targetsTarget

FGFR3

A growth-factor receptor that is mutated or fused in a sizeable minority of bladder cancers. Erdafitinib blocks it and is the first targeted drug approved for urothelial cancer selected by a genomic test.

FGFR3 activating mutations and FGFR3::TACC3 fusions drive a subset of urothelial carcinomas, especially the luminal-papillary type, and are also common in non-invasive bladder tumours. Erdafitinib, a pan-FGFR inhibitor, received accelerated US approval in 2019 for FGFR3- or FGFR2-altered advanced urothelial cancer and full approval in 2024 after the THOR trial showed a survival benefit over chemotherapy in patients previously treated with a checkpoint inhibitor. Hyperphosphataemia, from FGFR1 blockade in the kidney, and eye toxicity are the class effects. FGFR3-altered tumours tend to be immunologically cold, which shapes the debate about sequencing targeted therapy and immunotherapy.

FGFR3: what it is and how drugs act on it · animated generic schematic, not to scale

Target · the protein and the cell it sits on
Drug · antibody, small molecule, cell or radioligand
Effect · signal, damage or kill

In plain words · A growth-factor receptor that is mutated or fused in a sizeable minority of bladder cancers. Erdafitinib blocks it and is the first targeted drug approved for urothelial cancer selected by a genomic test.

1 · What it is
A growth-factor receptor that is mutated or fused in a sizeable minority of bladder cancers. Erdafitinib blocks it and is the first targeted drug approved for urothelial cancer selected by a genomic test.
2 · What goes wrong in cancer
Receptor tyrosine kinase for fibroblast growth factors; activating point mutations (S249C, Y373C) and TACC3 fusions in urothelial carcinoma.
3 · How drugs use it
No product in this corpus aims at FGFR3 yet. Kinases are switched on by binding ATP inside the cell, so most drugs are small molecules shaped to plug that ATP pocket.

Full dossier: hotspots, trials, resistance, assays, models, open questions →

External identifiers

FGFR3HGNCEnsemblUniProtAlphaFold DBOpen TargetsCIViCOncoKBCOSMICcBioPortalDepMapHuman Protein AtlasNCBI Gene

Biology

Receptor tyrosine kinase for fibroblast growth factors; activating point mutations (S249C, Y373C) and TACC3 fusions in urothelial carcinoma.

Where it is found

Urothelial carcinoma, most often luminal-papillary and non-invasive tumours
Multiple myeloma with t(4;14)

Class

kinase · FGFR3

How often this target appears

Cancer	Prevalence	Measure	Note	Source
Bladder & urothelial cancer	15-20%	FGFR3 mutation or FGFR2/3 fusion in advanced urothelial carcinoma	The BLC2001 trial of erdafitinib enrolled patients with these alterations, which its report describes as present in roughly a fifth of advanced urothelial carcinomas.	doi.org

Approximate, population-level figures; the measure column says what was counted. Ranges show the midpoint as a bar.