Prognostic Value and Clinical Significance of FGFR Genomic Alterations (GAs) in Metastatic Urothelial Cancer Patients

Fibroblast growth factor receptor (FGFR) genomic alterations (GAs) represent an actionable target, key to the pathogenesis of some urothelial cancers (UCs). Though FGFR GAs are common in noninvasive UC, little is known about their role in the metastatic(m) setting and response to therapy. This study aimed to assess the impact of FGFR alterations on sensitivity to systemic treatments and survival and to validate Bajorin’s and Bellmunt’s prognostic scores in mUC patients according to their FGFR status. We retrospectively analyzed data from 98 patients with tumor-sequenced UC who received treatment between January 2010 and December 2020. Up to 77 developed metastatic disease and were deemed the study population. Twenty-six showed FGFR GAs. A trend toward a better response to cisplatin and checkpoint inhibitors was suggested favoring FGFR GA tumors. FGFR GA patients who received an FGFR inhibitor as first-line had poorer responses compared with other options (20% vs. 68.4%, p = 0.0065). Median PFS was 6 vs. 5 months in the FGFR GA vs. FGFR WT cohort (p = 0.71). Median OS was significantly worse in the FGFR GA vs. FGFR WT cohort (16.2 vs. 31.9 months, p = 0.045). Multivariate analyses deemed FGFR GAs as a factor independently associated with the outcome (HR 2.59 (95% CI 1.21–5.55)). Bajorin’s model correctly predicted clinical outcomes in the whole study population but not in FGFR GA cases. FGFR GAs are a relevant biomarker in mUC that could condition the response to systemic therapy. New prognostic models, including this molecular determination, should be designed and validated.

Fibroblast Growth Factor Receptor 3 Alteration Status is Associated with Differential Sensitivity to Platinum-based Chemotherapy in Locally Advanced and Metastatic Urothelial Carcinoma

BACKGROUND

Alterations in fibroblast growth factor receptor 3 (FGFR3) occur in ∼15% of muscle-invasive bladder cancers (MIBCs) and metastatic urothelial carcinomas (mUCs).

OBJECTIVE

To determine the association between FGFR3 status and response to platinum-based chemotherapy in patients with MIBC or mUC.

DESIGN, SETTING, AND PARTICIPANTS

The authors conducted a retrospective review and comparison of patients having (1) MIBC treated with neoadjuvant chemotherapy (NAC), (2) mUC treated with first-line platinum-based chemotherapy (M1 cohort), and (3) MIBC who were from The Cancer Genome Atlas (TCGA).

INTERVENTION

Platinum-based chemotherapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Pathologic response, recurrence-free (RFS) or progression-free (PFS) survival, and overall survival (OS) were compared between patients with FGFR3 alteration (FGFR3alt) and those without it (FGFR3wild type [FGFR3wt]) in the three cohorts.

RESULTS AND LIMITATIONS

Nine of 72 NAC patients (13%) had FGFR3alt, of whom none had pathologic complete response and three had residual non-MIBC (carcinoma in situ, n = 1; pT1, n = 2). FGFR3alt was associated with shorter RFS (hazard ratio, 2.74; p = 0.044) but not OS. Among TCGA patients who underwent adjuvant chemotherapy (n = 74), FGFR3alt patients had shorter RFS as well. Conversely, among chemotherapy-naive TCGA patients, FGFR3alt was associated with longer RFS and OS. In the M1 cohort (FGFR3alt, n = 27; FGFR3wt, n = 81), FGFR3alt was associated with higher rates of pulmonary metastases and nonregional lymphadenopathy. Despite lower response rates among FGFR3alt patients (37% vs 49%; p = 0.056), PFS and OS were not significantly different from FGFR3wt patients.

CONCLUSIONS

FGFR3 status is associated with lower responses to platinum-based chemotherapy, which may prompt exploration of nonchemotherapeutic approaches for perioperative management of FGFR3alt urothelial cancers.

PATIENT SUMMARY

Approximately 15% of bladder cancers harbor mutations in the fibroblast growth factor receptor 3 (FGFR3) gene. Our findings suggest that FGFR3 mutations might be associated with lower responses and shorter time to recurrence among patients with muscle-invasive bladder cancer who received perioperative platinum-based chemotherapy. FGFR3 status does not significantly impact response to chemotherapy among those with metastatic urothelial cancers.

Urothelial carcinoma: the development of FGFR inhibitors in combination with immune checkpoint inhibitors

INTRODUCTION

The recent approval of erdafitinib and the emergence of other potent and selective fibroblast growth factor receptor (FGFR) inhibitors (FGFRi's) are shifting the treatment paradigm for patients with advanced urothelial carcinoma (UC) harboring FGFR3 alterations. Whether such therapies can, and should, be combined with immune checkpoint inhibitors (ICI's) is an area of major research interest. Areas covered: Herein, we review the FGFR signaling pathway and impact of altered FGFR signaling on UC tumorigenesis, the clinical development of FGFRi's, the rationale for FGFRi-ICI combinations, current trials, and future directions. Expert opinion: FGFR3 altered UCs are not less responsive to ICI's compared with FGFR3 wild-type (WT) tumors. However, FGFR3 altered tumors may exhibit distinct immunobiology compared with WT tumors that could potentially be exploited therapeutically. Given these considerations along with the clinical non-cross resistance of these therapeutic classes, clinical investigation of regimens combining FGFR3i and ICI is warranted.

The future of bladder cancer therapy: Optimizing the inhibition of the fibroblast growth factor receptor

Therapeutic options for metastatic bladder cancer (BC) have seen minimal evolution over the past 30 years, with platinum-based chemotherapy remaining the mainstay of standard of care for metastatic BC. Recently, five immune checkpoint inhibitors (ICIs) have been approved by the FDA as second-line therapy, and two ICIs are approved as first-line treatment in selected patients. Molecular alterations of muscle-invasive bladder cancer (MIBC) have been reported by The Cancer Genome Atlas. About 15% of patients with MIBC have molecular alterations in the fibroblast growth factor (FGF) axis. Several ongoing trials are testing novel FGF receptor (FGFR) inhibitors in patients with FGFR genomic aberrations. Recently, erdafitinib, a pan-FGFR inhibitor, was approved by the FDA in patients with metastatic BC who have progressed on platinum-based chemotherapy. We reviewed the literature over the last decade and provide a summary of current knowledge of FGF signaling, and the prognosis associated with FGFR mutations in BC. We cover the role of FGFR inhibition with non-selective and selective tyrosine kinase inhibitors as well as novel agents in metastatic BC. Efficacy and safety data including insights from mechanism-based toxicity are reported for selected populations of metastatic BC with FGFR aberrations. Current strategies to managing resistance to anti-FGFR agents is addressed, and the importance of developing reliable biomarkers as the therapeutic landscape moves towards an individualized therapeutic approach.

Targeting FGFR in bladder cancer: ready for clinical practice?

Objective: To give a brief literature overview of current knowledge regarding FGFR inhibition in bladder cancer.Background: The deeper molecular understanding of bladder urothelial carcinoma (UC) has reshaped the diagnostic and therapeutic landscape of this malignancy. Rapid technological development, including the frequent use of next-generation sequencing (NGS) in clinical practice, has boosted identification and development of potential biomarkers and targeted therapies. Genetic aberrations in the fibroblast growth factor receptor (FGFR)-pathway may drive tumorigenesis and are considered as attractive drug targets in advanced and/or metastatic UC. Several clinical trials have been performed or are ongoing to assess the safety and efficacy of (non-)selective FGFR inhibitors in patients with advanced or metatastic UC.Results: While non-selective FGFR inhibitors have shown limited clinical response with unacceptable toxicity, selective 'pan'-FGFR inhibitors had favourable response rates with manageable toxicity. To predict response, patients were screened for FGFR aberrations using NGS after DNA/RNA extraction of UC tissue specimen or collection of ctDNA or cfDNA.Conclusion: Early clinical trials have shown promising results for targeting FGFR in advanced or metastatic UC, though these findings need to be validated in phase III trials. It seems that FGFR aberrations can be detected in ctDNA and cfDNA as efficiently as in tumour tissue, showing their potential as predictive, non-invasive liquid biomarkers.