Erdafitinib has been primarily approved for locally advanced or metastatic urothelial carcinoma (UC), a malignant tumor of the urinary system, including bladder cancer. It is indicated for use in patients whose tumors have FGFR2 or FGFR3 genetic alterations vulnerable to this form of treatment. These modifications are detected by means of genetic testing, so that the treatment is directed at patients most likely to profit from it.