FGFR2/3 Gene Alterations and Clinical Outcomes in Advanced/Metastatic Urothelial Cancer in Japan: MONSTAR-SCREEN Database Study.

Advanced/metastatic urothelial cancer (a/m UC) still has a poor prognosis despite the recent medical advances. Recent studies demonstrated that fibroblast growth factor receptor (FGFR) gene alterations (GAs) may be driver genes for UC; however, the proportion of UC genetic panel testing in Japan remains low. We clarified the proportion of patients with FGFR2/3 GAs, treatment patterns, and clinical outcomes in a/m UC patients in Japan. This study was a descriptive epidemiological study using the MONSTAR-SCREEN database, and 138 patients with a/m UC were evaluated. The primary endpoint was the proportion of patients with FGFR2/3 GAs. The secondary endpoints included treatment patterns, clinical outcomes, genomic status before and after treatment, etc. The proportion of FGFR GA-positive patients in a/m UC was 11.9%. The most common FGFR mutation variant and fusion gene were S249C (4.4%) and FGFR3-TACC3 fusion (3.7%), respectively. Fifty-one patients were tested two or more times; a few changes were observed in the FGFR GA status, regardless of the treatment regimen. Co-occurrence association was observed in FGFR1 with TET2, and in FGFR3 with CHEK2 or MLL2. During the first-, second-, and third-line treatment, median progression-free survival (PFS) of GA-positive patients was 7.3, 2.9, and 6.2 months, while for GA-negative patients, 6.9, 3.1, and 6.9 months, respectively. This study revealed that one in eight a/m UC patients had FGFR2/3 GAs, and a few changes were observed in FGFR GA status before and after treatment. Genetic testing will be beneficial for the selection of appropriate treatments after a diagnosis of a/m UC.