On 12 April 2019, the FDA granted accelerated approval to erdafitinib (Balversa®, Janssen) for the treatment of locally advanced or metastatic urothelial carcinoma progressed during or following a platinum-containing regimen, including progression within 12 months of (neo)adjuvant platinum-based chemotherapy, and whose tumours harbour susceptible fibroblast growth factor receptor (FGFR) 3 or FGFR2 genetic alterations as determined by the FDA approved companion diagnostic (CDx), the therascreen® FGFR RGQ RT-PCR Kit by Qiagen.

BLC2001

The FDA approval was based on a cohort of 87 patients from the multicentre, open-label, single-arm BLC2001 study (NCT02365597) with locally advanced or metastatic urothelial carcinoma. All patients had progressed on or after at least one prior chemotherapy and had certain FGFR3 gene mutations or FGFR2 or FGFR3 gene fusions. 

The patients were treated with erdafitinib until disease progression or unacceptable toxicity, and dosing was adjusted to the patient’s serum phosphate levels. The efficacy measures included the objective response rate (ORR) by a blinded independent review committee (BIRC) using RECIST1.1. 

The ORR was 32.2% (95% CI, 22.4-42.0) with complete and partial responses in 2.3% and 29.9% of patients, respectively. The median duration of response was 5.4 months (95% CI, 4.2-6.9). Notably, among the responders were patients who had previously not responded to immunotherapy with anti-programmed death 1 (PD-1) or anti-PD-1 ligand (PD-L1) therapy. 

Safety

Common adverse reactions reported ≥40% of erdafitinib-treated patients included increased serum phosphate, stomatitis, fatigue, increased serum creatinine, diarrhoea, dry mouth, onycholysis, increased alanine aminotransferase, increased alkaline phosphatase, and decreased sodium. Erdafitinib can cause ocular disorders. Around 25% of patients experienced central serous retinopathy or retinal pigment epithelial detachment resulting in visual field defect.

Full prescribing information Balversa®