On April 12, 2019, the FDA accelerated the approval of erdafitinib (Balversa; Janssen), a fibroblast growth factor receptor (FGFR) kinase inhibitor, for the treatment of adults with locally advanced or metastatic urothelial carcinoma and FGFR3 or FGFR2 genetic alterations, as detected by an FDA-approved test, whose disease progressed during or after ≥1 lines of platinum-containing chemotherapy, making it the first targeted drug to receive approval for this patient population.
On the same day, the FDA approved the companion diagnostic test, therascreen FGFR RGQ RT-PCR Kit, to identify patients with bladder cancer and FGFR3 alterations who are candidates for erdafitinib therapy.
“We’re in an era of more personalized or precision medicine, and the ability to target cancer treatment to a patient’s specific genetic mutation or biomarker is becoming the standard, with advances being made in new disease types. Today’s approval represents the first personalized treatment targeting susceptible FGFR genetic alterations for patients with metastatic bladder cancer,” said Richard Pazdur, MD, Director of the FDA’s Oncology Center of Excellence. “FGFRs regulate important biological processes including cell growth and division during development and tissue repair. This drug works by targeting genetic alterations in FGFRs,” Dr Pazdur added.
The FDA approval of erdafitinib was based on results from a phase 2, multicenter, single-arm clinical trial of 87 patients with FGFR3- or FGFR2-positive, locally advanced or metastatic bladder cancer that had progressed during or after ≥1 chemotherapies and had at least 1 of the following genetic alterations: FGFR3 gene mutations (R248C, S249C, G370C, Y373C) or FGFR gene fusions (FGFR3-TACC3, FGFR3-BAIAP2L1, FGFR2-BICC1, FGFR2-CASP7).
The objective response rate was 32.2% (95% confidence interval [CI], 22.4-42.0), including 2.3% complete response, in patients who received erdafitinib, and the median duration of response was 5.4 months (95% CI, 4.2-6.9). Responses to erdafitinib were observed even among patients who had not responded to previous anti–PD-L1/PD-1 therapy. However, there were no confirmed responses to erdafitinib in patients with the FGFR2 fusion.
The most common (≥10%) adverse effects, including laboratory abnormalities, reported with erdafitinib included increased phosphate level, stomatitis, fatigue, increased creatinine level, diarrhea, dry mouth, onycholysis, increased alanine aminotransferase level, increased alkaline phosphatase level, decreased sodium level, decreased appetite, decreased albumin level, altered sense of taste, decreased hemoglobin level, and dry skin.