What are the precautions for Erdafitinib?

Among the warnings and precautions that emerged from clinical studies of Erdafitinib (Erdafitinib), eye disease , hyperphosphatemia and soft tissue mineralization, embryonic disease-Fetal toxicity is more common, Doctors may regularly check the patient's progress in drug treatment of urothelial carcinoma (mUC), and based on the duration and severity of the condition, discontinue, reduce the dose, or permanently stop erdafitinib.

1. Eye diseases: Erdafitinib can cause eye diseases including central serous retinopathy/retinal pigment epithelial detachment (CSR/RPED) leading to visual field defects. During treatment with erdafitinib, dry eye symptoms occurred in 28% of patients and grade 3 in 6%. All patients should use ocular emollients for dry eye prophylaxis as needed. Have an eye examination during the first 4 months of treatment and every 3 months thereafter, and urgently at any time for visual symptoms. The eye examination should include assessment of visual acuity, slit-lamp examination, fundoscopy, and optical coherence tomography. Discontinue erdafitinib when CSR occurs or permanently if CSR does not resolve within 4 weeks or is grade 4. For ocular adverse reactions, follow dosage adjustment guidelines.

2. Hyperphosphatemia and soft tissue mineralization: Erdafitinib can cause hyperphosphatemia, leading to soft tissue mineralization, skin calcinosis, non-uremic calcium allergy, and vascular calcification. The increase in phosphate levels is a pharmacodynamic effect of erdafitinib. Monitor for hyperphosphatemia throughout treatment. In all patients, limit phosphate intake to 600-800 mg per day, and if serum phosphate is greater than 7.0 mg/dL, consider adding an oral phosphate binder until serum phosphate levels return to <5.5 mg/dL.

3. Embryo-fetal toxicity: Based on the mechanism of action and findings in animal reproduction studies, erdafitinib can cause fetal damage when administered to pregnant women. In an embryo-fetal toxicity study, oral administration of erdafitinib to pregnant rats during organogenesis resulted in malformations and embryo-fetal death at maternal exposures below the maximum recommended human dose, based on the area under the curve (AUC). Inform pregnant women of potential risks to the fetus. Advise female patients of reproductive potential to use effective contraception during treatment with erdafitinib and for one month after the last dose. Advise male patients with a female partner of reproductive potential to use effective contraception during treatment with erdafitinib and for one month after the last dose.

The original version of erdafitinib has not yet been launched in China, so it cannot be covered by medical insurance. The original version of erdafitinib currently sold in Hong Kong may cost more than 20,000 yuan per box of specifications 4mg*14 tablets (the price may fluctuate due to exchange rates). Cheaper erdafitinib generic drugs produced by other pharmaceutical factories are also sold overseas. The pharmaceutical ingredients are basically the same as those of the original drug. For example, the price of 4mg*60 tablets produced by a Bangladeshi pharmaceutical factory may be more than 3,000 yuan per box (the price may fluctuate due to exchange rates).