Erdafitinib (Balversa) is a kinase inhibitor indicated for the treatment of adult patients with locally advanced or metastatic urothelial carcinoma harbouring susceptible FGFR3 or FGFR2 genetic alterations, which has progressed during or following at least one line of platinum-containing chemotherapy.
Dosage and Administration of Erdafitinib (Balversa)
Recommended Dosage and Administration Regimen
Initial dose: The recommended starting dose is 8 mg orally once daily (equivalent to two 4 mg tablets).
Dose escalation: Serum phosphate levels should be assessed between Day 14 and Day 21 after the initiation of treatment. If the serum phosphate level is below 5.5 mg/dL and the patient has no ocular disorders or adverse reactions of Grade 2 or higher, the dose should be increased to 9 mg orally once daily.
Administration method: Tablets should be swallowed whole, with or without food.
Duration of treatment: Treatment should continue until disease progression or unacceptable toxicity occurs.
Management of Missed Dose and Vomiting
Missed dose: If a dose is missed, take the missed dose as soon as remembered on the same day, and resume the normal dosing schedule the next day. Do not take an extra dose to make up for the missed one.
Vomiting after administration: If vomiting occurs after taking a dose, do not take a replacement dose. Resume the next scheduled dose on the following day as planned.
Dose Modification of Erdafitinib (Balversa)
Management of Hyperphosphatemia
Elevated serum phosphate is a pharmacodynamic effect of erdafitinib. All patients are recommended to limit daily phosphate intake to 600–800 mg.
If serum phosphate levels are between 7.0–9.0 mg/dL, interrupt treatment and monitor weekly until levels return to < 5.5 mg/dL, then treatment can be resumed at the original dose. If hyperphosphatemia persists for more than 1 week, dose reduction may be considered.
If levels are > 9.0 mg/dL, interrupt treatment until recovery, then restart at one dose level lower.
If levels are > 10.0 mg/dL or accompanied by significant changes in renal function or Grade 3 hypercalcemia, interrupt treatment until recovery, then restart at two dose levels lower.
Dose Modification for Ocular Disorders
Erdafitinib can cause ocular disorders such as central serous retinopathy/retinal pigment epithelial detachment.
Grade 1 (asymptomatic): Interrupt treatment until resolution. If resolved within 4 weeks, restart at one dose level lower; dose escalation may be considered subsequently.
Grade 2 (visual acuity 20/40 or better): Interrupt treatment until resolution, then restart at one dose level lower.
Grade 3 (visual acuity worse than 20/40): Interrupt treatment until resolution, then restart at two dose levels lower. If recurrence occurs, permanent discontinuation should be considered.
Grade 4 (visual acuity 20/200 or worse): Discontinue treatment permanently.
Use in Special Populations of Erdafitinib (Balversa)
Pregnant Women
Based on its mechanism of action and animal study data, erdafitinib has potential fetal hazards and may cause fetal malformation and death.
Pregnant women and women of reproductive potential should be informed of the risks to the fetus.
Women of reproductive potential are recommended to use effective contraceptive measures during treatment and for one month after the last dose.
Lactating Women
There are no data available on whether erdafitinib is excreted in human milk or its effects on breastfed infants.
Due to the potential risk of serious adverse reactions in breastfed infants, women are advised not to breastfeed during treatment and for one month after the last dose.
Men and Women of Reproductive Potential
Women: Pregnancy testing is recommended prior to treatment. Effective contraception must be used during treatment and for one month after the last dose.
Men: Male patients with female partners of reproductive potential are recommended to use effective contraception during treatment and for one month after the last dose.
Infertility: Animal studies have shown that erdafitinib may impair fertility in females.
