EGFR-targeted Agents Research Articles

Single agent maintenance therapy for advanced stage non-small cell lung cancer: A meta-analysis

BackgroundMaintenance therapy is a new treatment paradigm for advanced non-small cell lung cancer (NSCLC). We conducted a meta-analysis of randomized studies with single agent maintenance therapy. MethodsAn electronic literature search of public databases (MEDLINE, EMBASE, Cochrane library) and manual search of relevant conference proceedings was performed. A formal meta-analysis was conducted using Comprehensive Meta Analysis software (Version 2.0). Outcome data were pooled and reported as hazard ratio (HR). The primary outcome of interest was overall survival (OS) and secondary outcome was progression free survival (PFS). ResultsTwelve studies were included (5 meeting abstracts, 7 full manuscripts) with a total of 4286 patients (maintenance arm/control arm – 2449/1837, median age 61years, males – 69%). The OS (HR 0.86, 95% confidence intervals [CI] 0.80–0.92; P=0.0003) and PFS (HR 0.80, 95% CI 0.77–0.84; P<0.0001) were superior with maintenance therapy. ‘Switch’ maintenance was associated with significant OS and PFS improvement (OS HR 0.84, 95% CI 0.77–0.91; P=0.00026; PFS HR 0.62, 95% CI 0.57–0.67; P<0.0001). Despite a modest improvement in PFS (HR 0.90, 95%CI 0.85–0.95; P=0.007), “continuation” maintenance was not associated with survival benefit (HR 0.927, 95%CI 0.78–1.09; P=0.33). Improvements in OS and PFS were observed with both EGFR-targeted agents (HR 0.83, 95% CI 0.74–0.92; P=0.004; HR 0.64, 95% CI 0.58–0.71 P<0.0001) and cytotoxic agents (HR 0.89, 95% CI 0.80–0.98; P=0.018; HR 0.85, 95% CI 0.80–0.89; P<0.0001). ConclusionsSingle agent maintenance therapy improves overall survival, though statistical significance was only noted with ‘switch’ maintenance.

Abstract 4527: The HER3-EREG axis and its role in colorectal cancer aggression

Abstract Yearly, 50,000 Americans die of colorectal cancer metastases to liver and lung. EGFR-targeted agents improve survival in a subset of metastatic colorectal cancer (mCRC) cases, and overexpression of the HER-family ligands amphiregulin (AREG) and epiregulin (EREG) correlates with EGFR-targeted agent susceptibility. Here we present evidence of association between EREG overexpression and disease aggression by showing that knockdown of EREG or HER3 impede anchorage independent growth in the HCT 116 CRC cell line. We also find that a HER3-EREG axis gene signature groups mCRC tumors into prognostically distinct groups. Snap-frozen CRC hepatic metastases (65) with patient matched normal liver, as well as 71 primary CRC tumors with patient matched normal colonic mucosa were analyzed via qRT-PCR for receptors (HER1-4) and ligands (AREG, and EREG). Among the mCRC cases HER2, HER3, AREG, and EREG were expressed at higher levels than unmatched normal mucosa (p&amp;lt;0.005). HER2, AREG, and EREG were also overexpressed in mCRC compared to unmatched primary CRC tissue (p&amp;lt;0.005). Expression of AREG and EREG were highly correlated (Rs=0.90), and higher EREG mRNA expression was associated with markedly decreased post-hepatectomy overall survival (OS) (p=0.018). In a panel of 9 CRC cell lines HCT 116 had the highest EREG expression. Using the pLKO.1 viral vector, shRNAs targeting EREG, and HER3 were introduced to HCT 116 cells. Empty vector was used as a control. mRNA levels for HER3 and EREG were knocked down by 87% and 73% respectively and protein downregulation was confirmed by western blot. Knockdown and control cells were grown in 0.35% soft agar at a density of 5000 cells per well in 6 well plates. Knockdowns impeded anchorage independent growth with a mean colony count (&amp;gt;50 um diameter) of 170 for HER3, and 285 for EREG as compared to 530 for the empty vector (p&amp;lt;0.005). RNA from 3 distinct sets of HER3, EREG, and empty vector infections was assayed on Agilent Human GE 4x44K v2 microarrays. Unsupervised Principle Component Analysis (PCA) suggested broad concordance in the impact of EREG or HER3 knockdown upon the expression profile. Statistical Analysis of Microarrays (SAM) comparing HER3, and EREG knockdowns to empty vector control revealed 205, and 432 differentially expressed genes with at least a 1.5 fold-change and a false discovery rate of 0%. When HER3 and EREG differential gene lists were compared, 95 overlapping genes with 100% directional agreement were observed. For 51 mCRC cases RNA was available for microarray analysis. A predictor of HER3-EREG activity was constructed from 250 genes that discriminate HER3/EREG knockdown and empty vector control cells and are generally variable in tumors. The predictor was used to assign a HER3-EREG activity score to each mCRC case. This score is significantly associated with OS (p=0.005) with the top 50% of patients by HER3-EREG score demonstrating 5 year OS of 23% as compared to 49% for cases in the lower half of HER3-EREG activity. 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 4527. doi:1538-7445.AM2012-4527

Tumor Epidermal Growth Factor Receptor and EGFR PY1068 Are Independent Prognostic Indicators for Head and Neck Squamous Cell Carcinoma

To assess the prognostic value of epidermal growth factor receptor (EGFR) molecular characteristics of head and neck squamous cell carcinoma (HNSCC). HNSCC tumors from patients prospectively enrolled in either an Early Detection Research Network (EDRN) study and treated with surgery without an EGFR-targeted agent (N = 154) or enrolled in a chemoradiation trial involving the EGFR-targeted antibody cetuximab (N = 39) were evaluated for EGFR gene amplification by FISH and EGFR protein by immunohistochemical staining. Fresh-frozen tumors (EDRN) were also evaluated for EGFR protein and site-specific phosphorylation at Y992 and Y1068 using reverse-phase protein array (n = 67). Tumor (n = 50) EGFR and EGFRvIII mRNA levels were quantified using real-time PCR. EGFR expression by immunohistochemistry (IHC) was significantly higher in the EDRN tumors with EGFR gene amplification (P < 0.001), and a similar trend was noted in the cetuximab-treated cohort. In the EDRN and cetuximab-treated cohorts elevated EGFR by IHC was associated with reduced survival (P = 0.019 and P = 0.06, respectively). Elevated expression of total EGFR and EGFR PY1068 were independently significantly associated with reduced progression-free survival in the EDRN cohort [HR = 2.75; 95% confidence interval (CI) = 1.26-6.00 and HR = 3.29; 95% CI = 1.34-8.14, respectively]. In two independent HNSCC cohorts treated with or without cetuximab, tumor EGFR levels were indicative of survival. Tumor EGFR PY1068 levels provided prognostic information independent of total EGFR.

Abstract 9: Imbalanced oncogenic signaling: Analogies between structurally distinct EGFR mutants of relevance to lung and brain cancers

Abstract The epidermal growth factor receptor (EGFR) is expressed at elevated levels in a large fraction of brain, lung, breast, prostate, and head-and-neck cancers. Efforts to treat such cancers with EGFR-targeted antibodies and kinase inhibitors have had limited success, suggesting that the level of EGFR expression in a tumor is not generally a good predictor of response to drugs targeting EGFR. In some cases, however, response to EGFR-targeted agents correlates with the presence of certain EGFR mutations. For example, in non-small cell lung cancer (NSCLC), the small percentage of patients harboring kinase-activating mutations of EGFR (mostly small in-frame deletion and point mutations) respond unusually well to EGFR kinase inhibitors such as gefitinib and erlotinib. In glioblastoma multiforme (GBM), the presence of the EGFRvIII mutation (a distinct deletion mutation which also promotes elevated EGFR activity) is also associated with increased response to EGFR inhibitors, at least in cells expressing PTEN. Settings where the elevated activity of a particular kinase promotes cellular responsiveness to drugs targeting the kinase have been identified as examples of the phenomenon of “oncogene addiction.” One of the prevailing models for EGFR oncogene addiction holds that EGFR mutations simultaneously lead to the increased activities of pro-survival and pro-apoptotic signaling pathways, with the latter persisting longer in response to EGFR inhibition and ultimately prevailing in determining cellular phenotypes. Here, we offer an alternative explanation for at least part of the altered cellular sensitivity to EGFR inhibition observed in the context of EGFR mutation in NSCLC and GBM. Specifically, we demonstrate that downstream of these structurally distinct EGFR mutants an important pathway involving the activation of ERK via the protein tyrosine phosphatase SHP2 is functionally impaired, and that this perturbs cellular responsiveness to gefitinib. Based upon immunoprecipitation, immunofluorescence, activity, and receptor trafficking studies, this mechanism appears to involve the sequestration of biochemically active SHP2 with endocytosis-impaired EGFR mutants at the plasma membrane in a manner which prevents the participation of SHP2 in the complete activation of ERK. Thus, our findings demonstrate that distinct EGFR-activating mutations may result in qualitatively similar perturbations to downstream signaling leading to the surprising impairment of receptor-mediated ERK activation. Given that elevated expression of these EGFR mutants generally promotes cellular response to EGFR inhibitors, this work identifies SHP2 and ERK as potentially critical nodes in the signaling network downstream of EGFR for co-inhibition in settings where EGFR inhibitors are not effective as single agents. 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 9. doi:1538-7445.AM2012-9

Abstract 5472: Role of Harvey Ras (HRAS) mutations in head and neck squamous cell carcinoma (HNSCC)

Abstract Background: Harvey Ras (HRAS) was recently reported being mutated in head and neck squamous cell carcinomas (HNSCC) and likely plays an important role as an oncogene. The precise role of HRAS mutations for signaling and carcinogenesis of HNSCC remains to be determined. Methods: We completed mutational screening (Sanger Sequencing) for tissues and cell lines focused on the known hotspot mutations G12X and Q61X. Furthermore we performed viability testing for various cell lines and visualized the signaling-effects by itself, in presence of PI3K-, EGFR inhibitors and likewise in combination, by immunoblotting. After suppression of HRAS using siRNA, we determined the cell-viability. Results: In our study we sequenced 100 HNSCC tumor tissues and HNSCC cell lines and identified several canonical HRAS mutations. One cell line contained a G12D HRAS mutation and was further examined. Additional two cell lines with atypical HRAS variants were identified and compared to the classic hotspot mutated cell line. The viability for the mentioned cell lines were indicative of resistance to EGFR inhibition to different degrees. The protein activation levels in important signaling pathways (PI3K/MAPK) confirmed our viability data. HRAS signaling was primarily via PI3K/AKT. Silencing HRAS showed significantly decreased viability. Conclusions: Previous studies have shown that EGFR-targeting agents remain insufficient as single targeted therapy. HRAS appears to contribute to the EGFR-resistance of HNSCC. The canonical mutation G12D appears to signal primarily via PI3K and PI3K inhibitors may be effective. The G12D cell line model indicates a central role of mutated HRAS for signaling and viability consistent with role as a driver mutation. 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 5472. doi:1538-7445.AM2012-5472

Abstract 276: Targeting signaling networks via RNAi to improve therapy for ovarian cancer

Abstract Epithelial ovarian cancer (EOC) is the second most common gynecologic malignancy, and the leading cause of death from gynecological cancers. At the time of presentation, most ovarian cancers are no longer dependent on single genetic determinants for growth and/or survival, and targeted therapies used as single agents typically do not work in this disease. We hypothesized that network-based synthetic lethality screens would help identify critical pathways to target in combination therapy. We have used RNAi screening with a targeted library to identify a set of gene candidates that influence the response of EOC cells to the Src-targeting agent dasatinib, a promising agent for treatment of EOC. We identified sets of siRNAs that specifically modulated cell resistance to dasatinib, or directly affected EOC cell survival. We then compared this set of siRNAs with previously identified modulators of response to EGFR-targeting agents and cytotoxic drugs, contrasting action in EOC cell lines versus other types of cancer cell lines. From a set of 60 siRNAs intrinsically reducing cell growth and survival, some (16 siRNAs) were specific for EOC cells. In contrast, 38 siRNAs antagonized the response of EOC cells to dasatinib, and are promising drug treatment-resistance biomarkers. We concluded validation of EOC-specific hits. Mapping the pattern of drug treatment-resistance hits together with drug treatment-sensitive hits revealed suggestive clusters of very closely interacting proteins clustering with well validated modulators of cancer cell survival, implying we have identified key cancer signaling nodes. Screening candidates, e.g., PTPN12, Spry4, and HSPA8, which cluster with well-validated cancer-related signaling hubs, are being examined. These studies offer an opportunity to employ a functional approach to identify critical drug response-modifying genes that can be therapeutically targeted as biomarkers and drug targets to improve EOC treatment outcomes with emerging targeted agents. (This work was supported by the fellowship grant from Sass Foundation for Medical Research, Inc, Roslyn, New York to H. Liu, NIH FCCC-UPenn ovarian cancer SPORE (P50 CA083638), and NIH (R01 CA140323).) 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 276. doi:1538-7445.AM2012-276

New approaches to EGFR inhibition for locally advanced or metastatic squamous cell carcinoma of the head and neck (SCCHN).

Despite recent advances in radiotherapy and chemotherapy, survival rates for squamous cell carcinoma of the head and neck (SCCHN) have remained poor. The focus of SCCHN therapy has more recently shifted to the molecular level, particularly the epidermal growth factor receptor (EGFR/ErbB) pathway. Several agents that target the EGFR pathway, including monoclonal antibodies and tyrosine kinase inhibitors, are under investigation for SCCHN. Searches of PubMed and results of key oncology congresses were performed to identify relevant articles and abstracts. The EGFR-targeted monoclonal antibody cetuximab is approved for the treatment of locally advanced SCCHN in combination with radiotherapy, for first-line treatment of recurrent or metastatic SCCHN in combination with platinum-based chemotherapy and 5-fluorouracil, and for recurrent or metastatic SCCHN following progression with platinum-based chemotherapy. Other investigational EGFR-targeted monoclonal antibodies (e.g., panitumumab, nimotuzumab, zalutumumab) are in clinical development for SCCHN. Inhibition of the tyrosine kinase domain of EGFR has also been explored as a therapeutic approach in SCCHN using small-molecule reversible inhibitors, such as gefitinib and erlotinib. However, a key challenge in SCCHN is the development of resistance, and strategies are being pursued to delay or overcome resistance to EGFR-targeted agents. These strategies include development of agents that inhibit multiple ErbB receptors simultaneously (e.g., lapatinib) or that bind multiple ErbB family receptors irreversibly (e.g., afatinib, PF-00299804) and investigation of combinations of agents that target multiple pathways implicated in the pathogenesis of SCCHN. Ongoing large clinical trials are evaluating these emerging agents and combinations for the treatment of SCCHN.

An analysis of the survival rate after radiotherapy in lung cancer patients with bone metastasis: Is there an optimal subgroup to be treated with high-dose radiation therapy?

We investigated the prognostic factors after radiotherapy for bone metastasis from lung cancer while taking the recent findings in the treatment of such cases into consideration. A total of 132 patients with bone metastases from pathologically confirmed lung cancer were evaluated regarding the following potential prognostic factors: treatment for primary site (surgery vs. other), treatment site (spine vs. other), number of bone metastases (solitary vs. multiple), number of metastatic organs (0 vs. 1 vs. ≥2), neurological symptoms (no symptoms vs. numbness vs. paresis), degree of pain (no pain vs. mild pain vs. severe pain), performance status [PS] (0-1 vs. ≥2), biological effective dose [BED] (≥40 Gy vs. <40Gy), time to distant metastasis (≥1 year vs. <1 year), histology (adenocarcinoma vs. others), and use of epidermal growth factor receptor [EGFR]-targeted agents (Yes vs. No). The univariate analysis demonstrated that all factors except for the treatment site were significant. Surgery as treatment for primary site, solitary bone metastasis, no visceral organ metastasis, no symptoms or numbness, no pain, PS<2, BED≥40 Gy, time to distant metastasis ≥ 1year, adenocarcinoma histology, and use of EGFR-targeted agents were correlated with a favorable prognosis. In a multivariate analysis, solitary bone metastasis, PS<2, BED≥40 Gy, adenocarcinoma histology, and the use of EGFR-targeted agents were significantly correlated with a better survival (p = 0.038, 0.006, 0.003, 0.014, and <0.001, respectively). A contingency table to assess the relationship between each variable and the median survival time of the patients according to the administered BED showed that in patients with the time to distant metastasis ≥ 1year and the use of EGFR-targeted agents, the subgroups treated with BED≥40 Gy had a favorable prognosis. Our study suggests that high-dose radiotherapy is associated with a better prognosis in combination with other favorable prognostic factors.

Clinical Implications and Quality Assurance of Molecular Testing for EGFR-Targeting Agents in Colorectal Cancer

The introduction in clinical practice of anti-epidermal growth factor receptor (EGFR) antibodies has improved the clinical outcome of metastatic colorectal cancer (mCRC) patients. Nevertheless, only 10% of mCRC tumors respond to these treatments, thus rendering the efforts made to maximize their therapeutic index justified. Although several biomarkers have been identified, we do not know yet how to administer these drugs in colorectal cancer patients in a “personalized–targeted manner.” With this review we will try to demonstrate that we need to go beyond the assumption of a binary relationship between one genetic event and response or resistance to anti-EGFR drugs and that several factors can influence the response to these agents. Therefore, the introduction in future approaches of a holistic genomic discovery plan instead of an individual and specific identification of alterations is needed.

Cetuximab: a standard approach to the first-line treatment of recurrent and/or metastatic and locally advanced squamous cell carcinoma of the head and neck

The burden of squamous cell carcinoma of the head and neck (SCCHN) on healthcare systems is expected to rise in line with projected increases in population sizes in general, and the relative proportion of elderly individuals in particular, underlining the need for effective, well tolerated treatment strategies. The epidermal growth factor receptor (EGFR)-targeted IgG1 monoclonal antibody, cetuximab, is the only EGFR-targeted agent currently approved for use in the treatment of SCCHN. Adding cetuximab to standard first-line platinum-based chemotherapy in the treatment of recurrent and/or metastatic SCCHN significantly improved overall survival (hazard ratio [HR] 0.80; P = 0.04), progression-free survival (HR 0.54; P\0.001) and response rates (odds ratio 2.33; P\0.001), compared to platinum-based chemotherapy alone. This was the first time in 30 years that a significant increase in overall survival had been achieved over platinum- based therapy alone and established cetuximab plus platinum-based chemotherapy as the new standard first-line treatment approach for recurrent and/or metastatic disease. In locally advanced SCCHN, cetuximab plus radiotherapy significantly improved locoregional control (HR 0.68, P = 0.005) and overall survival (HR 0.74; P = 0.03) compared to radiotherapy alone. In both recurrent and/or metastatic disease and locally advanced disease, adding cetuximab to standard therapy was generally well tolerated and did not affect patients’ quality of life. The clinical benefits seen with the addition of cetuximab to standard chemotherapy or radiotherapy make it one of the most significant advances made in SCCHN treatment in recent years.

Cetuximab: a standard approach to the first-line treatment of recurrent and/or metastatic and locally advanced squamous cell carcinoma of the head and neck

The burden of squamous cell carcinoma of the head and neck (SCCHN) on healthcare systems is expected to rise in line with projected increases in population sizes in general, and the relative proportion of elderly individuals in particular, underlining the need for effective, well tolerated treatment strategies. The epidermal growth factor receptor (EGFR)-targeted IgG1 monoclonal antibody, cetuximab, is the only EGFR-targeted agent currently approved for use in the treatment of SCCHN. Adding cetuximab to standard first-line platinum-based chemotherapy in the treatment of recurrent and/or metastatic SCCHN significantly improved overall survival (hazard ratio [HR] 0.80; P = 0.04), progression-free survival (HR 0.54; P\0.001) and response rates (odds ratio 2.33; P\0.001), compared to platinum-based chemotherapy alone. This was the first time in 30 years that a significant increase in overall survival had been achieved over platinum- based therapy alone and established cetuximab plus platinum-based chemotherapy as the new standard first-line treatment approach for recurrent and/or metastatic disease. In locally advanced SCCHN, cetuximab plus radiotherapy significantly improved locoregional control (HR 0.68, P = 0.005) and overall survival (HR 0.74; P = 0.03) compared to radiotherapy alone. In both recurrent and/or metastatic disease and locally advanced disease, adding cetuximab to standard therapy was generally well tolerated and did not affect patients’ quality of life. The clinical benefits seen with the addition of cetuximab to standard chemotherapy or radiotherapy make it one of the most significant advances made in SCCHN treatment in recent years.

Epidermal growth factor receptor-targeted treatment strategies in advanced pancreatic cancer: Is K-RAS mutational testing ready for prime time?

The combination of gemcitabine with erlotinib is viewed as one standard in the treatment of patients with advanced pancreatic cancer. However, the magnitude of the survival benefit of the combination therapy compared to single agent gemcitabine is relatively small. Whether this statistically significant survival benefit translates to a relevant clinical benefit of the combined treatment in view of increased toxicity and costs is still a matter of debate. Consequently, there has been great interest in identifying molecular biomarkers predictive for response and survival benefit from EGFR-targeted agents in advanced pancreatic cancer. No data have been published up to now concerning the value of K-RAS mutations in pancreatic cancer as a predictive marker for lack of response to EGFR targeted agents. Nevertheless, the first prospective evaluation of K-RAS status and response to erlotinib in combination with either gemcitabine or capecitabine suggest a significant improvement of overall survival only for patients with K-RAS wild type tumors suggesting a possible role of K-RAS mutational status as predictive marker in pancreatic cancer.

Antitumor effect of cetuximab in combination with S-1 in EGFR-amplified gastric cancer cells

Overexpression of human epidermal growth factor receptor (EGFR) has been detected in gastric cancer (GC) and is associated with poor outcomes. Combination treatment regimens with EGFR-targeting agents and cytotoxic agents are considered to be a potential therapeutic option for EGFR-overexpressing GC. Herein, we have investigated the effects of combination treatment with the oral fluoropyrimidine S-1 and the EGFR-targeting agent cetuximab in GC cells with or without EGFR overexpression. EGFR expression was determined by FACS and quantitative PCR in GC cells. Experimental 5-fluorouracil (5FU) was used instead of S-1 for in vitro experiments. The efficacy of 5FU or cetuximab monotherapy or combination 5FU/cetuximab therapy was examined in vitro and in vivo. Clinical specimens were examined for EGFR by immunohistochemistry (IHC). EGFR expression score was defined as strong membrane and cytoplasmic staining in at least 50–75% of cells. The combination of 5FU and cetuximab synergistically inhibited cell proliferation and exhibited an enhanced proapoptotic effect in GC cells with EGFR overexpression. Cetuximab also induced down-regulation of phosphorylation of EGFR and AKT, leading to diminished signaling. The antitumor effect of the combination of S-1 and cetuximab in vivo was also greater than that of either drug alone. Our preclinical findings thus indicate that the combination of S-1 and EGFR-targeting therapy is a promising treatment option for GC with EGFR overexpression.

Mechanism of EGER-related cancer drug resistance

Drug resistance in cancer arises from a complex range of biochemical and molecular events, which ultimately result in tumor cell survival. Identifying key genes and signal pathways involved in the molecular mechanisms of drug resistance is essential for establishment of new drug targets for preventing further resistance development and spreading. Epidermal growth factor receptor (EGFR) was the first growth factor receptor proposed as a target for cancer therapy. Significant progress in studying EGFR gene expression and mutation has been made in understanding the molecular events involved in EGFR-targeted agents. Recently, some individual chromosomal features such as EGFR copy number variation were demonstrated as new aspects related to drug sensitivity. Identifying these functional regulators of drug resistance will benefit therapeutic decision-making. In this study, we describe an extensive investigation of the published literature on mutation, amplification, and expression of EGFR and its downstream signaling that directly contribute to EGFR inhibitor resistance, including the gene status of KRAS, BRAF, PIK3CA, PTEN, MEK, and AKT on response to therapy. Analysis of these gene signatures identified reveals general modes of action of multicomponent therapies and the mechanisms of specific drug combinations, highlights the potential value of molecular interaction profiles in the discovery of novel therapies, and provides more information for personalized cancer medicine.

Tracheal granuloma pyogenicum with erlotinib treatment for lung cancer

To the Editors: We present the case of a 64 yr-old ex-smoker (20 pack-yrs) with a squamous cell carcinoma of the lung who developed a tracheitis and granuloma pyogenicum during treatment with erlotinib. Among the specific side-effects of epidermal growth factor receptor (EGFR) inhibitors, paronychia with granuloma pyogenicum has been reported frequently; however, granuloma pyogenicum has never been described in the trachea with erlotinib treatment. Monoclonal antibodies against the EGFR ( e.g. cetuximab) and EGFR tyrosine receptor inhibitors (TKIs) ( e.g. gefinitib and erlotinib) have been shown to improve treatment outcomes in nonsmall cell lung cancer. Generally, these agents are better tolerated than classical cytotoxic agents showing a different toxicity profile. Specific side-effects of EGFR-targeting agents include diarrhoea and particularly skin toxicity, such as acneiform eruptions, xerosis, eczema, fissures, teleangiectasia, hyperpigmentation, hair changes and paronychia with granuloma pyogenicum [1]. Skin toxicity has been associated with EGFR inhibitor antitumor activity [1]. A 64 yr-old male was diagnosed with squamous cell carcinoma of the right upper lobe and was treated with a right upper lobectomy in December 2002 (pathological (p)T1 pN1 (three positive lymph nodes out of 33 removed)). No adjuvant …

Ciblage de la voie de signalisation RAS pour le traitement des cancers

RAS proteins are among the first proteins to demonstrate a crucial implication in the cell cycle regulation. The RAS signalling pathway plays a key role in the regulation of cell cycle through the activation of numerous downstream pathways including the RAF/MEK/ERK, PI3K/AKT/mTOR, RAL and PKC pathways. These pathways are involved in gene transcription, regulation of cell survival and angiogenesis. As the RAS signalling pathway was shown to be altered in several cancers, molecularly targeted agents that trigger various components of this pathway have been evaluated in clinical practice. This paper first reviews the regulation processes of the RAS protein in cancer, as well as RAS downstream main signalling pathways. Therapeutic approaches to target RAS or some of its effectors are then detailed. Finally, the ability of RAS mutations to predict response to EGFR-targeting agents is discussed in the context of colorectal and lung cancers.

Single-agent maintenance therapy for advanced-stage non-small cell lung cancer: A meta-analysis.

7553 Background: Maintenance therapy is a new treatment paradigm following first-line combination chemotherapy for patients with advanced non-small cell lung cancer (NSCLC). We conducted a meta-analysis of randomized studies that evaluated single agent maintenance therapy. Methods: We conducted an electronic literature search of public databases (MEDLINE, EMBASE, Cochrane library) and manual search of conference proceedings of ASCO and World Conference on Lung Cancer using relevant terms. Eligible studies were identified and reviewed independently by two co-authors. Randomized trials that reported the effect of single agent maintenance therapy on survival in NSCLC patients were included. A formal meta-analysis was conducted using Comprehensive Meta Analysis software (Version 2.0). The outcome data were pooled and reported as hazard ratio (HR). The primary outcome of interest was overall survival (OS) and secondary outcome was progression free survival (PFS). Results: We reviewed 210 published reports. Ten were eligible for inclusion (3 meeting abstracts, 7 journal publications) with a total of 3451 patients (maintenance arm/control arm- 1942/1509, median age 62.5 years, male -72 %). The OS (HR 0.87, 95% CI 0.82 to 0.94, P=0.0003) and PFS (HR 0.84, 95% CI 0.80 to 0.88, P< 0.0001) were superior with maintenance therapy. ‘Switch’ maintenance therapy was associated with significant OS and PFS improvement (HR 0.86 CI 0.80 to 0.93, P= 0.00046; PFS HR 0.71 CI 0.66 to 0.77, P<0.0001). Despite a modest improvement in PFS (HR 0.92, CI 0.87 to 0.98, P= 0.007), “continuation” maintenance therapy was not associated with survival benefit (HR 0.92, CI 0.77 to 1.08, P=0.33). Improvements in OS and PFS were observed with EGFR-targeted agents (HR 0.86, CI 0.78 to 0.95, P= 0.006; HR 0.76 CI 0.70 to 0.83, P<0.0001) and cytotoxic agents (HR 0.88, CI 0.80 to 0.97, P=0.018; HR 0.87, CI 0.82 to 0.91, P<0.0001). Conclusions: Single agent maintenance therapy improves overall survival, though statistical significance was only noted with ‘switch’ maintenance. Survival benefit was observed for chemotherapy and EGFR-targeted therapy. Supported by NIH P01 CA116676. TKO, FRK and SSR are Distinguished Cancer Scholars of the Georgia Cancer Coalition.

A comprehensive profiling of colorectal cancer patients through multiplexed functional pathway signature and somatic mutation analysis for effective therapy selection.

e14103 Background: Colorectal cancer (CRC) is a leading cause of death in the developed nations. The development of effective forms of cytotoxic chemotherapy for colorectal cancer has been paralleled by the emergence of monoclonal antibodies against proteins that are thought to be important in the proliferation of malignant cells. Recent clinical studies showed that EGFR-targeting agent improved response rate when added to chemotherapy, however patients with KRAS mutations did not benefit from such treatment. Here we report a comprehensive profiling of pathwy signal proteins for their level of expression/activation and presence of somatic mutations in tumor tissues obtained from 136 CRC patients. Methods: The collaborative enzyme enhanced reactive immunoassay (CEER) is a multiplexed protein microarray platform requiring co-localization of two detector enzyme-conjugated-antibodies. Once target proteins are captured on the microarray-surface, channeling events between two detector enzymes in proximity enable the profiling of the target proteins with high sensitivity. In this study, tumor lysates were prepared from frozen tissues obtained from 136 CRC patients. In addition to a multiplexed analysis for panel of mutations in KRAS and BRAF genes, the level of expression and activation of HER1, HER2, HER3, cMET, cKIT, IGF-1R, PI3K, AKT, ERK and other pathway proteins were determined using CEER technology. Results: KRAS and BRAF mutations were found in ~40% (54/136) and ~5% (6/136) respectively in this cohort. The most frequent mutant alleles were G12D (14%) and G13D (13%). Varying levels of RTKs and associated activation patterns were observed. Levels of phosphorylated ERK and AKT correlated to expression/activation patterns of HER1, cMET, HER3 and prevalence of each biomarker along with pathway redundancy will be presented. Conclusions: A comprehensive profiling of multiplexed pathway/ somatic mutation analysis provides critical information needed to select the most effective targeted agents to overcome pathway redundancy /activating mutation related drug resistance through treatment combination or sequencing.

Abstract 2560: The CK2 inhibitor CX-4945 enhances the antitumor activity of EGFR-targeted agents by attenuating signaling in the PI3K/AKT/mTOR pathway

Abstract The epidermal growth factor receptor (EGFR) regulates several oncogenic signaling pathways including PI3K/AKT/mTOR, MEK/ERK, and STAT. A number of EGFR antagonists have been approved for treatment of late-stage tumors of epithelial origin. Despite these advances, there are several limitations to these therapies, including primary and acquired resistance, prompting the need to combine EGFR antagonists with agents that target pathways downstream of EGFR. CK2 modulates multiple pro-proliferative and pro-survival signals through many of these same signaling pathways, and co-overexpression of EGFR and CK2 has been frequently observed in solid tumors. Here we present the combination of EGFR-targeted agents with CX-4945, a first-in-class selective CK2 inhibitor currently under evaluation in a Phase I clinical trial. CK2 phosphorylates several key proteins at multiple levels within the PI3K/AKT/mTOR signaling pathway including AKT, PTEN, and p70S6K1. CK2 also regulates the Hsp90/Cdc37 machinery, whose clients include EGFR, AKT, and Src. We proposed that top-down inhibition of EGFR, combined with lateral inhibition of the PI3K/ATK/mTOR pathway by CX-4945, would result in an improved cancer therapy compared to EGFR antagonism alone. This hypothesis was tested in vitro and in vivo in A431 squamous cell carcinoma (SCC) and non-small cell lung carcinoma (NSCLC) models of various genetic backgrounds. Signaling pathways and induction of apoptosis were analyzed by western blot and cell proliferation was measured in a 96-hour cell viability assay. The combination of CX-4945 and erlotinib resulted in enhanced reduction in phosphorylation of AKT (T308), AKT (S473), PRAS40 (S246), mTOR (S2481), mTOR (S2448), p70S6K1 (T389), S6 (S235/6), S6 (240/4), and 4E-BP1 (T37/46), and decreased Mcl-1 levels. These effects were accompanied by decreased cell proliferation and synergistic induction of apoptosis. CX-4945 plus erlotinib exhibited enhanced antitumor activity in A431 SCC and NCI-H2170 NSCLC xenograft models; moreover, in the erlotinib-resistant NCI-H1975 NSCLC xenograft model, CX-4945 plus cetuximab resulted in enhanced efficacy. These data suggest that CX-4945 in combination with EGFR-targeted agents may improve clinical outcomes in patients with EGFR and CK2-driven cancers by inhibiting multiple nodes of the EGFR signaling pathway. 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 2560. doi:10.1158/1538-7445.AM2011-2560

Protein expression status of p53 and epidermal growth factor receptor in thymoma.

Evaluating the state of malignancy of thymoma is a challenge due to the discrepancies between pathological classifications and clinical stage criteria. Therefore, the identification of markers contributing to the assessment of the stage of malignancy of thymoma would be useful. This study aimed to evaluate the prevalence of p53 and epidermal growth factor receptor (EGFR) in thymoma, demonstrate the clinical significance and assess the potential of specific-targeted therapy. A total of 16 thymic hyperplasia patients and 43 thymoma patients were included in the study. Samples were tested for the expression of p53 and EGFR using immunohistochemistry. In the multivariate analysis, the thymoma cases were followed up to analyze the relationship between survival rates and a number of potential factors, such as p53 and EGFR. There were 21 completely resected stage II cases which were evaluated for relapse-free time. The distribution of p53 with clinicopathological parameters was: type A/AB 57.1%, type B1 85.7%, type B2 85.7%, type B3 90.9% and type C 100%; and stage I 90.9%, stage II 90.9%, stage III 100% and stage IV 100%. The EGFR-positive rates were: type A/AB 42.9%, type B1 71.4%, type B2 57.1%, type B3 90.9% and type C 100%; and stage I 45.5%, stage II 76%, stage III 75% and stage IV 100%. EGFR expression correlated with tumor size, pathological classification and advanced clinical stage, whereas p53 correlated only with pathological classifications. Findings of our multivariate analysis showed that neither p53 nor EGFR are independent prognostic factors. Nevertheless, the fact that a statistical difference (p<0.05) was noted in relapse-free survival time between the EGFR-positive and EGFR-negative groups (48.182±33.757 vs. 76.3±10.339 months) suggests that EGFR plays a key role in thymoma progression. No positive results were found between the p53 groups following a survey conducted to assess relapse time. Therefore, the application of EGFR-targeting agents is warranted in invasive thymoma, whereas the targeting of p53 has yet to be elucidated.