Erdafitinib

Prescription oncology drug used under specialist supervision. Common effects include high blood phosphate, mouth sores, dry mouth, nail and skin changes, and eye issues affecting the retina, all of which are actively monitored. It is not a lifestyle or performance compound.

Erdafitinib (Balversa) is a substrate of CYP2C9 and CYP3A4; strong or moderate inhibitors of these enzymes (for example itraconazole for CYP3A4 or fluconazole for CYP2C9) increase erdafitinib exposure and toxicity, while strong inducers decrease its exposure and can reduce efficacy, so the label advises avoiding or carefully managing such combinations. Because dose titration depends on serum phosphate, the label directs avoiding agents that alter phosphate levels during the first weeks of therapy. Erdafitinib also inhibits P-glycoprotein and organic cation transporter 2 (OCT2), so it can raise concentrations of sensitive substrates such as digoxin or metformin; these should be separated or monitored. This is research information, not medical advice.

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Erdafitinib originated as a pan-FGFR tyrosine kinase inhibitor discovered through a collaboration between Astex Pharmaceuticals and Janssen, a Johnson & Johnson company, and carried the development code JNJ-42756493. Janssen advanced it in tumors driven by FGFR alterations, and in April 2019 the US Food and Drug Administration granted it accelerated approval under the brand name Balversa for locally advanced or metastatic urothelial carcinoma with susceptible FGFR2 or FGFR3 alterations, making it the first FGFR inhibitor approved for that indication. The approval was paired with a companion diagnostic to select patients, and the agency later converted it to full approval on the basis of confirmatory trial data. Erdafitinib remains a marketed oncology drug used within genetically defined bladder cancer populations.