EGFR-expressing Non-small Cell Lung Cancer Research Articles

Abstract 7194: Targeting AXL and MCL-1 to eradicate lazertinib tolerance in EGFR-mutated NSCLC cells

Abstract Lazertinib, a novel third-generation EGFR-tyrosine kinase inhibitor, has shown marked efficacy in patients with EGFR-mutant lung cancer. However, after various periods of therapeutic intervention, most patients eventually acquire resistance to lazertinib. A potential therapeutic approach to address this clinical issue is to overcome the initial drug resistance mechanism. To determine the underlying adaptive lazertinib resistance mechanisms, we evaluated signal transduction, cell apoptosis, and drug sensitivity in mutant EGFR-expressing non-small cell lung cancer (NSCLC) cells treated with lazertinib. The siRNA screening assay demonstrated that AXL knockdown significantly inhibited cell viability in the presence of lazertinib, indicating that AXL activation contributes to lazertinib resistance. However, long-term culture with a combination of lazertinib and AXL inhibitors eventually led to the proliferation of residual cells and increased MCL-1 expression, which was mediated by the nuclear translocation of the transcription factor YAP. Cell-based assays showed that triple therapy with an MCL-1 or YAP inhibitor, in combination with EGFR-TKI lazertinib, an AXL inhibitor, significantly reduced cell viability and increased apoptosis. These results demonstrate that AXL and YAP/MCL-1 signals contribute to the adaptive lazertinib resistance in EGFR-mutant NSCLC cells, suggesting that the initial dual inhibition of AXL and YAP/MCL-1 might be highly effective in eliminating lazertinib-resistant cells. Citation Format: Tadaaki Yamada, Yohei Matsui, Koichi Takayama. Targeting AXL and MCL-1 to eradicate lazertinib tolerance in EGFR-mutated NSCLC cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7194.

Ligand-based, piggyBac-engineered CAR-T cells targeting EGFR are safe and effective against non-small cell lung cancers

Epidermal growth factor receptor (EGFR) is overexpressed in various cancers, including non-small cell lung cancer (NSCLC), and in some somatic cells at a limited level, rendering it an attractive antitumor target. In this study, we engineered chimeric antigen receptor (CAR)-T cells using the piggyBac transposon system, autologous artificial antigen-presenting cells, and natural ligands of EGFR. We showed that this approach yielded CAR-T cells with favorable phenotypes and CAR positivity. They exhibited potent antitumor activity against NSCLC both invitro and invivo. When administered to tumor-bearing mice and non-tumor-bearing cynomolgus macaques, they did not elicit toxicity despite their cross-reactivity to both murine and simian EGFRs. In total we tested three ligands and found that the CAR candidate with the highest affinity consistently displayed greater potency without adverse events. Taken together, our results demonstrate the feasibility and safety of targeting EGFR-expressing NSCLCs using ligand-based, piggyBac-engineered CAR-T cells. Our data also show that lowering the affinity of CAR molecules is not always beneficial.

Targeting oncogenic KRAS in non-small cell lung cancer with EGFR aptamer-conjugated multifunctional RNA nanoparticles

KRAS mutations are one of the most common oncogenic driver mutations in human cancers, including non-small cell lung cancer (NSCLC), and have established roles in cancer pathogenesis and therapeutic resistance. The development of effective inhibitors of mutant KRAS represents a significant challenge. Three-way junction (3WJ)-based multi-functional RNA nanoparticles have the potential to serve as an effective invivo siRNA delivery platform with the ability to enhance tumor targeting specificity and visualize biodistribution through an imaging moiety. Herein, we assembled novel EGFRapt-3WJ-siKRASG12C mutation targeted nanoparticles to target EGFR-expressing human NSCLC harboring a KRASG12C mutation to silence KRASG12C expression in a tumor cell-specific fashion. We found that EGFRapt-3WJ-siKRASG12Cnanoparticles potently depleted cellular KRASG12C expression, resulting in attenuation of downstream MAPK pathway signaling, cell proliferation, migration/invasion ability, and sensitized NSCLC cells to chemoradiotherapy. Invivo, these nanoparticles induced tumor growth inhibition in KRASG12C NSCLC tumor xenografts. Together, this study suggests that the 3WJ pRNA-based platform has the potential to suppress mutant KRAS activity for the treatment of KRAS-driven human cancers, and warrants further development for clinical translation.

Structure-Guided Development of Dual Inhibitors of EGFR and JNK to Treat GBM and NSCLC

Abnormal epidermal growth factor receptor (EGFR) signaling is widespread in cancer, making the EGFR as an important target for therapy. The third-generation EGFR small-molecule inhibitors are at the forefront clinically for treatment of patients with non-small cell lung cancer (NSCLC). However, acquired resistance limits the effectiveness. The c-Jun N-terminal kinase (JNK) signaling axis mediates primary resistance to EGFR inhibition in glioblastoma (GBM) and NSCLC. Therefore, it's a new approach of using a dual EGFR and JNK inhibition to treat EGFR-expressing GBM and NSCLC is a new approach. On the basis of an iterative approach of docking, two series of trisubstituted 1,2,4-triazoles and thiazoles were designed and synthesized. Some compounds demonstrated inhibitory activity for EGFR and JNK kinases with IC50 values in the low nanomolar range. This work may lead to design and optimize the potent EGFR and JNK inhibitors in the future.

Ezrin Enhances EGFR Signaling and Modulates Erlotinib Sensitivity in Non–Small Cell Lung Cancer Cells

Ezrin is a scaffolding protein that is involved in oncogenesis by linking cytoskeletal and membrane proteins. Ezrin interacts with epidermal growth factor receptor (EGFR) in the cell membrane, but little is known about the effects of this interaction on EGFR signaling pathway. In this study, we established the biological and functional significance of ezrin-EGFR interaction in non–small cell lung cancer (NSCLC) cells. Endogenous ezrin and EGRF interaction was confirmed by co-immunoprecipitation and immunofluorescent staining. When expression of ezrin was inhibited, EGFR activity and phosphorylation levels of downstream signaling pathway proteins ERK and STAT3 were decreased. Cell fractionation experiments revealed that nuclear EGFR was significantly diminished in ezrin-knockdown cells. Consequently, mRNA levels of EGFR target genes AURKA, COX-2, cyclin D1, and iNOS were decreased in ezrin-depleted cells. A small molecule inhibitor of ezrin, NSC305787, reduced EGF-induced phosphorylation of EGFR and downstream target proteins, EGFR nuclear translocation, and mRNA levels of nuclear EGFR target genes similar to ezrin suppression. NSC305787 showed synergism with erlotinib in wild-type EGFR-expressing NSCLC cells, whereas no synergy was observed in EGFR-null cells. Phosphorylation of ezrin on Y146 was found as an enhancer of ezrin-EGFR interaction and required for increased proliferation, colony formation, and drug resistance to erlotinib. These findings suggest that ezrin-EGFR interaction augments oncogenic functions of EGFR and that targeting ezrin may provide a potential novel approach to overcome erlotinib resistance in NSCLC cells.

Abstract 5467: IMGN289, an EGFR-targeting antibody-maytansinoid conjugate with potent activity against non-small cell lung cancer (NSCLC) regardless of dependency on EGFR pathway.

Abstract NSCLC accounts for approximately 85% of all lung cancers. Based on tumor histology, NSCLC can be subdivided into adenocarcinoma (AC), squamous cell carcinoma (SCC), and large cell carcinoma (LCC), which account for 40%, 25-30% and 10-15% of NSCLC cases, respectively. In a fraction of AC cases, driver oncogenes have been identified that enable effective treatment with targeted therapies. For most NSCLC cases, however, etiology is still unknown and effective targeted therapies have yet to be achieved. Additionally, even cancers that initially respond to targeted therapies eventually develop resistance, creating the need for other therapeutic approaches. EGFR is one of the best characterized driver oncogenes in NSCLC and also is frequently expressed at high levels in this indication. In house immunohistochemical analysis found EGFR to be highly expressed in 23.8% of AC (n = 21), 60% of SCC (n = 10) and 50% of LCC (n = 8), confirming published data that EGFR represents an attractive therapeutic target for NSCLC. As a novel approach to targeting EGFR-expressing tumors, we have developed IMGN289, an antibody-“drug” conjugate (ADC) consisting of the J2898A antibody (Ab), which selectively binds to EGFR and inhibits EGFR-driven tumor cell growth, conjugated to the maytansinoid DM1, a potent anti-microtubule agent, via the SMCC thioether linker. IMGN289 showed significantly enhanced cytotoxic activity, relative to cetuximab or unconjugated J2898A, against a panel of NSCLC cell lines dependent on EGFR signaling. In vitro, anti-EGFR Abs typically inhibit less than 70% of tumor cell growth at 30 nM concentration, whereas IMGN289 exposure approached 100% inhibition at a significantly lower concentration. Enhanced potency of IMGN289 against EGFR-dependent tumors was demonstrated in vivo in the H292 xenograft tumor model, where the minimally effective doses of IMGN289 and its J2898A Ab were 1 and 3 mg/kg, respectively. In addition, IMGN289 was effective against EGFR-expressing NSCLC cells that are not dependent on EGFR signaling and therefore resistant to anti-EGFR Abs. For example, IMGN289 was active against H226 and H1703 mesenchymal cell lines in vitro and H1703 xenograft tumor in vivo, while neither cetuximab nor J2898A alone was active. IMGN289 was also active against EGFR mutant HCC827 cell lines that have acquired resistance to EGFR tyrosine kinase inhibitors through T790M EGFR mutation or MET gene amplification. Thus, EGFR-targeting IMGN289 achieves a distinct anti-tumor mechanism that is independent of EGFR pathway inhibition. In summary, IMGN289 is highly active against EGFR-positive NSCLC cells regardless of dependency on the EGFR pathway and represents a promising therapeutic candidate for NSCLC. Citation Format: Thomas D. Chittenden, Yulius Y. Setiady, Peter U. Park, Jose F. Ponte, Ling Dong, Anna Skaletskaya, Christina N. Carrigan, Alfred A. Villaluz, Jan Pinkas, Robert J. Lutz, John M. Lambert. IMGN289, an EGFR-targeting antibody-maytansinoid conjugate with potent activity against non-small cell lung cancer (NSCLC) regardless of dependency on EGFR pathway. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5467. doi:10.1158/1538-7445.AM2013-5467

EGFR-directed monoclonal antibodies in non-small cell lung cancer

Several monoclonal antibodies directed against the epidermal growth factor receptor (EGFR) have been evaluated in patients with non-small cell lung cancer (NSCLC). Cetuximab, a chimeric monoclonal antibody, has been studied in combination with first-line chemotherapy in phase II and two phase III trials in patients with advanced NSCLC. The phase III FLEX trial demonstrated an increase in survival for cisplatin/vinorelbine plus cetuximab compared to chemotherapy alone in patients with advanced EGFR-expressing NSCLC. Cetuximab added to carboplatin/paclitaxel failed to improve progression-free survival in the BMS099 phase III trial. However, a meta-analysis of four randomized trials confirmed a significant survival benefit for platinum-based chemotherapy plus cetuximab compared to chemotherapy alone. High EGFR expression of tumor cells was then shown to predict the benefit of cetuximab, whereas KRAS mutations and EGFR fluorescent in situ hybridization analysis were without predictive value. Matuzumab and panitumumab have also been studied in phase II trials. Necitumumab, a fully human monoclonal antibody, is currently evaluated in combination with chemotherapy in two phase III trials in patients with advanced NSCLC. Cetuximab is also studied in combination with chemoradiotherapy in patients with locally advanced NSCLC.

Molecular Imaging of Nonsmall Cell Lung Carcinomas Expressing Active Mutant EGFR Kinase Using PET with [124I]-Morpholino-IPQA

Mutations in the kinase domain of epidermal growth factor receptor (EGFR) have high levels of basal receptor phosphorylation and are associated with clinical responsiveness to Iressa in patients with nonsmall cell lung cancer (NSCLC). This study aimed to assess the feasibility of morpholino-[124I]IPQA derivative as an in vivo PET imaging tool for the expression of different EGFR mutants in NSCLC. In vitro radiotracer accumulation and washout studies demonstrated a rapid accumulation and progressive retention after washout of morpholino-[131I]IPQA derivative in high EGFR-expressing H1299 NSCLC derivative cell lines (L858R and E746-A750 del cell lines), but not in EGFR-transfected H1299 cell line and vector-transfected H1299 cell line. Using the morpholino-[124I]IPQA derivative, we obtained noninvasive microPET images of EGFR activity in L858R and E746-A750 del subcutaneous tumor xenografts, but not in subcutaneous tumor xenografts grown form control cell line. Different EGFR mutant (activity) tumors have a different morpholino-[∗I]IPQA derivative uptake. However, it still needs to modify the structure of IPQA to increase its water solubility and reduce hepatobiliary clearance. Morpholino-[124I]IPQA derivative may be a potential probe for selection of the candidate patients suffering from NSCLC for the small molecule tyrosine kinase inhibitor therapy (e.g., Iressa) in the future.

Metastatic non-small-cell lung cancer (NSCLC): ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Metastatic non-small-cell lung cancer (NSCLC): ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

Abstract 2904: EGFR-targeted gold liposome for molecular imaging and therapy on NSCLC cells

Abstract Nanotechnologies are in development for monitoring drug delivery and therapeutic effect for cancer. However, tumor-targeted multifunctional nanoparticles for imaging of and therapy of lung cancer are not available. The Epidermal growth factor receptor (EGFR) is overexpressed in approximately 80% of non-small cell lung cancer (NSCLC) and is a target for novel therapeutics, however, the clinical results using EGFR inhibitors for NSCLC treatment had mixed results. These results indicate that EGFR expression or its mutational status is solely not a reliable marker to determine the outcome. Therefore, we have developed liposome (120nm) encapsulated with colloidal gold that are conjugated to therapeutic anti-EGFR antibodies (Katayama Chemical Industries Co. Ltd. Osaka, Japan) to determine the molecular specific imaging of NSCLC. The colloidal gold is used for optical imaging and the anti-EGFR antibody for therapy. In the present study, we investigated in vitro effect of these liposomes on EGFR-expressing (HCC827 and H1299) and EGFR-null (H520) NSCLC cells. EGFR-targeted liposome exhibited a strong antitumor effect on EGFR-expressing NSCLC cells. On the other hands, no significant growth inhibitory effects were observed on non-targeted liposome-treated cells. Intriguingly, treatment with EGFR-targeted liposome resulted in significantly higher cell death as compared with anti-EGFR antibody and liposome alone. Furthermore, reflected polarizing microscopy showed that the concentration of EGFR-targeted liposome bound to EGFR-expressing NSCLC cells increased, but EGFR-null cells did not. When EGFR was inhibited pharmacologically, the binding efficiency of EGFR-targeted liposome was attenuated on EGFR-expressing NSCLC cells. These findings indicate that EGFR-targeted liposome are selectively bound and delivered to EGFR expressing NSCLC cells but not the EGFR-null NSCLC cells. We are currently determining in vivo effect of EGFR-targeted liposome using subcutaneous HCC827 and H520 tumor models. Our findings demonstrated that EGFR-targeted liposome is a promising agent for therapy and molecular imaging of NSCLC. 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 2904. doi:1538-7445.AM2012-2904

EGFR-targeted hybrid plasmonic magnetic nanoparticles synergistically induce autophagy and apoptosis in non-small cell lung cancer cells.

BackgroundThe epidermal growth factor receptor (EGFR) is overexpressed in 80% of non-small cell lung cancer (NSCLC) and is associated with poor survival. In recent years, EGFR-targeted inhibitors have been tested in the clinic for NSCLC. Despite the emergence of novel therapeutics and their application in cancer therapy, the overall survival rate of lung cancer patients remains 15%. To develop more effective therapies for lung cancer we have combined the anti-EGFR antibody (Clone 225) as a molecular therapeutic with hybrid plasmonic magnetic nanoparticles (NP) and tested on non-small cell lung cancer (NSCLC) cells.Methodology/Principal FindingsCell viability was determined by trypan-blue assay. Cellular protein expression was determined by Western blotting. C225-NPs were detected by electron microscopy and confocal microscopy, and EGFR expression using immunocytochemistry. C225-NP exhibited a strong and selective antitumor effect on EGFR-expressing NSCLC cells by inhibiting EGFR-mediated signal transduction and induced autophagy and apoptosis in tumor cells. Optical images showed specificity of interactions between C225-NP and EGFR-expressing NSCLC cells. No binding of C225-NP was observed for EGFR-null NSCLC cells. C225-NP exhibited higher efficiency in induction of cell killing in comparison with the same amount of free C225 antibody in tumor cells with different levels of EGFR expression. Furthermore, in contrast to C225-NP, free C225 antibody did not induce autophagy in cells. However, the therapeutic efficacy of C225-NP gradually approached the level of free antibodies as the amount of C225 antibody conjugated per nanoparticle was decreased. Finally, attaching C225 to NP was important for producing the enhanced tumor cell killing as addition of mixture of free C225 and NP did not demonstrate the same degree of cell killing activity.Conclusions/SignificanceWe demonstrated for the first time the molecular mechanism of C225-NP induced cytotoxic effects in lung cancer cells that are not characteristic for free molecular therapeutics thus increasing efficacy of therapy against NSCLC.

Targeted Delivery of Cisplatin to Lung Cancer Using ScFvEGFR-Heparin-Cisplatin Nanoparticles

The clinical application of cis-diamminedichloroplatinum(II) (DDP, cisplatin) for cancer therapy is limited by its nonspecific biodistribution and severe side effects. Here, we have developed EGFR-targeted heparin-DDP (EHDDP) nanoparticles for tumor-targeted delivery of DDP. This nanoparticle delivery system possesses the following unique properties: (i) succinic anhydride-modified heparin is biocompatible and biodegradable with no anticoagulant activity; (ii) single-chain variable fragment anti-EGFR antibody (ScFvEGFR) was conjugated to the nanoparticles as an EGFR-targeting ligand. Our results showed that EHDDP nanoparticles can significantly increase the intracellular concentrations of DDP and Pt-DNA adducts in EGFR-expressing non-small cell lung cancer H292 cells via an EGFR-mediated pathway. Compared to the free DDP, significantly prolonged blood circulation time and improved pharmacokinetics and biodistribution of Pt were observed after systemic delivery of the EHDDP nanoparticles. The new EHDDP nanoparticle delivery system significantly enhanced antitumor activity of DDP without weight loss or damage to the kidney and spleen in nude mice bearing H292 cell tumors.

Differential induction of antibody-dependent cellular cytotoxicity (ADCC) against human EGFR-expressing NSCLC cell lines by necitumumab, cetuximab, and panitumumab.

e21075 Background: Necitumumab, cetuximab and panitumumab are monoclonal antibodies specific for human epidermal growth factor receptor (EGFR). They act as functional antagonists by blocking ligand binding (EGF and TGFa) to EGFR and inhibit EGFR activation and downstream signaling in tumor cells. Necitumumab and cetuximab are IgG1 molecules and panitumumab is an IgG2 molecule. Methods: In the present study, we analyzed the binding of all three antibodies to EGFR, human Fc receptors and C1q. We also examined the ability to elicit antibody-dependent cellular cytotoxicity (ADCC) in vitro using non-small cell lung cancer (NSCLC) cells expressing various levels of EGFR. Fc-receptor and C1q binding activity was evaluated by ELISA. ADCC was evaluated with a reporter gene based assay using Jurkat cells or human peripheral blood mononuclear cells (PBMC) from normal donors as effector cells. Results: Necitumumab and cetuximab exhibited similar binding to FcgRIa, FcgRIIa, FcgRIIIa and C1q, whereas no binding activity was observed for panitumumab. Necitumumab and cetuximab induced potent ADCC against NSCLC tumor cells at a concentration as low as 1.0 nM. Interestingly, the extent of ADCC induced by cetuximab and necitumumab correlated with the level of EGFR expression on the cell surface. Panitumumab did not elicit ADCC against EGFR expressing tumor cells, even though panitumumab binding to EGFR was similar to that of necitumumab and cetuximab. Conclusions: Both necitumumab and cetuximab, but not panitumumab, target effector cells to EGFR-expressing NSCLC cells to elicit ADCC, with a magnitude that correlates with EGFR expression level. C1q binding studies suggest the relative abilities of EGFR antibodies to fix complement will parallel results with ADCC.

Abstract 3505: EGFR-targeted hybrid plasmonic magnetic nanoparticles induce autophagy and apoptosis through DNA damage in non-small cell lung cancer cells

Abstract Nanoparticles represent a novel class of agents for cancer treatment. In the present study, we examined the effects of epidermal growth factor receptor (EGFR)-targeted hybrid plasmonic magnetic nanoparticles (NP) on non-small cell lung cancer (NSCLC) cells. The nanoparticles (NP) consisted of a paramagnetic iron core that is surrounded by a gold layer and is functionalized with monoclonal anti-EGFR antibody (C225) or control rabbit IgG antibody (IgG). The nanoparticles were tested against a panel of human lung cancer cells that were mutant (HCC827, H1819), wild-type (H1299) or null (H520) for EGFR and compared to EGFR-positive normal fibroblasts (MRC9, WI38) and normal human bronchial epithelial (NHBE) cells. Treatment of tumor cells with C225-NP resulted in a strong and significant inhibitory effect of cell growth compared to normal cells. C225-NP-mediated inhibitory effect was observed only in EGFR-positive tumor cells (HCC827, H1819, H1299) but not in EGFR-null H520 cells. EGFR-mutant cells (HCC827) were the most sensitive to C225-NP. No significant growth inhibitory effects were observed in IgG-NP-treated cells when compared to untreated cells. Molecular analysis showed C225-NP selectively inhibited phosphorylated p-EGFR protein expression and EGFR-mediated signal transduction resulting in induction of autophagy followed by apoptosis. Autophagy occurred as early as twenty-four hours after treatment with an increase in LC3-II content and autophagic vacuoles observed by Western blotting and electron microscopy respectively. Apoptosis as determined by flow cytometry and Western blotting showed an increase in the number of sub-G1 population cells and cleavage of caspase-3 and PARP in C225-NP-treated cells. Optical images determined by dark-field microscopy showed an increase in the concentration of C225-NP bound to EGFR-expressing NSCLC cells but not EGFR-null NSCLC cells. C225-NP exhibited 2-7 fold higher efficiency in induction of cell killing in comparison with the same amount of free C225 antibody. Free C225 antibody did not induce autophagy in cells. Investigation into how C225-NP but not C225 antibody or NP-alone triggers autophagy and initiates apoptosis showed induction of a DNA damage response as evidenced by the formation of γH2AX foci in C225-NP-treated cells. Minimal to no γH2AX foci were observed in cells that were untreated, treated with C225 antibody or NP-alone or treated with IgG-NP. Our data show that EGFR specific NP selectively induced cytotoxic effects in EGFR-expressing lung cancer cells via a novel cell-death mechanism that is not characteristic of the free antibody thus increasing efficacy of therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3505.

Molecular and clinical predictors of outcome for cetuximab in non-small cell lung cancer (NSCLC): Data from the FLEX study

8007 Background: The multinational, randomized, phase III FLEX study compared cisplatin/vinorelbine (CT) plus the EGFR- antibody, cetuximab (Erbitux), with CT alone in the 1st-line treatment of patients (pts) with advanced EGFR-expressing NSCLC and demonstrated a statistically significant OS benefit for the cetuximab combination. We hypothesized that KRAS mutation status is predictive for cetuximab efficacy and enables optimal use of cetuximab. The relationship between early-onset acne-like rash (ie rash that developed ≤21 days of treatment initiation) and OS time of pts treated with CT and cetuximab was also evaluated. Methods: Archived tumor samples from 554/1125 pts were available. Genomic DNA derived from formalin-fixed paraffin embedded tumor tissue was analyzed for KRAS using an LNA-mediated qPCR clamping assay capable of detecting oncogenic mutations at codons 12 and 13. The Kaplan-Meier method was used to estimate OS time and PFS time in pts with KRAS wild-type (wt) and mutant (mt) tumors for each treatment arm. All pts treated with cisplatin/vinorelbine plus cetuximab who were alive at 21 days were included in a landmark analysis evaluating the relationship between early-onset acne-like rash and OS time. Results: KRAS results were obtained from 379 pts. A KRAS mutation was detected in 72 (19%) pts. The comparison of the cetuximab treatment effects in pts with KRAS wt tumors and pts with KRAS mt tumors showed no marked differences with regard to OS or PFS. A total of 518 pts were included in the landmark analysis. Pts treated with cetuximab who developed early acne-like rash of any grade (grade 1–3; 56%, n=290) had a longer median OS than those without acne-like rash (n=228) (median [95% CI]: 15.0 months [12.8–16.4] vs 8.8 months [7.6–11.1]; HR [95% CI]: 0.63 [0.52–0.77]; p<0.001). Analysis of EGFR FISH is ongoing and results will be presented. Conclusions: Clinical data from the FLEX study do not support the hypothesis that KRAS mutation status is predictive for cetuximab efficacy when combined with 1st- line chemotherapy in advanced NSCLC, whereas early acne-like rash of any grade appears to be associated with better outcome in pts treated with platinum-based chemotherapy plus cetuximab in this setting. [Table: see text]

Phase III study comparing cisplatin/vinorelbine plus cetuximab versus cisplatin/vinorelbine as first-line treatment for patients with epidermal growth factor (EGFR)-expressing advanced non-small cell lung cancer (NSCLC) (FLEX)

7109 Background: Cisplatin plus vinorelbine is a commonly used regimen for first-line therapy of advanced NSCLC, achieving response rates of 20–30% and median survival times of 6 to 11 months (mths). An earlier phase II trial investigated cetuximab in combination with cisplatin and vinorelbine in this setting and found improved response rates in the cetuximab arm, warranting this larger phase III trial. Methods: Patients (pts) with EGFR-expressing advanced NSCLC (stage IIIB with documented malignant pleural effusion and stage IV) were randomized 1:1 either to Group A (cetuximab 400 mg/m2 initial dose then 250 mg/m2 weekly, cisplatin 80 mg/m2 on day 1, vinorelbine 30 mg/m2 on day 1 and 8) or to Group B (cisplatin and vinorelbine as before) for a maximum of 6 three-weekly cycles. Cetuximab was administered until progression or unacceptable toxicity. Primary endpoint is overall survival time; secondary endpoints are progression-free-survival, tumor response, disease control, safety, and quality of life. Enrollment of 1,100 pts was planned to show an increase of median survival time of 25% with 90% power. The Data Safety Monitoring Board (DSMB) performed an independent preplanned safety analysis from the first 370 pts. Patients were followed for a minimum of 6 weeks (2 cycles). Results: Since November 2004, 1,037 pts have been randomized, 689 are under treatment, and 348 pts have discontinued the study. Demographics of the first 370 pts reflected known advanced NSCLC characteristics: 91% stage IV, median age 60 yrs (31–79), 38% female, 80% ECOG PS 0/1, 52% adenocarcinoma, 30% squamous cell carcinoma; 29% never-smokers, 17% Asian. The ten most frequent adverse events were: nausea, neutropenia, vomiting, anorexia, fatigue, constipation, anemia, febrile neutropenia, rash, and diarrhoea. Conclusions: The trial continued after review of all relevant baseline and safety information from the first 370 pts. Recruitment is ongoing. [Table: see text]