Expression of fibroblast growth factor receptor 1 correlates inversely with the efficacy of single-agent fibroblast growth factor receptor-specific inhibitors in pancreatic cancer

BACKGROUND AND PURPOSE

Elevated fibroblast growth factor receptor (FGFR) activity correlates with pancreatic adenocarcinoma (PDAC) progression and poor prognosis. However, its potential as a therapeutic target remains largely unexplored.

EXPERIMENTAL APPROACH

The mechanisms of action and therapeutic effects of selective pan-FGFR inhibitors (pan-FGFRi) were explored using in vitro and in vivo PDAC models ranging from gemcitabine-sensitive to highly gemcitabine-resistant (GemR). Gain-/loss-of-function investigations were employed to define the role of individual FGFRs in cell proliferation, migration, and treatment response and resistance.

RESULTS

The pan-FGFRi NVP-BGJ398 significantly inhibited cell proliferation, migration, and invasion, and downregulated key cell survival- and invasiveness markers in multiple PDAC cell lines. Gemcitabine is a standard-of-care for PDAC, but development of resistance to gemcitabine (GemR) compromises its efficacy. Acquired GemR was modelled experimentally by developing highly GemR cells using escalating gemcitabine exposure in vitro and in vivo. FGFRi treatment inhibited GemR cell proliferation, migration, GemR marker expression, and tumour progression. FGFR2 or FGFR3 loss-of-function by shRNA knockdown failed to decrease cell growth, whereas FGFR1 knockdown was lethal. FGFR1 overexpression promoted cell migration more than proliferation, and reduced FGFRi-mediated inhibition of proliferation and migration. Single-agent FGFRi suppressed the viability and growth of multiple patient-derived xenografts inversely with respect to FGFR1 expression, underscoring the influence of FGFR1-dependent tumour responses to FGFRi. Importantly, secondary data analysis showed that PDAC tumours expressed FGFR1 at lower levels than in normal pancreas tissue.

CONCLUSIONS AND IMPLICATIONS

Single-agent FGFR inhibitors mediate selective, molecularly-targeted suppression of PDAC proliferation, and their effects are greatest in PDAC tumours expressing low-to-moderate levels of FGFR1.

Fibroblast Growth Factor Receptor Inhibitors Decrease Proliferation of Melanoma Cell Lines and Their Activity Is Modulated by Vitamin D

Regardless of the unprecedented progress in malignant melanoma treatment strategies and clinical outcomes of patients during the last twelve years, this skin cancer remains the most lethal one. We have previously documented that vitamin D and its low-calcaemic analogues enhance the anticancer activity of drugs including a classic chemotherapeutic-dacarbazine-and an antiangiogenic VEGFRs inhibitor-cediranib. In this study, we explored the response of A375 and RPMI7951 melanoma lines to CPL304110 (CPL110), a novel selective inhibitor of fibroblast growth factor receptors (FGFRs), and compared its efficacy with that of AZD4547, the first-generation FGFRs selective inhibitor. We also tested whether 1,25(OH)2D3, the active form of vitamin D, modulates the response of the cells to these drugs. CPL304110 efficiently decreased the viability of melanoma cells in both A375 and RPMI7951 cell lines, with the IC50 value below 1 µM. However, the metastatic RPMI7951 melanoma cells were less sensitive to the tested drug than A375 cells, isolated from primary tumour site. Both tested FGFR inhibitors triggered G0/G1 cell cycle arrest in A375 melanoma cells and increased apoptotic/necrotic SubG1 fraction in RPMI7951 melanoma cells. 1,25(OH)2D3 modulated the efficacy of CPL304110, by decreasing the IC50 value by more than 4-fold in A375 cell line, but not in RPMI7951 cells. Further analysis revealed that both inhibitors impact vitamin D signalling to some extent, and this effect is cell line-specific. On the other hand, 1,25(OH)2D3, have an impact on the expression of FGFR receptors and phosphorylation (FGFR-Tyr653/654). Interestingly, 1,25(OH)2D3 and CPL304110 co-treatment resulted in activation of the ERK1/2 pathway in A375 cells. Our results strongly suggested possible crosstalk between vitamin D-activated pathways and activity of FGFR inhibitors, which should be considered in further clinical studies.

Computational identification and exploration of novel FGFR tyrosine kinase inhibitors for the treatment of cholangiocarcinoma

Tyrosine kinase inhibitors are a specific drug class revolutionizing cancer treatment. FGFR (Fibroblast Growth Factor Receptor) is a member of the receptor tyrosine kinase family that has been involved in various alterations which have been increasingly recognized as critical molecular drivers in cholangiocarcinoma, a malignant tumor originating from bile duct epithelial cells. The paper focuses on stepwise computational investigations for the discovery of novel inhibitors of FGFR using pharmacophore modeling, virtual screening, docking, ADMET analysis, molecular dynamics, and knowledge-based structure-activity relationship. To begin with, we have considered a library of 120314868 compounds from the ZINC 15 database through pharmacophore modeling, which was narrowed down to 110 having binding affinity >-8.0 kcal mol-1. The 110 compounds were analyzed using virtual screening and compared with the FDA-approved drug pemigatinib, which provided the 34 hits with binding affinities >-6.5 kcal mol-1. Finally, the top 4 hits were considered for docking, and ADMET property analysis for drug-likeness. MD and MM-GBSA analysis were performed to predict the binding free energy of these chemicals and determine their stability. To gain insight into the structure and binding interactions of these compounds, knowledge-based SAR analyses were performed using their electrostatic potential maps computed with DFT. Several techniques were employed to build improved inhibitors based on these SAR, and they were then analyzed utilizing ADMET, MD studies, and MM-GBSA analyses. Finally, the results suggested that the identified four compounds and developed inhibitors from this current work can be employed effectively as prospective FGFR inhibitors for treating Cholangiocarcinoma.Communicated by Ramaswamy H. Sarma.

Case Report: Persistent response to combination therapy of pemigatinib, chemotherapy, and immune checkpoint inhibitor in a patient with advanced intrahepatic cholangiocarcinoma

Patients with advanced intrahepatic cholangiocarcinoma (iCCA) often have a poor prognosis. Recent advancements in targeted molecular therapy and immunotherapy have been made. Herein, we report a case of advanced iCCA treated with a combination of pemigatinib (a selective FGFR inhibitor), chemotherapy, and an immune checkpoint inhibitor. A 34-year-old female was diagnosed with advanced iCCA with multiple liver masses and metastases in the peritoneum and lymph nodes. Next-generation sequencing (NGS) identified the genetic mutations. An FGFR2-BICC1 gene fusion was found in this patient. The patient was treated with pemigatinib in combination with pembrolizumab plus systemic gemcitabine and oxaliplatin. After 9 cycles of the combination therapy, the patient achieved a partial response, complete metabolic response, and normalization of tumor markers. Sequentially, the patient received pemigatinib and pembrolizumab for 3 months. Due to the elevated tumor biomarker, she is currently receiving chemotherapy, pemigatinib, and pembrolizumab treatment again. She regained an excellent physical status after 16 months of treatment. To the best of our knowledge, this was the first reported case of advanced iCCA successfully treated with a combination of pemigatinib, chemotherapy, and ICIs as a first-line regimen. This treatment combination may be effective and safe in the advanced iCCA.

Targeting FGFRs Using PD173074 as a Novel Therapeutic Strategy in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is an architecturally complex tumour with high heterogeneity. Discovery at later stages makes treatment challenging. However, the lack of early detection methodologies and the asymptomatic nature of CCA make early diagnosis more difficult. Recent studies revealed the fusions in Fibroblast Growth Factor Receptors (FGFRs), a sub-family of RTKs, as promising targets for targeted therapy for CCA. Particularly, FGFR2 fusions have been of particular interest, as translocations have been found in approximately 13% of CCA patients. Pursuing this, Pemigatinib, a small-molecule inhibitor of FGFR, became the first targeted therapy drug to be granted accelerated approval by the FDA for treating CCA patients harbouring FGFR2 fusions who have failed first-line chemotherapy. However, despite the availability of Pemigatinib, a very limited group of patients benefit from this treatment. Moreover, as the underlying mechanism of FGFR signalling is poorly elucidated in CCA, therapeutic inhibitors designed to inhibit this pathway are prone to primary and acquired resistance, as witnessed amongst other Tyrosine Kinase Inhibitors (TKIs). While acknowledging the limited cohort that benefits from FGFR inhibitors, and the poorly elucidated mechanism of the FGFR pathway, we sought to characterise the potential of FGFR inhibitors in CCA patients without FGFR2 fusions. Here we demonstrate aberrant FGFR expression in CCA samples using bioinformatics and further confirm phosphorylated-FGFR expression in paraffinised CCA tissues using immunohistochemistry. Our results highlight p-FGFR as a biomarker to guide FGFR-targeted therapies. Furthermore, CCA cell lines with FGFR expression were sensitive to a selective pan-FGFR inhibitor, PD173074, suggesting that this drug can be used to suppress CCA cells irrespective of the FGFR2 fusions. Finally, the correlation analysis utilising publicly available cohorts suggested the possibility of crosstalk amongst the FGFR and EGFR family of receptors as they are significantly co-expressed. Accordingly, dual inhibition of FGFRs and EGFR by PD173074 and EGFR inhibitor erlotinib was synergistic in CCA. Hence, the findings from this study provide support for further clinical investigation of PD173074, as well as other FGFR inhibitors, to benefit a larger cohort of patients. Altogether, this study shows for the first time the potential of FGFRs and the importance of dual inhibition as a novel therapeutic strategy in CCA.

Pan-tumor landscape of fibroblast growth factor receptor 1-4 genomic alterations

BACKGROUND

Selective tyrosine kinase inhibitors targeting fibroblast growth factor receptor (FGFR) 1-4 genomic alterations are in development or have been approved for FGFR-altered cancers (e.g. bladder cancer and advanced intrahepatic cholangiocarcinoma). Understanding FGFR inhibitor-resistance mechanisms is increasingly relevant; we surveyed the pan-tumor landscape of FGFR1-4 genomic alterations [short variants (SVs), gene rearrangements (REs), and copy number alterations (CNAs)], including their association with tumor mutational burden (TMB) and the genomic comutational landscape.

PATIENTS AND METHODS

Comprehensive genomic profiling of 355 813 solid tumor clinical cases was performed using the FoundationOne and FoundationOne CDx assays (Foundation Medicine, Inc.) to identify genomic alterations in >300 cancer-associated genes and TMB (determined on ≤1.1 megabases of sequenced DNA).

RESULTS

FGFR1-4 SVs and REs occurred in 9603/355 813 (2.7%), and CNAs in 15 078/355 813 (4.2%) samples. Most common FGFR alterations for bladder cancer, intrahepatic cholangiocarcinoma, and glioma were FGFR3 SVs (1051/7739, 13.6%), FGFR2 REs (618/6641, 9.3%), and FGFR1 SVs (239/11 550, 2.1%), respectively. We found several, potentially clinically relevant, tumor-specific associations between FGFR1-4 genomic alterations and other genomic markers. FGFR3 SV-altered bladder cancers and FGFR1 SV-altered gliomas were significantly less likely to be TMB-high versus unaltered samples. FGFR3 SVs in bladder cancer significantly co-occurred with TERT and CDKN2A/B alterations; TP53 and RB1 alterations were mutually exclusive. In intrahepatic cholangiocarcinoma, FGFR2 REs significantly co-occurred with BAP1 alterations, whereas KRAS, TP53, IDH1, and ARID1A alterations were mutually exclusive. FGFR1 SVs in gliomas significantly co-occurred with H3-3A and PTPN11 alterations, but were mutually exclusive with TERT, EGFR, TP53, and CDKN2A/B alterations.

CONCLUSIONS

Overall, our hypothesis-generating findings may help to stratify patients in clinical trials and guide optimal targeted therapy in those with FGFR alterations.

A novel parameter for cancer chemosensitivity to FGFR inhibitors

Fibroblast growth factor receptor inhibitors (FGFRi) were introduced into clinical trials on several cancer types and found to be particularly efficacious on urothelial cancer and cholangiocarcinoma. Although many enrolled patients responded well in clinical trials, there were some patients who did not respond to FGFRi despite that their tumors carried the genomic changes that met the enrollment criteria. As already established, fibroblast growth factor receptor (FGFR) and epidermal growth factor receptor (EGFR) share the downstream signaling pathway of MAPK activation. Accordingly, it is conceivable that targeted inhibition of FGFR alone may leave the MAPK signaling unaffected when the signaling through EGFR is relatively strong. To test this hypothesis, we calculated here the FGFR to EGFR mRNA ratio (F/E for short) of biliary-tract and urothelial cancer cell lines utilized in preclinical studies. In six biliary-tract cancer cell lines, two responsive lines had F/E of 9.5 and 9.0, whereas four nonresponsive lines had 0.1-1.8. In 22 urothelial cancer cell lines, four of the five responsive lines showed F/E of 2.8-4.9 (median, 3.6), whereas 17 nonresponsive lines had 0.01-2.7 (median, 0.6) (P = 0.004). We further investigated our 47 patient-derived colorectal cancer-stem cell (CRC-SC) spheroid lines. The 18 responsive lines showed relatively high F/E (median, 16.4), whereas 29 nonresponsive lines had low F/E (median, 9.2) (P = 0.0006). These results suggest that F/E is another strong predictor of responses to FGFRi that is as useful as the current genomic criteria based solely on the FGFR genomic changes.

Metastatic Urothelial Carcinoma: Have We Take the Road to the Personalized Medicine?

Urothelial cancer is a lethal malignancy characterized by a wide diffusion in Western countries due to a larger exposure to known risk factors, such as aromatic amines, tobacco smoke and benzene [...].

Fibroblast Growth Factor Receptor 1-4 Genetic Aberrations as Clinically Relevant Biomarkers in Squamous Cell Lung Cancer

Fibroblast growth factor receptor (FGFR) inhibitors (FGFRis) are a potential therapeutic option for squamous non-small cell lung cancer (Sq-NSCLC). Because appropriate patient selection is needed for targeted therapy, molecular profiling is key to discovering candidate biomarker(s). Multiple FGFR aberrations are present in Sq-NSCLC tumors-alterations (mutations and fusions), amplification and mRNA/protein overexpression-but their predictive potential is unclear. Although FGFR1 amplification reliability was unsatisfactory, FGFR mRNA overexpression, mutations, and fusions are promising. However, currently their discriminatory power is insufficient, and the available clinical data are from small groups of Sq-NSCLC patients. Here, we focus on FGFR aberrations as predictive biomarkers for FGFR-targeting agents in Sq-NSCLC. Known and suggested molecular determinants of FGFRi resistance are also discussed.

New Insights in the Interaction of FGF/FGFR and Steroid Receptor Signaling in Breast Cancer

Luminal breast cancer (BrCa) has a favorable prognosis compared with other tumor subtypes. However, with time, tumors may evolve and lead to disease progression; thus, there is a great interest in unraveling the mechanisms that drive tumor metastasis and endocrine resistance. In this review, we focus on one of the many pathways that have been involved in tumor progression, the fibroblast growth factor/fibroblast growth factor receptor (FGFR) axis. We emphasize in data obtained from in vivo experimental models that we believe that in luminal BrCa, tumor growth relies in a crosstalk with the stromal tissue. We revisited the studies that illustrate the interaction between hormone receptors and FGFR. We also highlight the most frequent alterations found in BrCa cell lines and provide a short review on the trials that use FGFR inhibitors in combination with endocrine therapies. Analysis of these data suggests there are many players involved in this pathway that might be also targeted to decrease FGF signaling, in addition to specific FGFR inhibitors that may be exploited to increase their efficacy.

Fibroblast growth factor receptor signalling dysregulation and targeting in breast cancer

Fibroblast Growth Factor Receptor (FGFR) signalling plays a critical role in breast embryonal development, tissue homeostasis, tumorigenesis and metastasis. FGFR, its numerous FGF ligands and signalling partners are often dysregulated in breast cancer progression and are one of the causes of resistance to treatment in breast cancer. Furthermore, FGFR signalling on epithelial cells is affected by signals from the breast microenvironment, therefore increasing the possibility of breast developmental abnormalities or cancer progression. Increasing our understanding of the multi-layered roles of the complex family of FGFRs, their ligands FGFs and their regulatory partners may offer novel treatment strategies for breast cancer patients, as a single agent or rational co-target, which will be explored in depth in this review.

FGFR Pathway Inhibition in Gastric Cancer: The Golden Era of an Old Target?

Gastric cancer (GC) is the third leading cause of cancer-associated death worldwide. The majority of patients are diagnosed at an advanced/metastatic stage of disease due to a lack of specific symptoms and lack of screening programs, especially in Western countries. Thus, despite the improvement in GC therapeutic opportunities, the survival is disappointing, and the definition of the optimal treatment is still an unmet need. Novel diagnostic techniques were developed in clinical trials in order to characterize the genetic profile of GCs and new potential molecular pathways, such as the Fibroblast Growth Factor Receptor (FGFR) pathway, were identified in order to improve patient's survival by using target therapies. The aim of this review is to summarize the role and the impact of FGFR signaling in GC and to provide an overview regarding the potential effectiveness of anti-FGFR agents in GC treatment in the context of precision medicine.

Targeted therapies: Expanding the role of FGFR3 inhibition in urothelial carcinoma

The management of urothelial carcinoma (UC) has rapidly advanced in recent years with new approvals for immune checkpoint inhibitors and antibody-drug conjugates. However, while many UC tumors contain potentially actionable mutations, the role for targeted small molecule inhibitors has been limited. One such target is the fibroblast growth factor receptor (FGFR) family of proteins. Activating mutations and amplifications of FGFR3 are common in UC with higher incidences seen in upper tract as compared to lower tract disease. Consequently, multiple FGFR-directed targeted therapies have been developed and trialed in both UC and other solid tumors harboring FGFR mutations. At current, erdafitinib, an inhibitor of FGFR1-4, is the only approved targeted therapy in metastatic UC following the BLC2001 study, which demonstrated a 49% overall response rate in patients with UC harboring an FGFR3 mutation. Additional FGFR-directed agents also continue to be investigated across multiple disease stages in FGFR-mutated UC including infigratinib, rogaratinib, and AZD4547, among others. Ongoing trials are combining these agents with immune checkpoint inhibitors and chemotherapy regimens. The precision medicine revolution has begun in UC, and FGFR3 inhibitors are leading the charge toward a more personalized, biomarker-driven treatment paradigm.

Biological Significance and Targeting of the FGFR Axis in Cancer

Simple Summary

All cells within tissues and organ systems must communicate with each other to ensure they function in a coordinated manner. One form of communication is signalling mediated by small proteins (for example fibroblast growth factors; FGFs) that are secreted by one cell and bind to specialised receptors (for example FGF receptors) on nearby cells. These receptors propagate the signal to the nucleus of the receiving cell, which in turn dictates to the cell how it should react. FGFR signalling is versatile, tightly controlled and important for normal body homeostasis, facilitating growth, healing and replacing old cells. However, cancer cells can take command of this pathway and use it to their advantage. This review will first explain the biology of FGFR signalling and then describe how it can be corrupted, the implications in cancer, and how it can be targeted to improve cancer therapy.

Abstract

The pleiotropic effects of fibroblast growth factors (FGFs), the widespread expression of all seven signalling FGF receptors (FGFRs) throughout the body, and the dramatic phenotypes shown by many FGF/R knockout mice, highlight the diversity, complexity and functional importance of FGFR signalling. The FGF/R axis is critical during normal tissue development, homeostasis and repair. Therefore, it is not surprising that substantial evidence also pinpoints the involvement of aberrant FGFR signalling in disease, including tumourigenesis. FGFR aberrations in cancer include mutations, gene fusions, and amplifications as well as corrupted autocrine/paracrine loops. Indeed, many clinical trials on cancer are focusing on targeting the FGF/FGFR axis, using selective FGFR inhibitors, nonselective FGFR tyrosine kinase inhibitors, ligand traps, and monoclonal antibodies and some have already been approved for the treatment of cancer patients. The heterogeneous tumour microenvironment and complexity of FGFR signalling may be some of the factors responsible for the resistance or poor response to therapy with FGFR axis-directed therapeutic agents. In the present review we will focus on the structure and function of FGF(R)s, their common irregularities in cancer and the therapeutic value of targeting their function in cancer.

State-of-the-Art of Monoclonal Antibodies for the Treatment of Gastric Cancer

Gastric cancer (GC) is a complex and heterogeneous disease with poor prognosis and limited available treatment options. During recent years, several molecular stratifications have been proposed to optimize the overall treatment strategy for GC patients. Breakthroughs in cancer biology and in molecular profiling through DNA and RNA sequencing are now opening novel landscapes, leading to the personalization of molecular matched therapy. In particular, therapies against HER2, Claudine 18.2, Fibroblast Growth Factor Receptors (FGFR), and other molecular alterations could significantly improve survival outcomes in the advance phase of the disease. Furthermore, immunotherapy with checkpoint inhibitors also represents a promising option in a selected population. Hoping that precision oncology will enter soon in clinical practice, our review describes the state of the art of many novel pathways and the current evidence supporting the use of monoclonal antibodies implicated in GC treatment.

Targeted Therapy for Advanced or Metastatic Cholangiocarcinoma: Focus on the Clinical Potential of Infigratinib

Cholangiocarcinoma is one of the most aggressive cancers, with a 5-year survival rate of 11-44% after surgical resection. However, there is no established systemic therapy after failure of the gemcitabine plus cisplatin first-line therapy with exception of FOLFOX. Fibroblast growth factor receptor (FGFR) genomic aberrations have been detected in cholangiocarcinoma, and targeting these genomic aberrations with FGFR inhibitors has shown remarkable clinical benefits in advanced cholangiocarcinoma. In this article, we provide up-to-date information on the clinical development of selective FGFR inhibitors in advanced cholangiocarcinoma, focusing on infigratinib. In a Phase 1 trial, infigratinib showed a safe profile. In a following Phase 2 trial, infigratinib showed remarkable efficacy in advanced cholangiocarcinoma with FGFR2 fusions or rearrangements, and the Food and Drug Administration (FDA) approved infigratinib for cholangiocarcinoma in May 2021 largely based on tumor response and duration of response. Currently infigratinib is on a Phase 3 trial (PROOF301) as a first-line setting compared to the GEMCIS therapy in advanced cholangiocarcinoma. Given that the FGFR genomic aberrations including FGFR2 fusions are rarely accompanied with other targetable mutations, infigratinib and other FGFR inhibitors are continuously expected to be the novel targeted agents in cholangiocarcinoma harboring these aberrations. Acquired resistance to infigratinib was reported in several recent studies which could potentially be a barrier to overcome. Active clinical trials including PROOF301 are expected to elucidate the clinical benefits of infigratinib in this disease. Infigratinib combined with immunotherapy is also a potential future direction of investigation in cholangiocarcinoma.

Infigratinib in Early-Line and Salvage Therapy for FGFR3-Altered Metastatic Urothelial Carcinoma

The optimal sequencing of systemic treatments for metastatic urothelial cancer (mUC) is unknown. We assessed the efficacy of infigratinib, a fibroblast growth factor receptor (FGFR) 1 to 3 inhibitor, in 67 patients with FGFR3-altered mUC by line of therapy. Objective response rates were 31% (early-line setting) and 24% (≥2nd-line setting). Infigratinib has notable activity in mUC regardless of line of therapy.

Targeting PI3K, FGFR, CDK4/6 Signaling Pathways Together With Cytostatics and Radiotherapy in Two Medulloblastoma Cell Lines

Objectives

Medulloblastoma (MB) is treated with surgery and chemotherapy, with or without irradiation, but unfortunately >20% of the patients are not cured, and treatment comes with serious long-term side effects, so novel treatments are urgently needed. Phosphoinositide 3-kinases (PI3K), fibroblast growth factor receptors (FGFR), and cyclin-D kinases (CDK) play critical roles in cancer, and especially PI3K is crucial in MB, so here targeted therapies against them were explored.

Methods

MB cell lines DAOY and UW228-3 were exposed to PI3K (BYL719), FGFR (JNJ-42756493), and CDK4/6 (PD-0332991) inhibitors, as single or combined treatments, and their viability, cell confluence, apoptosis, and cytotoxicity were examined. Moreover, the inhibitors were combined with cisplatin, vincristine, or irradiation.

Results

Single treatments with FGFR, PI3K, or CDK4/6 inhibitors decreased viability and proliferation slightly; however, when combining two inhibitors, or the inhibitors with irradiation, sensitivity was enhanced and lower doses could be used. A more complex pattern was obtained when combining the inhibitors with cisplatin and vincristine.

Conclusions

The data suggest that combination treatments with PI3K, FGFR, and CDK4/6 inhibitors for MB could be beneficial and their use should be pursued further. Likewise, their combination with irradiation gave positive effects, while the addition of cisplatin and vincristine resulted in more complex patterns, which need to be investigated further.

Application of Topical Lidocaine for Pain Relief in the Setting of Targeted Therapy-Induced Onycholysis: A Case Report

Selective pan fibroblast growth factor receptor (FGFR) inhibitors have been linked to severe onycholysis, the uncomfortable separation of the nail plate from the nail bed. Recommendations to assist with FGFR inhibitor onycholysis vary based on the severity. We hypothesized that the application of topical lidocaine to mimic a digital nerve block would be beneficial in addition to traditional supportive care interventions and subsequently report its immediate and continued efficacy for targeted therapy-induced onycholysis.

Emerging Targeted Therapy for Bladder Cancer

For the last decade, biology of urothelial tumorigenesis has been widely explored, helping to better understand the molecular pathways in urothelial carcinoma (UC). Until recently, no targeted therapies have been approved in UC. However, several new molecules have shown promising results in metastatic UC: fibroblast growth factor receptor inhibitors, conjugated antibodies, PARP inhibitors, and antiangiogenics. In this article, the authors review the targeted therapies that are being evaluated in bladder UC.

Fibroblast growth factor receptor: A systematic review and meta-analysis of prognostic value and therapeutic options in patients with urothelial bladder carcinoma

To evaluate the oncologic prognostic value of fibroblast growth factor receptor (FGFR) and to assess the safety and efficacy of its inhibitors in patients with urothelial bladder carcinoma. A literature search using PubMed, Scopus, and Cochrane Library was conducted on June 2020 to identify relevant studies according to the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. The pooled recurrence-free survival (RFS), progression-free survival (PFS), and cancer-specific survival (CSS) were calculated using a fixed or random effects model in patients with nonmuscle invasive bladder cancer (NMIBC). Overall, 62 studies comprising 9,229 patients were eligible and included in this systematic review and meta-analysis. Both FGFR3 mutation and protein overexpression were significantly associated with RFS, PFS, CSS, and overall survival. FGFR3 mutation was associated with worse RFS and better PFS (pooled hazard ratio: 1.30; 95% confidence interval: 1.08-1.57, and pooled hazard ratio: 0.62; 95% confidence interval: 0.42-0.92, respectively) in patients with NMIBC. In 11 studies reporting on the response to FGFR inhibitors, complete response rates, disease control rates, and overall response rate of 0% to 8%, 59.3% to 64.2%, and 40% were reported for dovitinib, infigratinib, and erdafitinib, respectively. Based on this study, FGFR3 mutation is a statistically significant prognostic factor for RFS in NMIBC. FGFR inhibitors have measurable benefit in patients with advanced and metastatic urothelial carcinoma. However, the results of ongoing RCTs and future well-designed studies are awaited to capture the differential biologic and clinical behavior of tumors harboring FGFR while helping to identify those who are most likely to benefit from FGFR inhibitors.

Effects of PI3K and FGFR inhibitors alone and in combination, and with/without cytostatics in childhood neuroblastoma cell lines

Neuroblastoma (NB) is a heterogenous disease with treatment varying from observation for low-risk tumors, to extensive therapy with chemotherapy, surgery, radiotherapy, and autologous bone-marrow-transplantation and immunotherapy. However, a high frequency of primary-chemo-refractory disease and recurrences urgently require novel treatment strategies. The present study therefore investigated the anti-NB efficacy of the recently FDA-approved phosphoinositide 3-kinase (PI3K) and fibroblast growth factor receptor (FGFR) inhibitors, alpelisib (BYL719) and erdafitinib (JNJ-42756493), alone and in combination with or without cisplatin, vincristine, or doxorubicin on 5 NB cell lines. For this purpose, the NB cell lines, SK-N-AS, SK-N-BE(2)-C, SK-N-DZ, SK-N-FI and SK-N-SH (where SK-N-DZ had a deletion of PIK3C2G and none had FGFR mutations according to the Cancer Program's Dependency Map, although some were chemoresistant), were tested for their sensitivity to FDA-approved inhibitors alone or in combination, or together with cytostatic drugs by viability, cytotoxicity, apoptosis and proliferation assays. The results revealed that monotherapy with alpelisib or erdafitinib resulted in a dose-dependent inhibition of cell viability and proliferation. Notably, the combined use of PI3K and FGFR inhibitors resulted in an enhanced efficacy, while their combined use with the canonical cytotoxic agents, cisplatin, vincristine and doxorubicin, resulted in variable synergistic, additive and antagonistic effects. Collectively, the present study provides pre-clinical evidence that PI3K and FGFR inhibitors exhibit promising anti-NB activity. The data presented herein also indicate that the incorporation of these inhibitors into chemotherapeutic regimens requires careful consideration and further research in order to obtain a beneficial efficacy. Nevertheless, the addition of PI3K and FGFR inhibitors to the treatment arsenal might reduce the occurrence of refractory and relapsing disease in NB without FGFR and PI3K mutations.

Practice change in the management of metastatic urothelial carcinoma after ASCO 2020

Metastatic urothelial carcinoma (mUC) is an incurable and aggressive disease. In the past decades there have been few effective treatment options that have impacted the prognosis of mUC patients. However, in the last few years, several drugs have emerged as new treatment choices that are changing the therapeutic landscape of mUC. Immune checkpoint inhibitors (ICIs) and targeted agents are useful treatment strategies that have been incorporated into our clinical practice. Nevertheless, cisplatin-based chemotherapy is still the standard of care in the first-line of metastatic disease. The results of the JAVELIN Bladder 100 phase 3 trial were presented at ASCO 2020, this trial evaluated the role of avelumab, an ICI, as maintenance therapy in patients who had not progressed after first-line platinum-based chemotherapy. The trial met its primary endpoint demonstrating an overall survival benefit with avelumab maintenance. In addition, new drugs and combinations are being evaluated to improve the outcomes of second and subsequent lines. Fibroblast growth factor receptor (FGFR) inhibitors and immunotherapy combinations were some of the strategies presented at ASCO 2020 that have shown promising results. Finally, the development of predictive biomarkers that help us in the decision-making process will be one of the most important challenges in the next years.

Fibroblast Growth Factor Receptor (FGFR) Inhibitors in Urothelial Cancer

Dysregulated fibroblast growth factor receptor (FGFR) signaling is associated with several cancers, including urothelial carcinoma. Preclinical studies with FGFR inhibitors have shown significant antitumor activity, which has led to clinical evaluation of multiple FGFR inhibitors. Recently, erdafitinib was approved by the U.S. Food and Drug Administration for advanced urothelial carcinoma with FGFR gene alterations as the first molecularly targeted therapy. Additional ongoing clinical trials with other types of FGFR inhibitors have shown encouraging results. This review summarizes the oncogenic signaling of FGFR alterations, completed and ongoing clinical trials of FGFR inhibitors, and resistance patterns. IMPLICATIONS FOR PRACTICE: Dysregulated fibroblast growth factor receptor (FGFR) signaling is associated with several cancers, including urothelial carcinoma. Preclinical studies with FGFR inhibitors have shown significant antitumor activity, which has led to clinical evaluation of multiple FGFR inhibitors. Most recently, erdafitinib was approved by the U.S. Food and Drug Administration for advanced urothelial carcinoma with FGFR gene alterations as the first molecularly targeted therapy. Additional ongoing clinical trials with other types of FGFR inhibitors have shown encouraging results. This review summarizes the oncogenic signaling of FGFR alterations, completed and ongoing clinical trials of FGFR inhibitors, and resistance patterns.

The Future of ER+/HER2- Metastatic Breast Cancer Therapy: Beyond PI3K Inhibitors

Most breast cancers express the estrogen receptor (ER) receptor and are negative for the human epidermal growth factor receptor 2 (HER2) receptor. ER+/HER2- cancers are treated with hormone-based therapies in the adjuvant setting and derive significant survival benefit from these therapies in the metastatic setting. However, hormone resistance develops in most metastatic patients. An increased understanding of the biology of ER+/HER2- breast cancers has led to the development of new therapies for this disease including CDK4/6 inhibitors and PI3K inhibitors. Several other neoplastic processes are targeted by novel drugs in clinical development, addressing cancer vulnerabilities. These include newer ways to block the ER and targeting the HER2 receptors in ER+/HER2- cancers expressing HER2 in low levels not qualifying for clinical positivity. In addition, promising therapeutic options include targeting other surface receptors or their downstream pathways, as well as targeting the apoptotic machinery and boosting the immune response which is initially insufficient in these cancers. A selection of new drugs in advanced development for ER+/HER2- breast cancer will be discussed in this review.

FGFR Fusions in Cancer: From Diagnostic Approaches to Therapeutic Intervention

Fibroblast growth factor receptors (FGFRs) are tyrosine kinase receptors involved in many biological processes. Deregulated FGFR signaling plays an important role in tumor development and progression in different cancer types. FGFR genomic alterations, including FGFR gene fusions that originate by chromosomal rearrangements, represent a promising therapeutic target. Next-generation-sequencing (NGS) approaches have significantly improved the discovery of FGFR gene fusions and their detection in clinical samples. A variety of FGFR inhibitors have been developed, and several studies are trying to evaluate the efficacy of these agents in molecularly selected patients carrying FGFR genomic alterations. In this review, we describe the most frequent FGFR aberrations in human cancer. We also discuss the different approaches employed for the detection of FGFR fusions and the potential role of these genomic alterations as prognostic/predictive biomarkers.

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.

FGFR1 and FGFR4 oncogenicity depends on n-cadherin and their co-expression may predict FGFR-targeted therapy efficacy

BACKGROUND

Fibroblast growth factor receptor (FGFR)1 and FGFR4 have been associated with tumorigenesis in a variety of tumour types. As a therapeutic approach, their inhibition has been attempted in different types of malignancies, including lung cancer, and was initially focused on FGFR1-amplified tumours, though with limited success.

METHODS

In vitro and in vivo functional assessments of the oncogenic potential of downregulated/overexpressed genes in isogenic cell lines were performed, as well as inhibitor efficacy tests in vitro and in vivo in patient-derived xenografts (PDXs). mRNA was extracted from FFPE non-small cell lung cancer samples to determine the prognostic potential of the genes under study.

FINDINGS

We provide in vitro and in vivo evidence showing that expression of the adhesion molecule N-cadherin is key for the oncogenic role of FGFR1/4 in non-small cell lung cancer. According to this, assessment of the expression of genes in different lung cancer patient cohorts showed that FGFR1 or FGFR4 expression alone showed no prognostic potential, and that only co-expression of FGFR1 and/or FGFR4 with N-cadherin inferred a poorer outcome. Treatment of high-FGFR1 and/or FGFR4-expressing lung cancer cell lines and patient-derived xenografts with selective FGFR inhibitors showed high efficacy, but only in models with high FGFR1/4 and N-cadherin expression.

INTERPRETATION

Our data show that the determination of the expression of FGFR1 or FGFR4 alone is not sufficient to predict anti-FGFR therapy efficacy; complementary determination of N-cadherin expression may further optimise patient selection for this therapeutic strategy.

Targeting Fibroblast Growth Factor Receptor (FGFR) and Phosphoinositide 3-kinase (PI3K) Signaling Pathways in Medulloblastoma Cell Lines

BACKGROUND/AIM

Medulloblastoma (MB) accounts for ~20% of pediatric malignant central nervous system tumors. Treatment strategies, including surgery, radiation therapy and/or chemotherapy, are effective, but recurrence and metastasis frequently occur. Therefore, novel therapies are required. Herein, the effects of fibroblast growth factor receptor (FGFR) and phosphoinositide 3-kinase (PI3K) inhibitors on MB cells lines were evaluated.

MATERIALS AND METHODS

MB cell lines (UW228-3, DAOY, Med8a, D425, D283) were tested for sensitivity to FGFR (AZD4547) and PI3K (BEZ235 and BYL719) inhibitors by viability, cytotoxicity, apoptosis, and proliferation assays.

RESULTS

Single treatments with FGFR and PI3K inhibitors decreased viability and proliferation in a dose-dependent pattern in most cell lines. Combinination of the two type of drugs, increased sensitivity, especially of the most resistant cell line UW228-3.

CONCLUSION

Combination treatments with FGFR and PI3K inhibitors were superior to single treatments with FGFR and PI3K inhibitors, especially with BEZ235, for MB cell lines.

Targeted therapies for advanced bladder cancer: new strategies with FGFR inhibitors

Inhibitors of fibroblast growth factor receptor (FGFR) represent an outstanding treatment approach for selected patients with urothelial cancer (UC). These agents are changing the clinical approach to a subgroup of UC, the luminal-papillary subtype, characterized by FGFR mutations, fusions, or amplification. In this review, we provide an overview of the results of recent clinical trials on FGFR tyrosine kinase inhibitors (TKIs) currently in clinical development for the treatment of UC: erdafitinib, rogaratinib, infigratinib, and the monoclonal antibody vofatamab. The Food and Drug Administration recently granted accelerated approval to erdafitinib for patients with advanced UC with alterations of FGFR2 or FGFR3 after progression on platinum-based chemotherapy. We also look at future therapeutic options of combination regimens with immune-checkpoint inhibitors as strategies for improving the antitumor effects of this class of drug, and for preventing or delaying the development of resistance.

Fibroblast growth factor receptor inhibitors: patent review (2015-2019)

Introduction: fibroblast growth factor receptors (FGFRs) are a family of tyrosine-kinase receptors whose signaling cascade regulates cellular proliferation, differentiation, and survival. Deregulation of the FGFR pathway is recognized as a driving factor in tumor development. On this basis, FGFR is an attractive target for anti-cancer small-molecule therapeutic agents.Areas covered: This review summarizes patent and literature publications spanning from 2015 to 2019 pertaining to small-molecule FGFR kinase inhibitors.Expert opinion: The first generation of non-covalent FGFR inhibitors is characterized by a broad spectrum of activity and a relatively high toxicity profile. The second generation of FGFR inhibitors shows higher selectivity and a more favorable toxicity profile, but the clinical use appears restricted only to small subsets of cancers strongly dependent on FGFR signaling. Nevertheless, erdafitinib has been approved for the treatment of metastatic urothelial carcinoma, becoming the first marketed selective FGFR inhibitor. The insurgence of mutant kinases, resistant to available therapies, has led to the development of irreversible FGFR inhibitors. The adoption of safer and more selective covalent inhibitors might supersede reversible inhibitors in specific therapeutic areas. Alternative strategies, such as FGF trapping by protein or small-molecule therapeutics, deserve attention and further investigations to unravel their potential.

Gain of FGF4 is a frequent event in KIT/PDGFRA/SDH/RAS-P WT GIST

Gastrointestinal stromal tumors (GIST) lacking mutations in KIT/PDGFRA or RAS pathways and retaining an intact SDH complex are usually referred to as KIT/PDGFRA/SDH/RAS‐P WT GIST or more simply quadruple WT GIST (~5% of all GIST). Despite efforts made, no recurrent genetic event in quadruple WT GIST has been identified so far. To further investigate this disease, we performed high throughput copy number analysis on quadruple WT GIST specimens identifying a recurrent focal gain in band 11q13.3 (involving FGF3/FGF4) in 6/8 cases. This event was not found in the other molecular GIST subgroups. FGF3/FGF4 duplication was associated with high expression of FGF4, both at mRNA and protein level, a growth factor normally not expressed in adult tissues or in KIT/PDGFRA‐mutated GIST. FGFR1 was found to be the predominant FGF receptor expressed and phosphorylation of AKT was detected, suggesting that a FGF4‐FGFR1 autocrine loop could stimulate downstream signaling in quadruple WT GIST. Together with the recent reports of quadruple WT cases carrying FGFR1 activating alterations, these findings strengthen the hypothesis of a potential involvement of FGFR pathway deregulation in quadruple WT GIST, which may represent a rationale for novel therapeutic approaches.

Nanoformulations of anticancer FGFR inhibitors with improved therapeutic index

Fibroblast growth factor receptor (FGFR) inhibitors like ponatinib and nintedanib are clinically approved for defined cancer patient cohorts but often exert dose-limiting adverse effects. Hence, we encapsulated the FGFR inhibitors ponatinib, PD173074, and nintedanib into polylactic acid nanoparticles and liposomes to enable increased tumor accumulation/specificity and reduce side effects. Different methods of drug loading were tested and the resulting formulations compared regarding average size distribution as well as encapsulation efficiency. Appropriate encapsulation levels were achieved for liposomal preparations only. Nanoencapsulation resulted in significantly decelerated uptake kinetics in vitro with clearly decreased short-term (up to 72 h) cytotoxicity at higher concentrations. However, in long-term clonogenic assays liposomal formations were equally or even more active as compared to the free drugs. Accordingly, in an FGFR inhibitor-sensitive murine osteosarcoma transplantation model (K7M2), only liposomal but not free ponatinib resulted in significant tumor growth inhibition (by 60.4%) at markedly reduced side effects.

FGFR a promising druggable target in cancer: Molecular biology and new drugs

INTRODUCTION

The Fibroblast Growth Factor Receptor (FGFR) family consists of Tyrosine Kinase Receptors (TKR) involved in several biological functions. Recently, alterations of FGFR have been reported to be important for progression and development of several cancers. In this setting, different studies are trying to evaluate the efficacy of different therapies targeting FGFR.

AREAS COVERED

This review summarizes the current status of treatments targeting FGFR, focusing on the trials that are evaluating the FGFR profile as inclusion criteria: Multi-Target, Pan-FGFR Inhibitors and anti-FGF (Fibroblast Growth Factor)/FGFR Monoclonal Antibodies.

EXPERT OPINION

Most of the TKR share intracellular signaling pathways; therefore, cancer cells tend to overcome the inhibition of one tyrosine kinase receptor by activating another. The future of TKI (Tyrosine Kinase Inhibitor) therapy will potentially come from multi-targeted TKIs that target different TKR simultaneously. It is crucial to understand the interaction of the FGF-FGFR axis with other known driver TKRs. Based on this, it is possible to develop therapeutic strategies targeting multiple connected TKRs at once. One correct step in this direction is the reassessment of multi target inhibitors considering the FGFR status of the tumor. Another opportunity arises from assessing the use of FGFR TKI on patients harboring FGFR alterations.

Drug-sensitive FGFR3 mutations in lung adenocarcinoma

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths across the world. In this study, we present therapeutically relevant genetic alterations in lung adenocarcinoma of Indian origin.

MATERIALS AND METHODS

Forty-five primary lung adenocarcinoma tumors were sequenced for 676 amplicons using RainDance cancer panel at an average coverage of 1500 × (reads per million mapped reads). To validate the findings, 49 mutations across 23 genes were genotyped in an additional set of 363 primary lung adenocarcinoma tumors using mass spectrometry. NIH/3T3 cells over expressing mutant and wild-type FGFR3 constructs were characterized for anchorage independent growth, constitutive activation, tumor formation and sensitivity to FGFR inhibitors using in vitro and xenograft mouse models.

RESULTS

We present the first spectrum of actionable alterations in lung adenocarcinoma tumors of Indian origin, and shows that mutations of FGFR3 are present in 20 of 363 (5.5%) patients. These FGFR3 mutations are constitutively active and oncogenic when ectopically expressed in NIH/3T3 cells and using a xenograft model in NOD/SCID mice. Inhibition of FGFR3 kinase activity inhibits transformation of NIH/3T3 overexpressing FGFR3 constructs and growth of tumors driven by FGFR3 in the xenograft models. The reduction in tumor size in the mouse is paralleled by a reduction in the amounts of phospho-ERK, validating the in vitro findings. Interestingly, the FGFR3 mutations are significantly higher in a proportion of younger patients and show a trend toward better overall survival, compared with patients lacking actionable alterations or those harboring KRAS mutations.

CONCLUSION

We present the first actionable mutation spectrum in Indian lung cancer genome. These findings implicate FGFR3 as a novel therapeutic in lung adenocarcinoma.

FGFR Signaling as a Target for Lung Cancer Therapy

Lung cancer is the leading cause of cancer-related death in developed countries. Recently, molecular targeted therapies have shown promising results in the management of lung cancer. These therapies require a clear understanding of the relevant pathways that drive carcinogenesis and maintenance of the malignant phenotype. The fibroblast growth factor receptor (FGFR) signaling axis is one such pathway that plays a central role in normal cellular function. Alterations in this pathway have been found in many cancers. In this review article, we focus on the role of this pathway in lung cancer. We present the molecular structure of FGFR, the interaction of the receptor with its ligands (the fibroblast growth factors), its downstream signaling, and aberrations in the FGFR pathway. We also discuss clinical trials involving selective and multikinase FGFR inhibitors in lung cancer treatment.

Characterization of FGFR signaling pathway as therapeutic targets for sarcoma patients

The fibroblast growth factor receptor (FGFR) family plays important roles in regulating cell growth, proliferation, survival, differentiation and angiogenesis. Deregulation of the FGF/FGFR signaling pathway has been associated with multiple development syndromes and cancers, and thus therapeutic strategies targeting FGFs and FGFR in human cancer are currently being explored. However, few studies on the FGF/FGFR pathway have been conducted in sarcoma, which has a poor outcome with traditional treatments such as surgery, chemotherapy, and radiotherapy. Hence, in the present review, we provide an overview of the role of the FGF/FGFR pathway signal in sarcoma and FGFR inhibitors, which might be new targets for the treatment of sarcomas according to recent research.

FGFR3-TACC3: A novel gene fusion in cervical cancer

Cervical cancer epitomizes the success of cancer prevention through the human papillomavirus (HPV) vaccine, but significant challenges remain in the treatment of advanced disease. We report the first three cases of cervical carcinoma harboring an FGFR3-TACC3 fusion, which serves as a novel therapeutic target. The fusion, identified by comprehensive genomic profiling, activates the FGFR pathway that has been implicated in HPV-driven carcinogenesis. One of the patients whose tumor contained the FGFR3-TACC3 fusion was treated with an investigational FGFR tyrosine kinase inhibitor. Concomitant molecular alterations involving the PI3K/AKT/mTOR and RAF/MEK pathways were also identified and suggest other treatment strategies that deserve investigation. This case series highlights the role of comprehensive genomic profiling in the identification of new therapeutic targets and in targeted therapy selection for patients with cervical cancer.