FGF19 Amplification Research Articles

Pembrolizumab plus nab-paclitaxel and platinum as first-line treatment in patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC): A prospective, single-arm, open-label, phase 2 study.

6023 Background: Based on KN-048, pembrolizumab combined with PF regimen has become the first-line standard treatment for R/M HNSCC. KN-B10 confirmed pembrolizumab combined with carboplatin and paclitaxel has a promising effect with manageable safety. This study aims to supplement the efficacy and safety data of pembrolizumab combined with nab-paclitaxel and platinum in the Chinese population. Methods: Untreated R/M HNSCC patients were treated with pembrolizumab 200mg, nab-paclitaxel 260mg/m2, plus cisplatin 75 mg/m2 or carboplatin AUC 5 (only if patients have cisplatin contraindications) on day 1 every 21 days for up to six cycles, followed by pembrolizumab maintenance therapy until progression or intolerable toxicity or completion of 35 cycles. Efficacy was evaluated according to RECIST 1.1, and survival analysis was performed using the Kaplan-Meier method. Adverse events were assessed using the CTCAE 5.0. The primary endpoint was ORR. Secondary endpoints include safety, DCR, OS, and PFS. High-resolution sequencing based on probe capture was performed on eligible patients. Results: Between Sep 15, 2020, and Nov 8, 2023, 67 R/M HNSCC patients were enrolled. Baseline characteristics are shown in the table. The median follow-up time was 12.7 months at the data cut-off date of January 8th, 2023, the ORR was 62.7%, and the DCR was 88.1%. The median PFS and OS were 11.6 months and 18.7 months, respectively. The median DOR was 14.7 months. The most common TRAEs of grade ≥3 were leukopenia (22.4%) and neutropenia (28.4%). Grade≥3 immune-related AEs were pneumonitis (1.5%), hepatitis (1.5%), and enteritis (1.5%). Of the 35 patients with sequencing results, the most common alterations were the TP53 mutation (86%), CDKN2A mutation (22%), FGF19 (26%), FGF4 (20%), FGF3 (20%), and CCND1 (20%) amplification. FGF19, FGF4, FGF3, and CCND1 amplification were associated with poor ORR, and CDKN2A mutation was associated with poor OS. Conclusions: Pembrolizumab combined with nab-paclitaxel and platinum shows encouraging antitumor activity accompanied by a manageable safety profile in untreated R/M HNSCC patients in China. CDKN2A mutation was a potential independent prognostic factors for this patient population. Clinical trial information: NCT04857164 . [Table: see text]

TP53 mutations predict poor response to immunotherapy in patients with metastatic solid tumors.

TP53 is the most commonly mutated gene across all cancer types. R175H mutation was considered structural mutation where the mutation causes misfolding of the protein and leads to a significant conformational alterations within p53's DNA binding domain. The aim of this study was to explain the reason why R175H worse the response to immunotherapy by analyzing tumor immune microenvironment through the expression of immune cells and PD-1. Patients diagnosed with metastatic carcinoma, including colorectal cancer (CRC), breast cancer (BRCA), gastric cancer (GC), non-small cell lung cancer (NSCLC), and 20 other cancer types, treated in a palliative setting at Samsung Medical Center between October 2019 and April 2021, were enrolled. Of these patients, those who underwent TDS analysis (TruSight™ Oncology 500 assay [TSO 500]) were finally analyzed. Of 1770 patients, 1012 (57.2%) harbored genetic alterations in TP53. All mutations were single nucleotide variants (SNVs), and the most frequent SNV was R175H (n = 84, 7.5%) which was known as one of the most common hotspot TP53 mutation. The overall survival of patients with TP53 R175H mutations was significantly worse following chemotherapy (606 vs. 456 days, p < 0.001) or immunotherapy (822 vs. 350 days, p < 0.001) compared to those with TP53 mutation in other loci. RNA sequencing indicated that the immune response-related pathways were downregulated in tumors harboring TP53 R175H mutation. Moreover, the expression of CD8(+) T cells PD-1 were lowered in R175H mutation tumors. In the analysis of TP53 structural domain, compared to those having TP53 mutation in other domain, patients with mutations occurring in the nuclear exporter signal (NES) and E4F1-binding domains had significantly worse overall survival following chemotherapy (NES: 606 vs. 451 days, p = 0.043; E4F1: 606 vs. 469 days, p = 0.046) and immunotherapy (NES: 822 vs. 403 days, p < 0.001; E4F1: 822 vs. 413 days, p < 0.001). In addition, tumors with TP53 mutation and co-existing copy number amplification of CCND1, FGF4, and FGF19 in chromosome 11 conferred worse prognosis than those with only TP53 mutation (p < 0.050). Each TP53 mutations indicated differential treatment outcomes following chemotherapy or immunotherapy in patients with metastatic cancer. Functional analysis including RNASeq suggested that TP53 mutation downregulated immune response. Overall, we found each TP53 mutation to indicate different prognoses in patients with metastatic tumors undergoing chemotherapy and ICI treatment. Further validations, including a prospective cohort study or a functional study, would be particularly valuable in advancing the knowledge on this aspect and developing improved prognostic parameters.

Abstract 5793: Comprehensive characterization of FGF/FGFR alterations in invasive breast cancers

Abstract BACKGROUND FGFR signaling is central for cancer cell proliferation, migration, angiogenesis, and survival. The frequency and type of FGF/FGFR aberrations are not well-characterized across invasive breast cancer subtypes and metastatic sites of disease. In hormone receptor positive breast cancers, FGFR1 amplification correlates with early progression on endocrine therapy and promotes resistance to CDK4/6 inhibition. Our study evaluated the incidence and characterization of FGF alterations in invasive breast cancers and examined differences based on histologic subtype, molecular subtype and site. METHODS Breast cancer samples underwent molecular profiling by Caris Life Sciences. Analyses included NGS of DNA (592 Gene Panel, NextSeq, and WES, NovaSEQ), and IHC (Caris Life Sciences, Phoenix, AZ). Biomarker results were compiled from cases within the breast cohort including data from any sequencing panel, gene expression/RNA seq panel, and IHC. All results listed below were statistically significant (p &amp;lt; 0.05) as determined by chi-square test and Benjamini Hochberg correction. RESULTS 12058 breast cancer tumors were analyzed: 4189 from primary breast specimens (35%) and 7869 from metastatic sites (65%). 4305 (36%) were ductal and 671 (6%) were lobular histology with remaining other/unknown. 6413 (53%) were HR+HER2-, 3504 (29%) were triple negative, 403 (3%) were HR+HER2+ and 363 (3%) were HR-HER2+ with 1375 (13%) of unknown subtype. In the entire cohort, the most commonly amplified genes were FGF19 (11.49%), FGF3 (10.75%), FGF4 (9.98%), CCND1 (12.36%), and FGFR1 (9.08%). FGFR1-4 amplification was present in 11.01% of all cases. FGF19 amplification was more prevalent in lobular breast cancer compared to ductal (12.1% vs 9.1%). FGF19, FGF23, FGF3, FGF4, FGF6 amplification varied across molecular subtypes being most prevalent in HR+/HER2- (15.7%), HR+/HER2+ (12.1%), and least prevalent in HR-/HER+ tumors (3.4%). FGFR1 amplification was most common among FGFR1-4 amplifications and most prevalent in HR+HER2- (12%). Across metastatic sites, FGF ligands displayed different patterns of amplification with FGF19, FGF3 and FGF4 amplification most prevalent in liver and bone metastases. FGFR1 amplification was statistically different across metastatic sites and most prevalent in liver metastases (16%) followed by bone (10%). Patients receiving CDK4/6 inhibitors with FGFR1 amplification had shorter time on treatment than FGFR1 wild type (HR = 0.892, p = 0.03). CONCLUSION FGF alterations in invasive breast cancers vary by molecular subtype and site of disease. FGFR1, FGF19, FGF23, FGF3, FGF4, and FGF6 amplifications were statistically different across subtypes (most prevalent in HR+/HER2- and HR+/HER2+) and metastatic sites (most prevalent in liver and bone metastases). The prevalence in HR+ subtypes lend support to the role of FGF in endocrine resistance. Citation Format: Kush C. Gaur, Justin Tiu-Lim, Julie McGrath, Phil Walker, Michael Korn, Joanne Xiu, Arielle Heeke, Virginia Kaklamani, Antoinette Tan, Janice Lu, Darcy Spicer, Evanthia Roussos-Torres, Priya Jayachandran, Audrey Saghian, Amir Goldkorn, Irene Kang. Comprehensive characterization of FGF/FGFR alterations in invasive breast cancers [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 5793.

Exploring the mechanism of PARPi resistance in ovarian cancer by integrated analyze of pre- and post-progression samples in 5 patients.

e17582 Background: PARP inhibitors (PARPi) have been widely used in the treatment of homologous recombination repair-deficient tumors. Comprehensive investigations on the resistance mechanisms of PARPi and tumor microenvironment alterations after PARPi therapy are largely insufficient. Methods: 5 ovarian cancer patients (pts) treated with PARPi at West China Second University Hospital were enrolled in this study (Ethical Lot Number: 20200076). Clinicopathological information of the pts are shown in table below. Paired PARPi treatment-naive surgical samples (TNS) and the biopsy samples that progressed after PARPi maintenance therapy (PPS) were obtained. Multi-omic profiling was conducted by an NGS panel (Master Panel, AmoyDx) containing DNA exon regions of 563 genes and RNA expression of 1831 genes analyzing genetic mutations and dynamics of gene expression profile in these paired tumor samples. Results: Median duration of treatment with PARPi was 18 months (11-22). Comprehensive genomic profiling discovered MYC amplification (n = 3), ZFHX4 mutation (n = 2) and IDH1 mutation (n = 1) in PPS. One PPS harbored simultaneous amplification of PDCD1, FGF3, MYC, FGF19 and ZFHX4 mutation. In addition, BRCA1 intron11: c.4096+1G &gt; T mutation was detected in one PPS carrying germline BRCA1 mutation (E1066*), which putatively resulted in restoration of BRCA1 function. At RNA level, single-sample enrichment analysis showed that B cells, T cells, and co-activation factors were significantly up-regulated in PPS. In addition, expression of CXCL13 and activation of CCL19/21-CCR7 axis were significantly increased, which indicated a PARPi-triggered “hot” immune-microenvironment. Moreover, immune-checkpoint TIGIT was significantly upregulated, paved the way for immunotherapy. Nevertheless, stromal remodeling, and tumor proliferation signatures were also up-regulated in PPS. In parallel, cancer-related pathways, PI3K/AKT, Epithelial-Mesenchymal transition, cell-cycle as well as G2M checkpoint were observed in the pathway enrichment analysis, which further verified the aforementioned findings. Conclusions: This small sample size study confirmed the complexity of the resistance mechanisms to PARPi, including BRCA reversion mutation, oncogene activation and bypass signaling activation. The activation of both positive and negative immune regulators in the tumor microenvironment shed light on future clinical management for patients with PARPi resistance.[Table: see text]

Abstract CT158: ctDNA analysis in the savolitinib phase II study in Non-Small Cell Lung Cancer (NSCLC) patients (pts) harboring MET exon 14 skipping alterations (METex14)

Abstract Background: Savolitinib is a potent and selective MET tyrosine kinase inhibitor. It demonstrated clinical efficacy and a manageable safety profile in Chinese NSCLC pts with METex14 alterations in a phase 2 study (NCT028997479). Here, we report the post-hoc ctDNA analysis of METex14 at baseline and clearance upon treatment and the association of these findings with clinical outcome. In addition, concurrent gene alterations in ctDNA samples from the patients treated with savolitinib and impact on clinical efficacy is explored. Methods: Plasma samples were prospectively collected pre-dose and at tumor assessment visits, until disease progression or end of treatment. MET and other somatic gene alterations in the ctDNA samples were detected by next generation sequencing (425-gene panel, Geneseeq). Results: Sixty-six pts provided baseline plasma samples, of which METex14 ctDNA was detectable in 46 (70%) and undetectable in the remaining 20 pts (30%). Among the 46 ctDNA detectable pts, 19 were pulmonary sarcomatoid carcinoma (19/22, 86%) and 27 were other NSCLC (27/44, 61%), respectively. Of the 46 baseline-detectable pts, 24 were clearance evaluable and 22 had no qualified post baseline samples for clearance evaluation. Of the 24 clearance evaluable pts, 14 achieved ctDNA clearance (undetectable) with a median time to clearance of 1.4 months of treatment (Min 1.4 m, Max 4.2 m). The PFS and OS were compared for pts based on their METex14 ctDNA status at baseline and upon treatment. As shown in the table, METex14 baseline undetectable or clearance pts demonstrated significantly longer mPFS and mOS. Furthermore, in 21 pts with analyzable ctDNA samples at baseline and at disease progression, additional gene alterations were observed such as KRAS, NRAS, BRAF, PIK3CA as well as secondary MET mutations and FGF19 amplification in 12 pts (57%). These alterations might be associated with treatment resistance. Conclusions: The results suggest that ctDNA METex14 undetectable at baseline or clearance upon savolitinib treatment may define favorable treatment outcome. Confirmation of this finding and the predictive value of the ctDNA with larger sample size is desirable. METex14 ctDNAmPFS(mon, 95% CI)HR (95% CI)P valuemOS(mon, 95% CI)HR (95% CI)P valueBaseline undetectable (n=20)13.8(4.2, 22.1)--NC(10.9, NC)--Baseline detectable (n=46)5.6(4.1, 6.9)1.77(0.88, 3.57)0.10810.9(9.2, 14.0)3.26(1.35, 7.89)0.006- Clearance (n=14)30.3(6.8, NC)0.72(0.28, 1.87)0.50135.8(14, NC)0.89(0.25, 3.18)0.835- Non-clearance (n=10)5.5(0.66, 5.6)4.94(1.83, 13.36)0.0028.7(0.8, 10.6)7.06(2.39, 20.89)&amp;lt;0.001- Non-evaluable (n=22)4.1(4.0, 6.9)3.45(1.48, 8.03)0.00610.6(4.8, 12.0)5.88(2.24, 15.47)&amp;lt;0.001CI, confidence interval; HR, hazard ratio; NC, non-calculable Citation Format: Yongfeng Yu, Yongxin Ren, Jian Fang, Lejie Cao, Zongan Liang, Qisen Guo, Sen Han, Zimei Ji, Ye Wang, Yulan Sun, Yuan Chen, Xingya Li, Hua Xu, Jianying Zhou, Liyan Jiang, Ying Cheng, Zhigang Han, Jianhua Shi, Gongyan Chen, Rui Ma, Yun Fan, Sanyuan Sun, Longxian Jiao, Xiaoyun Jia, Linfang Wang, Puhan Lu, Jing Li, Qian Xu, Xian Luo, Weiguo Su, Shun Lu. ctDNA analysis in the savolitinib phase II study in Non-Small Cell Lung Cancer (NSCLC) patients (pts) harboring MET exon 14 skipping alterations (METex14) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT158.

Fibroblast Growth Factor 19 is an Independent Prognostic Parameter for Hepatocellular Carcinoma Recurrence

Background: Hepatocellular carcinoma (HCC) remains a common cancer associated with a high mortality rate. Genes that drive HCC development accumulate randomly that could be a target for therapeutic management. In large-scale studies, the dysregulation of fibroblast growth factors (FGFRs) was detected in over 7% of cancers and served as an oncogenic signalling pathway. Amplification of FGF19 was found to be associated with the development of HBV and NAFLD related HCC with an ongoing clinical trial for targeting this pathway. Therefore, we aimed to study FGF19 in HCV related HCC and to compare its expression within the two main morphological patterns. Material and methods: This was a retrospective, case-control study that included 76 HCC cases and 53 adjacent non-tumour liver, 20 cirrhosis and 20 normal liver tissue as normal control. The Immunohistochemical expression turned into assessed in the studied groups. Results: FGF19 was expressed in 26.3% of HCC cases with no significant difference in its expression between two HCC subgroups (P=0.073). The expression of FGF19 was not differed in the HCC group according to the aetiology (P=0.605), prior HCV treatment (P=0.912) or background liver cirrhosis (P=0.931). The only factor increased FGF19 expression with the marked inflammatory activity of the background liver (P=0.026). COX regression analysis revealed that FGF19 was the single independent factor affecting tumour recurrence (P=0.04). Conclusions: FGF19 is commonly expressed in HCC cases independent from the etiological, background liver or morphological subtypes. FGF19 could be used as an indicator to predict tumour recurrence.

Tumor mutation burden and PIK3CA mutations are associated with pathological complete response in human epidermal growth factor receptor 2-positive breast cancer patients receiving pyrotinib combined with trastuzumab neoadjuvant treatment.

e12610 Background: Our previous study reported a good efficacy and safety of pyrotinib combined with trastuzumab neoadjuvant treatment in human epidermal growth factor receptor 2 (HER2)-positive breast cancer patients. We further explored the potential biomarkers for the efficacy of pyrotinib combined with trastuzumab neoadjuvant treatment in HER2-positive breast cancer patients. Methods: To date, a total of 96 patients with early-stage breast cancer were enrolled for the neoadjuvant pyrotinib combined with trastuzumab treatment clinical trial (ChiCTR1900022293). By the method of 425 genes next-generation sequencing (NGS), the genomic characteristics of them were evaluated for the potential correlation with postoperative pathological complete response (pCR). Results: Among the cohort of 96 cases, a total of 32 patients have completed the whole therapy as well as final surgery and acquired qualified sequencing analysis report, and 18 of them achieved total pCR. The most frequently mutated driver genes were TP53 (75%), PIK3CA (44%), NBN (9%), RUNX1 (9%), FANCD2 (9%), ATRX (9%), MAP3K1 (9%) and NF1 (9%), respectively. In terms of somatic copy number alterations, the most frequent alterations are gain or amplification of ERBB2 (63%), MYC (22%), CCND1 (19%), CDK12 (16%) and FGF19 (16%), respectively. The median tumor mutation burden (TMB) of the 36 patients was 4.23 mut/Mb (0.00-29.61). Compared with pCR populations, non-pCR populations had significantly higher median TMB (5.29 vs 3.17 mut/Mb, P = 0.025). In addition, the pCR rate of patients with wild-type PIK3CA is significantly higher than that of patients with mutated PIK3CA (88.9% vs 14.3%, P &lt; 0.001). Conclusions: Preliminary results suggested that HER2-positive breast cancer patients with higher TMB and activating mutations in PIK3CA are less likely to benefit from pyrotinib combined with trastuzumab neoadjuvant therapy, which need larger sample size to validate. *Qiyun Shi and Juncheng Xuhong contributed equally. #Co-corresponding author (Dr. Jun Jiang, jcbd@medmail.com.cn; Dr. Xiaowei Qi, qxw9908@foxmail.com). Clinical trial information: ChiCTR1900022293.

Comprehensive characterization and clinical impact of concomitant genomic alterations in EGFR-mutant NSCLCs treated with EGFR kinase inhibitors

ObjectivesAlthough the majority of epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) patients respond to EGFR tyrosine kinase inhibitors (TKIs), significant heterogeneity in clinical response is observed which might be attributed to the distinct sub-molecular characteristics. The present study aims to identify genetic alterations correlated with clinical outcomes and treatment response to different EGFR-TKI inhibitors. Materials and methodsWe integrated the genomic data and clinical outcomes including progression-free survival (PFS) and overall survival (OS) in 179 patients with advanced EGFR-mutant NSCLC who were treated with EGFR-TKI as 1st line of treatment. ResultsWe found that EGFR-mutant patients harboring concomitant TP53 mutation (OS: 21 vs. 40 months, P = 0.05), ERBB2 amplification (PFS: 6.1 vs. 12.5 months, P = 0.01) or FGF19 amplification (OS: 11.2 vs. 27.1 months, P = 0.01) were significantly associated with a poorer clinical prognosis after treated with 1st generation EGFR-TKI. In contrast, the presence of TP53 mutation did not affect the PFS nor OS of patients treated with 2nd generation EGFR-TKI. Furthermore, EGFR-mutant and TP53-wild type (WT) patients benefited more from a combinatorial treatment consisting of EGFR-TKI and bevacizumab comparing to EGFR-TKI as a single agent (PFS: 21.7 vs. 9.3 months, P < 0.01). Copy number variation (CNV) (PFS: 4.6 vs.9.4 months, p = 0.018) was identified as an unfavorable predictive factor to 3rd-generation TKI. We also revealed distinct resistance mechanisms associated with different EGFR-TKIs. ConclusionOur study highlights the heterogeneity both in the primary molecular landscape and acquired alterations in EGFR-mutated NSCLCs, which might play a role in determining the clinical efficacy of EGFR-TKIs. We also revealed the differential prognostic role of TP53 mutation in patients treated with the 1st or 2nd generation of EGFR-TKI. Our study also suggests that EGFR-mutant and TP53-WT patients may benefit more from combinatorial treatment consisting of EGFR-TKI and bevacizumab, highlighting the importance of further stratifying EGFR-mutant patients.

Enhanced autocrine FGF19/FGFR4 signaling drives the progression of lung squamous cell carcinoma, which responds to mTOR inhibitor AZD2104

Lung cancer occurrence and associated mortality ranks top in all countries. Despite the rapid development of targeted and immune therapies, many patients experience relapse within a few years. It is urgent to uncover the mechanisms that drive lung cancer progression and identify novel molecular targets. Our group has previously identified FGF19 as a prognostic marker and potential driver gene of lung squamous cell carcinomas (LSQ) in Chinese smoking patients. However, the underlying mechanism of how FGF19 promotes the progression of LSQ remains unclear. In this study, we characterized and confirmed that FGF19 serves as an oncogenic driver in LSQ development and progression, and reported that the amplification and high expression of FGF19 in LSQ was significantly associated with poor overall and progression-free survival. A higher serum level of FGF19 was found in lung cancer patients, which could also serve as a novel diagnostic index to screen lung cancer. Overproduction of FGF19 in LSQ cells markedly promoted cell growth, progression and metastasis, while downregulating FGF19 effectively inhibited LSQ progression in vitro and in vivo. Moreover, downregulating the receptor FGFR4 was also effective to suppress the growth and migration of LSQ cells. Since FGF19 could be induced by smoking or endoplasmic reticulum stress, to tackle the more malignant FGF19-overproducing LSQ, we reported for the first time that inhibiting mTOR pathway by using AZD2014 was effective and feasible. These findings have offered a new strategy by using anti-FGF19/FGFR4 therapy or mTOR-based therapy in FGF19-driven LSQ.

Abstract 853: Essential role of autocrine FGF19-FGFR4 signaling in head and neck tumorigenesis

Abstract The fibroblast growth factor 19 gene FGF19 has been reported to be amplified in several cancer types and encodes for a key autocrine signaler known to promote tumorigenic growth. Thus, it is imperative to understand which cancers are oncogenically addicted to FGF19 amplification as well as the role it serves in these cancer types. We report for the first time that high FGF19 amplification in head and neck squamous cell carcinomas (HNSCC) is associated with increased autocrine secretion of FGF19 and poor patient outcome in HNSCC. FGF19 amplification corresponded with constitutive activation of FGFR4-dependent ERK/AKT-p70S6K-S6 signaling, and addition of human recombinant FGF19 could promote proliferation and soft agar colony formation in HNSCC cells with low FGF19 expression through activating FGFR4 and downstream signaling cascades. Consistently, FGF19 knockout counteracted the observed effects in HNSCC cells carrying high endogenous FGF19, and significantly suppressed tumor growth in an orthotopic mouse model of HNSCC. This study demonstrates that FGF19 gene amplification corresponds with an increased dependency upon FGF19/FGFR4 autocrine signaling in HNSCC, revealing a therapeutic target for this cancer type. Note: This abstract was not presented at the meeting. Citation Format: Liwei Lang, Lixia Gao, Chloe Shay, Xiangdong Zhao, Austin Shull, Yong Teng. Essential role of autocrine FGF19-FGFR4 signaling in head and neck tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 853.

Interrupting the FGF19-FGFR4 Axis to Therapeutically Disrupt Cancer Progression.

Coordination between the amplification of the fibroblast growth factor FGF19, overexpression of its corresponding receptor FGFR4, and hyperactivation of the downstream transmembrane enzyme β-klotho has been found to play pivotal roles in mediating tumor development and progression. Aberrant FGF19-FGFR4 signaling has been implicated in driving specific tumorigenic events including cancer cell proliferation, apoptosis resistance, and metastasis by activating a myriad of downstream signaling cascades. As an attractive target, several strategies implemented to disrupt the FGF19-FGFR4 axis have been developed in recent years, and FGF19-FGFR4 binding inhibitors are being intensely evaluated for their clinical use in treating FGF19-FGFR4 implicated cancers. Based on the established work, this review aims to detail how the FGF19-FGFR4 signaling pathway plays a vital role in cancer progression and why disrupting communication between FGF19 and FGFR4 serves as a promising therapeutic strategy for disrupting cancer progression.

FGF19 amplification reveals an oncogenic dependency upon autocrine FGF19/FGFR4 signaling in head and neck squamous cell carcinoma.

The fibroblast growth factor 19 gene FGF19 has previously been reported to be amplified in several cancer types and encodes for a key autocrine signaler known to promote tumorigenic growth. Thus, it is imperative to understand which cancers are oncogenically addicted to FGF19 amplification as well as the role it serves in these cancer types. We report for the first time high FGF19 amplification in head and neck squamous cell carcinomas (HNSCC), which is associated with increased autocrine secretion of FGF19 and poor patient outcome in HNSCC. FGF19 amplification corresponded with constitutive activation of FGF receptor 4 (FGFR4)-dependent ERK/AKT-p70S6K-S6 signaling activation in HNSCC cells, and addition of human recombinant FGF19 could promote cell proliferation and soft agar colony formation in HNSCC cells with low FGF19 expression through activation of FGFR4 and downstream signaling cascades. In contrast, FGF19 knockout counteracts the observed effects in HNSCC cells carrying high endogenous FGF19, with knockout of FGF19 significantly suppressing tumor growth in an orthotopic mouse model of HNSCC. Collectively, this study demonstrates that FGF19 gene amplification corresponds with an increased dependency upon FGF19/FGFR4 autocrine signaling in HNSCC, revealing a therapeutic target for this cancer type.

Abstract LB-272: Discovery and characterization of a novel FGFR4 Inhibitor for the treatment of hepatocellular carcinoma

Abstract Introduction: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and has one of the fastest growing incidence among cancers. Aberrant FGF19-FGFR4 signaling occurs in 10-30% of HCC patients and drives tumor development and progression. Pan-FGFR inhibitors are associated with hyperphosphatemia in clinic due to inhibition of FGFR1. Therefore, selectively targeting FGFR4 may render a safer treatment approach with improved clinical benefits. Using advanced computation-aided structural analysis and medicinal chemistry design, we have discovered a novel and highly selective small molecular FGFR4 inhibitor, ABSK-011, demonstrating robust anti-tumor activity in hepatocellular carcinoma models. Method: ABSK-011 was evaluated in biochemical Caliper assay and Celltiter-Glo assay for its inhibition on FGFR4 enzymatic and cellular activities. Its selectivity against other FGFR family members was analyzed through related biochemical, cellular, and KinomeScan profiling assays. The pharmacokinetics (PK) profile of ABSK-011 was characterized across various species of animals including mouse, rat and dog. Efficacy studies were conducted in two HCC xenograft models, and preliminary toxicity profile was also evaluated. Results: ABSK-011 inhibits FGFR4 with IC50 &amp;lt; 10 nM in biochemical assay and exhibits at least 50 fold selectivity against other FGFR kinases. The strong selectivity arises from the ability of ABSK-011 to irreversibly modify Cys552, a residue within the active site of FGFR4 that is not conserved among other FGFR kinases. ABSK-011 also shows greater than 800-fold selectivity against other RTK members. In HCC cells with autocrine production of FGF19, ABSK-011 inhibits the auto-phosphorylation of FGFR4 and blocks signal transduction from FGFR4 to downstream pathway activation. HCC cell lines harboring amplification and overexpression of FGF19 are uniquely sensitive to growth inhibition by ABSK-011 (EC50 &amp;lt; 50 nM) compared with cancer cell lines with FGFR1 dependence (EC50 &amp;gt; 2000 nM), confirming selectivity for FGFR4 over FGFR1. In vivo PK study demonstrated high exposure and superior DMPK profile of ABSK-011 in mouse, rat and dog. In preclinical in vivo studies, oral administration of ABSK-011 strongly inhibits the growth and induces regressions of subcutaneous xenograft tumors dependent upon FGFR4 activity. Suppression of tumor growth is dose dependent and well correlated with pharmacodynamic inhibition of FGFR4 signaling. Safety studies showed that ABSK-011 has no inhibition on CYP family members, hERG, etc. Conclusion: ABSK-011, presented here by Abbisko Therapeutics, is a highly potent, selective, and oral-available small molecular FGFR4 inhibitor. Its superior profile supports fast-track preclinical development. Citation Format: Zhui Chen. Discovery and characterization of a novel FGFR4 Inhibitor for the treatment of hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-272.

Characterization of Hepatocellular Carcinoma Patients with FGF19 Amplification Assessed by Fluorescence in situ Hybridization: A Large Cohort Study

Background: FGF19 amplification is a relatively novel type of genetic aberration that has been proposed to be a driver of hepatocarcinogenesis. Selective inhibitors of FGFR4, a receptor of FGF19, have been developed as targeted therapies for hepatocellular carcinoma (HCC). Despite the role of FGF19 in mediating HCC progression, the clinicopathological characterization of patients exhibiting FGF19 amplification remains unclear. Immunohistochemical staining is the simplest and most widely used method of identifying aberrations in the FGF19 gene, although its specificity is very low. Methods: This study investigated the prognostic significance of FGF19 amplification in a large cohort of 989 HCC patients using fluorescence in situ hybridization (FISH), which has a high degree of specificity. In addition, FISH data from formalin-fixed, paraffin-embedded sections were compared with copy number variation (CNV) data obtained from fresh frozen sections to validate the use of FISH as a diagnostic tool. Results: FGF19 amplifications were detected by FISH in 51 (5.15%) of the 989 patients, and were independently associated with poor survival and a higher risk of tumor recurrence, as well as with poor prognostic factors such as a high α-fetoprotein level, hepatitis B or C virus infection, a large tumor size, microvascular invasion, and necrosis. In addition, FGF19 amplification was associated with TP53 mutation, and was mutually exclusive with CTNNB1 mutation. The results of the FISH and CNV analyses exhibited a significant concordance rate of 96% (κ = 0.618, p < 0.001). Conclusions: These data indicate that FGF19 amplification represents a unique molecular subtype associated with poor prognostic characteristics, which supports the hypothesis that the FGF19-FGFR4 signaling pathway plays an important role in hepatocarcinogenesis. We have also demonstrated that FISH is a viable alternative to CNV analysis, offering a number of advantages in the clinical setting.

A Phase 1 study of ARQ 087, an oral pan-FGFR inhibitor in patients with advanced solid tumours

Background:ARQ 087 is an orally administered pan-FGFR inhibitor with multi-kinase activity. This Phase 1 study evaluated safety, pharmacokinetics, and pharmacodynamics of ARQ 087 and defined the recommended Phase 2 dose (RP2D).Methods:Patients with advanced solid tumours received ARQ 087 administered initially at 25 mg every other day and dose-escalated from 25 to 425 mg daily (QD) continuous dosing. FGF19, 21, 23, and serum phosphate were assessed as potential biomarkers of target engagement.Results:80 patients were enrolled, 61 in dose-escalation/food-effect cohorts and 19 with pre-defined tumour types in the expansion cohort. The most common ARQ 087-related adverse events were fatigue (49%), nausea (46%), aspartate aminotransferase (AST) increase (30%), and diarrhoea (23%). Four patients (5%) experienced grade 1 treatment-related hyperphosphataemia. Dose-limiting toxicity was reversible grade 3 AST increase. The RP2D was 300 mg QD. Pharmacokinetics were linear and dose-proportional from 25 to 325 mg QD, and were unaffected by food. Statistically significant changes (P-value<0.05) suggest phosphate and FGF19 levels as markers of target engagement. In 18 evaluable patients with FGFR genetic alterations, 3 confirmed partial responses (two intrahepatic cholangiocarcinomas (iCCA) with FGFR2 fusions and one urothelial cancer with FGFR2 and FGF19 amplification) and two durable stable disease at ⩾16 weeks with tumour reduction (FGFR2 fusion-positive iCCA and adrenocortical carcinoma with FGFR1 amplification) were observed.Conclusions:ARQ 087 had manageable toxicity at the RP2D of 300 mg QD, showed pharmacodynamics effects, and achieved objective responses, notably in patients with FGFR2 genetic alterations.

Abstract 1234: The novel FGFR4-selective inhibitor INCB062079 is efficacious in models of hepatocellular carcinoma harboring FGF19 amplification

Abstract Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer with limited treatment options for advanced stage disease. Thus, there is a critical medical need for improved therapies. In approximately 10% of HCC, a focal amplicon at 11q13 harboring FGF19 has been reported. High levels of FGF19 have been shown to drive HCC tumor development and progression in preclinical models, suggesting that selective targeting of FGFR4, a high affinity receptor for FGF19, may be efficacious in these HCC tumors. INCB062079 a potent and selective irreversible inhibitor of FGFR4 (&amp;gt;250-fold vs FGFR1/2/3) suppresses the growth of HCC cell lines driven by amplification and overexpression of FGF19. In subcutaneous xenograft models of HCC, oral dosing of INCB062079 at tolerated doses resulted in dose-dependent inhibition of tumor growth with regressions observed at higher doses consistent with inhibition of FGFR4 signaling in the tumors. In combination with sorafenib, the only approved targeted therapy for HCC, FGFR4 inhibition exhibited additive tumor growth inhibition in the Huh7 model. To assess exposure of INCB062079 in orthotopic tumors after oral dosing, Hep3B tumors were implanted surgically into the liver and their development monitored by analysis of plasma alpha-fetoprotein (AFP). At efficacious doses, INCB062079 strongly suppressed the levels of AFP and FGF19 secreted by the tumors, and their levels correlated well with the reduction in terminal liver tumor mass, suggesting that these may be surrogate markers for response of HCC tumors to INCB062079. In two PDX models of HCC with amplification of FGF19 (4-6 CNV), INCB062079 administration reduced tumor growth by 50-66% at doses that were well tolerated. Additional surrogate markers for FGFR4 inhibition were explored including several parameters related to FGF19 regulation of bile acid metabolism. The mRNA levels of CYP7A1, encoding cholesterol 7a-hydroxlyase, the rate limiting enzyme in bile acid synthesis, were induced in the livers of cynomolgus monkeys upon dosing with INCB062079. Correspondingly there was a dose-dependent increase in fecal bile acids. In summary these data demonstrate that INCB062079 is highly and selectively efficacious in models of HCC with FGF19-FGFR4 oncogene addiction and elicits pharmacodynamic responses in primates providing support for the clinical evaluation of INCB062079 in genetically selected liver cancer patients. Citation Format: Bruce Ruggeri, Matthew Stubbs, Yan-ou Yang, Ashish Juvekar, Liang Lu, Sindy Condon, Darlise DiMatteo, Xiaoming Wen, Paul Collier, Timothy Burn, Liangxing Wu, Daniel Wilson, Swamy Yeleswaram, Alan Roberts, Wenqing Yao, Gregory Hollis, Reid Huber, Peggy Scherle, Phillip CC Liu. The novel FGFR4-selective inhibitor INCB062079 is efficacious in models of hepatocellular carcinoma harboring FGF19 amplification [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1234. doi:10.1158/1538-7445.AM2017-1234

Abstract 2100: Selective inhibition of FGFR4 by INCB062079 is efficacious in models of FGF19- and FGFR4-dependent cancers

Abstract Aberrant signaling through Fibroblast Growth Factor Receptors (FGFR) has been reported in multiple types of human cancers. FGFR4 signaling contributes to the development and progression of subsets of cancer: in approximately 10 percent of hepatocellular carcinoma (HCC), genetic amplification of FGF19, encoding an endocrine FGF ligand that activates FGFR4-KLB receptors, has been reported. In models with this alteration, FGF19-FGFR4 signaling is oncogenic and antagonism of the FGF19-FGFR4 axis has been shown to be efficacious suggesting that selective targeting of FGFR4 may be an effective strategy for malignancies with FGFR4 activation. We describe the preclinical characterization of INCB062079 a potent and selective inhibitor of the FGFR4 kinase. In biochemical assays INCB062079 inhibited FGFR4 with low nM potency and exhibited at least 250-fold selectivity against other FGFR kinases and greater than 800-fold selectivity against a large kinase panel. This selectivity derives from the ability of INCB062079 to bind irreversibly to Cys552, a residue within the active site of FGFR4 that is non-conserved among other FGFR receptors. Covalent binding of INCB062079 to Cys552 was demonstrated using a LC/MS/MS-based proteomic analysis that confirmed specificity for the target Cys. In assays using HCC cells with autocrine production of FGF19, INCB062079 inhibited the autophosphorylation of FGFR4 and blocked signal transduction by FGFR4 to downstream markers of pathway activation. Cancer cell lines that have amplification and expression of FGF19 are uniquely sensitive to growth inhibition by INCB062079 (EC50 less than 200 nM) compared with HCC cell lines or normal cells without FGF19-FGFR4 dependence (EC50 &amp;gt; 5000 nM) confirming selectivity for FGFR4. In vivo, oral administration of INCB062079 inhibited the growth and induced significant regressions of subcutaneous xenograft tumors dependent upon FGFR4 activity at doses that were well-tolerated (10-30 mg/kg BID) and did not result in a significant increase in serum phosphate levels which is observed with FGFR1/2/3 inhibition. Suppression of tumor growth correlated with pharmacodynamic inhibition of FGFR4 signaling. Collectively, these preclinical studies demonstrate that INCB062079 potently and selectively inhibits models of FGF19-FGFR4-dependent cancers in vitro and in vivo, supporting clinical evaluation in patients harboring oncogenic FGFR4 activation. Citation Format: Phillip C.C. Liu, Liang Lu, Kevin Bowman, Matthew C. Stubbs, Liangxing Wu, Darlise DiMatteo, Sindy Condon, Ronald Klabe, Ding-Quan Qian, Xiaoming Wen, Paul Collier, Karen Gallagher, Michael Hansbury, Xin He, Bruce Ruggeri, Yan-ou Yang, Maryanne Covington, Timothy C. Burn, Sharon Diamond-Fosbenner, Richard Wynn, Reid Huber, Wenqing Yao, Swamy Yeleswaram, Peggy Scherle, Gregory Hollis. Selective inhibition of FGFR4 by INCB062079 is efficacious in models of FGF19- and FGFR4-dependent cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2100. doi:10.1158/1538-7445.AM2017-2100

Abstract 3126: H3B6527, a selective and potent FGFR4 inhibitor for FGF19-driven hepatocellular carcinoma

Abstract Hepatocellular carcinoma (HCC) has limited treatment options and generally poor prognosis. Recent genomic studies have identified FGF19 as a driver oncogene in HCC. FGF19 is a gut secreted hormone that acts in the liver through FGFR4 to regulate bile acid synthesis. Consistent with the notion that FGF19 is a driver oncogene in HCC, transgenic mice overexpressing FGF19 form liver tumors and genetic ablation of FGFR4 prevented tumor formation. These data suggest targeting FGFR4 would have therapeutic benefit in HCC with altered FGF19 signaling. While a number of Pan-FGFR inhibitors are being clinically evaluated, their application to FGF19-driven HCC may be limited by their FGFR1-3 related dose limiting toxicities. Using structure guided drug design, we have generated a highly selective covalent FGFR4 inhibitor, H3B-6527. Biochemical and cellular selectivity assays showed that H3B-6527 is &amp;gt;300 fold selective towards FGFR4 compared to other FGFR isoforms. Addition of H3B-6527 to FGF19 amplified HCC cell lines led to dose dependent inhibition of FGF19/FGFR4 signaling and concomitant reduction in cell viability. In a panel of 40 HCC cell lines, H3B-6527 selectively reduced the viability of cells that harbor FGF19 amplification and showed no effect in FGF19 non-amplified HCC cell line models. Oral dosing of H3B-6527 to mice led to dose-dependent pharmacodynamic modulation of FGFR4 signaling and tumor regression in FGF19 altered HCC cell line derived xenograft models. H3B-6527 demonstrated inhibition of tumor growth in an orthotopic liver xenograft model of FGF19 altered HCC grown in nude mice. Importantly, the inhibition of tumor growth occurred at doses that were well tolerated in mice and no evidence of FGFR1-3 related toxicities were observed at efficacious doses. In a panel of 30 HCC patient-derived xenograft (PDX) models, H3B-6527 demonstrated tumor regressions in the context of FGF19-amplified tumors. In addition, H3B-6527 showed antitumor activity and tumor regressions in PDX models with high FGF19 expression but no FGF19 amplification. The mechanism for FGF19 overexpression in the absence of gene amplification is under investigation. In conclusion, our preclinical studies demonstrate that FGF19 expression is a predictive biomarker for response to FGFR4 inhibitor therapy. Genomic analysis of public and proprietary data sets indicates that at least approximately 30% of HCC patients exhibit altered FGF19 expression and could potentially benefit from H3B-6527 monotherapy treatment. Citation Format: Anand Selvaraj, Erik Corcoran, Heather Coffey, Sudeep Prajapati, Ming-Hong Hao, Nicholas Larsen, Jennifer Tsai, Takashi Satoh, Kana Ichikawa, Julie Jaya Joshi, Raelene Hurley, Jeremy Wu, Chia-Ling Huang, Suzanna Bailey, Craig Karr, Pavan Kumar, Victoria Rimkunas, Crystal Mackenzie, Nathalie Rioux, Amy Kim, Sandeep Akare, George Lai, Lihua Yu, Peter Fekkes, John Wang, Markus Warmuth, Peter Smith, Dominic Reynolds. H3B6527, a selective and potent FGFR4 inhibitor for FGF19-driven hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3126. doi:10.1158/1538-7445.AM2017-3126

Identification of FGF19 as a prognostic marker and potential driver gene of lung squamous cell carcinomas in Chinese smoking patients.

Comprehensive genomic characterizations of lung squamous cell carcinoma (LSCC) have been performed, but the differences between smokers (S-LSCC) and never smokers (NS-LSCC) are not clear, as NS-LSCC could be considered as a different disease from S-LSCC. In this study we delineated genomic alterations in a cohort of 21 NS-LSCC and 16 S-LSCC patients, and identified common gene mutations and amplifications as previously reported. Inclusion of more NS-LSCC patients enabled us to identify unreported S-LSCC- or NS-LSCC-specific alterations. Importantly, an amplification region containing FGF19, FGF3, FGF4 and CCND1 was found five-times more frequent in S-LSCC than in NS-LSCC. Amplification of FGF19 was validated in independent LSCC samples. Furthermore, FGF19 stimulated LSCC cell growth in vitro. These data implicate FGF19 as a potential driver gene in LSCC with clinic characteristics as smoking.

Abstract S3-03: Nuclear FGFR1 interaction with estrogen receptor (ER) α is associated with resistance to endocrine therapy in ER+/FGFR1-amplified breast cancer

Abstract Background: Estrogen receptor (ER)-positive breast cancers (BC) initially respond to antiestrogens but eventually become hormone-independent and recur. FGFR1 is amplified in ∼10% of ER+ BC and is associated with early recurrence on antiestrogen therapy. Notably, one third of FGFR1-amplified tumors have simultaneous amplification of CCND1, FGF3, FGF4 and FGF19 on chromosome 11q12-14. Herein, we investigated the mechanisms by which FGFR1 amplification confers resistance to antiestrogen therapy in ER+ BC cells. Results: We performed whole exome sequencing in tumor biopsies from 130 patients with an operable ER+/HER2- BC who had received letrozole for 10-21 days prior to surgery. Tumors were categorized by the natural log (ln) of post-letrozole Ki67 as sensitive (ln ≤1 or ≤2.7% Ki67+ cells; n=68) or resistant (ln ≥2 or ≥7.4%; n=18). We found amplifications in FGFR1 and/or 11q12-14 in 6/11 (55%) resistant tumors compared with 5/34 (15%) in sensitive tumors (p=0.006); all cases were confirmed by FGFR1-fluorescence in situ hydridization (FISH). Resistant tumors with FGFR1 and/or 11q12-14-amplification showed a marked increase in nuclear FGFR1 with letrozole. ER+/FGFR1-amplified CAMA1 and MDA134 cell lines also exhibited co-localization of ER and FGFR1 in the nucleus. Cell proliferation was partially reduced by estrogen deprivation, and FGFR1 siRNA further reduced cell growth in hormone-depleted medium. We generated CAMA1 and MDA134 cells resistant to long-term estrogen deprivation (LTED). These cells exhibited overexpression of FGF3/4/19 and ERα with a concomitant increase in ligand-independent ER transcriptional activity and growth. An ER-FGFR1 interaction was observed in the nucleus and cytosol of CAMA1 parental cells with enhanced interaction in CAMA1 LTED cells. Genetic (with siRNA) and pharmacologic (with lucitinib) inhibition of FGFR1 reduced a) nuclear localization of FGFR1; b) ER transcriptional activity; and c) cell proliferation. Nuclear localization and ER-FGFR1 interaction were disrupted by a kinase-deficient FGFR1. Conversely, addition of FGF3 ligand stimulated ER-FGFR1 interaction and ER transcriptional activity, suggesting FGFR activation can regulate ER function. Inhibition of FGF receptor-specific substrate (FRS2), a principal mediator of FGFR1 signal transduction to the MAPK and PI3K pathways, with siRNA or pharmacologic inhibition of PI3K with buparlisib or MEK with GSK1120212 did not reduce ER transcriptional activity suggesting that, in ER+/FGFR1-amplified cancer cells, ER function is not modulated by FGFR signal transducers. Finally, using chromatin immunoprecipitation (ChIP) we showed that FGFR1 binds directly to estrogen response elements (ERE). This association was reduced with lucitanib. We are currently investigating genes modulated by ER/FGFR1 in ER+ BC and the in vivo anti-tumor efficacy of dual inhibition of FGFR1 and ER in ER+/FGFR1-amplified patient-derived breast cancer xenografts. Conclusions: These data support a critical role of ER and FGFR1 interaction in endocrine resistance in ER+/FGFR1-amplified breast cancer. Targeting of FGFR1 in combination with antiestrogens may abrogate resistance to endocrine therapy in these tumors and is worthy of clinical investigation. Citation Format: Formisano L, Young CD, Bhola NE, Bulen B, Estrada VM, Wagle N, Van Allen E, Red Brewer ML, Jansen VM, Guerrero AL, Giltnane JM, Strcker T, Arteaga CL. Nuclear FGFR1 interaction with estrogen receptor (ER) α is associated with resistance to endocrine therapy in ER+/FGFR1-amplified breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S3-03.