On January 19, 2024, the Food and Drug Administration approved erdafitinib for adult patients with locally advanced or metastatic urothelial carcinoma (mUC) with susceptible FGFR3 genetic alterations, as determined by an FDA-approved companion diagnostic test, whose disease has progressed on or after at least one line of prior systemic therapy. Erdafitinib is not recommended for the treatment of patients who are eligible for and have not received prior PD-1 or PD-L1 inhibitor therapy. This approval amends the indication previously granted under accelerated approval for patients with mUC with susceptible FGFR3 or FGFR2 alterations after prior platinum-containing chemotherapy.

Full prescribing information for erdafitinib will be posted here.

Efficacy was evaluated in Study BLC3001 Cohort 1, a randomised, open-label trial of 266 patients with mUC harbouring selected FGFR3 alterations who had received 1-2 prior systemic treatments, including a PD-1 or PD-L1 inhibitor. Patients were randomised 1:1 to receive erdafitinib or investigator’s choice of chemotherapy (docetaxel or vinflunine). Randomisation was stratified by region, performance status, and presence of visceral or bone metastases. FGFR3 alterations were identified from tumour tissue in a central laboratory by the therascreen FGFR RGQ RT-PCR kit (Qiagen) in 75% of patients, while the remainder were identified by local next-generation sequencing assays.

The major efficacy outcome measure was overall survival (OS). Investigator-assessed progression-free survival (PFS) and objective response rate (ORR) were additional outcome measures.

Statistically significant improvements in OS, PFS, and ORR were demonstrated for erdafitinib compared with chemotherapy. Median OS was 12.1 months (95% CI: 10.3, 16.4) for patients who received erdafitinib and 7.8 months (95% CI: 6.5, 11.1) for those who received chemotherapy (hazard ratio [HR] 0.64 [95% CI: 0.47, 0.88]; p-value=0.0050). Median PFS was 5.6 months (95% CI: 4.4, 5.7) for patients who received erdafitinib and 2.7 months (95% CI: 1.8, 3.7) for those who received chemotherapy (HR 0.58 [95% CI: 0.44, 0.78]; p-value=0.0002). Confirmed ORR was 35.3% (95% CI: 27.3, 43.9) for those who received erdafitinib and 8.5% (95% CI: 4.3, 14.6) for those who received chemotherapy (p-value<0.001).

The most common (>20%) adverse reactions, including laboratory abnormalities, were increased phosphate, nail disorders, diarrhoea, stomatitis, increased alkaline phosphatase, decreased haemoglobin, increased alanine aminotransferase, increased aspartate aminotransferase, decreased sodium, increased creatinine, dry mouth, decreased phosphate, palmar-plantar erythrodysesthesia syndrome, dysgeusia, fatigue, dry skin, constipation, decreased appetite, increased calcium, alopecia, dry eye, increased potassium, and decreased weight.

The recommended erdafitinib dose is 8 mg orally once daily, with a dose increase to 9 mg once daily based on tolerability, including hyperphosphatemia, at 14 to 21 days. Treatment should continue until disease progression or unacceptable toxicity.

Source: FDA