Christelle Stamm

FGFR Genetic Alterations Predict for Sensitivity to NVP-BGJ398, a Selective Pan-FGFR Inhibitor

UNLABELLED Patient stratification biomarkers that enable the translation of cancer genetic knowledge into clinical use are essential for the successful and rapid development of emerging targeted anticancer therapeutics. Here, we describe the identification of patient stratification biomarkers for NVP-BGJ398, a novel and selective fibroblast growth factor receptor (FGFR) inhibitor. By intersecting genome-wide gene expression and genomic alteration data with cell line-sensitivity data across an annotated collection of cancer cell lines called the Cancer Cell Line Encyclopedia, we show that genetic alterations for FGFR family members predict for sensitivity to NVP-BGJ398. For the first time, we report oncogenic FGFR1 amplification in osteosarcoma as a potential patient selection biomarker. Furthermore, we show that cancer cell lines harboring FGF19 copy number gain at the 11q13 amplicon are sensitive to NVP-BGJ398 only when concomitant expression of β-klotho occurs. Thus, our findings provide the rationale for the clinical development of FGFR inhibitors in selected patients with cancer harboring tumors with the identified predictors of sensitivity. SIGNIFICANCE The success of a personalized medicine approach using targeted therapies ultimately depends on being able to identify the patients who will benefit the most from any given drug. To this end, we have integrated the molecular profiles for more than 500 cancer cell lines with sensitivity data for the novel anticancer drug NVP-BGJ398 and showed that FGFR genetic alterations are the most significant predictors for sensitivity. This work has ultimately endorsed the incorporation of specific patient selection biomakers in the clinical trials for NVP-BGJ398.

FGF receptors control vitamin D and phosphate homeostasis by mediating renal FGF-23 signaling and regulating FGF-23 expression in bone.

The functional interaction between fibroblast growth factor 23 (FGF‐23) and Klotho in the control of vitamin D and phosphate homeostasis is manifested by the largely overlapping phenotypes of Fgf23‐ and Klotho‐deficient mouse models. However, to date, targeted inactivation of FGF receptors (FGFRs) has not provided clear evidence for an analogous function of FGFRs in this process. Here, by means of pharmacologic inhibition of FGFRs, we demonstrate their involvement in renal FGF‐23/Klotho signaling and elicit their role in the control of phosphate and vitamin D homeostasis. Specifically, FGFR loss of function counteracts renal FGF‐23/Klotho signaling, leading to deregulation of Cyp27b1 and Cyp24a1 and the induction of hypervitaminosis D and hyperphosphatemia. In turn, this initiates a feedback response leading to high serum levels of FGF‐23. Further, we show that FGFR inhibition blocks Fgf23 transcription in bone and that this is dominant over vitamin D–induced Fgf23 expression, ultimately impinging on systemic FGF‐23 protein levels. Additionally, we identify Fgf23 as a specific target gene of FGF signaling in vitro. Thus, in line with Fgf23‐ and Klotho‐deficient mouse models, our study illustrates the essential function of FGFRs in the regulation of vitamin D and phosphate levels. Further, we reveal FGFR signaling as a novel in vivo control mechanism for Fgf23 expression in bone, suggesting a dual function of FGFRs in the FGF‐23/Klotho pathway leading to vitamin D and phosphate homeostasis.

Rescue Screens with Secreted Proteins Reveal Compensatory Potential of Receptor Tyrosine Kinases in Driving Cancer Growth

The overall power of kinase inhibitors is substantially overshadowed by the acquisition of drug resistance. To address this issue, we systematically assessed the potential of secreted proteins to induce resistance to kinase inhibitors. To this end, we developed a high-throughput platform for screening a cDNA library encoding 3,432 secreted proteins in cellular assays. Using cancer cells originally dependent on either MET, FGFR2, or FGFR3, we observed a bypass of dependence through ligand-mediated activation of alternative receptor tyrosine kinases (RTK). Our findings indicate a broad and versatile potential for RTKs from the HER and FGFR families as well as MET to compensate for loss of each other. We further provide evidence that combined inhibition of simultaneously active RTKs can lead to an added anticancer effect.

Polyclonal Secondary FGFR2 Mutations Drive Acquired Resistance to FGFR Inhibition in Patients with FGFR2 Fusion-Positive Cholangiocarcinoma

Genetic alterations in the fibroblast growth factor receptor (FGFR) pathway are promising therapeutic targets in many cancers, including intrahepatic cholangiocarcinoma (ICC). The FGFR inhibitor BGJ398 displayed encouraging efficacy in patients with FGFR2 fusion-positive ICC in a phase II trial, but the durability of response was limited in some patients. Here, we report the molecular basis for acquired resistance to BGJ398 in three patients via integrative genomic characterization of cell-free circulating tumor DNA (cfDNA), primary tumors, and metastases. Serial analysis of cfDNA demonstrated multiple recurrent point mutations in the FGFR2 kinase domain at progression. Accordingly, biopsy of post-progression lesions and rapid autopsy revealed marked inter- and intralesional heterogeneity, with different FGFR2 mutations in individual resistant clones. Molecular modeling and in vitro studies indicated that each mutation led to BGJ398 resistance and was surmountable by structurally distinct FGFR inhibitors. Thus, polyclonal secondary FGFR2 mutations represent an important clinical resistance mechanism that may guide the development of future therapeutic strategies.Significance: We report the first genetic mechanisms of clinical acquired resistance to FGFR inhibition in patients with FGFR2 fusion-positive ICC. Our findings can inform future strategies for detecting resistance mechanisms and inducing more durable remissions in ICC and in the wide variety of cancers where the FGFR pathway is being explored as a therapeutic target. Cancer Discov; 7(3); 252-63. ©2016 AACR.See related commentary by Smyth et al., p. 248This article is highlighted in the In This Issue feature, p. 235.

Fibroblast growth factor receptors as novel therapeutic targets in SNF5-deleted malignant rhabdoid tumors.

Malignant rhabdoid tumors (MRTs) are aggressive pediatric cancers arising in brain, kidney and soft tissues, which are characterized by loss of the tumor suppressor SNF5/SMARCB1. MRTs are poorly responsive to chemotherapy and thus a high unmet clinical need exists for novel therapies for MRT patients. SNF5 is a core subunit of the SWI/SNF chromatin remodeling complex which affects gene expression by nucleosome remodeling. Here, we report that loss of SNF5 function correlates with increased expression of fibroblast growth factor receptors (FGFRs) in MRT cell lines and primary tumors and that re-expression of SNF5 in MRT cells causes a marked repression of FGFR expression. Conversely, siRNA-mediated impairment of SWI/SNF function leads to elevated levels of FGFR2 in human fibroblasts. In vivo, treatment with NVP-BGJ398, a selective FGFR inhibitor, blocks progression of a murine MRT model. Hence, we identify FGFR signaling as an aberrantly activated oncogenic pathway in MRTs and propose pharmacological inhibition of FGFRs as a potential novel clinical therapy for MRTs.

Biotinylated phosphotyrosine containing peptides: A valuable tool for studies on phosphopeptide interactions with SH2 and PTB domains

A series of biotinylated phosphopeptides has been synthesized and used in the development of an ELISA-based approach to assess SH2/PTB-phosphoprotein interactions in vitro in terms of affinity and specificity.

Abstract 3575: Dovitinib (TKI258), a dual inhibitor of FGFR and VEGFR, induces tumor growth suppression in xenograft models of human bladder cancer

Introduction: The aim of this study was to evaluate the efficacy of dovitinib (TKI258), a small molecule dual inhibitor of fibroblast growth factor receptor (FGFR) and vascular endothelial growth factor receptor (VEGFR) in mouse models of human bladder cancer. Molecular epidemiological studies have implicated FGFR and VEGFR pathways in the pathogenesis of high grade, muscle invasive bladder cancer. Somatic activating mutations in FGFR3 have been identified in 16%-20% of muscle-invasive bladder cancer and FGFR3 overexpression has also been documented in a high fraction of bladder cancers. High microvessel density, serum VEGF levels and urine FGF2 levels have also been associated with high grade bladder cancer and poor disease-free survival. Dual FGFR/VEGFR inhibitory activities of dovitinib make it an attractive molecule targeting advanced bladder cancer. Experimental Design: Dovitinib was evaluated in the RT112 human bladder carcinoma xenograft model. Dovitinib was administered orally at three dose levels (n = 10/group), once daily for 28 consecutive days (qd × 28). A rat RT112 xenograft study was also carried out to evaluate the PK/PD effect of single dose dovitinib administration. Results: Dovitinib at 15, 30, and 60 mg/kg resulted in tumor growth suppression, with mean changes of 60% T/C, 6% T/C (P Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3575. doi:10.1158/1538-7445.AM2011-3575

Abstract 2098: NVP-FGF401, a first-in-class highly selective and potent FGFR4 inhibitor for the treatment of HCC

Hepatocellular carcinoma (HCC) is the seventh most common cancer worldwide and the third leading cause of cancer-related death. Sorafenib is the only targeted agent to show a marginal improvement in overall survival (OS) for patients with advanced HCC. Recent data have implicated aberrant activation of the FGF19-FGFR4/KLB axis as the driver of certain forms of HCC, making this pathway a novel therapeutic target in this disease. The first evidence for this is the finding that aberrant expression of FGF19, as a consequence of gene amplification and other not yet known mechanisms, occurs in subsets of HCC’s and HCC cell lines leading to constitutive FGFR4 activation. In this setting, conditional knock down of FGF19, as well as its receptors FGFR4 and KLB, suppresses proliferation of HCC cell lines, supporting the notion that FGF19 activates FGFR4 in an autocrine fashion. Secondly, in transgenic mouse models, FGF19 produced by non-tumor cells at an ectopic site (skeletal muscle) acts in a paracrine fashion on the liver hepatocytes leading to liver dysplasia and HCC. In these mice, tumorigenesis is abolished in an FGFR4 null background, as well as upon treatment with anti-FGF19 and anti-FGFR4 blocking antibodies. Thus, we anticipate that targeted therapies aimed at blocking the FGFR4 pathway might be efficacious in subsets of HCC’s. We have identified and developed NVP-FGF401, a first in class, highly selective and potent FGFR4 inhibitor that is currently in PhI/II clinical testing. NVP-FGF401 binds in a reversible covalent manner to the FGFR4 kinase domain and it inhibits FGFR4 with an IC50 of 1.1 nM. In biochemical assays, it shows at least 1,000 fold selectivity against of panel of 65 kinases and in a kinome wide scan, consisting of 456 kinases, FGFR4 was the only target of NVP-FGF401. In xenograft animal models in vivo, NVP-FGF401 showed a consistent pharmacokinetic / pharmacodynamic (PK/PD) relationship with phospho-FGFR4 over total FGFR4 (p/tFGFR4) levels in tumor robustly inhibited in a dose dependent manner. The data support a lowest observed trough concentration (Ctrough) driven PD/efficacy relationship. The anti-tumor activity was confirmed across several xenograft animal models, as well as in patient-derived tumor xenografts (PDX) established in mice. The excellent drug-like properties of NVP-FGF401 drove us to test its efficacy in HCC patients in a PhI/II study, being the first selective FGFR4 inhibitor to ever enter into clinical trials (NCT02325739). Citation Format: Diana Graus Porta, Andreas Weiss, Robin A. Fairhurst, Markus Wartmann, Christelle Stamm, Flavia Reimann, Alexandra Buhles, Jaqueline Kinyamu-Akunda, Dario Sterker, Masato Murakami, Youzhen Wang, Jeffrey Engelman, Francesco Hofmann, William R. Sellers. NVP-FGF401, a first-in-class highly selective and potent FGFR4 inhibitor for the treatment of HCC [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 2098. doi:10.1158/1538-7445.AM2017-2098

Abstract 2103: NVP-FGF401: Cellular and in vivo profile of a novel highly potent and selective FGFR4 inhibitor for the treatment of FGF19/FGFR4/KLB+ tumors

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and a deadly disease. Treatment options are limited and prognosis generally is poor. Aberrant signaling through the fibroblast growth factor 19 (FGF19) - fibroblast growth factor receptor 4 (FGFR4) axis has been implicated in the development of HCC, and recently FGF19 has been determined as a specific driver gene amplification in a subset of liver tumors and cancer cell lines. Here, we describe the cellular and in vivo profile of NVP-FGF401, a highly potent and selective, first in class, reversible-covalent small-molecule inhibitor of the kinase activity of FGFR4. NVP-FGF401 is exquisitely selective for FGFR4 versus other FGFR family members and all other kinases. We show that among the FGF19-amplified liver cancer cells in the cancer cell line encyclopedia (CCLE), only those with concomitant expression of β-klotho (KLB), a co-receptor for FGF19 that facilitates its binding to FGFR4, are sensitive to NVP-FGF401. NVP-FGF401 has good oral PK properties and shows an excellent in vivo PK/PD relationship. NVP-FGF401 has remarkable anti-tumor activity in mice bearing HCC tumor xenografts and PDX models that are positive for FGF19, FGFR4 and KLB. NVP-FGF401 is the first FGFR4 inhibitor to enter clinical trials, and a PhI/II study is currently ongoing in HCC and other types of solid tumors. Citation Format: Andreas Weiss, Diana Graus Porta, Flavia Reimann, Alexandra Buhles, Christelle Stamm, Robin A. Fairhurst, Jacqueline Kinyamu-Akunda, Dario Sterker, Masato Murakami, Markus Wartmann, Youzhen Wang, Jeffrey A. Engelman, Francesco Hofmann, Wiliam R. Sellers. NVP-FGF401: Cellular and in vivo profile of a novel highly potent and selective FGFR4 inhibitor for the treatment of FGF19/FGFR4/KLB+ tumors [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 2103. doi:10.1158/1538-7445.AM2017-2103

Abstract 854: Patient stratification strategies for NVP-BGJ398, a selective pan-FGFR inhibitor in phase I clinical trials

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL The mammalian fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) family comprises 22 FGF ligands, which exert their action through 4 highly conserved transmembrane tyrosine kinase receptors (FGFR1, FGFR2, FGFR3 and FGFR4). This highly complex signaling network regulates fundamental developmental pathways and physiological processes in the adult organism. A growing body of evidence linking deregulation of the FGF/FGFR system, as a consequence of genetic alterations, to the pathogenesis of cancer makes these receptors attractive targets for therapeutic intervention. To this purpose we have developed NVP-BGJ398, an orally bioavailable, selective pan-FGFR kinase inhibitor which is currently in clinical Phase I dose escalation trial. In order to preclinically identify and validate patient stratification biomarkers that accurately predict for response to NVP-BGJ398 in the clinic, we have utilized the Cancer Cell Line Encyclopedia (CCLE). The CCLE is a collection of almost 1000 cancer cell lines representing multiple tumor types that, in a collaborative effort between The Novartis Institutes for BioMedical Research and the Broad Institute, has been comprehensively annotated in terms of genome-scale mRNA expression, gene copy number alterations and gene mutations (http:/www.broadinstitute.org/ccle). In addition, over half of these cell lines were subjected to high-throughput cell viability assays in the presence NVP-BGJ398, with the aim of generating cell line sensitivity data. Here we show the validation of predictive biomarkers of response in primary human tumor xenografts, revealed through the analysis of the CCLE, as well as the identification of potentially new indications for NVP-BGJ398. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 854. doi:1538-7445.AM2012-854