On April 15, the U.S. Food and Drug Administration (FDA) granted accelerated approval to erdafitinib (Balversa) for patients with locally advanced or metastatic urothelial carcinoma with susceptible FGFR3 or FGFR2 genetic alterations that has progressed during or following platinum-containing chemotherapy, including within 12 months of neoadjuvant or adjuvant platinum-containing chemotherapy.
Patients should be selected for therapy based on an FDA-approved companion diagnostic for erdafitinib. Today, the FDA also approved the therascreen FGFR RGQ RT-PCR kit, developed by QIAGEN, for use as a companion diagnostic for this therapeutic indication.
Erdafitinib approval was based on data from a cohort of 87 patients enrolled in Study BLC2001 (ClinicalTrials.gov identifier: NCT02365597), a multicenter, open-label, single-arm trial. These patients had locally advanced or metastatic urothelial carcinoma that had progressed on or after at least one prior chemotherapy and had certain FGFR3 gene mutations or FGFR2 or FGFR3 gene fusions.
Patients received erdafitinib at a starting dose of 8 mg once daily with a dose increase to 9 mg daily in those whose serum phosphate levels were below the target of 5.5 mg/dL, between days 14 and 17. The starting dose was increased to 9 mg daily in 41% of the patients. Erdafitinib was administered until disease progression or unacceptable toxicity.
The major efficacy outcome measure was objective response rate (ORR) as determined by blinded independent review committee according to Response Evaluation Criteria in Solid Tumors, version 1.1. The ORR was 32.2% (95% confidence interval [CI] = 22.4%–42.0%), with complete responses in 2.3% of patients and partial responses in 29.9%. The median response duration was 5.4 months (95% CI = 4.2–6.9 months). Responders included patients who had previously not responded to anti–programmed cell death ligand 1 or programmed cell death protein 1 treatment.
Erdafitinib can cause ocular disorders. For example, central serous retinopathy or retinal pigment epithelial detachment resulting in visual field defect was reported in 25% of patients.
The most common adverse reactions reported in at least 40% of patients were increased serum phosphate, stomatitis, fatigue, increased serum creatinine, diarrhea, dry mouth, onycholysis, increased alanine aminotransferase, increased alkaline phosphatase, and decreased sodium.