Selective Fibroblast Growth Factor Receptor Inhibitors Research Articles

INCB054828 (pemigatinib), a potent and selective inhibitor of fibroblast growth factor receptors 1, 2, and 3, displays activity against genetically defined tumor models.

Alterations in fibroblast growth factor receptor (FGFR) genes have been identified as potential driver oncogenes. Pharmacological targeting of FGFRs may therefore provide therapeutic benefit to selected cancer patients, and proof-of-concept has been established in early clinical trials of FGFR inhibitors. Here, we present the molecular structure and preclinical characterization of INCB054828 (pemigatinib), a novel, selective inhibitor of FGFR 1, 2, and 3, currently in phase 2 clinical trials. INCB054828 pharmacokinetics and pharmacodynamics were investigated using cell lines and tumor models, and the antitumor effect of oral INCB054828 was investigated using xenograft tumor models with genetic alterations in FGFR1, 2, or 3. Enzymatic assays with recombinant human FGFR kinases showed potent inhibition of FGFR1, 2, and 3 by INCB054828 (half maximal inhibitory concentration [IC50] 0.4, 0.5, and 1.0 nM, respectively) with weaker activity against FGFR4 (IC50 30 nM). INCB054828 selectively inhibited growth of tumor cell lines with activation of FGFR signaling compared with cell lines lacking FGFR aberrations. The preclinical pharmacokinetic profile suggests target inhibition is achievable by INCB054828 in vivo with low oral doses. INCB054828 suppressed the growth of xenografted tumor models with FGFR1, 2, or 3 alterations as monotherapy, and the combination of INCB054828 with cisplatin provided significant benefit over either single agent, with an acceptable tolerability. The preclinical data presented for INCB054828, together with preliminary clinical observations, support continued investigation in patients with FGFR alterations, such as fusions and activating mutations.

An evaluation of the efficacy and safety of erdafitinib for the treatment of bladder cancer

ABSTRACT Introduction Treatment of unresectable or metastatic urothelial carcinoma (UC) has historically relied upon platinum-based chemotherapy and, more recently, immune checkpoint inhibitors. When tumors progress despite those therapies, remaining effective options are limited. Areas covered In this review, the authors review the advancement in genomic targets in UC, most notably fibroblast growth factor receptor (FGFR). FGFR has been identified as a target in UC as it is commonly genomically altered (activating mutations or fusions), and may be enriched in UC subtypes that are relatively resistant to immune checkpoint blockade. Erdafitinib, a potent and selective inhibitor of FGFRs, represents the first targeted therapy approved for the treatment of UC by virtue of a confirmed response rate of 40% in an open-label, single-armed phase II trial in molecularly selected tumors. The authors provide their expert opinion of its approval and place it in the context of the current and forthcoming treatment strategies for metastatic UC. Expert opinion The approval of erdafitinib provides clinicians with an important new treatment option for patients with metastatic UC and projects forward into an era of enhanced molecular precision in identifying effective therapies in UC.

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

BackgroundFibroblast growth factor receptor (FGFR)1 and FGFR4 have been associated with tumorigenesis in a variety of tumour types. As a therapeutic approach, their inhibition has been attempted in different types of malignancies, including lung cancer, and was initially focused on FGFR1-amplified tumours, though with limited success.MethodsIn vitro and in vivo functional assessments of the oncogenic potential of downregulated/overexpressed genes in isogenic cell lines were performed, as well as inhibitor efficacy tests in vitro and in vivo in patient-derived xenografts (PDXs). mRNA was extracted from FFPE non-small cell lung cancer samples to determine the prognostic potential of the genes under study.FindingsWe provide in vitro and in vivo evidence showing that expression of the adhesion molecule N-cadherin is key for the oncogenic role of FGFR1/4 in non-small cell lung cancer. According to this, assessment of the expression of genes in different lung cancer patient cohorts showed that FGFR1 or FGFR4 expression alone showed no prognostic potential, and that only co-expression of FGFR1 and/or FGFR4 with N-cadherin inferred a poorer outcome. Treatment of high-FGFR1 and/or FGFR4-expressing lung cancer cell lines and patient-derived xenografts with selective FGFR inhibitors showed high efficacy, but only in models with high FGFR1/4 and N-cadherin expression.InterpretationOur data show that the determination of the expression of FGFR1 or FGFR4 alone is not sufficient to predict anti-FGFR therapy efficacy; complementary determination of N-cadherin expression may further optimise patient selection for this therapeutic strategy.

FIGHT-205: Phase II study of first-line pemigatinib (PEMI) plus pembrolizumab (PEMBRO) versus PEMI alone versus standard of care (SOC) for cisplatin (CIS)—Ineligible urothelial carcinoma (UC) with FGFR3 mutation or rearrangement.

TPS592 Background: Fibroblast growth factor receptor (FGFR) 3 gene alterations (GAs) are involved in UC pathogenesis. Pts with metastatic UC and FGFR3 GAs express low programmed cell death ligand 1 (PD-L1) levels; combination with FGFR inhibitors may confer added benefit via tumor-direct and immunomodulatory effects. Preliminary data from a phase 2 monotherapy trial of PEMI (INCB054828), a selective, potent, oral FGFR1–3 inhibitor, confirmed efficacy in previously treated relapsed/refractory pts with UC and FGFR3 GAs (NCT02872714). FIGHT-205, a randomized, open-label, phase 2 study, will assess efficacy and safety of PEMI + PEMBRO vs PEMI alone vs SOC (carboplatin [CARB] + gemcitabine [GEM] or PEMBRO alone) in CIS-ineligible metastatic/unresectable UC with FGFR3 mutation/rearrangement (NCT04003610). Methods: Eligible pts are adults with confirmed metastatic/unresectable UC; ≥1 measurable target lesion (per RECIST v1.1); platinum (PT)/CIS-ineligible; centrally confirmed FGFR3 mutation/rearrangement; ECOG PS ≤2. Exclusions include prior selective FGFR inhibitor, anti-PD-1/PD-L1/2, or co-inhibitory T-cell receptor directed agent; chemotherapy (except adjuvant, neoadjuvant); clinically significant corneal/retinal disorder; Ca/PO4 homeostasis disorder/systemic mineral imbalance with ectopic calcification; untreated CNS metastases. Pts will be randomized (1:1:1) to 3 groups: PEMI 13.5 mg QD (continuous, 21-d cycle) + PEMBRO 200 mg Q3W, PEMI alone (same dose), or SOC (GEM [1000 mg/m2 on D1 + D8] + CARB [AUC 5 (or 4.5) on D1 or D2] Q3W or PEMBRO [same dose] if PD-L1 score high/PT-ineligible). PEMI titration to 18 mg starting at cycle 2 is required for pts without hyperphosphatemia (serum PO4 >5.5 mg/dL) and grade ≥2 treatment-related AEs during cycle 1. Hyperphosphatemia will be managed by diet modifications, PO4 binders, diuretics, or dose adjustments. PEMI will continue until progression/unacceptable toxicity. Primary endpoint is progression-free survival. Secondary endpoints are overall survival, objective response rate, duration of response, safety, and quality of life. Clinical trial information: NCT04003610.

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 >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

Abstract 335: Efficacy of FGFR inhibitors and combination therapies for acquired resistance in FGFR2-fusion cholangiocarcinoma

Abstract Background. The fibroblast growth factor receptor (FGFR) signaling pathway is aberrantly activated in approximately 20% of cases of cholangiocarcinoma through various genomic alterations including gene fusions, point mutations, and copy number amplifications. Currently, several FGFR kinase inhibitors are being assessed in clinical trials for patients with FGFR-altered cholangiocarcinoma. Despite evidence of initial responses and disease control, virtually all tumors eventually develop drug resistance. Overcoming acquired drug resistance to FGFR inhibitors has not been comprehensively studied. Methods. Apatient with metastatic cholangiocarcinoma and an activating FGFR2-KIAA1598fusion was enrolled on a Phase 2 clinical trial for the oral FGFR inhibitor, BGJ398. BGJ398 treatment was initially effective with radiographic and tumor marker response; however, after eight months of BGJ398 therapy, the patient developed disease progression. Sequencing of a post-progression liver biopsy revealed a novel secondary mutation (E566A) in the FGFR2 kinase domain, which was absent in the pre-treatment biopsy suggesting that this mutation may be responsible for the resistance to BGJ398. To confirm this, we conducted in vitrostudies to characterize the sensitivity of the FGFR2 secondary mutation to FGFR inhibitors. Results and Conclusions. In vitrocharacterization of the fusion and putative resistance mutation demonstrated that FGFR2-KIAA1598 WT cells were sensitive to BGJ398 with (IC50value of 10.95 nM) whereas the FGFR2-KIAA1598 E566A cells were resistant (IC50values of 422.4 nM). We investigated additional selective (AZD4547 and JNJ42756493), non-selective (dovtinib and ponatinib), and irreversible (TAS120) FGFR inhibitors. FGFR2-KIAA1598 WT cells were sensitive to AZD4547, JNJ42756493, and TAS120, whereas FGFR2-KIAA1598 E566A cells were resistant to these inhibitors. Interestingly, neither the FGFR2-KIAA1598 WT cells nor the FGFR2-KIAA1598 E566A cells were sensitive to dovitinib, a nonspecific tyrosine kinase inhibitor. Lastly, both populations of cells were equally sensitive to ponatinib, a non-selective FGFR kinase inhibitor. Proteomic analysis by reverse phase protein array (RPPA) revealed upregulation of the mTOR/PI3K/AKT pathway in fusion cells compared to empty controls (FDR: 0.00618), and this expression was further potentiated in FGFR2-KIAA1598 E566A (FDR: 1.96e-19). Furthermore, combination studies with the above FGFR inhibitors and the mTOR inhibitor, INK128, yielded synergistic antitumor effects suggesting that combination therapy may be able to overcome resistance to FGFR inhibitors. Significance. In conclusion, further elucidation of the mechanisms driving resistance to FGFR inhibitors will support the development of next generation FGFR inhibitors as well as combination therapeutic strategies. Citation Format: Melanie A. Krook, Alexandria M. Lenyo, Maxwell J. Wilberding, Hannah D. Barker, Mikayla Dantuono, Hui-Zi Chen, Julie W. Reeser, Michele R. Wing, Jharna Miya, Eric Samorodnitsky, Amy M. Smith, Thuy Dao, Dorrelyn M. Martin, Kristin Dittmar, Kristen K. Ciombor, John L. Hays, Aharon G. Freud, Sameek Roychowdhury. Efficacy of FGFR inhibitors and combination therapies for acquired resistance in FGFR2-fusion cholangiocarcinoma [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 335.

Abstract 4881: Molecular screening of patients with FGFR alterations for phase 1 (ph1) study with the selective FGFR inhibitor Debio 1347

Abstract Background: Oncogenic alterations in fibroblast growth factor receptors (FGFR) are seen across multiple solid tumors. Debio 1347 is an orally available, highly selective FGFR1,2,3 inhibitor that is undergoing phase I clinical trial evaluation in patients harboring an FGFR genetic abnormality. The availability of tumor tissue for retrospective genotyping, diversity of genetic alterations identified, and concordance with central laboratory testing were evaluated. Methods: Patients harboring an FGFR1/2/3 gene amplification, mutation, or fusion were identified by local laboratories using different technologies. Patients received escalating doses of Debio 1347 from 10mg up to 150mg daily. Diagnostic tumor tissue was secured for post-hoc analysis at a central laboratory (CL) to confirm the alterations reported on enrollment. Whenever possible, fresh biopsies were collected prior to starting treatment for comparison. Results: Archived diagnostic samples were available for most patients but material adequacy allowed for post-hoc genotyping to be performed in only 43 of 58 patients. For 23 of these patients, both a diagnostic sample and an on-study screening biopsy were secured and suitable for comparative analysis. Availability of screening material varied across tumor types. Overall, post hoc genetic testing on diagnostic tissue did not confirm the main FGFR alteration in 9 cases (23%): 4 FGFR amplifications, 2 fusions and 3 mutations. Four of FGFR amplifications could not be confirmed: two discordant calls were attributed to the difference in identifying polysomy over focal gene amplification. Two of 11 fusion cases were not centrally confirmed. For one of these cases, the low number of fusion reads for an FGFR3:TACC3 fusion was below the cutoff for CL reporting. When comparing genotypes between diagnostic and screening samples, concordance was 76% between the 2 CL sites. Efforts are ongoing to address all examples of discordance. Conclusions: The clinical diagnostic landscape proves to be complex. The use of different technologies with different sensitivities and analysis pipelines constitute one of many diagnostic hurdles. Biopsy availability across different cancer types and tumor heterogeneity add to its complexity, as well as tumor evolution over time from initial diagnosis to treatment. Citation Format: Anthony J. Iafrate, Darrell R. Borger, Ana Vivancos, Martin Voss, James Cleary, Funda Meric-Bernstam, Josep Tabernero, Keith Flaherty, Nobuya Ishii, Franck Brichory, Hiroaki Tanaka, Anna Pokorska-Bocci, Jose Baselga, Paolo Nuciforo. Molecular screening of patients with FGFR alterations for phase 1 (ph1) study with the selective FGFR inhibitor Debio 1347 [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 4881.

A Selective FGFR inhibitor AZD4547 suppresses RANKL/M-CSF/OPG-dependent ostoclastogenesis and breast cancer growth in the metastatic bone microenvironment

Aberrant activation of fibroblast growth factor receptor (FGFR) signalling contributes to progression and metastasis of many types of cancers including breast cancer. Accordingly, FGFR targeted tyrosine kinase inhibitors (TKIs) are currently under development. However, the efficacy of FGFR TKIs in the bone microenvironment where breast cancer cells most frequently metastasize and also where FGFR is biologically active, has not been clearly investigated. We investigated the FGFR-mediated interactions among cancer and the bone microenvironment stromal cells (osteoblasts and osteoclasts), and also the effects of FGFR inhibition in bone metastasis. We showed that addition of culture supernatant from the MDA-MB-134-VI FGFR-amplified breast cancer cells-activated FGFR siganalling in osteoblasts, including increased expression of RANKL, M-CSF, and osteoprotegerin (OPG). Further in vitro analyses showed that AZD4547, an FGFR TKI currently in clinical trials for breast cancer, decreased RANKL and M-CSF, and subsequently RANKL and M-CSF-dependent osteoclastogenesis of murine bone marrow monocytes. Moreover, AZD4547 suppressed osteoclastogenesis and tumor-induced osteolysis in an orthotopic breast cancer bone metastasis mouse model using FGFR non-amplified MDA-MB-231 cells. Collectively, our results support that FGFR inhibitors inhibit the bone microenvironment stromal cells including osteoblasts and osteoclasts, and effectively suppress both tumor and stromal compartments of bone metastasis.

FUZE clinical trial: a phase 2 study of Debio 1347 in FGFR fusion-positive advanced solid tumors irrespectively of tumor histology.

TPS3157 Background: Dysregulation of fibroblast growth factor receptor (FGFR) signaling by FGFR fusions is implicated in many cancers. Debio 1347 is a selective oral inhibitor of FGFR 1-3 tyrosine kinases. It exhibited high antitumor activity in in vitro and in vivo tumor models with FGFR1-3 gene fusions. Preliminary data from an ongoing phase 1 trial show efficacy and tolerability in patients (pts) harboring FGFR 1-3 fusion irrespectively of tumor type. We present the design for a multicenter, basket, 2-stage, adaptive single arm Phase 2 trial investigating Debio 1347 in pts with solid tumors harboring FGFR1-3 fusion/rearrangement. Methods: Adults with locally advanced/unresectable or metastatic tumors with documented FGFR1-3 gene fusion/rearrangement who require systemic therapy and have progression after ≥1 prior standard treatment or have no satisfactory alternative treatment option are eligible. Three cohorts are included: biliary tract cancer (cohort 1), urothelial cancer (cohort 2) and all other solid tumors (cohort 3). Primary brain tumors are excluded. Other key exclusion criteria include prior treatment with FGFR1-3 selective inhibitor; clinically significant corneal/retinal disorder; history of calcium/phosphate homeostasis disorder or systemic mineral imbalance with ectopic soft tissue calcification, and symptomatic/unstable brain metastases < 1 month before enrollment. Genomic screening of tumor tissue is done at local or central laboratory with post-hoc central confirmation by RNA sequencing. Eligible pts will receive Debio 1347, 80 mg PO once daily in 28-day cycles until occurrence of progression or unacceptable toxicity. Primary Endpoint is objective response rate (ORR) based on independent central review using RECIST v.1.1. The targeted sample size (N=125) will provide approximately 90% power to reject H0: ORR ≤ 15% at an overall 5% significance level based on an expected ORR of 30% in at least one of the cohorts. Secondary endpoints are: duration of response, disease control rate, progression-free survival, overall survival, safety, tolerability, and quality of life. An interim analysis for futility and homogeneity will be performed after 27 evaluable pts. PK sparse sampling is performed to assess exposure-response relationships with efficacy and safety. Biomarkers of response and resistance will be explored. Accrual is opened in US, EU, Asia and Australia. Clinical trial information: NCT03834220.

C11, a novel fibroblast growth factor receptor 1 (FGFR1) inhibitor, suppresses breast cancer metastasis and angiogenesis.

The fibroblast growth factor receptors (FGFRs) are increasingly considered attractive targets for therapeutic cancer intervention due to their roles in tumor metastasis and angiogenesis. Here, we identified a new selective FGFR inhibitor, C11, and assessed its antitumor activities. C11 was a selective FGFR1 inhibitor with an IC50 of 19 nM among a panel of 20 tyrosine kinases. C11 inhibited cell proliferation in various tumors, particularly bladder cancer and breast cancer. C11 also inhibited breast cancer MDA-MB-231 cell migration and invasion via suppression of FGFR1 phosphorylation and its downstream signaling pathway. Suppression of matrix metalloproteinases 2/9 (MMP2/9) was associated with the anti-motility activity of C11. Furthermore, the anti-angiogenesis activity of C11 was verified in endothelial cells and chicken chorioallantoic membranes (CAMs). C11 inhibited the migration and tube formation of HMEC-1 endothelial cells and inhibited angiogenesis in a CAM assay. In sum, C11 is a novel selective FGFR1 inhibitor that exhibits potent activity against breast cancer metastasis and angiogenesis.

Oncogenic Characterization and Pharmacologic Sensitivity of Activating Fibroblast Growth Factor Receptor (FGFR) Genetic Alterations to the Selective FGFR Inhibitor Erdafitinib.

Fibroblast growth factor receptor (FGFR) genetic alterations are frequently observed in cancer, suggesting that FGFR inhibition may be a promising therapy in patients harboring these lesions. Identification of predictive and pharmacodynamic biomarkers to select and monitor patients most likely to respond to FGFR inhibition will be the key to clinical development of this class of agents. Sensitivity to FGFR inhibition and correlation with FGFR pathway activation status were determined in molecularly annotated panels of cancer cell lines and xenograft models. Pathway inhibition in response to FGFR inhibitor treatment was assessed in cell lines (both in vitro and in vivo) and in samples from patients treated with the FGFR inhibitor JNJ-42756493 (erdafitinib). Frequency of FGFR aberrations was assessed in a panel of NSCLC, breast, prostate, ovarian, colorectal, and melanoma human tumor tissue samples. FGFR translocations and gene amplifications present in clinical specimens were shown to display potent transforming activity associated with constitutive pathway activation. Tumor cells expressing these FGFR activating mutants displayed sensitivity to the selective FGFR inhibitor erdafitinib and resulted in suppression of FGFR phosphorylation and downstream signal transduction. Clinically, patients receiving erdafitinib showed decreased Erk phosphorylation in tumor biopsies and elevation of serum phosphate. In a phase I study, a heavily pretreated bladder cancer patient with an FGFR3-TACC3 translocation experienced a partial response when treated with erdafitinib. This preclinical study confirmed pharmacodynamics and identified new predictive biomarkers to FGFR inhibition with erdafitinib and supports further clinical evaluation of this compound in patients with FGFR genetic alterations. Mol Cancer Ther; 16(8); 1717-26. ©2017 AACR.

Enhancement of the anti-tumor activity of FGFR1 inhibition in squamous cell lung cancer by targeting downstream signaling involved in glucose metabolism.

Fibroblast Growth Factor Receptor (FGFR) signaling is a complex pathway which controls several processes, including cell proliferation, survival, migration, and metabolism. FGFR1 signaling is frequently deregulated via amplification/over-expression in NSCLC of squamous histotype (SQCLC), however its inhibition has not been successfully translated in clinical setting. We determined whether targeting downstream signaling implicated in FGFR1 effects on glucose metabolism potentiates the anti-tumor activity of FGFR1 inhibition in SQCLC. In FGFR1 amplified/over-expressing SQCLC cell lines, FGF2-mediated stimulation of FGFR1 under serum-deprivation activated both MAPK and AKT/mTOR pathways and increased glucose uptake, glycolysis, and lactate production, through AKT/mTOR-dependent HIF-1α accumulation and up-regulation of GLUT-1 glucose transporter. These effects were hindered by PD173074 and NVP-BGJ398, selective FGFR inhibitors, as well as by dovitinib, a multi-kinase inhibitor. Glucose metabolism was hampered by the FGFR inhibitors also under hypoxic conditions, with consequent inhibition of cell proliferation and viability. In presence of serum, glucose metabolism was impaired only in cell models in which FGFR1 inhibition was associated with AKT/mTOR down-regulation. When the activation of the AKT/mTOR pathway persisted despite FGFR1 down-regulation, the efficacy of NVP-BGJ398 could be significantly improved by the combination with NVP-BEZ235 or other inhibitors of this signaling cascade, both in vitro and in xenotransplanted nude mice. Collectively our results indicate that inhibition of FGFR1 signaling impacts on cancer cell growth also by affecting glucose energy metabolism. In addition, this study strongly suggests that the therapeutic efficacy of FGFR1 targeting molecules in SQCLC may be implemented by combined treatments tackling on glucose metabolism.

Targeting FGFR in Squamous Cell Carcinoma of the Lung.

Unlike for adenocarcinomas of the lung, no molecular targeted therapies have yet been developed for squamous cell lung cancers, because targetable oncogenic aberrations are scarce in this tumor type. Recent discoveries have established that the fibroblast growth factor (FGF) signaling pathway plays a fundamental role in cancer development by supporting tumor angiogenesis and cancer cell proliferation via different mechanisms. Through comprehensive genomic studies, aberrations in the FGF pathway have been identified in various tumor types, including squamous cell lung cancer, making FGF receptor (FGFR) a potentially druggable target in this malignancy. Several multi-targeted tyrosine kinase inhibitors include FGFR in their target spectrum and a number of these compounds have been approved for clinical use in different cancers. Novel agents selectively targeting FGFRs have been developed and are currently under investigation in clinical trials, showing promising results. This article reviews FGFR aberrations and the clinical data involving selective and multikinase FGFR inhibitors in squamous cell lung cancer.

Abstract 2095: E7090, a novel and selective FGFR inhibitor, for the treatment of cholangiocarcinoma cells harboring FGFR2-fusion genes

Abstract Genetic abnormalities (gene fusion, mutation and amplification) of fibroblast growth factor receptor (FGFR) family members are known to cause constitutive activation of their signaling pathways, which play an important role in proliferation, survival and migration of cancer cells, as well as tumor angiogenesis. Several recent studies have identified that FGFR2 gene fusions were found in about 10% of intrahepatic cholangiocarcinoma and acted as oncogenes. E7090, an orally available FGFR1, 2 and 3 inhibitor, whose chemical-structure and basic kinase inhibitory profile have been disclosed at AACR2015, is currently under a first-in-human study (NCT02275910). The antitumor activity of E7090 against NIH3T3 and human cholangiocarcinoma cells harboring FGFR2-fusion genes was investigated. NIH3T3 cells stably infected of five FGFR2-fusion genes (FGFR2-AHCYL1, FGFR2-BICC1 type1, FGFR2-BICC1 type2, FGFR2-TXLNA, or FGFR2-KCTD1), all of which were discovered in human intrahepatic cholangiocarcinoma patients, were successfully established and exhibited anchorage-independent cell growth in soft agar assay. E7090 revealed an inhibitory activity on soft agar colony formation of these cells with IC50 values of 0.9 to 17.3 nmol/L in a dose dependent manner. E7090 also reduced activation of downstream pathways of FGFR signaling (MAPK and STAT3) in these cells. Subcutaneous transplantation of FGFR2-BICC1 type2, FGFR2-TXLNA, or FGFR2-KCTD1 expressing cells into immune-deficient mice produced tumor growth, and then oral administration of E7090 at 12.5, 25 and 50 mg/kg showed significant tumor growth inhibition. Finally, antitumor activity of E7090 was examined in a patient derived xenograft (PDX) model of human cholangiocarcinoma harboring FGFR2-BICC1 fusion gene. E7090 also showed dose-dependent antitumor activity and more than 50% of tumor regression was achieved at a dose of 50 mg/kg. In conclusion, E7090 showed potent antitumor activity against FGFR2-fusion genes found in intrahepatic cholangiocarcinoma both in vitro and in vivo models, suggesting that E7090 may provide therapeutic opportunities for cholangiocarcinoma harboring FGFR2-fusion genes. Citation Format: Saori W. Miyano, Yasuhito Arai, Junji Matsui, Tatsuhiro Shibata. E7090, a novel and selective FGFR inhibitor, for the treatment of cholangiocarcinoma cells harboring FGFR2-fusion genes [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 2095. doi:10.1158/1538-7445.AM2017-2095

Abstract 4799: Fibroblast growth factor receptor (FGFR) promotes progression of cutaneous squamous cell carcinoma

Abstract Cutaneous squamous cell carcinoma (cSCC) is a keratinocyte-derived invasive and metastatic tumor of the skin. It is the second-most commonly diagnosed form of skin cancer (16%) striking 200,000 Americans annually. Increased understanding of the mechanisms involved in pathogeneses of cSCC could identify means to prevent, inhibit and reverse this process. In our previous studies, inhibition of Fibroblast growth factor receptor (FGFR) significantly decreased Ultraviolet B-induced (UVB) epidermal hyperplasia and hyperproliferation in SKH-1 mice suggesting an important role of FGFR signaling in skin cancer prevention. However, the role of FGFR signaling in the progression of cSCC is not yet elucidated. Analysis of the expression of FGFR2 in cSCC cells and normal epidermal keratinocytes revealed overexpression and increased FGFR2 activity in cSCC cells. Tumor cell-specific overexpression of FGFR2 was detected in human cSCCs and in UVB-induced mouse cSCCs, whereas the expression of FGFR2 was low in premalignant lesions and normal skin. Further, treatment with a selective FGFR inhibitor; AZD4547 significantly decreased proliferation, migration, and invasion of cSCC cells in culture. The decrease in FGFR activation was associated with an inhibition of mTORC1 and mTORC2 signaling markers. Our studies provide mechanistic evidence for the role of FGFR2 in early progression of cSCC and identify FGFR as a putative therapeutic target in the treatment of skin cancer. Citation Format: Alok R. Khandelwal, Xiaohua Rong, Tara Moore-Medlin, Xiaohua Ma, Amelia Warner, John DiGiovanni, Cherie-Ann O. Nathan. Fibroblast growth factor receptor (FGFR) promotes progression of cutaneous squamous cell 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 4799. doi:10.1158/1538-7445.AM2017-4799

Abstract CT063: Phase 2, open-label, multicenter study of the efficacy and safety of INCB054828 in patients (pts) with advanced, metastatic, or surgically unresectable cholangiocarcinoma (CCA) with inadequate response to prior therapy

Abstract Background: Dysregulation of fibroblast growth factor receptor (FGFR) signaling by FGFR translocations and activating mutations is implicated in many cancers, including CCA. FGFR2 translocations are the most common FGFR alterations, which occur in ~13% of pts with intrahepatic CCA and involve a variety of fusion partners/breakpoints. INCB054828 is a novel, orally available, selective inhibitor of FGFR1, FGFR2, and FGFR3 tyrosine kinase activities (AACR 2015; Abstract 771). Methods: This phase 2, open-label trial will evaluate INCB054828 monotherapy in pts with advanced/metastatic or surgically unresectable CCA (Table; NCT02924376). Pts will be prescreened centrally for FGF/FGFR status and enrolled in the following cohorts prior to start of treatment: FGFR2 translocations (Cohort A); other FGF/FGFR alterations (Cohort B); no FGF/FGFR alterations (Cohort C; negative control for effects of FGF/FGFR alterations on objective response rate [ORR]). Pts must be aged ≥18 years, with Eastern Cooperative Oncology Group performance status ≤2, disease progression after ≥1 prior systemic therapy, and no prior use of selective FGFR inhibitors. Pts will self-administer INCB054828 orally at a starting dose of 13.5 mg once-daily on a 21-day cycle (2 weeks on; 1 week off); treatment will continue until disease progression or unacceptable toxicity. The primary endpoint will be ORR (complete or partial response per independent radiologic review committee using Response Evaluation Criteria in Solid Tumors v1.1) in pts with FGFR2 translocations (Cohort A). Secondary endpoints will include ORR in pts positive or negative for any FGF/FGFR alterations and duration of response, progression-free survival, overall survival, and safety (all cohorts). The study is currently open for enrollment (estimated primary completion date, April, 2018). Study DesignPrescreen for FGF/FGFR Status• Adults with metastatic/surgically unresectable cholangiocarcinoma with disease progression after ≥1 previous systemic treatment- FGFR2 translocations → cohort A (n~60)- Other FGF/FGFR alterations → cohort B (n~20)- No FGF/FGFR alterations → cohort C (n~20)Screen for eligibility criteria and patient characteristics• Eastern Cooperative Oncology Group performance status ≤2• Adequate hepatic function (total bilirubin ≤1.5 × upper limit of normal [ULN; ≤2.5 × ULN for Gilbert syndrome or disease involving liver]; aminotransferases <2.5 × ULN [<5 × ULN with liver metastases])• Adequate renal function (creatinine clearance ≥30 mL/min; serum phosphate >institutional ULN; serum calcium >institutional normal range; potassium >institutional lower limit of normal)• Life expectancy ≥12 weeksEnroll and initiate INCB054828 treatment• Oral once daily dosing: 21-day (2-weeks-on/1-week-off) cycleStart response assessment after cycle 2• Stable disease/partial or complete response → continue treatment with restaging after cycle 4; imaging assessments increase to every 3 cycles after cycle 4• Disease progression → discontinue treatment; safety and survival follow-up Citation Format: Mitesh J. Borad, S. Lindsey Davis, Maeve A. Lowery, Ekaterine Asatiani, Christine F. Lihou, Huiling Zhen, Ghassan K. Abou-Alfa. Phase 2, open-label, multicenter study of the efficacy and safety of INCB054828 in patients (pts) with advanced, metastatic, or surgically unresectable cholangiocarcinoma (CCA) with inadequate response to prior therapy [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 CT063. doi:10.1158/1538-7445.AM2017-CT063

Abstract 2088: The activity of the FGFR selective inhibitor Debio 1347 is correlated with high mRNA expression

Abstract Dysregulation of the fibroblast growth factor receptor (FGFR) signaling pathway due to receptor overexpression, gene amplification, point mutations or fusions/chromosomal translocations is associated with cancer development and progression. Debio 1347 (CH5183284) is an oral selective FGFR inhibitor (FGFR1, 2 and 3) currently in clinical development. The aim of this study was to investigate Debio 1347 activity in patient derived xenograft (PDX) mouse models harboring diverse FGFR alterations in multiple indications. The trial was conducted in 66 PDX models of diverse histotypes selected according to their FGFR1, 2 and 3 alteration status. Debio 1347 was administered orally once daily at 40 up to 80 mg/kg for 10 to 22 consecutive days (N=3/group). Tumor volume was compared to the vehicle control group and measured by caliper twice weekly. Treatment response was determined by relative treatment-to-control ratios (ΔT/ΔC) of which a responding model was defined as ΔT/ΔC <0. PDX tumors were collected at the end of the treatment period and extensively characterized using FISH, nCounter Gene Expression and immunohistochemistry (IHC). Effect on downstream Dual Specificity Phosphatase 6 (DUSP6) signaling was also investigated by qPCR and RNA in situ hybridization (ISH). Debio 1347 induced tumor regression in 33% of PDX models that exhibited a gene copy number gain and/or the presence of a FGFR fusion gene and/or an FGFR mutation. In addition, Debio 1347 treatment led to tumor regression in 29% of models that did not harbor any FGFR genetic alteration. In contrast, all models that responded to Debio 1347 were shown to display a high expression level (mRNA) of at least one FGFR gene. These findings suggest that high expression of at least one FGFR might be a better predictor of sensitivity to Debio 1347 than genetic alteration. Furthermore, response to Debio 1347 was associated with a decrease in DUSP6 mRNA levels, suggesting that it could be a reliable pharmacodynamic biomarker in clinical trials. These results provide new mechanistic insights into the predictive sensitivity to Debio 1347 and will help refine patient selection for FGFR-targeted therapy. Citation Format: Franck Brichory, Anna Pokorska-Bocci, Paolo Nuciforo, Stefania Rigotti, Nathalie Lembrez, Grégoire Vuagniaux, Corinne Moulon, Anne Vaslin. The activity of the FGFR selective inhibitor Debio 1347 is correlated with high mRNA expression [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 2088. doi:10.1158/1538-7445.AM2017-2088

Abstract CT059: Phase 2, open-label, multicenter study of the efficacy and safety of INCB054828 for metastatic or surgically unresectable urothelial carcinoma harboring fibroblast growth factor (FGF)/FGF receptor (FGFR) alterations

Abstract Background: Aberrant FGFR signaling results in tumor cell proliferation, migration, and survival, as well as angiogenesis, and is implicated in the development and progression of many cancers, including urothelial carcinoma (UC). Ten to 15% of patients with advanced UC have FGFR3 mutations and 6% have an FGFR3 translocation. INCB054828 is a novel, selective, orally administered inhibitor of FGFR1, FGFR2, and FGFR3 tyrosine kinase activities (AACR 2015; Abstract 771). Methods: This phase 2, open-label trial will evaluate INCB054828 monotherapy for histologically confirmed metastatic or unresectable UC (NCT02872714; Table). Eligible patients will have known FGF/FGFR alterations, will be ≥18 years of age, have Eastern Cooperative Oncology Group performance status ≤2, adequate liver and renal function, and have life expectancy ≥12 wks. Patients will have inadequate response to ≥1 previous treatment in this setting or will be platinum-ineligible, and must not have received any investigational drugs within 21 days of first dose, including selective FGFR inhibitors. Patients will self-administer INCB054828 orally once daily at a starting dose of 13.5 mg on a 21-day 2-weeks-on and 1-week-off cycle. Patients will receive treatment until disease progression or unacceptable toxicity. The primary endpoint will be objective response rate (complete plus partial responses assessed from CT scans [or MRI per investigator] using Response Evaluation Criteria in Solid Tumors v1.1). Secondary endpoints will include safety, duration of response, progression-free survival, and overall survival. Exploratory endpoints will include predictive biomarker assessment. The study is currently recruiting; 96 patients are planned for the primary analysis (estimated to occur in March 2018). Study DesignPrescreen for FGF/FGFR Status• Adults with metastatic/surgically unresectable urothelial carcinoma with inadequate response to ≥1 previous treatment or platinum-ineligible- Positive for FGF/FGFR alterations → continue screening- Negative for FGF/FGFR alterations → discontinue studyScreen for eligibility criteria and patient characteristics• Eastern Cooperative Oncology Group performance status ≤2• Adequate hepatic function (total bilirubin ≤1.5 × upper limit of normal [ULN; ≤2.5 × ULN for Gilbert syndrome or liver metastasis]; aminotransferases <2.5 × ULN [<5 × ULN for liver metastases])• Adequate renal function (creatinine clearance ≥30 mL/min; serum phosphate >institutional ULN; serum calcium >institutional normal range)• Life expectancy ≥12 weeksEnroll and start INCB054828 treatment• Oral once daily dosing: 21-day (2-weeks-on/1-week-off) cycleStart clinical assessment after cycle 3• Stable disease/partial or complete response → continue treatment on 21-day cycle; clinical assessments every 3 cycles• Disease progression → discontinue treatment; safety and survival follow-up Citation Format: Neal D. Shore, Ekaterine Asatiani, Christine F. Lihou, Huiling Zhen, Sumati Gupta. Phase 2, open-label, multicenter study of the efficacy and safety of INCB054828 for metastatic or surgically unresectable urothelial carcinoma harboring fibroblast growth factor (FGF)/FGF receptor (FGFR) alterations [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 CT059. doi:10.1158/1538-7445.AM2017-CT059

Phase 2, open-label, multicenter study of the efficacy and safety of INCB054828 in patients (pts) with advanced, metastatic, or surgically unresectable cholangiocarcinoma (CCA) with inadequate response to prior therapy.

TPS4145 Background: Dysregulation of fibroblast growth factor receptor (FGFR) signaling by FGFR translocations and activating mutations is implicated in many cancers, including CCA. FGFR2 translocation, the most common FGFRalteration, occurs in ~13% of pts with intrahepatic CCA. INCB054828 is a novel, orally available, selective inhibitor of FGFR1, FGFR2, and FGFR3 tyrosine kinase activity (AACR 2015; Abstract 771). Methods: This phase 2, open-label trial will evaluate INCB054828 monotherapy in pts with advanced/metastatic or unresectable CCA (NCT02924376). Pts will be prescreened locally or centrally for FGF/FGFR status prior to enrollment (Table): FGFR2 translocation (Cohort A); other FGF/FGFR alteration (Cohort B); no FGF/FGFR alteration (Cohort C; negative control for effects of FGF/FGFR alteration on objective response rate [ORR]). Eligibility criteria include: age ≥18 years; ECOG performance status ≤2; adequate liver and renal function; life expectancy ≥12 wks; disease progression after ≥1 prior systemic therapy; no prior use of selective FGFR inhibitors. Pts will self-administer INCB054828 orally at a starting dose of 13.5 mg QD on a 21-day cycle (2 wks on; 1 wk off); treatment will continue until disease progression or unacceptable toxicity. The primary endpoint will be ORR (complete or partial response, independent radiologic review committee, RECIST v1.1) in pts with FGFR2 translocation (Cohort A). Secondary endpoints include ORR in pts positive or negative for any FGF/FGFRalteration and duration of response, PFS, OS, and safety (all cohorts). The study has currently enrolled 2 pts (recruitment ongoing; estimated primary completion, April 2018). Clinical trial information: NCT02924376. [Table: see text]

Discovery and Biological Evaluation of a Series of Pyrrolo[2,3-b]pyrazines as Novel FGFR Inhibitors.

Abnormality of fibroblast growth factor receptor (FGFR)-mediated signaling pathways were frequently found in various human malignancies, making FGFRs hot targets for cancer treatment. To address the consistent need for a new chemotype of FGFR inhibitors, here, we started with a hit structure identified from our internal hepatocyte growth factor receptor (also called c-Met) inhibitor project, and conducted a chemical optimization. After exploring three parts of the hit compound, we finally discovered a new series of pyrrolo[2,3-b]pyrazine FGFR inhibitors, which contain a novel scaffold and unique molecular shape. We believe that our findings can help others to further develop selective FGFR inhibitors.