Erdafitinib
FGFR inhibitors
FGFR inhibitorsHigh alert
An error with this medicine can cause serious harm: double checks and protocols are used.Pregnancy: avoid
Avoid in pregnancy. Erdafitinib may harm the fetus: a pregnancy test may be done first, contraception is used during treatment and for a month after, and breastfeeding is stopped.
An oral pan-FGFR inhibitor for urothelial cancer with FGFR3 changes. Raises blood phosphate and harms the eyes, skin and nails.
Quick facts
- Group
- FGFR inhibitors
- Target
- Fibroblast growth factor receptor kinases (FGFR1–4)
- Used for
- Locally advanced
- Key effects
- High blood phosphate · Mouth sores · Diarrhoea
- Monitor
- FGFR3 alteration test before starting · Skin
- ATC
- L01EN01
No doses: the clinician sets them by the current guideline.
Mechanism of action
The crystal shows erdafitinib (code JNJ-42756493) in the ATP site of the human FGFR1 kinase domain; in urothelial cancer the main target is FGFR3, whose site is very similar.
Some urothelial cancers depend on mutated or fused FGFR3. Erdafitinib occupies the ATP site of FGFR1, 2, 3 and 4 and blocks their signalling, so tumour cells stop growing and die. FGFR inhibition also raises blood phosphate: an expected on-target effect, not an off-target toxicity.
- Erdafitinib fills the ATP site of FGFR1–4
- FGFR3-driven tumour signalling stops
- FGFR blockade raises blood phosphate (on-target)
Indications
- Locally advanced or metastatic urothelial carcinoma with susceptible FGFR3 alterations that progressed after at least one prior systemic therapy. Bladder cancer →
Adverse effects
Common
- High blood phosphate
- Mouth sores, dry mouth, taste change
- Diarrhoea, nausea, decreased appetite
- Dry skin, hand-foot reactions, nail changes
- Dry eyes, hair loss, fatigue
Contraindications
- Hypersensitivity to erdafitinib
Key interactions
- Phosphate-rich foods and phosphate supplements
- Worsen hyperphosphataemia; a low-phosphate diet may be advised.
What is monitored
- FGFR3 alteration test before starting
- Serum phosphate, especially early in treatment
- Eye examinations, including the retina, regularly
- Skin, nails and mouth
Administration and safety
- Oral tablets swallowed whole, not split, chewed or crushed.
- If vomiting follows a dose, no extra dose is taken.
- Artificial tears or lubricating eye drops are often used.
Pregnancy and breastfeeding
Avoid in pregnancy. Erdafitinib may harm the fetus: a pregnancy test may be done first, contraception is used during treatment and for a month after, and breastfeeding is stopped.
Nursing care
- Teach to report blurred vision or other vision changes at once.
- Explain the low-phosphate diet if ordered, and check phosphate results.
- Teach skin and nail care and to report painful, cracked skin or nail changes.
- Contraception during treatment and for a month after; breastfeeding is stopped.
Pharmacokinetics
- Absorption
- Oral tablets once a day, with or without food.
Test yourself
Think of the answer, then tap the question to see it.
Which FGFR gene is altered in tumours treated with erdafitinib?
FGFR3 (urothelial carcinoma).
Is the high blood phosphate on erdafitinib an off-target effect?
No: it is an expected on-target consequence of FGFR inhibition.
Which organ requires regular examinations on erdafitinib?
The eye (retina), for central serous retinopathy.
Connections
← Back to the class: FGFR inhibitors
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Erdafitinib: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); Erdafitinib - NCI (National Cancer Institute, 2024); RCSB PDB - 5EW8: FIBROBLAST GROWTH FACTOR RECEPTOR 1 IN COMPLEX WITH JNJ-4275693 (RCSB Protein Data Bank, 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.