Clinical development and management of adverse events associated with FGFR inhibitors

Case Series of Patients With FGFR1-Related Pheochromocytoma and Paraganglioma With a Focus on Biochemical, Imaging Signatures and Treatment Options

Pheochromocytoma and paraganglioma (together PPGL) are tumours with a high degree of heritability. Genetic landscape is divided into three clusters, cluster 1 (Krebs/pseudohypoxia signalling pathway), cluster 2 (kinase signalling pathway) and cluster 3 (Wnt signalling pathway). With increasing knowledge in the field of genetics, cluster-specific tumour characteristics, biochemical phenotype and imaging signatures are established in commonly found genes. The association of FGFR1 pathogenic mutations with PPGL have been recently described although its features are not yet well established. Here, we present four patients with PPGL who were found to have somatic FGFR1 pathogenic mutations. We discuss their clinical presentations, biochemical phenotypes, imaging signatures and treatment options that will be relevant for practicing physicians in managing these patients effectively.

Pharmacologic features, clinical applications, and drug safety evaluation of futibatinib in the treatment of biliary tract cancer (BTC)

INTRODUCTION

Futibatinib is a small, potent, covalent, irreversible fibroblast growth factor receptor (FGFR) 1-4 inhibitor that has been added as a new standard of care for previously treated unresectable and/or advanced FGFR2 fusion/rearrangement-positive BTC. FGFR2 fusions/rearrangements play a key role in BTC survival, proliferation, invasion, and development of distant metastasis. The inhibition of this pathway is an important target in the treatment of BTC.

AREAS COVERED

The article covers the development of futibatinib for the treatment of refractory unresectable/advanced BTC, its mechanism of action, and key pharmacodynamic/pharmacokinetic data with a focus on the safety profile. Data are based on published clinical trials, pooled analysis, and retrospective studies indexed in PubMed (2010-2024).

EXPERT OPINION

Futibatinib is an FDA and EMA approved FGFR2 inhibitor for the treatment of patients with refractory BTC with FGFR2 fusions/rearrangements. Ongoing drug development strategies are centered on designing new FGFR2 fusion inhibitors able to overcome on-target and off-target resistances coupled with a high target selectivity to spare the most common treatment-related adverse events (hyperphosphatemia, stomatitis, alopecia, nail toxicity, skin reactions, eye toxicity).

Safety and efficacy of pemigatinib in patients with cholangiocarcinoma: a systematic review

Background

Cholangiocarcinoma (CCA) is an aggressive bile duct cancer with limited therapeutic options and poor prognosis. pemigatinib, a selective FGFR inhibitor, has emerged as a promising targeted therapy for CCA patients harboring FGFR2 fusions or rearrangements. This systematic review evaluated the safety and efficacy of pemigatinib in this patient population.

Methods

A comprehensive systematic review was conducted across PubMed, Scopus, Embase, Cochrane Library, and Web of Science to identify studies investigating pemigatinib in CCA patients. Five studies involving a total of 459 patients met the inclusion criteria.

Results

Pemigatinib demonstrated an overall objective response rate (ORR) of 43.2%, with a complete response (CR) achieved in 3% of patients. Stable disease was observed in 36.9% of patients, while 14.9% experienced disease progression. Median progression-free survival (PFS) varied across studies, due to differences in patient cohorts. The most common adverse effects (AEs) included hyperphosphatemia (48%), diarrhea (28.6%), fatigue (33%), and dry eyes (20.1%).

Conclusions

This systematic review suggests that pemigatinib has modest therapeutic efficacy in CCA patients, with a considerable proportion achieving disease control. However, the ORR of less than 50% highlights the potential need for combination or sequential therapies to improve outcomes. Close monitoring and management of AEs, particularly hyperphosphatemia, are crucial for optimizing treatment. Further large-scale randomized trials and research are warranted to identify predictive biomarkers and optimize pemigatinib-based treatment strategies for CCA patients with FGFR2 alterations.

Targeting FGFR Attenuates Tumor Growth in an Anal Squamous Cell Carcinoma Patient Derived Xenograft Model

Anal squamous cell carcinoma (ASCC) is a rare malignancy with a rising incidence and limited treatment options. To identify actionable therapeutic targets, we developed a patient-derived xenograft (PDX) model using a metastatic ASCC sample and performed single-cell RNA sequencing. Our analysis confirmed previously reported genetic mutations highly expressed in the sample, along with copy number alterations, and revealed epithelial cancer cell heterogeneity. Notably, epithelial cells exhibited a low hybrid epithelial-mesenchymal transition (hEMT) signature compared to stromal cells. Among epithelial subpopulations, the most abundant cluster displayed high expression of FGFR1-2 and FGF ligands. Treatment with AZD4547, an FGFR1-3 inhibitor, resulted in a significant reduction in tumor volume over time (p = 0.0036). Immunohistochemistry staining for proliferative Ki67 and cleaved caspase 3 suggested ongoing proliferation in residual cells. Fourier-transform infrared (FTIR) spectroscopy of post-treatment residual tumors revealed significant differences in the Amide I and Amide II regions between AZD4547-treated and control groups. These findings demonstrate that FGFR inhibition effectively attenuates ASCC tumor growth and highlights the promise of precision medicine in managing this rare cancer.

Treating intrahepatic cholangiocarcinoma with pemigatinib: two case reports of Nordic patients

BACKGROUND

Cholangiocarcinoma (CCA) is a diverse group of aggressive liver tumors with up to 20% being intrahepatic CCA (iCCA). Up to 15% of patients with iCCA have fibroblast growth factor receptor 2 (FGFR2) fusions or rearrangements. Here we evaluated iCCA treatment with pemigatinib, a selective inhibitor of FGFR1-3, in two patients from Denmark and Finland.

PATIENTS

We identified a total of two Nordic patients with iCCA in our clinics, who received first-line cisplatin/gemcitabine before initiating pemigatinib.

RESULTS

Case 1 was a 34-year-old woman with aggressive, metastatic iCCA upon presentation, who progressed on cisplatin/gemcitabine. Pemigatinib was initiated after FGFR2 fusion detection by genomic testing. She had a partial response after three cycles (9 weeks) of pemigatinib but experienced disease progression after three more pemigatinib cycles. Adverse events were primarily managed by supportive care and dose reduction, except hyperphosphatemia, which was complicated by food allergies and required medication. She received subsequent chemotherapy but deteriorated rapidly and died 1 month later. Case 2 was an 81-year-old man with unresectable iCCA who achieved stable disease with first-line chemotherapy. He switched to pemigatinib after FGFR2 fusion detection by next-generation sequencing. The tumor shrank by 20% after three pemigatinib cycles and completely calcified with continued treatment. Adverse events were managed by two dose adjustments. Treatment has continued for 57 months and is ongoing.

INTERPRETATION

CCA is an aggressive disease that requires early molecular testing of abundant biopsy tissue so not to delay second-line therapies, such as pemigatinib. Variability in treatment outcomes is expected.

Safety and Activity of Fibroblast Growth Factor Receptor Inhibitors in Advanced Malignancies: A Pooled Analysis of Early-Phase Clinical Trials

PURPOSE

Aberrant signaling through the fibroblast growth factor receptor (FGFR) due to activating somatic alterations has been associated with multiple malignancies. FGFR inhibitors (FGFRi) with distinct profiles recently entered standard of care. This work summarizes the experience of a dedicated clinical trial unit with FGFRi developed in the last decade within the context of clinical trials.

METHODS

Demographic and clinical data were collected for patients enrolled in FGFR-targeting phase I to II trials conducted at Sarah Cannon Research Institute, United Kingdom between January 2012 and August 2023.

RESULTS

Fifty-four patients across seven trials were identified: 50% male; median age 55 years. An FGFR alteration was present in 81% of cases; rearrangements, amplifications, and mutations were present in 59%, 43%, and 9.1% of the cases, respectively, with coexisting alterations in 27%. The most frequent primary tumors were cholangiocarcinomas (31%), urothelial (15%), and colorectal (15%); 85% of the patients were FGFRi-naïve. The most common adverse events (AEs) were hyperphosphatemia (42%), dry mouth (35%), fatigue (24%), mucositis (24%), nail changes (22%), and palmar-plantar erythrodysesthesia (20%), with significant differences between pan-FGFRi and FGFR-2i. The rate of G3 AEs was 22%; no G4-5 events were observed. The median time on treatment was 3.5 months (0.2-72.8). Higher disease control rate was observed in the presence of any FGFR alteration, compared with all-comers (odds ratio [OR], 7; P = .0226). The objective response rate was 38%, 25%, and 25% in patients with gene rearrangements, amplification, and mutations, respectively. The median duration of response was 2.3 months (1.6-7.7). After a median follow-up time of 20 months (95% CI, 12.9 to 71.8), median progression-free survival (mPFS) was 3.2 months (95% CI, 1.9 to 4.6) and median overall survival was 13 months (95% CI, 6.4 to 19.6). PFS was significantly different by response, FGFR status, and tumor type. Patients who experienced a G2-3 AE were more likely to achieve a response (OR, 5.24; P = .0256).

CONCLUSION

FGFRi are effective treatment strategies for patients with advanced solid tumors harboring FGFR alterations, with manageable toxicities in most patients.

Activation of FGFR genes by genetic and epigenetic alterations in uterine leiomyomas

BACKGROUND

Fibroblast growth factor 1-4 (FGFR1-4) are well-known oncogenic drivers in many cancer types. Here, we studied the role of FGFRs in uterine leiomyoma (UL) that is a benign neoplasm arising from the myometrium and the most common tumour in women. Although ULs can be classified to molecular subtypes based on genetic drivers, potential secondary drivers are not well characterised.

METHODS

We performed mutation analysis of RNA-sequencing data of ULs, followed by screening of FGFR alterations in our Finnish (n = 2677) and Swedish (n = 372) UL collections, utilising Sanger-, next-generation and Nanopore sequencing and SNP array data. The role of FGFR genes in UL predisposition was examined by GWAS.

RESULTS

We identified FGFR activation in a subset of ULs on both genetic and epigenetic levels. In addition to single-nucleotide mutations in FGFR1/2, we detected an FGFR2-ERC1 fusion gene, FGFR1 gains and hypomethylation of regulatory regions of FGFR2/3. FGFR alterations were enriched in molecularly similar HMGA2, HMGA1 and PLAG1 UL subtypes. We also unveil a UL predisposing variant upstream of FGFR4 associated with increased expression in both normal myometrium and ULs.

CONCLUSIONS

Our results establish the role of FGFR signalling in the genesis of UL.

Preparation and Characterization of an Engineered FGF1 Conjugated to 161Tb for Targeting of FGFRs

The fibroblast growth factor receptor family members, FGFR1-4, are frequently overexpressed in various solid tumors, including breast cancer and sarcomas. This overexpression highlights the potential of the family of FGFRs as promising targets for cancer therapy. However, conventional FGFR kinase inhibitors often encounter challenges such as limited efficacy or drug resistance. In this study, we pursue an alternative strategy by designing a conjugate of the FGFR ligand FGF1 with the radioisotope 161Tb, for targeted therapy in FGFR-overexpressing cancer cells. FGF1 was engineered (eFGF1) to incorporate a single cysteine at the C terminus for site-specific labeling with a DOTA chelator. eFGF1-DOTA was mixed with the radioisotope 161Tb under mild conditions, resulting in a labeling efficiency above 90%. The nonradioactive ligands were characterized by mass spectrometry, while radioligands were characterized by thin-layer chromatography. The targeting function of the radioligands was assessed through confocal microscopy, flow cytometry, and Western blot analysis, focusing on binding to cancer cells and the activation of downstream signaling pathways related to FGFR. When compared to MCF-7 and RD cell lines with low FGFR expression, eFGF1-DOTA-Tb[161Tb] radioligands demonstrated significantly higher accumulation in FGFR-overexpressing cell lines (MCF-7 FGFR1 and RMS559), leading to enhanced cytotoxicity. Besides radionuclides, eFGF1 can also deliver doxorubicin (DOX) into cancer cells. Considering these characteristics, eFGF1-DOTA-Tb[161Tb] and eFGF1-DOX emerge as promising candidates for FGFR-targeted cancer therapy, and further evaluation in vivo is warranted.

Exploring potential plasma drug targets for cholelithiasis through multiancestry Mendelian randomization

BACKGROUND

Cholelithiasis poses significant health and economic burdens, necessitating novel pharmacological targets to enhance treatment efficacy.

METHOD

Based on genome-wide association analysis studies, the authors performed a two-sample Mendelian randomization (MR) analysis based on plasma proteomics to explore potential drug targets in European (n Case =40 191 and n Control =361 641) and Asian (n Case =9305 and n Control =168 253) populations. The authors confirmed the directionality and robust correlation of the drug targets with the results through reverse MR analysis, Steiger filtering, Bayesian colocalization, phenotype scanning, and replication in multiple databases. Further exploration of the safety and possible mechanisms of action of phenome-wide MR analysis and protein-protein interactions (PPIs) as individual drug targets was performed.

RESULTS

Our proteomics-based MR analyses suggested that FUT3 (OR=0.87; 95% CI: 0.84-0.89; P =4.70×10 -32 ), NOE1 (OR=0.58; 95% CI: 0.52-0.66; P =4.21×10 -23 ), UGT1A6 (OR=0.68; 95% CI: 0.64-0.73; P =9.58×10 -30 ), and FKBP52 (OR=1.75; 95% CI: 1.37-2.24; P =8.61×10 -6 ) were potential drug targets in Europeans, whereas KLB (OR=1.11; 95% CI: 1.07-1.16; P =7.59×10 -7 ) and FGFR4 (OR=0.94; 95% CI: 0.91-0.96; P =4.07×10 -6 ) were valid targets in East Asians. There was no reverse causality for these drug targets. Evidence from Bayesian colocalization analyses supported that exposure and outcome shared consistent genetic variables. Phenome-wide MR analysis suggested the potential deleterious effects of NOE1 and FGFR4. PPI analysis confirmed the pathways associated with the potential targets involved in bile acid metabolism.

CONCLUSIONS

Genetically predicted levels of the plasma proteins FUT3, NOE1, UGT1A6, and FKBP52 have the potential as prospective targets in Europeans. Moreover, the plasma levels of KLB and FGFR4 may serve as potential targets for the treatment of cholelithiasis in East Asians.

The Complexity and Significance of Fibroblast Growth Factor (FGF) Signaling for FGF-Targeted Cancer Therapies

Fibroblast growth factors (FGFs) have diverse functions in the regulation of cell proliferation and differentiation in development, tissue maintenance, wound repair, and angiogenesis. The goal of this review paper is to (i) deliberate on the role of FGFs and FGF receptors (FGFRs) in different cancers, (ii) present advances in FGF-targeted cancer therapies, and (iii) explore cell signaling mechanisms that explain how FGF expression becomes dysregulated during cancer development. FGF is often mutated and overexpressed in cancer and the different FGF and FGFR isoforms have unique expression patterns and distinct roles in different cancers. Among the FGF members, the FGF 15/19 subfamily is particularly interesting because of its unique protein structure and role in endocrine function. The abnormal expression of FGFs in different cancer types (breast, colorectal, hepatobiliary, bronchogenic, and others) is examined and correlated with patient prognosis. The classification of FGF ligands based on their mode of action, whether autocrine, paracrine, endocrine, or intracrine, is illustrated, and an analysis of the binding specificity of FGFs to FGFRs is also provided. Moreover, the latest advances in cancer therapeutic strategies involving small molecules, ligand traps, and monoclonal antibody-based FGF inhibitors are presented. Lastly, we discuss how the dysregulation of FGF and FGFR expression affects FGF signaling and its role in cancer development.

Engineering an fgfr4 knockout zebrafish to study its role in development and disease

Fibroblast growth factor receptor 4 (FGFR4) has a role in many biological processes, including lipid metabolism, tissue repair, and vertebrate development. In recent years, FGFR4 overexpression and activating mutations have been associated with numerous adult and pediatric cancers. As such, FGFR4 presents an opportunity for therapeutic targeting which is being pursued in clinical trials. To understand the role of FGFR4 signaling in disease and development, we generated and characterized three alleles of fgfr4 knockout zebrafish strains using CRISPR/Cas9. To generate fgfr4 knockout crispants, we injected single-cell wildtype zebrafish embryos with fgfr4 targeting guide RNA and Cas9 proteins, identified adult founders, and outcrossed to wildtype zebrafish to create an F1 generation. The generated mutations introduce a stop codon within the second Ig-like domain of Fgfr4, resulting in a truncated 215, 223, or 228 amino acid Fgfr4 protein compared to 922 amino acids in the full-length protein. All mutant strains exhibited significantly decreased fgfr4 mRNA expression during development, providing evidence for successful knockout of fgfr4 in mutant zebrafish. We found that, consistent with other Fgfr4 knockout animal models, the fgfr4 mutant fish developed normally; however, homozygous fgfr4 mutant zebrafish were significantly smaller than wildtype fish at three months post fertilization. These fgfr4 knockout zebrafish lines are a valuable tool to study the role of FGFR4 in vertebrate development and its viability as a potential therapeutic target in pediatric and adult cancers, as well as other diseases.

The FGFR inhibitor Rogaratinib reduces microglia reactivity and synaptic loss in TBI

Background

Traumatic brain injury (TBI) induces an acute reactive state of microglia, which contribute to secondary injury processes through phagocytic activity and release of cytokines. Several receptor tyrosine kinases (RTK) are activated in microglia upon TBI, and their blockade may reduce the acute inflammation and decrease the secondary loss of neurons; thus, RTKs are potential therapeutic targets. We have previously demonstrated that several members of the Fibroblast Growth Factor Receptor (FGFR) family are transiently phosporylated upon TBI; the availability for drug repurposing of FGFR inhibitors makes worthwhile the elucidation of the role of FGFR in the acute phases of the response to TBI and the effect of FGFR inhibition.

Methods

A closed, blunt, weight-drop mild TBI protocol was employed. The pan-FGFR inhibitor Rogaratinib was administered to mice 30min after the TBI and daily up to 7 days post injury. Phosphor-RTK Arrays and proteomic antibody arrays were used to determine target engagement and large-scale impact of the FGFR inhibitor. pFGFR1 and pFGFR3 immunostaining were employed for validation. As outcome parameters of the TBI injury immunostainings for NeuN, VGLUT1, VGAT at 7dpi were considered.

Results

Inhibition of FGFR during TBI restricted phosphorylation of FGFR1, FGFR3, FGFR4 and ErbB4. Phosphorylation of FGFR1 and FGFR3 during TBI was traced back to Iba1+ microglia. Rogaratinib substantially dowregulated the proteomic signature of the neuroimmunological response to trauma, including the expression of CD40L, CXCR3, CCL4, CCR4, ILR6, MMP3 and OPG. Prolonged Rogaratinib treatment reduced neuronal loss upon TBI and prevented the loss of excitatory (vGLUT+) synapses.

Conclusion

The FGFR family is involved in the early induction of reactive microglia in TBI. FGFR inhibition selectively prevented FGFR phosphorylation in the microglia, dampened the overall neuroimmunological response and enhanced the preservation of neuronal and synaptic integrity. Thus, FGFR inhibitors may be relevant targets for drug repurposing aimed at modulating microglial reactivity in TBI.

Clinical advances and challenges in targeting FGF/FGFR signaling in lung cancer

Fibroblast growth factors (FGFs) and their receptors regulate numerous cellular processes, such as metabolism and signal transduction, but can also drive tumorigenesis. Specifically, in lung cancer, the overexpression of FGFs, as well as the amplification, mutation and fusion of FGFR genes, are closely linked to the initiation, progression and resistance of the disease, suggesting that targeting FGF/FGFR is an attractive therapeutic strategy for lung cancer treatment. Nintedanib, a multitarget tyrosine kinase inhibitor (TKI) used in combination with docetaxel, has shown some success as a second-line therapy for lung cancer. However, clinical trials evaluating other FGFR inhibitors have yielded mixed results, indicating substantial complexity in targeting aberrant FGF/FGFR signaling. In this review, we describe the aberrations in FGF/FGFR signaling in lung cancer and summarize the clinical efficacy of FGFR inhibitors, such as multitarget TKIs, selective FGFR-TKIs and biological agents. We also discuss various challenges associated with FGFR targeting in lung cancer, including precision patient selection, toxicity and resistance. Finally, we provide perspectives on future directions, namely, developing novel FGFR-targeting drugs, such as FGFR degraders and more specific FGFR-TKIs, adopting combination therapy and targeting FGFs.

The Clinical and Molecular Landscape of Rosette-Forming Glioneuronal Tumors

BACKGROUND

Rosette-Forming Glioneuronal Tumors (RGNTs) are rare, typically benign central nervous system tumors primarily located in the fourth ventricle and pineal region. Despite being classified as WHO grade I with generally favorable prognoses, RGNTs present complexities in their molecular mechanisms, occasional malignant transformation, and epidemiological characteristics that require further investigation.

METHOD

This study systematically reviews the existing literature to analyze the epidemiological patterns, MRI characteristics, pathological features, diagnostic challenges, and molecular mechanisms associated with RGNTs, aiming to provide a comprehensive theoretical foundation for clinical practice and future research.

RESULTS

Through an in-depth review of recent studies, key molecular mechanisms, including mutations in FGFR1, PIK3CA, TERT, and IDH1/2, are highlighted. Additionally, the challenges in accurate diagnosis and the potential for misdiagnosis are discussed, emphasizing the importance of thorough molecular analysis in clinical settings. The literature indicates that RGNTs predominantly affect young adults and adolescents, with a slight female predominance. MRI typically reveals mixed cystic-solid lesions, often accompanied by hydrocephalus. Pathologically, RGNTs are characterized by a combination of neuronal and glial components, with immunohistochemical staining showing positivity for Synaptophysin and GFAP. High frequencies of FGFR1 and PIK3CA mutations underscore the significance of these pathways in RGNT pathogenesis and progression. Although RGNTs generally exhibit low malignancy, the TERT mutations identified in some cases suggest a risk of malignant transformation.

CONCLUSIONS

This study concludes that while current treatment strategies focus on surgical resection, integrating molecular diagnostics and targeted therapies may be essential for managing recurrent or refractory RGNTs. Future research should explore the impact of various gene mutations on tumor behavior and their correlation with clinical outcomes, to optimize individualized therapeutic strategies and improve patient survival and quality of life.

FGFR3 alterations in bladder cancer: Sensitivity and resistance to targeted therapies

In this review, we revisit the pivotal role of fibroblast growth factor receptor 3 (FGFR3) in bladder cancer (BLCA), underscoring its prevalence in both non-muscle-invasive and muscle-invasive forms of the disease. FGFR3 mutations in up to half of BLCAs play a well-established role in tumorigenesis, shaping distinct tumor initiation patterns and impacting the tumor microenvironment (TME). Emphasizing the importance of considering epithelial-mesenchymal transition profile and TME status, we revisit their relevance in predicting responses to immune checkpoint inhibitors in FGFR3-mutated BLCAs. This writing highlights the initially promising yet transient efficacy of the FGFR inhibitor Erdafitinib on FGFR3-mutated BLCA, stressing the pressing need to unravel resistance mechanisms and identify co-targets for future combinatorial studies. A thorough analysis of recent preclinical and clinical evidence reveals resistance mechanisms, including secondary mutations, epigenetic alterations in pathway effectors, phenotypic heterogeneity, and population-specific variations within FGFR3 mutational status. Lastly, we discuss the potential of combinatorial treatments and concepts like synthetic lethality for discovering more effective targeted therapies against FGFR3-mutated BLCA.

Discovery of TYRA-300: First Oral Selective FGFR3 Inhibitor for the Treatment of Urothelial Cancers and Achondroplasia

Activating FGFR3 alterations have been identified in up to 15-20% of muscle-invasive bladder cancer and metastatic urothelial carcinoma (mUC), and as high as 80% in nonmuscle invasive bladder cancers. FGFR3 germline mutations have also been associated with a variety of skeletal dysplasias. Achondroplasia, the most common form of dwarfism in humans, results from a G380R mutation in FGFR3. The pan-FGFR inhibitor erdafitinib was approved for the treatment of mUC with FGFR3 alterations but is limited due to FGFR isoform off-target toxicities and the development of on-target gatekeeper resistance mutations. TYRA-300 (22) was conceived using a structure-based approach as a potent FGFR3-selective inhibitor to avoid the toxicities associated with inhibition of FGFR1, FGFR2, and FGFR4, and to be agnostic for the FGFR3 gatekeeper mutations. TYRA-300 is being evaluated in a Phase 1 clinical trial in urothelial cancers and solid tumors, with intention to initiate Phase 2 studies in urothelial cancers and achondroplasia.

Discovery and characterization of novel FGFR1 inhibitors in triple-negative breast cancer via hybrid virtual screening and molecular dynamics simulations

The overexpression of FGFR1 is thought to significantly contribute to the progression of triple-negative breast cancer (TNBC), impacting aspects such as tumorigenesis, growth, metastasis, and drug resistance. Consequently, the pursuit of effective inhibitors for FGFR1 is a key area of research interest. In response to this need, our study developed a hybrid virtual screening method. Utilizing KarmaDock, an innovative algorithm that blends deep learning with molecular docking, alongside Schrödinger's Residue Scanning. This strategy led us to identify compound 6, which demonstrated promising FGFR1 inhibitory activity, evidenced by an IC50 value of approximately 0.24 nM in the HTRF bioassay. Further evaluation revealed that this compound also inhibits the FGFR1 V561M variant with an IC50 value around 1.24 nM. Our subsequent investigations demonstrate that Compound 6 robustly suppresses the migration and invasion capacities of TNBC cell lines, through the downregulation of p-FGFR1 and modulation of EMT markers, highlighting its promise as a potent anti-metastatic therapeutic agent. Additionally, our use of molecular dynamics simulations provided a deeper understanding of the compound's specific binding interactions with FGFR1.

The evolving landscape of tissue-agnostic therapies in precision oncology

Tumor-agnostic therapies represent a paradigm shift in oncology by altering the traditional means of characterizing tumors based on their origin or location. Instead, they zero in on specific genetic anomalies responsible for fueling malignant growth. The watershed moment for tumor-agnostic therapies arrived in 2017, with the US Food and Drug Administration's historic approval of pembrolizumab, an immune checkpoint inhibitor. This milestone marked the marriage of genomics and immunology fields, as an immunotherapeutic agent gained approval based on genomic biomarkers, specifically, microsatellite instability-high or mismatch repair deficiency (dMMR). Subsequently, the approval of NTRK inhibitors, designed to combat NTRK gene fusions prevalent in various tumor types, including pediatric cancers and adult solid tumors, further underscored the potential of tumor-agnostic therapies. The US Food and Drug Administration approvals of targeted therapies (BRAF V600E, RET fusion), immunotherapies (tumor mutational burden ≥10 mutations per megabase, dMMR) and an antibody-drug conjugate (Her2-positive-immunohistochemistry 3+ expression) with pan-cancer efficacy have continued, offering newfound hope to patients grappling with advanced solid tumors that harbor particular biomarkers. In this comprehensive review, the authors delve into the expansive landscape of tissue-agnostic targets and drugs, shedding light on the rationale underpinning this approach, the hurdles it faces, presently approved therapies, voices from the patient advocacy perspective, and the tantalizing prospects on the horizon. This is a welcome advance in oncology that transcends the boundaries of histology and location to provide personalized options.

Engineering an fgfr4 knockout zebrafish to study its role in development and disease

Fibroblast growth factor receptor 4 (FGFR4) has a role in many biological processes, including lipid metabolism, tissue repair, and vertebrate development. In recent years, FGFR4 overexpression and activating mutations have been associated with numerous adult and pediatric cancers. As such, FGFR4 presents an opportunity for therapeutic targeting which is being pursued in clinical trials. To understand the role of FGFR4 signaling in disease and development, we generated and characterized three alleles of fgfr4 knockout zebrafish strains using CRISPR/Cas9. To generate fgfr4 knockout crispants, we injected single-cell wildtype zebrafish embryos with fgfr4 targeting guide RNA and Cas9 proteins, identified adult founders, and outcrossed to wildtype zebrafish to create an F1 generation. The generated mutations introduce a stop codon within the second Ig-like domain of Fgfr4, resulting in a truncated 215, 223, or 228 amino acid Fgfr4 protein compared to 922 amino acids in the full-length protein. All mutant strains exhibited significantly decreased fgfr4 mRNA expression during development, providing evidence for successful knockout of fgfr4 in mutant zebrafish. We found that, consistent with other Fgfr4 knockout animal models, the fgfr4 mutant fish developed normally; however, homozygous fgfr4 mutant zebrafish were significantly smaller than wildtype fish at three months post fertilization. These fgfr4 knockout zebrafish lines are a valuable tool to study the role of FGFR4 in vertebrate development and its viability as a potential therapeutic target in pediatric and adult cancers, as well as other diseases.

Erdafitinib and checkpoint inhibitors for first-line and second-line immunotherapy of hepatic, gastrointestinal, and urinary bladder carcinomas: Recent concept

Cancer immunotherapy is administered for first-line, second-line, neoadjuvant, or adjuvant treatment of advanced, metastatic, and recurrent cancer in the liver, gastrointestinal tract, and genitourinary tract, and other solid tumors. Erdafitinib is a fibroblast growth factor receptor (FGFR) inhibitor, and it is an adenosine triphosphate competitive inhibitor of FGFR1, FGFR2, FGFR3, and FGFR4. Immune checkpoint inhibitors are monoclonal antibodies that block programmed cell death protein 1 (PD-1) and its ligand that exert intrinsic antitumor mechanisms. The promising results of first-line treatment of advanced and metastatic urothelial carcinoma with PD-1 blockades with single or combined agents, indicate a new concept in the treatment of advanced, metastatic, and recurrent hepatic and gastrointestinal carcinomas. Cancer immunotherapy as first-line treatment will improve overall survival and provide better quality of life. Debate is arising as to whether to apply the cancer immunotherapy as first-line treatment in invasive carcinomas, or as second-line treatment in recurrent or metastatic carcinoma following the standard chemotherapy. The literature in the field is not definite, and so far, there has been no consensus on the best approach in this situation. At present, as it is described in this editorial, the decision is applied on a case-by-case basis.

Discovery of lirafugratinib (RLY-4008), a highly selective irreversible small-molecule inhibitor of FGFR2

Fibroblast growth factor receptor (FGFR) kinase inhibitors have been shown to be effective in the treatment of intrahepatic cholangiocarcinoma and other advanced solid tumors harboring FGFR2 alterations, but the toxicity of these drugs frequently leads to dose reduction or interruption of treatment such that maximum efficacy cannot be achieved. The most common adverse effects are hyperphosphatemia caused by FGFR1 inhibition and diarrhea due to FGFR4 inhibition, as current therapies are not selective among the FGFRs. Designing selective inhibitors has proved difficult with conventional approaches because the orthosteric sites of FGFR family members are observed to be highly similar in X-ray structures. In this study, aided by analysis of protein dynamics, we designed a selective, covalent FGFR2 inhibitor. In a key initial step, analysis of long-timescale molecular dynamics simulations of the FGFR1 and FGFR2 kinase domains allowed us to identify differential motion in their P-loops, which are located adjacent to the orthosteric site. Using this insight, we were able to design orthosteric binders that selectively and covalently engage the P-loop of FGFR2. Our drug discovery efforts culminated in the development of lirafugratinib (RLY-4008), a covalent inhibitor of FGFR2 that shows substantial selectivity over FGFR1 (~250-fold) and FGFR4 (~5,000-fold) in vitro, causes tumor regression in multiple FGFR2-altered human xenograft models, and was recently demonstrated to be efficacious in the clinic at doses that do not induce clinically significant hyperphosphatemia or diarrhea.

Pemigatinib: A Review in Advanced Cholangiocarcinoma

Pemigatinib (Pemazyre®), a selective, potent, reversible, oral inhibitor of fibroblast growth factor receptor (FGFR) 1-3, has received conditional (in the EU) or accelerated (in the USA) approval for the treatment of adults with previously treated, unresectable locally-advanced or metastatic cholangiocarcinoma (CCA) with an FGFR2 gene fusion or rearrangement. Over the course of a single-arm, phase 2 study (FIGHT-202), just over a third of patients with pretreated, advanced CCA [almost exclusively intrahepatic CCA (iCCA)] harbouring an FGFR2 fusion or rearrangement who received pemigatinib once daily (2 weeks on, 1 week off) had an objective response; nearly half had stable disease. Median progression-free survival and overall survival at the time of the final analysis were 7.0 months and 17.5 months, respectively. Pemigatinib was generally well tolerated and had a manageable safety profile. The most common treatment-related adverse event, hyperphosphataemia, was exclusively grade 1-2 in severity and, similarly, observed ocular and nail toxicities were rarely grade ≥ 3 in severity. Pending confirmation of its clinical benefits in an ongoing cisplatin plus gemcitabine-controlled, phase 3 study (FIGHT-302), pemigatinib provides a valuable targeted therapy for pretreated patients with advanced (i)CCA harbouring a FGFR2 fusion or rearrangement.

Durable benefit and slowdown in tumor growth dynamics with erdafitinib in a FGFR3-TACC3 fusion-positive IDH-wild type glioblastoma

FGFR3-TACC3 fusion-positive IDH-wild-type (IDH-WT) glioblastoma (GB) is a rare GB subtype occurring in approximately 3% of cases. It is clinical behavior and molecular profile is different from those of fusion-negative IDH-WT GBs. Evidence on the role of FGFR inhibitors in FGFR-altered gliomas is limited. We present the case of a patient with a FGFR3-TACC3 fusion-positive IDH-WT GB that at its second recurrence was treated with the FGFR inhibitor erdafitinib through a compassionate use program. Although no objective response was achieved, an overt deceleration in tumor growth was evidenced and the patient remained on treatment for 5.5 months.