Erdafitinib

How it works

It inhibits FGFR1-4 kinase activity, blocking downstream signalling that drives proliferation and survival in tumours harbouring activating FGFR mutations or fusions.

Prescribing in practice

• Central serous retinopathy and other retinal pigment epithelial detachments can cause visual disturbance, so ophthalmological assessment is required at baseline and periodically, with dose interruption if visual symptoms occur.
• Hyperphosphataemia is an expected on-target effect that is used to guide dose titration and may require phosphate-lowering measures and dietary restriction.
• It is given only to patients with confirmed susceptible FGFR alterations and carries a risk of fetal harm, so effective contraception is needed.

Monitoring

Monitor serum phosphate to guide dosing, perform regular ophthalmic (including OCT) examinations, and check for nail and skin toxicity and stomatitis during treatment.

Counselling the patient

• Report any change in vision, blurring or seeing spots promptly.
• Follow advice on diet and phosphate-lowering treatment if your phosphate level rises.
• Use reliable contraception and report dry mouth, mouth ulcers or nail changes.

Evidence & guidelines

Erdafitinib's benefit in FGFR-altered advanced urothelial cancer is based on clinical trial data and reflected in its licensed indication and biomarker-restricted use.