The rogaratinib treatment group had 87 patients, while the chemotherapy group had 88 patients. Overall, 10.9% of the cohort also harbored mutations in PIK3CA or RAS. The median follow-up duration was 10.8 months, while the median treatment duration was 12 weeks for rogaratinib and 9.4 weeks for chemotherapy. The objective response rate was 20.7% in the rogaratinib group and 19.3% in the chemotherapy group. Among those who responded to treatment, 66.7% of those in the rogaratinib group and 52.9% of those in the chemotherapy group had previously received immunotherapy. The median duration of response was 4.9 months for rogaratinib and 5.8 months for chemotherapy. Median overall survival was 8.3 months for rogaratinib and 9.8 months for chemotherapy. Post hoc analysis revealed four distinct hotspot mutations in FGFR3 and two fusions in patients with FGFR3 overexpression.
Grade 3 treatment-emergent adverse events (TEAE) occurred in 43% of patients on rogaratinib and 39% of patients on chemotherapy. The incidence of grade 4 TEAEs was 4.7% and 18.3% in the rogaratinib and chemotherapy groups, respectively. Retinal events occurred in 30.2% of rogaratinib patients and 3.7% of chemotherapy patients. Interestingly, grade 2 retinal disorders only occurred in the rogaratinib group (7%). These events included retinal pigment epithelium detachment and retinopathy. Grade 5 TEAEs were observed in 16.3% and 6.1% of rogaratinib and chemotherapy groups, respectively. The most common TEAEs that led to dose modification were hyperphosphatemia and diarrhea in the rogaratinib group and neutropenia and fatigue in the chemotherapy group. Adverse events led to permanent treatment discontinuation in 17.4% of patients on rogaratinib and 11% on chemotherapy. No rogaratinib-related deaths occurred. Importantly, TEAE occurrence was equivalent to those on the initial dose of rogaratinib and the reduced dose.
Overall, there were no significant differences in objective response rates between rogaratinib and chemotherapy treatment groups. The study could not proceed to phase III due to a failure to meet prespecified efficacy criteria. Moreover, although researchers initially had a secondary objective of clarifying the effect of PIK3CA or RAS mutations on response to FGFR inhibition, they were unable to do so due to the small number of patients harboring these mutations. Nevertheless, the potential benefit of rogaratinib treatment among patients with genetic alteration in and overexpression of FGFR3 was promising and requires additional validation.
Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine
References:
- Sternberg CN, Petrylak DP, Bellmunt J, et al. FORT-1: Phase II/III Study of Rogaratinib Versus Chemotherapy in Patients With Locally Advanced or Metastatic Urothelial Carcinoma Selected Based on FGFR1/3 mRNA Expression [published online ahead of print, 2022 Oct 14]. J Clin Oncol. 2022;JCO2102303. doi:10.1200/JCO.21.02303