Targeting FGFR3 alterations with adjuvant infigratinib in invasive urothelial carcinoma: the phase III PROOF 302 trial

Case report: a case of lung squamous cell carcinoma with a novel FGFR3-IER5L fusion mutation responding to anlotinib

Lung squamous cell carcinoma (LUSC) is the second most common pathological type of non-small cell lung cancer (NSCLC). However, compared with lung adenocarcinoma (LUAD), the incidence of driver gene mutations in LUSC is relatively lower and treatment options for LUSC patients are very limited. We described a LUSC patient with a novel FGFR3-IER5L fusion revealed by next generation sequencing in this report. The patient refused surgery, radiotherapy or chemotherapy and received anlotinib treatment. Anlotinib is a small molecular multi-target tyrosine kinase inhibitor, which can inhibit the activity of kinases including vascular endothelial growth factor receptor 2/3 (VEGFR2/3), fibroblast growth factor receptor 1-4 (FGFR1-4), platelet-derived growth factor receptor α/β (PDGFRα/β), and c-Kit. The patient achieved partial response and the progression-free survival was 3.8 months.

FGFR Inhibition in Urothelial Carcinoma

BACKGROUND AND OBJECTIVE

The 2024 US Food and Drug Administration approval of erdafitinib for the treatment of metastatic urothelial carcinoma (mUC) with FGFR3 alterations ushered in the era of targeted therapy for bladder cancer. In this review, we summarize the effects of FGFR pathway alterations in oncogenesis, clinical data supporting FGFR inhibitors in the management of bladder cancer, and the challenges that remain.

METHODS

Original articles relevant to FGFR inhibitors in urothelial cancer between 1995 and 2024 were systematically identified in the PubMed and MEDLINE databases using the search terms "FGFR" and "bladder cancer". An international expert panel with extensive experience in FGFR inhibitor treatment was convened to synthesize a collaborative narrative review.

KEY FINDINGS AND LIMITATIONS

Somatic FGFR3 alterations are found in up to 70% of low-grade non-muscle-invasive bladder cancers; these activate downstream signaling cascades and culminate in cellular proliferation. Beyond a link to lower-grade/lower-stage tumors, there is little consistency regarding whether these alterations confer prognostic risks for cancer recurrence or progression. FGFR3-altered tumors have been linked to a non-inflamed tumor microenvironment, but paradoxically do not seem to impact the response to systemic immunotherapy. Several pan-FGFR inhibitors have been investigated in mUC. With the introduction of novel intravesical drug delivery systems, FGFR inhibitors are poised to transform the therapeutic landscape for early-stage UC.

CONCLUSIONS AND CLINICAL IMPLICATIONS

With deepening understanding of the biology of bladder cancer, novel diagnostics, and improved drug delivery methods, we posit that FGFR inhibition will lead the way in advancing precision treatment of bladder cancer.

New Advances in Metastatic Urothelial Cancer: A Narrative Review on Recent Developments and Future Perspectives

The standard of care for advanced or metastatic urothelial carcinoma (mUC) was historically identified with platinum-based chemotherapy. Thanks to the advances in biological and genetic knowledge and technologies, new therapeutic agents have emerged in this setting recently: the immune checkpoint inhibitors and the fibroblast growth factor receptor inhibitors as the target therapy for patients harboring alterations in the fibroblast growth factor receptor (FGFR) pathway. However, chasing a tumor's tendency to recur and progress, a new class of agents has more recently entered the scene, with promising results. Antibody-drug conjugates (ADCs) are in fact the latest addition, with enfortumab vedotin being the first to receive accelerated approval by the U.S. Food and Drug Administration in December 2019, followed by sacituzumab govitecan. Many other ADCs are still under investigation. ADCs undoubtedly represent the new frontier, with the potential of transforming the management of mUC treatment in the future. Therefore, we reviewed the landscape of mUC treatment options, giving an insight into the molecular basis and mechanisms, and evaluating new therapeutic strategies in the perspective of more and more personalized treatments.

Targeting FGFR for cancer therapy

The FGFR signaling pathway is integral to cellular activities, including proliferation, differentiation, and survival. Dysregulation of this pathway is implicated in numerous human cancers, positioning FGFR as a prominent therapeutic target. Here, we conduct a comprehensive review of the function, signaling pathways and abnormal alterations of FGFR, as well as its role in tumorigenesis and development. Additionally, we provide an in-depth analysis of pivotal phase 2 and 3 clinical trials evaluating the performance and safety of FGFR inhibitors in oncology, thereby shedding light on the current state of clinical research in this field. Then, we highlight four drugs that have been approved for marketing by the FDA, offering insights into their molecular mechanisms and clinical achievements. Our discussion encompasses the intricate landscape of FGFR-driven tumorigenesis, current techniques for pinpointing FGFR anomalies, and clinical experiences with FGFR inhibitor regimens. Furthermore, we discuss the inherent challenges of targeting the FGFR pathway, encompassing resistance mechanisms such as activation by gatekeeper mutations, alternative pathways, and potential adverse reactions. By synthesizing the current evidence, we underscore the potential of FGFR-centric therapies to enhance patient prognosis, while emphasizing the imperative need for continued research to surmount resistance and optimize treatment modalities.

Genomic Profiling and Molecular Characterisation of Metastatic Urothelial Carcinoma

The clinical management of metastatic urothelial carcinoma (mUC) is undergoing a major paradigm shift; the integration of immune checkpoint inhibitors (ICIs) and antibody-drug conjugates (ADCs) into the mUC therapeutic strategy has succeeded in improving platinum-based chemotherapy outcomes. Given the expanding therapeutic armamentarium, it is crucial to identify efficacy-predictive biomarkers that can guide an individual patient's therapeutic strategy. We reviewed the literature data on mUC genomic alterations of clinical interest, discussing their prognostic and predictive role. In particular, we explored the role of the fibroblast growth factor receptor (FGFR) family, epidermal growth factor receptor 2 (HER2), mechanistic target of rapamycin (mTOR) axis, DNA repair genes, and microsatellite instability. Currently, based on the available clinical data, FGFR inhibitors and HER2-directed ADCs are effective therapeutic options for later lines of biomarker-driven mUC. However, emerging genomic data highlight the opportunity for earlier use and/or combination with other drugs of both FGFR inhibitors and HER2-directed ADCs and also reveal additional potential drug targets that could change mUC management.

Recent advances in cancer-associated fibroblast: Biomarkers, signaling pathways, and therapeutic opportunities

ABSTRACT

Anti-cancer therapies usually focus on tumor cells, but non-tumor stromal components in the tumor microenvironment also play vital roles in tumor initiation and progression, which may be the prognostic factors and potential therapeutic targets. Cancer-associated fibroblasts (CAFs) are the essential component in the tumor environment, exhibiting high heterogeneity in their cell origin and phenotype with diverse functions that influence tumor angiogenesis, immune systems, and metabolism. Single-cell RNA sequencing and genetically engineered mouse models have increased our understanding of CAF diversity, and many subtypes have been defined. However, the precise functions of these subtypes need to be studied and validated. Studies of signaling pathways and epigenetic changes in CAFs facilitate understanding of the phenotypes of CAFs and the crosstalk between tumor cells and CAFs to provide potential therapeutic targets. Some clinical trials, including phase III trials targeting CAFs, have been performed recently. However, few of these trials have generated promising results, which indicates that the complexity of CAFs in the tumor microenvironment remains largely unknown, and in-depth investigations of CAFs should be performed. This review summarizes the research on CAFs, focusing on the heterogeneity of their phenotypes and functions, specific signaling pathways, and the therapeutic strategies involving CAFs. Additionally, we briefly discuss the current technologies commonly used in CAF studies and describe the challenges and future perspectives of CAF research.

A comprehensive overview of selective and novel fibroblast growth factor receptor inhibitors as a potential anticancer modality

The arrival of comprehensive genome sequencing has accelerated the understanding of genetically aberrant advanced cancers and target identification for possible cancer treatment. Fibroblast growth factor receptor (FGFR) gene alterations are frequent findings in various rare and advanced cancers refractive to mainstay chemo-therapy or surgical interventions. Several FGFR inhibitors have been developed for addressing these genetically altered FGFR-harboring malignancies, and some have performed well in clinical trials. In contrast, others are still being investigated in different phases of clinical trials. FDA has approved four anticancer agents such as erdafitinib, pemigatinib, infigratinib, and futibatinib, for clinical use in oncogenic FGFR-driven malignancies. These include cholangiocarcinoma, urothelial carcinoma, and myeloid/lymphoid malignancies. Pemigatinib is the only FGFR inhibitor globally approved (USA, EU, and Japan) and available as a targeted therapy for two types of cancer, including FGFR2 fusion or other rearrangements harboring cholangiocarcinoma and relapsed/refractory myeloid/lymphoid neoplasms with FGFR1 rearrangements. Myeloid/lymphoid neoplasm is the latest area of application added to the therapeutic armamentarium of FGFR inhibitors. Furthermore, futibatinib is the first-in-class covalent or irreversible pan-FGFR inhibitor that has received FDA approval for locally advanced or metastatic intrahepatic cholangiocarcinoma harboring FGFR2 gene aberrations. This review highlights the current clinical progress concerning the safety and efficacy of all the approved FGFR-TKIs (tyrosine kinase inhibitors) and their ongoing investigations in clinical trials for other oncogenic FGFR-driven malignancies.

Targeting FGFR3 signaling and drug repurposing for the treatment of SLC26A2-related chondrodysplasia in mouse model

Background

Mutations in Slc26a2 cause a spectrum of autosomal-recessive chondrodysplasia with a significant and negligible influence on the quality of life. It has been reported that Slc26a2 deficiency triggers the ATF6 branch of the UPR, which may, in turn, activate the negative regulator of the FGFR3 signaling pathway. However, the correlation between the deletion of Slc26a2 and the augmentation of downstream phosphorylation of FGFR3 has not been investigated in vivo.

Methods

First, we constructed Slc26a2 and Fgfr3 double knockout mouse lines and observed gross views of the born mice and histological staining of the tibial growth plates. The second approach was to construct tamoxifen-inducible Cre-ERT2 mouse models to replicate SLC26A2-related non-lethal dysplastic conditions. Pharmacological intervention was performed by administering the FGFR3 inhibitor NVP-BGJ398. The effect of NVP-BGJ398 on chondrocytes was assessed by Alcian blue staining, proliferation, apoptosis, and chondrocyte-specific markers and then verified by western blotting for variations in the downstream markers of FGFR3. The growth process was detected using X-rays, micro-CT examination, histomorphometry staining of growth plates, and immunofluorescence.

Results

Genetic ablation of Fgfr3 in embryonic Slc26a2-deficient chondrocytes slightly attenuated chondrodysplasia. Subsequently, in the constructed mild dysplasia model, we found that postnatal intervention with Fgfr3 gene in Slc26a2-deficient chondrocytes partially alleviated chondrodysplasia. In chondrocyte assays, NVP-BGJ398 suppressed the defective phenotype of Slc26a2-deficient chondrocytes and restored the phosphorylation downstream of FGFR3 in a concentration-dependent manner. In addition, in vivo experiments showed significant alleviation of impaired chondrocyte differentiation, and micro-CT analysis showed a clear improvement in trabecular bone microarchitectural parameters.

Conclusion

Our results suggested that inhibition of FGFR3 signaling pathway overactivation and NVP-BGJ398 has promising therapeutic implications for the development of SLC26A2-related skeletal diseases in humans.

The translational potential of this article

Our data provide genetic and pharmacological evidence that targeting FGFR3 signaling via NVP-BGJ398 could be a route for the treatment of SLC26A2-associated skeletal disorders, which promisingly advances translational applications and therapeutic development.

FGFR Inhibition: Understanding and Overcoming Resistance

SUMMARY

Facchinetti and colleagues provide key insights into the evolution of resistance to fibroblast growth factor receptor (FGFR) inhibitors, including the development of kinase domain mutations and activation of the PI3K-AKT signaling axis. In a separate study, Subbiah and colleagues report extensive preclinical data and initial clinical data for RLY-4008, an FGFR2-selective inhibitor that is poised to minimize toxicity and overcome resistance through greater potency and selectivity. See related article by Facchinetti et al., p. 1998 (5). See related article by Subbiah et al., p. 2012 (7).

Treatment approaches for FGFR-altered urothelial carcinoma: targeted therapies and immunotherapy

The treatment of metastatic urothelial carcinoma has dramatically changed over the past decade with the approval of several therapies from multiple drug classes including immune checkpoint inhibitors, targeted therapies, and antibody drug conjugates. Although next generation sequencing of urothelial carcinoma has revealed multiple recurring mutations, only one targeted therapy has been developed and approved to date. Erdafitinib, a pan-fibroblast growth factor receptor (FGFR) inhibitor, has been approved for treating patients with select FGFR2 and FGFR3 alterations and fusions since 2019. Since then, emerging data has demonstrated efficacy of combining erdafitinib with immunotherapy in treating FGFR-altered urothelial carcinoma. Ongoing trials are evaluating the use of erdafitinib in non-muscle invasive urothelial carcinoma as well as in combination with enfortumab vedotin in the metastatic setting, while other FGFR targeted agents such as infigratinib, AZD4547, rogaratinib and pemigatinib continue to be in development. Future challenges will include strategies to overcome FGFR acquired resistance and efficacy and safety of combination therapies with erdafitinib and other FGFR targeted agents.

Safety and efficacy of the pan-FGFR inhibitor erdafitinib in advanced urothelial carcinoma and other solid tumors: A systematic review and meta-analysis

Objective

This review aimed to comprehensively analyze the safety and efficacy of erdafitinib in treating advanced and metastatic urothelial carcinoma and other solid tumors.

Methods

PubMed, Embase, and ClinicalTrials.gov were searched until 10 February 2022. The safety outcome as adverse events and efficacy outcomes, including objective response rate, stable disease rates, and progressive disease rates, were selected and analyzed by comprehensive meta-analysis version 3.0 and STATA 15.0.

Results

The most common all-grade adverse events were hyperphosphatemia, dry mouth, stomatitis, diarrhea, and dysgeusia. The occurrence of ≥3 adverse events was relatively low, and stomatitis and hyponatremia were the most common. Moreover, eye disorders could not be ignored. Efficacy in urothelial carcinoma patients was obviously better than in other solid tumor patients, with a higher objective response rate (0.38 versus 0.10) and lower progressive disease rate (0.26 versus 0.68). All responses occurred in patients with fibroblast growth factor receptor (FGFR) alteration. In those patients, a specific FGFR alteration (FGFR3-TACC3) was observed to have a maximum response.

Conclusion

Erdafitinib has satisfactory clinical activity for metastatic urothelial carcinoma and other solid tumors, while the toxicity is acceptable. With more RCTs and combination therapy trials published, erdafitinib will be applied widely.

The Roles of miRNAs in Predicting Bladder Cancer Recurrence and Resistance to Treatment

Bladder cancer (BCa) is associated with significant morbidity, with development linked to environmental, lifestyle, and genetic causes. Recurrence presents a significant issue and is managed in the clinical setting with intravesical chemotherapy or immunotherapy. In order to address challenges such as a limited supply of BCG and identifying cases likely to recur, it would be advantageous to use molecular biomarkers to determine likelihood of recurrence and treatment response. Here, we review microRNAs (miRNAs) that have shown promise as predictors of BCa recurrence. MiRNAs are also discussed in the context of predicting resistance or susceptibility to BCa treatment.

Advanced Bladder Cancer: Changing the Treatment Landscape

Bladder cancer is the 10th most common cancer type in the world. There were more than 573,000 new cases of bladder cancer in 2020. It is the 13th most common cause of cancer death with an estimated more than 212,000 deaths worldwide. Low-grade non-muscle-invasive bladder cancer (NMIBC) is usually successfully managed with transurethral resection (TUR) and overall survival for NMIBC reaches 90% according to some reports. However, long-term survival for muscle-invasive bladder cancer (MIBC) and metastatic bladder cancer remains low. Treatment options for bladder cancer have undergone a rapid change in recent years. Immune checkpoint inhibitors (ICI), targeted therapies, and antibody-drug conjugates are available now. As bladder cancer is genetically heterogeneous, the optimization of patient selection to identify those most likely to benefit from a specific therapy is an urgent issue in the treatment of patients with bladder cancer.