration and severity of hyperphosphatemia.

3. Embryonic-Fetal Toxicity: Based on findings from animal studies and its mechanism of action, pemetinib can cause fetal damage when administered to pregnant women. Therefore, it is recommended that female patients of childbearing potential and their partners use effective contraception during treatment with pemetinib and within 1 week after the last dose. Women should not breastfeed during treatment and within 1 week after the last dose.