FGFR1 Expression Levels Predict BGJ398 Sensitivity of FGFR1-Dependent Head and Neck Squamous Cell Cancers

Safety, pharmacokinetic, and pharmacodynamics of erdafitinib, a pan-fibroblast growth factor receptor (FGFR) tyrosine kinase inhibitor, in patients with advanced or refractory solid tumors

Introduction This phase 1, open-label, multicenter, single-arm, dose-escalation study aimed to evaluate safety, pharmacokinetics (PK), and pharmacodynamics of erdafitinib (JNJ-42756493), an oral selective pan-fibroblast growth factor receptor (FGFR) tyrosine kinase inhibitor, and to determine the recommended phase 2 dose in Japanese patients with advanced or refractory solid tumors. Methods Three to 6 patients were enrolled into sequentially escalating dose cohorts (erdafitinib 2, 4, or 6 mg) with a daily dosing schedule of 21-day cycles or a 7 days-on/7 days-off intermittent schedule (erdafitinib 10 mg or 12 mg) of 28-day cycles. Results Nineteen patients received escalating doses of erdafitinib with a daily or intermittent schedule. The most common treatment-emergent adverse events (TEAEs) were hyperphosphatemia (73.7%), nausea (36.8%), stomatitis (26.3%), dysgeusia (26.3%) and dry mouth (21.1%). The maximum tolerated dose was not reached in this study. No Grade 3 or higher TEAEs, or serious TEAEs were noted and no clinically significant changes in vital signs, laboratory parameters, and electrocardiogram readings were observed. However, one case of dose-limiting toxicity in the 12 mg intermittent dosing group was observed: Grade 2 detachment of retinal pigment epithelium (bilateral) with treatment discontinuation. The maximum plasma concentrations of erdafitinib exhibited a dose-dependent increase. The median t_max ranged from 2 to 3 h after the initial dose to 2-6 h following multiple daily dosing. Based on the safety and PK data, the 10 mg 7 days-on/7 days-off regimen was determined as the recommended phase 2 dose in this study. Conclusions Erdafitinib was well tolerated in Japanese patients with advanced or refractory solid tumors.

TRIAL REGISTRATION

NCT01962532.

FGFR Family Members Protein Expression as Prognostic Markers in Oral Cavity and Oropharyngeal Squamous Cell Carcinoma

Introduction

Fibroblast growth factor receptor family member proteins (FGFR1–4) have been identified as promising novel therapeutic targets and prognostic markers in a wide spectrum of solid tumors. The present study investigates the expression and prognostic value of four FGFR family member proteins in a large multicenter oral cavity squamous cell carcinoma (OCSCC) and oropharyngeal squamous cell carcinoma (OPSCC) cohort.

Methods

Protein expression of FGFR1–4 was determined by immunohistochemistry on tissue microarrays containing 951 formalin-fixed paraffin embedded OCSCC and OPSCC tissues from the University Medical Center Utrecht and University Medical Center Groningen. Protein expression was correlated to overall survival using Cox regression models, and bootstrapping was performed as internal validation.

Results

FGFR proteins were highly expressed in 39–64 % of OCSCC and 63–79 % of OPSCC. Seventy-three percent (299/412) of OCSCC and 85 % (305/357) of OPSCC highly co-expressed two or more FGFR family member proteins. FGFR1 protein was more frequently highly expressed in human papillomavirus (HPV)-negative OPSCC than HPV-positive OPSCC (82 vs. 65 %; p = 0.008). Furthermore, protein expression of FGFR family members was not related to overall survival in OCSCC or OPSCC (p > 0.05).

Conclusion

FGFR family members are frequently highly expressed in OCSCC and OPSCC. These FGFR family member proteins are therefore potential targets for novel therapies that are urgently required to improve survival of OCSCC and OPSCC patients.

Electronic supplementary material

The online version of this article (doi:10.1007/s40291-016-0204-5) contains supplementary material, which is available to authorized users.

Clinical association analysis of ependymomas and pilocytic astrocytomas reveals elevated FGFR3 and FGFR1 expression in aggressive ependymomas

BACKGROUND

Fibroblast growth factor receptors (FGFRs) are well-known proto-oncogenes in several human malignancies and are currently therapeutically targeted in clinical trials. Among glioma subtypes, activating FGFR1 alterations have been observed in a subpopulation of pilocytic astrocytomas while FGFR3 fusions occur in IDH wild-type diffuse gliomas, resulting in high FGFR3 protein expression. The purpose of this study was to associate FGFR1 and FGFR3 protein levels with clinical features and genetic alterations in ependymoma and pilocytic astrocytoma.

METHODS

FGFR1 and FGFR3 expression levels were detected in ependymoma and pilocytic astrocytoma tissues using immunohistochemistry. Selected cases were further analyzed using targeted sequencing.

RESULTS

Expression of both FGFR1 and FGFR3 varied within all tumor types. In ependymomas, increased FGFR3 or FGFR1 expression was associated with high tumor grade, cerebral location, young patient age, and poor prognosis. Moderate-to-strong expression of FGFR1 and/or FGFR3 was observed in 76% of cerebral ependymomas. Cases with moderate-to-strong expression of both proteins had poor clinical prognosis. In pilocytic astrocytomas, moderate-to-strong FGFR3 expression was detected predominantly in non-pediatric patients. Targeted sequencing of 12 tumors found no protein-altering mutations or fusions in FGFR1 or FGFR3.

CONCLUSIONS

Elevated FGFR3 and FGFR1 protein expression is common in aggressive ependymomas but likely not driven by genetic alterations. Further studies are warranted to evaluate whether ependymoma patients with high FGFR3 and/or FGFR1 expression could benefit from treatment with FGFR inhibitor based therapeutic approaches currently under evaluation in clinical trials.

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.

Inhibition of the fibroblast growth factor receptor (FGFR) pathway: the current landscape and barriers to clinical application

The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) is a tyrosine kinase signaling pathway that has a fundamental role in many biologic processes including embryonic development, tissue regeneration, and angiogenesis. Increasing evidence indicates that this pathway plays a critical role in oncogenesis via gene amplification, activating mutations, or translocation in tumors of various histologies. With multiplex sequencing technology, the detection of FGFR aberrations has become more common and is tied to cancer cell proliferation, resistance to anticancer therapies, and neoangiogenesis. Inhibition of FGFR signaling appears promising in preclinical studies, suggesting a pathway of clinical interest in the development of targeted therapy. Phase I trials have demonstrated a manageable toxicity profile. Currently, there are multiple FGFR inhibitors under study with many non-selective (multi-kinase) inhibitors demonstrating limited clinical responses. As we progress from the first generation of non-selective drugs to the second generation of selective FGFR inhibitors, it is clear that FGFR aberrations do not behave uniformly across cancer types; thus, a deeper understanding of biomarker strategies is undoubtedly warranted. This review aims to consolidate data from recent clinical trials with a focus on selective FGFR inhibitors. As Phase II clinical trials emerge, concentration on patient selection as it pertains to predicting response to therapy, feasible methods for overcoming toxicity, and the likelihood of combination therapies should be utilized. We will also discuss qualities that may be desirable in future generations of FGFR inhibitors, with the hope that overcoming these current barriers will expedite the availability of this novel class of medications.

Insight into resistance mechanisms of AZD4547 and E3810 to FGFR1 gatekeeper mutation via theoretical study

Inhibitors targeting the amplification of the fibroblast growth factor receptor 1 (FGFR1) have found success in the treatment of FGFR1-positive squamous cell lung and breast cancers. A secondary mutation of gatekeeper residue (V561M) in the binding site has been linked to the acquired resistance. Recently, two well-known small molecule inhibitors of FGFR1, AZD4547 and E3810, reported that the V561M mutation confers significant resistance to E3810, while retaining affinity for AZD4547. FGFR1 is widely investigated as potential therapeutic target, while there are few computational studies made to understand the resistance mechanisms about FGFR1 V561M gatekeeper mutation. In this study, molecular docking, classical molecular dynamics simulations, molecular mechanics/generalized born surface area (MM/GBSA) free energy calculations, and umbrella sampling (US) simulations were carried out to make clear the principle of the binding preference of AZD4547 and E3810 toward FGFR1 V561M gatekeeper mutation. The results provided by MM/GBSA reveal that AZD4547 has similar binding affinity to both FGFR1^WT and FGFR1^V561M, whereas E3810 has much higher binding affinity to FGFR1^WT than to FGFR1^V561M. Comparison of individual energy terms indicates that the major variation of E3810 between FGFR1^WT and FGFR1^V561M are van der Waals interactions. In addition, US simulations prove that the potential of mean force (PMF) profile of AZD4547 toward FGFR1^WT and FGFR1^V561M has similar PMF depth. However, the PMF profile of E3810 toward FGFR1^WT and FGFR1^V561M has much higher PMF depth, suggesting that E3810 is more easily dissociated from FGFR1^V561M than from FGFR1^WT. The results not only show the drug-resistance determinants of FGFR1 gatekeeper mutation but also provide valuable implications and provide vital clues for the development of new inhibitors to combat drug resistance.

Targeting Fibroblast Growth Factor Receptor 1 for Treatment of Soft-Tissue Sarcoma

Purpose: Altered FGFR1 signaling has emerged as a therapeutic target in epithelial malignancies. In contrast, the role of FGFR1 in soft-tissue sarcoma (STS) has not been established. Prompted by the detection and subsequent therapeutic inhibition of amplified FGFR1 in a patient with metastatic leiomyosarcoma, we investigated the oncogenic properties of FGFR1 and its potential as a drug target in patients with STS.Experimental Design: The frequency of FGFR1 amplification and overexpression, as assessed by FISH, microarray-based comparative genomic hybridization and mRNA expression profiling, SNP array profiling, and RNA sequencing, was determined in three patient cohorts. The sensitivity of STS cell lines with or without FGFR1 alterations to genetic and pharmacologic FGFR1 inhibition and the signaling pathways engaged by FGFR1 were investigated using viability assays, colony formation assays, and biochemical analysis.Results: Increased FGFR1 copy number was detected in 74 of 190 (38.9%; cohort 1), 13 of 79 (16.5%; cohort 2), and 80 of 254 (31.5%; cohort 3) patients. FGFR1 overexpression occurred in 16 of 79 (20.2%, cohort 2) and 39 of 254 (15.4%; cohort 3) patients. Targeting of FGFR1 by RNA interference and small-molecule inhibitors (PD173074, AZD4547, BGJ398) revealed that the requirement for FGFR1 signaling in STS cells is dictated by FGFR1 expression levels, and identified the MAPK-ERK1/2 axis as critical FGFR1 effector pathway.Conclusions: These data identify FGFR1 as a driver gene in multiple STS subtypes and support FGFR1 inhibition, guided by patient selection according to the FGFR1 expression and monitoring of MAPK-ERK1/2 signaling, as a therapeutic option in this challenging group of diseases. Clin Cancer Res; 23(4); 962-73. ©2016 AACR.

Implication of the Receptor Tyrosine Kinase AXL in Head and Neck Cancer Progression

Head and neck squamous cell carcinoma (HNSCC) remains a clinical challenge and identification of novel therapeutic targets is necessary. The receptor tyrosine kinase AXL has been implicated in several tumor entities and a selective AXL small molecule inhibitor (BGB324) is currently being tested in clinical trials for patients suffering from non-small cell lung cancer or acute myeloid leukemia. Our study investigates AXL expression during HNSCC progression and its use as a potential therapeutic target in HNSCC. AXL protein expression was determined in a HNSCC cohort (n = 364) using immunohistochemical staining. For functional validation, AXL was either overexpressed or inhibited with BGB324 in HNSCC cell lines to assess proliferation, migration and invasion. We found AXL protein expression increasing during tumor progression with highest expression levels in recurrent tumors. In HNSCC cell lines in vitro, AXL overexpression increased migration as well as invasion. Both properties could be reduced through treatment with BGB324. In contrast, proliferation was neither affected by AXL overexpression nor by inhibition with BGB324. Our patient-derived data and in vitro results show that, in HNSCC, AXL is important for the progression to more advanced tumor stages. Moreover, they suggest that AXL could be a target for precision medicine approaches in this dismal tumor entity.

Prognostic implications of FGFR1 and MYC status in esophageal squamous cell carcinoma

AIM

To investigate the clinicopathological features and prognostic implications of combined MYC and fibroblast growth factor receptor 1 (FGFR1) status in esophageal squamous cell carcinomas (ESCCs).

METHODS

All patients with ESCC (n = 180) underwent surgical resection at Seoul National University Hospital sometime between 2000 and 2013. A tissue microarray was constructed using cores obtained from representative tumor areas of formalin-fixed, paraffin-embedded tissue blocks. FGFR1 and MYC copy numbers were quantified using fluorescence in situ hybridization. The level of MYC expression was determined using immunohistochemistry. FGFR1 and MYC amplification status was compared between primary and metastatic lymph nodes. Univariate and multivariate survival analyses were performed according to adjuvant therapy status.

RESULTS

FGFR1 and MYC amplifications were observed in 21.4% (37/173) and 54.2% (91/168) of patients, respectively, while MYC expression was observed in 58.9% (106/180) of patients. There was a positive correlation between MYC amplification and overexpression (P = 0.002). Although FGFR1 amplification was not associated with MYC amplification or expression, 12.3% (20/163) of patients exhibited both FGFR1 amplification and MYC expression. There was also a correlation in FGFR1 amplification status between matched primary tumors and metastatic lymph nodes (P < 0.001). MYC expression was higher in ESCCs with pT1 (P < 0.001) and in those with no lymph node metastasis (P = 0.023). MYC expression was associated with prolonged disease-free survival (P = 0.036) and overall survival (OS) (P = 0.017) but was not an independent prognostic factor. FGFR1 amplification was an independent predictor for prolonged OS in all patients (P = 0.029) and in those who did not receive adjuvant therapy (P = 0.013). Combined FGFR1 amplification and MYC expression predicted better OS in patients who did not receive adjuvant therapy (P = 0.034) but not in those who did receive adjuvant therapy.

CONCLUSION

FGFR1 amplification and MYC expression have prognostic implications in resected ESCCs with respect to adjuvant therapy. The role of FGFR1-targeted therapy in ESCC remains to be explored.

Targeted Therapy of Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) is one of the most common solid cancers worldwide. It is mainly caused by exposure to tobacco smoke and alcohol as well as infection with the human papilloma virus (HPV). The prognosis is poor, especially once it recurs or metastasizes. Current therapeutic options include surgery, radio- and chemotherapy. Epidermal growth factor receptor (EGFR) inhibitors are so far the only targeted agents that have been approved in head and neck cancer. Primary or secondary resistance is frequent or will eventually develop. Several driver mutations and other genomic aberrations have been described in HNSCC including EGFR overexpression and amplification. Yet, no predictive biomarkers for the application of EGFR inhibitors have been identified. Further targeted agents are in development for HNSCC, of which inhibitors of the PI3K pathway are the closest to clinical application. In recent years, the incidence of HPV-driven HNSCC has risen in Western countries. HPV-positive and -negative HNSCC are distinct molecular tumor entities, and consequences for targeted therapies have been discussed. This review looks at approved and investigational targeted treatment strategies as well as potential predictive biomarkers such as the HPV status to guide treatment.

The Stem Cell Factor HMGA2 Is Expressed in Non-HPV-Associated Head and Neck Squamous Cell Carcinoma and Predicts Patient Survival of Distinct Subsites

BACKGROUND

The transcription factor high-mobility AT-hook 2 (HMGA2) is involved in stem cell renewal and is expressed in many tumor tissues. Head and neck squamous cell carcinomas (HNSCC) comprise tumors of the upper aerodigestive tract and are characterized by high recurrence rates that represent a challenge to patient management. The study addresses the potential of HMGA2 as a molecular biomarker for HNSCC patient survival.

METHODS

Patients with HNSCC of the larynx, pharynx, tonsils, or oral cavity were recruited in a hospital-based case-control study (n = 202). Quantitative expression of HMGA2 in tumor tissues was measured by RT-PCR. In a 6- to 10-year follow-up, secondary cancers, vital status, and cause of death were ascertained. The HR and 95% confidence intervals (CI) for overall, tumor-specific, and progression-free survival were estimated by Cox proportional hazards with HMGA2 expression level as the independent variable.

RESULTS

High HMGA2 expression in tumor tissues of HNSCC patients was significantly correlated with negative HPV status (P = 0.01), and associated with shorter overall survival time. In Cox regression modeling, HMGA2 expression yielded a risk increase for overall and tumor-specific death in subsets of HNSCC patients, that is, laryngeal cancer patients (overall survival: HR = 4.00; 95% CI, 1.18-13.62) and in oral cancer patients (tumor-specific survival: HR = 2.88; 95% CI, 1.06-7.84), but not in patients with pharyngeal and tonsillar HNSCC.

CONCLUSIONS

HMGA2 expression is associated with a risk increase for adverse outcomes in patients with HNSCC of the larynx and oral cavity.

IMPACT

The understanding of stem cell signaling in HNSCC may offer new strategies for cancer treatment. Cancer Epidemiol Biomarkers Prev; 26(2); 197-205. ©2016 AACR.

Targeting DDR2 in head and neck squamous cell carcinoma with dasatinib

Squamous cell carcinoma of the head and neck (HNSCC) is the tenth most common tumor entity in men worldwide. Nevertheless therapeutic options are mostly limited to surgery and radio-chemotherapy resulting in 5-year survival rates of around 50%. Therefore new therapeutic options are urgently needed. During the last years, targeting of receptor tyrosine kinases has emerged as a promising strategy that can complement standard therapeutical approaches. Here, we aimed at investigating if the receptor tyrosine kinase DDR2 is a targetable structure in HNSCC. DDR2 expression was assessed on a large HNSCC cohort (554 patients) including primary tumors, lymph node metastases and recurrences and normal mucosa as control. Subsequently, DDR2 was stably overexpressed in two different cell lines (FaDu and HSC-3) using lentiviral technology. Different tumorigenic properties such as proliferation, migration, invasion, adhesion and anchorage independent growth were assessed with and without dasatinib treatment using in-vitro cell models and in-vivo zebrafish xenografts. DDR2 was overexpressed in all tumor tissues when compared to normal mucosa. DDR2 overexpression led to increased migration, invasion, adhesion and anchorage independent growth whereas proliferation remained unaltered. Upon dasatinib treatment migration, invasion and adhesion could be inhibited in-vitro and in-vivo whereas proliferation was unchanged. Our data suggest treatment with dasatinib as a promising new therapeutic option for patients suffering from DDR2 overexpressing HNSCC. Since dasatinib is already FDA-approved we propose to test this drug in clinical trials so that patients could directly benefit from this new treatment option.

Activation of the Met kinase confers acquired drug resistance in FGFR-targeted lung cancer therapy

Aberrant fibroblast growth factor receptor (FGFR) activation/expression is a common feature in lung cancer (LC). In this study, we evaluated the antitumor activity of and the mechanisms underlying acquired resistance to two potent selective FGFR inhibitors, AZD4547 and BAY116387, in LC cell lines. The antitumor activity of AZD4547 and BAY1163877 was screened in 24 LC cell lines, including 5 with FGFR1 amplification. Two cell lines containing FGFR1 amplifications, H1581 and DMS114, were sensitive to FGFR inhibitors (IC50<250 nm). Clones of FGFR1-amplified H1581 cells resistant to AZD4547 or BAY116387 (H1581AR and H1581BR cells, respectively) were established. Receptor tyrosine kinase (RTK) array and immunoblotting analyses showed strong overexpression and activation of Met in H1581AR/BR cells, compared with that in the parental cells. Gene set enrichment analysis against the Kyoto Encyclopedia of Genes and Genomes (KEGG) database showed that cytokine-cytokine receptor interaction pathways were significantly enriched in H1581AR/BR cells, with Met contributing significantly to the core enrichment. Genomic DNA quantitative PCR and fluorescent in situ hybridization analyses showed MET amplification in H1581AR, but not in H1581BR, cells. Met amplification drives acquired resistance to AZD4547 in H1581AR cells by activating ErbB3. Combination treatment with FGFR inhibitors and an anaplastic lymphoma kinase (ALK)/Met inhibitor, crizotinib, or Met-specific short interfering RNA (siRNA) synergistically inhibited cell proliferation in both H1581AR and H1581BR cells. Conversely, ectopic expression of Met in H1581 cells conferred resistance to AZD4547 and BAY1163877. Acquired resistance to FGFR inhibitors not only altered cellular morphology, but also promoted migration and invasion of resistant clones, in part by inducing epithelial-to-mesenchymal transition. Taken together, our data suggest that Met activation is sufficient to bypass dependency on FGFR signaling. Concurrent inhibition of the Met and FGFR pathways may have synergistic clinical benefits when targeting FGFR-dependent LC.

Efficacy and safety of dovitinib in pretreated patients with advanced squamous non-small cell lung cancer with FGFR1 amplification: A single-arm, phase 2 study

BACKGROUND

Fibroblast growth factor receptor 1 (FGFR1) amplification is a potential driving oncogene in squamous cell cancer (SCC) of the lung. The current phase 2 study evaluated the efficacy and tolerability of dovitinib, an FGFR inhibitor, in patients with advanced SCC of the lung.

METHODS

Patients with pretreated advanced SCC of the lung whose tumors demonstrated FGFR1 amplification of > 5 copies by fluorescence in situ hybridization were enrolled. Dovitinib at a dose of 500 mg was administered orally, once daily, on days 1 to 5 of every week, followed by 2 days off. The primary endpoint was overall response. Secondary endpoints were progression-free survival, overall survival, and toxicity.

RESULTS

All 26 patients were men with a median age of 68 years (range, 52-80 years). The majority of patients were ever-smokers. The median duration of dovitinib administration (28 days per cycle) was 2.5 months (range, 0.7-8.6 months). The overall response rate was 11.5% (95% confidence interval [95% CI], 0.8%-23.8%) and the disease control rate was 50% (95% CI, 30.8%-69.2%), with 3 patients achieving partial responses. Response durations for the patients with partial responses were ≥4.5 months, ≥ 5.1 months, and 6.1 months, respectively. After a median follow-up of 15.7 months (range, 1.2-25.6 months), the median overall survival was 5.0 months (95% CI, 3.6-6.4 months) and the median progression-free survival was 2.9 months (95% CI, 1.5-4.3 months). The most common grade 3 or higher adverse events were fatigue (19.2%), anorexia (11.5%), and hyponatremia (11.5%) (event severity was graded based on National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.0]).

CONCLUSIONS

Treatment with dovitinib demonstrated modest efficacy in patients with advanced SCC with FGFR1 amplification. Further studies to evaluate other biomarkers correlated with the efficacy of dovitinib in patients with SCC are warranted. Cancer 2016;122:3024-3031. © 2016 American Cancer Society.

Genomically personalized therapy in head and neck cancer

The current treatment paradigm in head and neck cancer does not adequately address its clinical and biological heterogeneity. Data from genomic profiling studies in head and neck squamous cell carcinoma (HNSCC) have revealed the molecular features that are unique to HNSCC subgroups. This progress in the understanding of HNSCC biology provides an opportunity to develop personalized therapies for patients with distinct molecular subtypes to achieve better clinical outcomes including survival. However there are several well-recognized challenges that need to be overcome before genotype-matched therapies make precision medicine a reality for patients with HNSCC. Selection of appropriate patients for biomarker directed clinical trials based on sound scientific rationale will be critical in making cancer genomics more applicable in this malignancy.

FGFR1 Is a Potential Prognostic Biomarker and Therapeutic Target in Head and Neck Squamous Cell Carcinoma

PURPOSE

FGFR1 is a promising therapeutic target in multiple types of solid tumors, including head and neck squamous cell carcinoma (HNSCC). FGFR inhibitors have shown great therapeutic value in preclinical models. However, resistance remains a major setback. In this study, we have investigated the prognostic value of FGFR1 expression in HNSCC, the therapeutic relevance of targeting FGFR with AZD4547, and potential resistant mechanisms.

EXPERIMENTAL DESIGN

IHC and FISH were applied on tissue microarrays to investigate FGFR1 protein expression and FGFR1 gene copy numbers in 452 HNSCCs. The sensitivity of HNSCC cell lines to AZD4547, either as single or combination treatment with the EGFR inhibitor gefitinib, was assessed using long-term colony formation assays, short-term viability assays, and biochemical analysis.

RESULTS

FGFR1 protein overexpression occurred in 82% (36/44) of human papillomavirus (HPV)-positive HNSCC and 75% (294/392) of HPV-negative HNSCC and relates with poor overall survival and disease-free survival in HPV-negative HNSCC [HR, 3.07; 95% confidence interval (CI), 1.74-6.90; P = 0.001 and HR, 1.53; 95% CI, 1.04-2.39; P = 0.033]. Moreover, the FGFR1 gene was amplified in 3% (3/110) of HPV-negative HNSCC. Treatment of the high FGFR1-expressing cell line CCL30 with AZD4547 reduced cell proliferation and FGFR signaling. Two FGFR-amplified cell lines, SCC147 and BICR16, were resistant to AZD4547 treatment due to EGFR signaling. Combined AZD4547 and gefitinib treatment synergistically inhibited the proliferation of resistant cell lines.

CONCLUSIONS

Here, we identify high FGFR1 expression as a candidate prognostic biomarker in HPV-negative HNSCC. Furthermore, we provide a rationale for treating FGFR1-expressing HNSCC with the FGFR inhibitor AZD4547 and for combining AZD4547 and gefitinib in FGFR inhibitor-resistant HNSCC patients. Clin Cancer Res; 22(15); 3884-93. ©2016 AACR.

Characterization of FGFR1 Locus in sqNSCLC Reveals a Broad and Heterogeneous Amplicon

FGFR1 amplification occurs in ~20% of sqNSCLC and trials with FGFR inhibitors have selected FGFR1 amplified patients by FISH. Lung cancer cell lines were profiled for sensitivity to AZD4547, a potent, selective inhibitor of FGFRs 1–3. Sensitivity to FGFR inhibition was associated with but not wholly predicted by increased FGFR1 gene copy number. Additional biomarker assays evaluating expression of FGFRs and correlation between amplification and expression in clinical tissues are therefore warranted. We validated nanoString for mRNA expression analysis of 194 genes, including FGFRs, from clinical tumour tissue. In a panel of sqNSCLC tumours 14.4% (13/90) were FGFR1 amplified by FISH. Although mean FGFR1 expression was significantly higher in amplified samples, there was significant overlap in the range of expression levels between the amplified and non-amplified cohorts with several non-amplified samples expressing FGFR1 to levels equivalent to amplified samples. Statistical analysis revealed increased expression of FGFR1 neighboring genes on the 8p12 amplicon (BAG4, LSM1 and WHSC1L1) in FGFR1 amplified tumours, suggesting a broad rather than focal amplicon and raises the potential for codependencies. High resolution aCGH analysis of pre-clinical and clinical samples supported the presence of a broad and heterogeneous amplicon around the FGFR1 locus. In conclusion, the range of FGFR1 expression levels in both FGFR1 amplified and non-amplified NSCLC tissues, together with the breadth and intra-patient heterogeneity of the 8p amplicon highlights the need for gene expression analysis of clinical samples to inform the understanding of determinants of response to FGFR inhibitors. In this respect the nanoString platform provides an attractive option for RNA analysis of FFPE clinical samples.

Novel Targeted Agents in Head and Neck Squamous Cell Carcinoma

Based on currently available genomic data, most head and neck squamous cell carcinoma have few targetable aberrations and immediate clinical translation is challenging. However, potential therapeutic agents listed in this article need to be thoroughly evaluated because there are compelling scientific rationales supporting their development. Concerted effort is required to identify better predictive biomarkers of clinical benefit and improve the therapeutic index. Clinicians need to better understand resistance mechanisms, generate novel hypotheses for appropriate combination regimens and dosing schedules, develop more accurate model systems, and conduct innovative clinical trials.

FGFR1 Amplification Is Often Homogeneous and Strongly Linked to the Squamous Cell Carcinoma Subtype in Esophageal Carcinoma

Background and Aims

Amplification of the fibroblast growth factor receptor 1 (FGFR1) is believed to predict response to multi-kinase inhibitors targeting FGFR1. Esophageal cancer is an aggressive disease, for which novel targeted therapies are highly warranted.

Methods

This study was designed to investigate the prevalence and clinical significance of FGFR1 amplification in a tissue microarray containing 346 adenocarcinomas and 254 squamous cell carcinomas of the esophagus, using dual-labeling fluorescence in situ hybridization (FISH) analysis.

Results

FGFR1 amplification, defined as a ratio of FGFR1:centromere 8 copy numbers ≥ 2.0, was more frequently seen in squamous cell carcinoma (8.9% of 202 interpretable cases) than in adenocarcinoma (1.6% of 308; p<0.0001). There was no association between FGFR1 amplification and tumor phenotype or clinical outcome. To study potential heterogeneity of FGFR1 amplification, all available tumor blocks from 23 FGFR1 amplified tumors were analyzed on conventional large sections. This analysis revealed complete homogeneity of FGFR1 amplification in 20 (86.9%) primary tumors and in all available lymph node metastases. Remarkably, FGFR1 amplification was also seen in dysplasia adjacent to tumor in 6 of 9 patients with FGFR1 amplified primary cancers.

Conclusions

In conclusion, FGFR1 amplification occurs in a relevant subgroup of carcinomas of the esophagus and may play a particular role for development of squamous cell cancers. The high homogeneity of FGFR1 amplification suggests that patients with FGFR1 amplified esophageal cancers may particularly benefit from anti-FGFR1 therapies and prompt for clinical studies in this tumor type.