Fibroblast Growth Factor Receptor Fusions Research Articles

Novel therapies for pediatric low grade glioma.

Current biological findings provide new insights into the genetics driving growth of low-grade gliomas in pediatric patients. This has provided new targets for novel therapies. The purpose of this paper is to review novel therapies for pediatric low-grade gliomas that have been published in the past 24 months. Low-grade gliomas are often driven by mitogen activated protein kinase (MAPK) alterations either with BRAF V600E point mutations or BRAF fusions. Current advances have also highlighted novel fusions of fibroblast growth factor receptor (FGFR), myeloblastosis family of transcription factors (MYB), meningioma 1 tumor suppressor (MN1), neurotrophic receptor kinase family of receptors (NTRK), Kristen RAS (Rat Sarcoma Virus) oncogene homolog in mammals (KRAS), Receptor tyrosine kinase ROS proto oncogene 1 (ROS1), protein kinase C alpha (PRKCA), and platelet derive growth factor receptor (PDGFR) amplification. Novel therapies have been employed and are showing encouraging results in pediatric low-grade gliomas. Current trials are underway with newer generation pan RAF inhibitors and mitogen activated protein kinase - kinase (MEK) inhibitors. Other early phase clinical trials have provided safety data in pediatric patients targeting FGFR fusion, NTRK fusion, PDGFR amplification and ROS1 mutations. Historical treatment options in pediatric low-grade gliomas have utilized surgery, radiation therapy and conventional chemotherapy. Recently greater insight into their biology has found that alterations in MAPK driven pathways are often the hallmark of tumorigenesis. Targeting these novel pathways has led to tumor control and shrinkage without the use of conventional chemotherapy. Caution should be taken however, since these treatment options are still novel, and we do not fully appreciate the long-term effects. Nonetheless a new era of targeted medicine is here.

FGFR2-fusions define a clinically actionable molecular subset of pancreatic cancer

Genomic alterations in fibroblast growth factor receptor (FGFR) genes are present in a small number of metastatic pancreatic ductal adenocarcinomas (PDAC) and may represent an emerging subgroup of patients likely to benefit from FGFR targeted therapies. Here we present four FGFR2 fusion-positive metastatic PDAC patients who exhibited durable responses or disease control to FGFR kinase inhibitors. Utilizing our custom FGFR focused cell-free DNA assay, FGFR-Dx, we serially monitored variant allele fractions of FGFR2 fusions during FGFR inhibitor treatment and observed dynamic changes correlating with clinical responses. Genomic analysis of 30,229 comprehensively profiled pancreatic cancers revealed FGFR1-3 fusions in 245 cases, an incidence of 0.81%. FGFR fusions were generally mutually exclusive from other known oncogenes. Our findings provide clinical evidence for identifying and treating FGFR2 fusion-positive PDAC patients with FGFR targeted therapy.

Expert Consensus on the Diagnosis and Treatment of FGFR Gene-Altered Solid Tumors

AbstractThe fibroblast growth factor receptor (FGFR) is a crucial receptor tyrosine kinase involved in essential biological processes, including growth, development, and tissue repair. However, FGFR gene mutations, including amplification, fusion, and mutation, can disrupt epigenetics, transcriptional regulation, and tumor microenvironment interactions, leading to cancer development. Targeting these kinase mutations with small molecule drugs or antibodies has shown clinical benefits. For example, erdafitinib is approved for treating locally advanced or metastatic urothelial cancer patients with FGFR2/FGFR3 mutations, and pemigatinib is approved for treating cholangiocarcinoma with FGFR2 fusion/rearrangement. Effective screening of FGFR variant patients is crucial for the clinical application of FGFR inhibitors. Various detection methods, such as polymerase chain reaction, next-generation sequencing, fluorescence in situ hybridization, and immunohistochemistry, are available, and their selection should be based on diagnostic and treatment decision-making needs. Our developed expert consensus aims to standardize the diagnosis and treatment process for FGFR gene mutations and facilitate the practical application of FGFR inhibitors in clinical practice.

EANO guideline on rational molecular testing of gliomas, glioneuronal, and neuronal tumors in adults for targeted therapy selection.

The mainstay of treatment for adult patients with gliomas, glioneuronal and neuronal tumors consists of combinations of surgery, radiotherapy, and chemotherapy. For many systemic cancers, targeted treatments are a part of the standard of care, however, the predictive significance of most of these targets in central nervous system (CNS) tumors remains less well-studied. Despite that, there is increasing use of advanced molecular diagnostics that identify potential targets, and tumor-agnostic regulatory approvals on targets also present in CNS tumors have been granted. This raises the question of when and for which targets it is meaningful to test in adult patients with CNS tumors. This evidence-based guideline reviews the evidence available for targeted treatment for alterations in the RAS/MAPK pathway (BRAF, NF1), in growth factor receptors (EGFR, ALK, fibroblast growth factor receptor (FGFR), neurotrophic tyrosine receptor kinase (NTRK), platelet-derived growth factor receptor alpha, and ROS1), in cell cycle signaling (CDK4/6, MDM2/4, and TSC1/2) and altered genomic stability (mismatch repair, POLE, high tumor mutational burden (TMB), homologous recombination deficiency) in adult patients with gliomas, glioneuronal and neuronal tumors. At present, targeted treatment for BRAF p.V600E alterations is to be considered part of the standard of care for patients with recurrent gliomas, pending regulatory approval. For approved tumor agnostic treatments for NTRK fusions and high TMB, the evidence for efficacy in adult patients with CNS tumors is very limited, and treatment should preferably be given within prospective clinical registries and trials. For targeted treatment of CNS tumors with FGFR fusions or mutations, clinical trials are ongoing to confirm modest activity so far observed in basket trials. For all other reviewed targets, evidence of benefit in CNS tumors is currently lacking, and testing/treatment should be in the context of available clinical trials.

Abstract 167: Pre-clinical characterization of a novel series of FGFR2 selective inhibitors with potency against clinically relevant mutations

Abstract The fibroblast growth factor receptor (FGFR) family of protein tyrosine kinases plays a role in many physiological processes including angiogenesis and wound healing. FGFR mutations, fusions, rearrangements, and amplifications have been linked to the pathogenesis of multiple tumor types. For example, approximately 10-15% of patients with intrahepatic cholangiocarcinoma have FGFR2 fusions, and amplification of FGFR2 is prevalent in gastric cancer and implicated in tumor growth. Approved FGFR inhibitors produce responses in patients that harbor FGFR genetic alterations but show reduced activity against key mutations (e.g., V565, N550, etc.). These pan-FGFR inhibitors also frequently show dose-limiting toxicities including hyperphosphatemia which can be linked to the inhibition of FGFR1. To address these issues, a novel series of FGFR inhibitors that are potent and selective reversible inhibitors of FGFR2 with selectivity over FGFR1 have been identified. This series also maintains activity against clinically relevant mutations in the FGFR2 protein. Inhibition of cellular FGFR phosphorylation was measured using engineered cell lines to demonstrate that the inhibitors target both wild-type FGFR2 and activating FGFR2 mutations while sparing FGFR1. In addition, CDX tumor models showed in vivo target engagement and FGFR isoform selectivity. Herein, the in vitro and in vivo characterization of a representative selective reversible FGFR2 inhibitor is described. Citation Format: John Fischer, Karyn Bouhana, Mark J. Chicarelli, Josh Dahlke, Brad Fell, Jennifer Fulton, Anna Guarnieri, Ravi Jalluri, Amber Johnson, Brent Mclean, Max Mejia, Rob Rieger, John Robinson, Mareli Rodriguez, Francis Sullivan, Yang Wang, Shannon Winski, Yeyun Zhou. Pre-clinical characterization of a novel series of FGFR2 selective inhibitors with potency against clinically relevant mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 167.

Screening of FGFR patients for FGFR directed clinical trials in Network Genomic Medicine (NGM): Real-world data.

e21013 Background: The fibroblast growth factor receptor (FGFR) 1-4 genes show a heterogenic landscape of alterations in non-small cell lung cancer (NSCLC) whereas only a small amount is yet considered to have oncogenic potential. The frequency of activating FGFR alterations is low, counting for approximately 2% of NSCLC. We have screened NSCLC patients (pts) for FGFR translocations/mutations within NGM and analysed them on FGFR alteration frequency, patient characteristics and outcome. Methods: From 04/2019 to 01/2020 we screened 472 squamous NSCLC for FGFR gene alterations and from 02/2020 to 12/2021 an additional 5286 patients including all NSCLC cases. Of these 5286 pts, 1097 pts were analysed for FGFR fusions. We used DNA-NGS for FGFR-mutations and RNA-NGS for FGFR–translocations. Activating mutations were defined according to the publicly available molecular data bases and published data. Results: Within the cohort of 5758 NSCLC patients, we found 316 (5.5%) patients with FGFR alterations. Sixty-six (20.9% of FGFR, 1.1% of NSCLC) patients had alterations classified as activating, of whom 39 had FGFR point mutations and 27 FGFR translocations. Concerning the patients with activating alterations, they had UICC stage III or IV at time of diagnosis; 22 were females; 58 patients had squamous cell carcinoma, 6 patients had adenocarcinoma and 2 had large cell neuroendocrine carcinoma. Fifty-three patients (80.3%) with activating FGFR alteration had a co-mutation: TP53 (inactivating) co-mutation was seen in 41 cases (62.1%) and 19 cases had either PTEN (7 pts), KRAS (4), EGFR (3), PIK3CA (2), ROS1 (1), ALK (1) or BRAF (1) mutations. Ten patients were included in a FGFR-targeted trial. Sixty patients were available for follow-up. The median overall survival (mOS) was 21.4 month (95%CI: 16.8–25.9) for all patients with activating FGFR alteration, whereas mOS was 18.5 month (95%CI: 13.2-23.9) for FGFR mutation and 25.3 months (95%CI: 17.8-32.9) for FGFR fusions. Conclusions: FGFR 1-4 gene alterations are rare. Large molecular and clinical networks are necessary to identify these pts. Prognostic factors of FGFR patients are currently not defined. Further assessments on molecular and clinical features in FGFR altered NSCLC are needed to identify sensitivity to FGFR inhibition. Clinical trials with specific FGFR inhibitors are ongoing.

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.

Abstract P3-08-02: The frequency and somatic mutation landscape of Fibroblast growth factor receptor (FGFR) alterations in breast cancer

Abstract Background: FGFR dysregulation is observed in multiple cancers and targeting FGFR is an emerging therapeutic strategy with FDA approved treatments in bladder and cholangiocarcinoma. Here we examined the prevalence of FGFR mutations, fusions, and high-level amplifications in breast cancer, stratified by receptor subtype and local/metastatic status, in both Foundation Medicine (FM) and institutional Mayo Clinic (MC) cohorts. Methods: For the FM cohort, comprehensive genomic profiling (CGP) examining at least 324 genes for all classes of alterations, including FGFR1-4 was carried out for 32,048 breast cancers during the course of routine clinical care in a Clinical Laboratory Improvement Amendments (CLIA)-certified lab (Foundation Medicine Inc., Cambridge, MA, USA). Tumor mutational burden (TMB) was determined on up to 1.1 Mb, microsatellite instability high (MSI-High) was determined on up to 114 loci and predicted ancestry from >10,000 SNPs. Estrogen receptor (ER) and HER2 status were available for a subset of FM samples. Additionally, 131 patients with metastatic breast cancer from a subset of patients at three Mayo Clinic sites (MC cohort) with clinical characteristics and cancer-panel DNA sequencing data from a CLIA-certified lab (Tempus, Chicago, IL) were included. Results: In the FM cohort, the prevalence of FGFR1-4 high-level amplification (CN≥10) was 10.1%, while mutations (1.5%) and fusions (0.72%) were rare. Most amplifications occurred in FGFR1 (9.2%); most fusions and mutations occurred in FGFR2 (0.46%, 0.77%). FGFR alteration prevalence was highest in ER+/HER2- subtype (14.4%) and lowest in HER2+ disease (7.7%). FGFR alterations were more common in IDC (11.7%) than ILC (7.7%), p<3E-08. FGFR alterations were more prevalent in the metastatic setting relative to breast-biopsied disease (13.6% v 10.1%; OR = 1.4; p=2E-17), especially in the HER2+ (OR =1.9, p=0.004) and ER-/HER2- (OR = 1.9, p = 0.05) disease; no enrichment was seen in the ER+/HER2- metastases (OR =1.0, p = 1). FGFR amplifications were observed at a higher prevalence in patients with predicted East Asian ancestry, relative to patients with European ancestry (12.1% v 10.0%; p = 0.03). Overall, the most common activating mutations in FGFR were FGFR2 N549K (n=85), FGFR1 N546K (n=78), FGFR4 V510M (n=28), FGFR2 K659E (n=28), FGFR4 V510L (n=20), and FGFR2 Y375C (n=15). The most common recurrent fusions were FGFR3:TACC3 (n=36), FGFR2:TACC2 (n=17), FGFR1:TACC1 (n=9), FGFR1:BAG4 (n=6), and FGFR2:ATE1 (n=5). In patients with FGFR amplifications, the most frequently co-occurring alterations were ZNF703 (78.4%), TP53 (51.5%), CCND1 (36.1%), FGF3/4/19 (32.9 - 34.4%), PIK3CA (30.7%), MYC (29.6%), ESR1 (17.2%), EMSY (16.3%), and PTEN (10.6%). Significant co-occurrence was observed for a number of genes including FGF3/4/19, CDK4, and CDK8 (all OR>2, p<1E-07); mutual exclusivity was observed with PIK3R1, BRCA1, and BRCA2 (all OR <0.5, p<4E-13), among other genes. In the 131 metastatic tumors from MC, the prevalence of FGFR1-4 high-level amplifications was 19.8% [FGFR1 (12.4%), FGFR2 (7.4%), and FGFR3 (0.8%)]. The prevalence of high-level FGFR amplifications did not differ by clinical subtypes: HR-/HER2- (7/31), HR+/HER2- (15/79), and HER2+ (2/11), p=0.68. Conclusions: High-level FGFR amplifications are observed in >11% of breast cancers, especially the ER+/HER2- subtype, while mutations/fusions are rare. These data support the ongoing studies evaluating targeted therapies for FGFR amplified ER + breast cancer. Correlations with clinical information (MC cohort) and associations with actionable alterations are ongoing and may inform potential combination strategies. Citation Format: Karthik V Giridhar, Ethan S Sokol, Peter T Vedell, Jason P Sinnwell, Aakash Desai, Tufia C Haddad, Ciara C O’Sullivan, Roberto A Leon-Ferre, Siddhartha Yadav, Kostandinos Sideras, Brenda Ernst, Minetta C Liu, Abe Eyman Casey, Xiaojia Tang, Zoe Fleischmann, Karthikeyan Murugesan, Krishna R Kalari, Matthew P Goetz. The frequency and somatic mutation landscape of Fibroblast growth factor receptor (FGFR) alterations in breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-08-02.

Updated analysis with longer follow up of a phase 2a study evaluating erdafitinib in Asian patients (pts) with advanced cholangiocarcinoma (CCA) and fibroblast growth factor receptor (FGFR) alterations.

430 Background: Pts with CCA progressing after first-line therapy have limited treatment options. We report an updated analysis of the ongoing LUC2001 open-label, multicenter, phase 2a study (NCT02699606) investigating the efficacy and safety of erdafitinib in Asian pts with advanced CCA and FGFR alterations who progressed after ≥1 prior systemic treatment. Methods: Eligible adults (aged ≥18 years) received erdafitinib 8 mg once daily (QD) with pharmacodynamically guided up-titration to 9 mg QD. The primary endpoint was objective response rate (ORR; RECIST 1.1); secondary endpoints included best overall response (BOR), disease control rate (DCR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. Survival estimates were determined by the Kaplan–Meier method. Results: Of 232 patients with CCA who underwent molecular screening, 39 (16.8%) had FGFR alterations (21 [9.1%] fusions and 19 [8.2%] mutations). Overall, 22 (9.5%) eligible pts (median age, 52 [range, 29–69] years) were enrolled and received treatment. Median follow-up was 22.4 (range, 2.3–47.0) months; median treatment duration was 6.2 (range, 1.5–35.6) months. All 22 pts received ≥1 line of prior systemic therapy and 12 (55.0%) pts had ≥2 prior lines of therapy. The ORR was 40.9% (95% CI, 20.7%–63.6%) and median time to response was 1.8 (range, 1.5–5.6) months. Median DOR was 7.3 (95% CI, 3.7–17.5) months, median PFS was 5.6 (95% CI, 3.6–12.7) months, and median OS was 40.2 (95% CI: 9.9–not estimable) months (Table). Responses were observed in 8/14 pts with FGFR fusions and 1/8 pts with FGFR mutations and in pts who received 1 or ≥2 prior lines of therapy. All 22 pts had ≥1 treatment-emergent adverse event (TEAE), the most common being dry mouth (15/22 [68.2%]) and stomatitis (14/22 [63.6%]). Grade ≥3 TEAEs occurred in 15/22 (68.2%) pts (11/22 [50.0%] were treatment related), of which the most common were stomatitis (3/22 [13.6%]) and alanine aminotransferase (ALT) increased (3/22 [13.6%]); 11/22 (50.0%) pts had ≥1 serious TEAE (1/22 [4.5%] pts had a serious treatment-related TEAE). A TEAE leading to death occurred in 1 patient (sepsis; not treatment-related). Conclusions: Asian pts with advanced CCA and FGFR alterations treated with erdafitinib had durable efficacy and a manageable safety profile, supporting the earlier findings of erdafitinib benefit in this population. Clinical trial information: NCT02699606. [Table: see text]

Intrahepatic cholangiocarcinoma: Tumour heterogeneity and its clinical relevance.

Treatment of intrahepatic cholangiocarcinoma (iCCA) is currently at a significant turning point due to the identification of isocitrate dehydrogenase (IDH) mutations and fibroblast growth factor receptor (FGFR) fusions that can be targeted with currently available therapies. Clinical trials of these targeted therapies have been promising, and the iCCA patients who may benefit from these targeted treatments can be identified by pathological examination prior to molecular investigations. This is because IDH mutations and FGFR fusions are mainly seen in the small duct type iCCA, a subtype of iCCA defined by the 5th World Health Organization classification, which can be recognized by the pathological diagnostic process. Therefore, pathology plays an important role in precision medicine for iCCA, not only in confirming the diagnosis, but also in identifying the iCCA patients who may benefit from targeted treatments. However, caution is advised with the pathological diagnosis, as iCCA shows tumour heterogeneity, making it difficult to distinguish small duct type iCCA from hepatocellular carcinoma (HCC), and combined HCC-CCA. This review focuses on the pathological/molecular features of both subtypes of iCCA (large and small duct types), as well as their diagnostic pitfalls, clinical relevance, and future perspectives.

Detection of FGFR fusions in intrahepatic cholangiocarcinoma using targeted RNA sequencing.

e16185 Background: Comprehensive sequencing efforts have identified fibroblast growth factor receptor (FGFR) translocations in numerous cancers. FGFR2 fusions were recently identified as an actionable therapeutic target in ̃17% of cholangiocarcinoma patients, predominantly found in patients with intrahepatic cholangiocarcinoma. Genomic partners for FGFR fusions are variable. In addition, obtaining high yield tissue biopsies for CCA remains challenging and tumor tissue available for molecular analyses is scarce. When combined, these two factors make detection of FGFR fusions in CCA challenging. An accurate molecular assay to detect FGFR fusions in CCA could improve utilization of FGFR-targeted therapies. Methods: The objective of our study was to develop an approach for targeted RNA analysis to improve sensitivity for FGFR fusion detection from limited tumor material. We adapted the sensitive targeted digital sequencing (TARDIS) approach recently developed in our lab for analysis of RNA. This approach utilizes a combination of open-ended targeted amplification followed by ligation, enabling detection of tyrosine kinase fusions without prior knowledge of the precise sequence of the fusion breakpoint or identity of the fusion partner. For evaluation of analytical performance, we analyzed RNA from a CCA organoid model with a known FGFR2 fusion, and Seraseq Fusion RNA Mix v3 Reference Material with two known FGFR3 fusions. Results: Without prior knowledge the partner or coordinates of the fusion breakpoint, we detected an FGFR2-KIF5C fusion in RNA from a CCA organoid model. The fusion breakpoint coordinates predicted by TARDIS-RNA were validated by comparison with RNA-Seq. To assess sensitivity and quantitative performance of the assay, we analyzed a serial dilution of the reference RNA sample from Seraseq with concentration of RNA molecules representing candidate fusions verified by digital PCR. Using TARDIS-RNA to analyze replicates with 5 ng RNA input, we were able to detect candidate fusions represented by as few as 2.7 fusion molecules on average. Concentrations of fusion molecules measured using the two methods were highly correlated (R = 0.96). Conclusions: These results demonstrate sensitivity and quantitative performance of a targeted RNA sequencing assay to detect and quantify FGFR fusions in tumor specimen from intrahepatic cholangiocarcinoma. On-going work is focused on further evaluating assay performance and characterizing FGFR fusions using additional tissue specimen.

Targeting FGFR in non-small cell lung cancer: implications from the landscape of clinically actionable aberrations of FGFR kinases.

Objective:Dysfunction in fibroblast growth factor receptor (FGFR) signaling has been reported in diverse cancer types, including non-small cell lung cancer (NSCLC). The frequency of FGFR aberrations in Chinese NSCLC patients is therefore of great clinical significance.Methods:A total of 10,966 NSCLC patients whose tumor specimen and/or circulating cell-free DNA (cfDNA) underwent hybridization capture-based next-generation sequencing were reviewed. Patients’ clinical characteristics and treatment histories were also evaluated.Results:FGFR aberrations, including mutations, fusions, and gene amplifications, were detected in 1.9% (210/10,966) of the population. FGFR abnormalities were more frequently observed in lung squamous cell carcinomas (6.8%, 65/954) than lung adenocarcinomas (1.3%, 128/9,596). FGFR oncogenic mutations were identified in 19 patients (∼0.17%), of which, 68% were male lung squamous cell carcinoma patients. Eleven out of the 19 patients (58%) had concurrent altered PI3K signaling, thus highlighting a potential combination therapeutic strategy of dual-targeting FGFR and PI3K signaling in such patients. Furthermore, FGFR fusions retaining the intact kinase domain were identified in 12 patients (0.11%), including 9 FGFR3-TACC3, 1 FGFR2-INA, 1 novel FGFR4-RAPGEFL1, and 1 novel fusion between the FGFR1 and SLC20A2 5′-untranslated regions, which may have caused FGFR1 overexpressions. Concomitant EGFR mutations or amplifications were observed in 6 patients, and 4 patients received anti-EGFR inhibitors, in whom FGFR fusions may have mediated resistance to anti-EGFR therapies. FGFR amplification was detected in 24 patients, with the majority being FGFR1 amplifications. Importantly, FGFR oncogenic mutations, fusions, and gene amplifications were almost always mutually exclusive events.Conclusions:We report the prevalence of FGFR anomalies in a large NSCLC population, including mutations, gene amplifications, and novel FGFR fusions.

Dermatologic Adverse Events Associated with Selective Fibroblast Growth Factor Receptor Inhibitors: Overview, Prevention, and Management Guidelines.

Fibroblast growth factor receptor (FGFR) tyrosine kinases, which are expressed on the cell membrane, are involved in a wide range of biological functions such as cell proliferation, survival, migration, and differentiation. The identification of FGFR fusions and other alterations in a wide range of solid tumors, including cholangiocarcinoma and bladder cancer, has resulted in the development of several selective FGFR inhibitors for use in these indications, for example, infigratinib, erdafitinib, derazantinib, pemigatinib, and futibatinib. In addition to the typical adverse events associated with tyrosine kinases, the FGFR inhibitors appear to give rise to a number of adverse events affecting the skin. Here we describe these skin events, which include the more common nail adverse events (e.g., onycholysis), palmar–plantar erythrodysesthesia syndrome, and stomatitis, as well as less common reactions such as calciphylaxis. This review aims to provide oncologists with an understanding of these dermatologic events and proposes guidelines for the management of treatment‐emergent dermatologic adverse events. Awareness of possible adverse events associated with specific drugs should allow physicians to educate patients as to what to expect and implement effective management plans at the earliest possible opportunity, thereby preventing premature discontinuation while maintaining patient quality of life.Implications for PracticeIdentification of fibroblast growth factor receptor (FGFR) aberrations in cholangiocarcinoma and bladder cancer led to development of selective FGFR inhibitors for these indications, based on clinical benefit and safety profiles. The most frequent adverse events (AEs) include those affecting skin, hair, and nails, a unique class effect of these agents. These are usually mild to moderate in severity. This work reviewed skin AEs reported with FGFR inhibitors and provides management guidelines for physicians, aiming to increase awareness of skin events and provide effective treatment strategies. Early intervention and effective management may improve treatment adherence, optimize outcomes, and improve quality of life.

A comprehensive pan-cancer study of fibroblast growth factor receptor aberrations in Chinese cancer patients.

BackgroundThe prevalence and types of fibroblast growth factor receptor (FGFR) mutations vary significantly among different ethnic groups. The optimal application of FGFR inhibitors depends on these variations being comprehensively understood. However, such an analysis has yet to be conducted in Chinese patients.MethodsWe retrospectively screened the genomic profiling results of 10,582 Chinese cancer patients across 16 cancer types to investigate the frequency and distribution of FGFR aberrations.ResultsFGFR aberrations were identified in 745 patients, equating to an overall prevalence of 7.0%. A majority of the aberrations occurred on FGFR1 (56.8%), which was followed by FGFR3 (17.7%), FGFR2 (14.4%), and FGFR4 (2.8%). Further, 8.5% of patients had aberrations of more than 1 FGFR gene. The most common types of aberrations were amplification (53.7%), other mutations (38.8%), and fusions (5.6%). FGFR fusion and amplification occurred concurrently in 1.9% of the patients. FGFR aberrations were detected in 12 of the 16 cancers, with the highest prevalence belonging to colorectal cancer (CRC) (31%). Other FGFR-aberrant cancer types included stomach (16.8%), breast (14.3%), and esophageal (12.7%) cancer. Breast tumors were also more likely than other cancer types to have concurrent FGFR rearrangements and amplifications (P<0.001). In comparison with the public dataset, our cohort had a significantly higher number of FGFR aberrations in colorectal (P<0.001) and breast cancer (P=0.05).ConclusionsAmong the Chinese cancer patients in our study, the overall prevalence of FGFR aberrations was 7.0%. FGFR1 amplification was the most common genetic alteration in CRC, breast cancer, and lung cancer; while FGFR2 amplification was more commonly observed in gastric cancer than in other cancers in our cohort. Our study advances the understanding of the distribution of FGFR aberrations in various cancer types in the Chinese population, which will facilitate the further development of FGFR inhibitors.

603TiP Phase II, open-label study of erdafitinib in adult and adolescent patients (pts) with advanced solid tumours harboring fibroblast growth factor receptor (FGFR) gene alterations

The pan-FGFR tyrosine kinase inhibitor erdafitinib is approved by the US Food and Drug Administration for adults with locally advanced or metastatic urothelial carcinoma and susceptible FGFR3/2 alterations who have progressed during or after ≥ 1 line of platinum-containing chemotherapy. FGFR alterations are potential oncogenic drivers that have been reported in many solid tumours in adult and pediatric pts. Because of limited response to standard of care options in patients failing systemic therapy, there is strong rationale to assess the safety and efficacy of erdafitinib in adolescent and adult pts with advanced solid tumours and FGFR alterations. This phase II open-label study (RAGNAR/42756493CAN2002; NCT04083976) will include pts aged ≥ 12 years with histologically confirmed unresectable locally advanced or metastatic solid tumours (except urothelial) harboring predefined FGFR mutations or fusions. Eligibility screening includes molecular screening for FGFR alterations by central or local next-generation sequencing assays and other clinical criteria. Pts will enroll into either a broad panel cohort (BPC) of target FGFR alterations or an exploratory cohort (EC) for FGFR alterations not meeting BPC criteria. ∼280 pts (BPC, n = 240; EC, n = 40) will be enrolled. The primary efficacy end point is overall response rate (ORR) per Independent Review Committee. Secondary end points include investigator-assessed ORR, duration of response, disease control rate, progression-free survival, overall survival, safety, pharmacokinetics, and health-related quality of life. Safety assessments include adverse events, vital signs, electrocardiograms, physical examinations, laboratory tests, performance status assessment, growth assessments in adolescents, and ophthalmologic examination. Starting in December 2019, pts will be enrolled at ∼158 sites in 15 countries. Results of this study will provide efficacy and safety data for erdafitinib across multiple solid tumours with FGFR alterations and evaluate potential benefit of targeting underlying altered biology of FGFR irrespective of tumour histology in adult and adolescent pts. NCT04083976. Writing assistance was provided by Sally Hassan, PhD, of Parexel, and was funded by Janssen Global Services, LLC. Janssen Research & Development, LLC.

Abstract 745: Landscape of FGFRactivating aberrations in Chinese non-small cell lung cancer

Abstract Background Dysfunction in fibroblast growth factor receptor (FGFR) signaling has been reported in non-small cell lung cancer (NSCLC), particularly in lung squamous cell carcinoma (LUSC). We hereby assessed the frequency of FGFR aberrations in a large Chinese NSCLC population. Methods A total of 10,966 NSCLCs whose tumor specimen and/or circulating cell-free DNA (cfDNA) underwent hybridization capture-based next-generation sequencing (NGS) of 400+ cancer-related genes were retrospectively reviewed. Patients' clinical characteristics and treatment histories were further evaluated. Results FGFR aberrations, including mutations, fusions, and gene amplifications, were detected in approximately 1.9% (210/10,966) of the population. FGFR abnormalities were more frequently observed in LUSCs (6.8%, 65/954) than lung adenocarcinomas (1.3%, 128/9596). Previously reported FGFR oncogenic mutations were identified in 19 patients (~0.17%), of which, 68% were male LUSC patients. Eleven out of the 19 patients (58%) had concurrent altered PI3K signaling, thus, highlighting an intriguing molecular characteristic and potential combination therapeutic strategy of dual-targeting FGFR and PI3K signaling in those patients. Furthermore, FGFR fusions retaining the intact kinase domain were identified in 12 patients (0.11%), including nine FGFR3-TACC3 cases, one FGFR2-INA fusion, one novel FGFR4-RAPGEFL1 rearrangement event, and one novel gene fusion between FGFR1 and the SLC20A2 5'-untranslated region, which may result in FGFR1 overexpression. Concomitant EGFR mutations or EGFR amplifications were observed in six patients, four of whom were previously treated with EGFR tyrosine kinase inhibitors, suggesting that FGFR fusions may act as acquired resistance to anti-EGFR therapies. In addition, FGFR amplification was detected in 24 patients, with FGFR1 amplification being the most common event. Notably, FGFR oncogenic mutations, fusions, and gene amplifications were almost always mutually exclusive events. Conclusion We herein report an incidence of FGFR anomalies in a large Chinese NSCLC population, including mutations, gene amplifications, and previously characterized and novel FGFR fusions involving TACC3, INA, RAPGEFL1, and SLC20A2. Keywords: FGFR, activating mutation, fusion, gene amplification, NSCLC, FGFR inhibitors Citation Format: Zhen Zhou, Zichuan Liu, Qiuxiang Ou, Xue Wu, Xiaonan Wang, Yang Shao, Hongyan Liu, Yu Yang. Landscape of FGFRactivating aberrations in Chinese non-small cell lung cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 745.

Phase II Study of AZD4547 in Patients With Tumors Harboring Aberrations in the FGFR Pathway: Results From the NCI-MATCH Trial (EAY131) Subprotocol W

NCI-MATCH is a nationwide, histology-agnostic, signal-finding, molecular profile-driven trial for patients with refractory cancers, lymphomas, or myelomas. Patients with tumors harboring actionable aberration(s) in fibroblast growth factor receptor (FGFR) 1-3 were treated with AZD4547, an oral FGFR1-3 inhibitor. Patients' tumors were screened by next-generation sequencing for predefined FGFR amplification, activating mutations, or fusions. Patients were treated with AZD4547, 80 mg orally twice daily until progression of disease or drug intolerance. A response rate of 16% was considered promising. Between July 2016 and June 2017, 70 patients were assigned and 48 received protocol therapy and are eligible for analysis. Patients' tumors harbored FGFR1 or FGFR2 amplification (n = 20), FGFR2 or FGFR3 single-nucleotide variants (n = 19), or FGFR1 or FGFR3 fusions (n = 9). The most common primary tumors were breast (33.3%), urothelial (12.5%), and cervical cancer (10.4%).Grade 3 adverse events were consistent with those described in previous clinical trials. Confirmed partial responses were seen in 8% (90% CI, 3% to 18%) and were observed only in patients whose tumors harbored FGFR1-3 point mutations or fusions. Stable disease was observed in 37.5% (90% CI, 25.8% to 50.4%). The median progression-free survival (PFS) was 3.4 months, and the 6-month PFS rate was 15% (90% CI, 8% to 31%). For patients with tumors harboring FGFR fusions, the response rate was 22% (90% CI, 4.1% to 55%), and 6-month PFS rate was 56% (90% CI, 31% to 100%). Preliminary signals of activity appeared to be limited to cancers harboring FGFR activating mutations and fusions, although AZD4547 did not meet the primary end point. Different FGFR somatic alterations may confer different levels of signaling potency and/or oncogene dependence.

Histological features in pediatric central nervous system tumors with FGFR alterations.

Identification of genetic alterations in central nervous system (CNS) tumors provides diagnostic and prognostic information and allows identification of potential therapeutic targets. Next-generation sequencing (NGS) technologies currently used for molecular testing are costly and remain largely limited to major academic centers or reference labs. Identification of histologic or immunohistochemical correlates for particular molecular alterations can serve as surrogates and can help triage cases for subsequent NGS-based confirmation. Recently, adult IDH-wildtype adult glioblastomas (GBMs) with fibroblast growth factor receptor (FGFR) gene alterations were reported to show palisading monomorphic cells, delicate arcuate vasculature, and microcalcifications. We explored whether pediatric tumors with FGFR fusion also show these histologic features and whether these features could predict the presence of this gene alteration. We reviewed pediatric CNS tumors with FGFR-fusions to retrospectively determine the presence/absence of the above-mentioned histological features in fusion-positive tumors. 10 pediatric tumors with FGFR fusions were identified. Pediatric tumors demonstrated histologic and tumor type diversity, with diagnoses of pilocytic/pilomyxoid astrocytoma, pediatric-type oligodendroglioma, anaplastic astrocytoma, polymorphous low-grade neuroepithelial tumor of the young, rosette-forming glioneuronal tumor, and extraventricular neurocytoma. Pediatric FGFR-fused CNS tumors demonstrate histologic features similar to their adult counterparts but also exhibit significant morphologic variability. As such, this histologic variability prevents the prediction of FGFR fusion and necessitates molecular testing for the identification of this alteration.

Abstract A077: FIGHT-207: Phase 2 study of pemigatinib in patients with previously treated, locally advanced/metastatic or unresectable solid tumor malignancies harboring activating fibroblast growth factor receptor (FGFR) gene alterations

Abstract Introduction: Activating mutations, rearrangements, and amplifications of FGFR, resulting in either ligand-independent or aberrant ligand-dependent FGFR signaling have been identified in many tumor types. A recent large-scale sequencing study across tumor types identified FGFR alterations in 7.1% of cancers, including gene amplification (66%), mutations (26%), and rearrangements (8%) (Helsten CCR 2016). Pemigatinib (INCB054828) is a selective, potent, oral inhibitor of FGFR1–3 that has demonstrated antitumor activity in FGFR-driven tumors in phase 1/2 (FIGHT-101) and phase 2 (FIGHT-201, -202, and -203) studies. FIGHT-207 is a phase 2, open-label, single-arm, tumor-agnostic study that will evaluate the efficacy and safety of pemigatinib monotherapy in patients with advanced/metastatic or surgically unresectable solid tumor malignancies with activating FGFR mutations, fusions or rearrangements (NCT03822117). Methods: Eligible patients (aged ≥18 years) have histologically or cytologically confirmed solid tumor malignancy that is advanced/metastatic or is surgically unresectable; radiographically measurable disease (per Response Evaluation Criteria in Solid Tumors version 1.1 [RECIST v1.1] or Response Assessment in Neuro-Oncology [RANO] for primary brain tumors); documented FGFR1–3 mutation or translocation; objective progression after at least 1 prior therapy, and no therapy available that is likely to provide clinical benefit; Eastern Cooperative Oncology Group performance status 0 to 2; and no prior receipt of a selective FGFR inhibitor. Patients are assigned to 1 of 3 cohorts based on FGFR status: Cohort A (n ~ 60): FGFR1–3 in-frame fusions or FGFR2 intron 17 rearrangements; Cohort B (n ~ 90): known/predicted activating point mutations in FGFR1–3; and Cohort C (n ~ 20): any FGFR1–3 point mutations in the kinase domain, variants of unknown significance or FGFR1/FGFR3 rearrangements without an identified partner gene. All patients receive a starting dose of pemigatinib 13.5 mg once daily on a 21-day cycle. Patients with no grade ≥2 treatment-related adverse events and no hyperphosphatemia (serum phosphate &amp;gt;5.5 mg/dL) during cycle 1 are allowed to increase dose to pemigatinib 18 mg from cycle 2. Treatment continues as long as patients are receiving benefit or until treatment withdrawal criteria are met. Hyperphosphatemia is managed with diet modifications, phosphate binders, and diuretics, or pemigatinib dose reduction/interruption. The primary endpoint is objective response rate (assessed by independent review committee [IRC] per RECIST v1.1 or RANO) in Cohorts A and B. Secondary endpoints are progression-free survival, duration of response, and overall survival in Cohorts A and B; safety and tolerability in all cohorts. Biopsies will be obtained for select tumors at screening, on-treatment, and at end of treatment. Additional biomarkers that may be indicative of clinical response, resistance, and safety may also be investigated. The study is currently recruiting. Citation Format: Luis Féliz, Ekaterine Asatiani, Christine Lihou, Huiling Zhen, Ian Silverman, Jordi Rodon Ahnert. FIGHT-207: Phase 2 study of pemigatinib in patients with previously treated, locally advanced/metastatic or unresectable solid tumor malignancies harboring activating fibroblast growth factor receptor (FGFR) gene alterations [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A077. doi:10.1158/1535-7163.TARG-19-A077

1988P - Identification of novel and known FGFR gene fusions in Chinese non-small cell lung cancer

BackgroundOncogenic fibroblast growth factor receptor (FGFR) gene fusions have been described in diverse tumor histology. FGFR inhibitors including erdafitinib have demonstrated promising results in patients whose tumors harbor FGFR gene fusions or mutations. We hereby assessed the frequency of FGFR rearrangements in the Chinese non-small cell lung cancer (NSCLC) population. MethodsA total of 10,966 NSCLC patients whose tumor specimen and/or circulating cell-free DNA (cfDNA) submitted for genomic profiling by hybridization capture-based targeted next-generation sequencing (NGS) of exons and introns of cancer related genes were retrospectively reviewed. Patients’ clinical characteristics and treatment history were retrieved from the database for further evaluation. ResultsFGFR fusions retaining the intact kinase domain were identified in 0.11% (12/10966) of NSCLC cases examined, including 9 fibroblast growth factor receptor 3 (FGFR3)-transforming acidic coiled-coil containing protein 3 gene (TACC3) fusion-positive cases that was mostly reported in solid tumors, one fibroblast growth factor receptor 2 (FGFR2)-internexin neuronal intermediate filament protein α gene (INA) fusion that was previously reported in gliomas, one novel fibroblast growth factor receptor 4 (FGFR4)-Rap guanine nucleotide exchange factor like 1 gene (RAPGEFL1) fusion case, and one novel fibroblast growth factor receptor 1 (FGFR1) gene fusion involving the 5’UTR of Solute Carrier Family 20 Member 2 gene (SLC20A2) which may possibly drive the overexpression of FGFR1. Concomitant EGFR mutations or EGFR amplification were observed in 6 patients, four of which were previously treated with EGFR tyrosine kinase inhibitors (TKIs), but disease progressed prior to NGS tests. FGFR fusions may arise as resistance mechanism to EGFR TKI therapies in patients who carried founder EGFR alterations. No other known concurrent driver mutations were detected in the remaining 6 cases. ConclusionsWe hereby report a frequency of FGFR fusions of 0.11% in a large Chinses NSCLC population involving known and novel FGFR gene fusion partners including TACC3, INA, RAPGEFL1, and SLC20A2. Oncogenic FGFR fusions may arise as mechanisms of acquired resistance. Legal entity responsible for the studyGeneseeq Technology Inc. FundingHas not received any funding. DisclosureQ. Ou: Full / Part-time employment, NA: Geneseeq Technology Inc. X. Wu: Leadership role, NA: Geneseeq Technology Inc. X. Wang: Full / Part-time employment, NA: Nanjing Geneseeq Technology Inc. Y.W. Shao: Leadership role, NA: Geneseeq Technology Inc. All other authors have declared no conflicts of interest.