Inhibitors In Non-small Cell Lung Cancer Research Articles

Role of FBXW7 in the quiescence of gefitinib-resistant lung cancer stem cells in EGFR-mutant non-small cell lung cancer.

Several recent studies suggest that cancer stem cells (CSCs) are involved in intrinsic resistance to cancer treatment. Maintenance of quiescence is crucial for establishing resistance of CSCs to cancer therapeutics. F-box/WD repeat-containing protein 7 (FBXW7) is a ubiquitin ligase that regulates quiescence by targeting the c-MYC protein for ubiquitination. We previously reported that gefitinib-resistant persisters (GRPs) in EGFR-mutant non-small cell lung cancer (NSCLC) cells highly expressed octamer-binding transcription factor 4 (Oct-4) as well as the lung CSC marker CD133, and they exhibited distinctive features of the CSC phenotype. However, the role of FBXW7 in lung CSCs and their resistance to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors in NSCLC is not fully understood. In this study, we developed GRPs from the two NSCLC cell lines PC9 and HCC827, which express an EGFR exon 19 deletion mutation, by treatment with a high concentration of gefitinib. The GRPs from both PC9 and HCC827 cells expressed high levels of CD133 and FBXW7, but low levels of c-MYC. Cell cycle analysis demonstrated that the majority of GRPs existed in the G0/G1 phase. Knockdown of the FBXW7 gene significantly reduced the cell number of CD133-positive GRPs and reversed the cell population in the G0/G1-phase. We also found that FBXW7 expression in CD133-positive cells was increased and c-MYC expression was decreased in gefitinib-resistant tumors of PC9 cells in mice and in 9 out of 14 tumor specimens from EGFR-mutant NSCLC patients with acquired resistance to gefitinib. These findings suggest that FBXW7 plays a pivotal role in the maintenance of quiescence in gefitinib-resistant lung CSCs in EGFR mutation-positive NSCLC.

P2.04-21 Real World Experience of Immune Checkpoint Inhibitors In NSCLC: Our First 10 Months Experience at Leeds Cancer Centre, UK

Pembrolizumab and Nivolumab are monoclonal antibodies to the PD-1 receptor and have shown significant overall survival(OS) and progression free survival(PFS) in the second line setting compared to chemotherapy in non-small cell lung cancer(NSCLC). Pembrolizumab has shown significant OS and PFS in the first line setting in high PD-1 expressors(>50%). In January 2017, immune checkpoint inhibitors became standard of care in the UK initially in the second line setting and subsequently first line later that year. Studies report fewer treatment-related adverse events in the checkpoint inhibitor arm Vs chemotherapy (10-20% Vs 54%). We report our first 10 months experience with routine use of checkpoint inhibitors in NSCLC at Leeds Cancer Centre(LCC), UK. All patients receiving pembrolizumab and nivolumb between 1/1/17 and 31/10/17 at LCC, UK were included. Retrospective review of medical notes was performed and outcomes recorded including: checkpoint inhibitor received; time to response; OS and treatment-related adverse effects. Kaplan-Meier survival curves were used to assess survival outcomes. Thirty-six patients received checkpoint inhibitors during this period. Median age was 68 years. Eleven patients received first line therapy with a response rate of 90% (n=10). Twenty-five patients received second line therapy with a response rate of 32% (n=8). For the whole cohort, median time to response was 52days. Median time to progression in responding patients was not reached. Median PFS was 152days (95%CI 57-232). Median OS was 467days (95% CI 194-not reached). Pseudoprogression occurred in one patient. Treatment-related adverse effects occurred in 58% (n=21). Of these, 57% (n=12) were non-autoimmune and 43% (n=9) were autoimmune. Grade 3-5 toxicities occurred in 8% (n=3), all were autoimmune mediated on pembrolizumab. In all cases, treatment was stopped. Thirty-one percent (n=11) remain on check-point inhibitors. Overall response rate to immune checkpoint inhibitors in this small cohort was better than reported data in both the first and second line setting (90% Vs 45% and 32% Vs 19% respectively). Time to response was comparable to previous trials (1.7months Vs 2.1months). Median PFS and OS were in keeping with large randomised controlled trials (PFS - 5months Vs 2.3-10.3months and OS - 15months Vs 12.2months). Frequency of treatment-related adverse effects and grade 3-5 effects were lower in this cohort at 58% and 8% respectively, compared to 69-73.4% and 10-26.6% in trials. In conclusion, our initial results in this real world cohort show immune checkpoint inhibitors are a safe, effective treatment in this group of patients.

Safety and tolerability of PD-1/PD-L1 inhibitors in the treatment of non-small cell lung cancer: a meta-analysis of randomized controlled trials.

Significant improvement in survival outcome with the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) inhibitors has been shown in advanced non-small cell lung cancer (NSCLC) patients compared with chemotherapy. However, the full spectrum of toxic events of PD-1/PD-L1 inhibitors was not well characterized. We conducted a comprehensive meta-analysis to state the safety profile of PD-1/PD-L1 inhibitors in NSCLC, and identify the exact incidence and relative risk (RR) of both summary and detailed AEs. Electronic databases (PubMed, EMBASE and the Cochrane library databases) and major conference proceedings were systematically searched for all clinical trials in lung cancer using PD-1/PD-L1 inhibitors. Eligible studies included randomized controlled trials (RCTs) comparing PD-1/PD-L1 inhibitors with chemotherapy in NSCLC patients reporting all-grade (1-4) or high-grade (3-4) AEs [toxic symptoms, hematologic toxicities, and immune-related AEs (irAEs)], treatment discontinuation due to toxicities, or toxic deaths. The pooled incidence, RR, and corresponding 95% confidence interval (CI) of toxicity outcomes were calculated. A total of 4413 patients from 8 RCTs (3 with nivolumab; 2 with atezolizumab, and 3 with pembrolizuma) were included. In terms of summary toxic events, PD-1/PD-L1 inhibitors had a significantly lower risk of any all-grade AEs (66.20 vs. 86.08%; RR 0.77) and high-grade AEs (14.26 vs. 43.53%; RR 0.32), treatment discontinuation (5.94 vs. 13.92%; RR 0.44), and toxic deaths (0.48 vs. 1.12%; RR 0.45) than chemotherapy. With regard to detailed toxic events, the risk of toxic symptoms (including all-grade fatigue, nausea, constipation, diarrhea and peripheral sensory neuropathy; high-grade fatigue, anorexia, diarrhea and peripheral sensory neuropathy) and hematologic toxicities (including all-grade and high-grade neutropenia, thrombocytopenia, and anemia) from PD-1/PD-L1 inhibitors was significantly lower than from chemotherapy. However, there was a small but significantly increased risk of irAEs, including all-grade rash, pruritus, colitis, hypothyroidism, hyperthyroidism, ALT/AST elevations and pneumonitis, as well as high-grade pneumonitis. PD-1/PD-L1 inhibitors are generally safer and better tolerated than chemotherapy for patients with NSCLC with regard to summary toxic events, detailed toxic symptoms and hematologic toxicities. However, PD-1/PD-L1 inhibitors can generate a unique spectrum of irAEs, and several of them can be severe and even life-threatening. Clinicians should be aware of the risk of these AEs, as they may have a potentially negative impact on the patients' quality of life and survival outcome.

Abstract 1841: Integrative analysis of resistance to BRAF-targeted therapies in lung adenocarcinomas

Abstract Background: BRAF mutations occur in 2 to 3% of patients (pts) with non-small cell lung cancer (NSCLC). In these pts vemurafenib, a selective oral BRAF inhibitor is associated with a response rate (RR) of 42%, rising to 64% for combination treatment with dabrafenib and trametinib. Despite initial responses, most pts ultimately develop resistance to therapy. Mechanisms of resistance to BRAF inhibitors in NSCLC have only been reported in 2 pts (acquired KRAS G12D and primary resistance due to BRAF G469L) Objective: To assess the molecular mechanisms of resistance and to monitor disease response to treatment using liquid biopsies in NSCLC pts treated with BRAF inhibitors. Strategy: We performed a longitudinal genomic analysis of circulating-tumor DNA (ctDNA) in BRAF-mutated NSCLC pts treated in the AcSé vemurafenib program (NCT02304809) (n=44), or with the combination of dabrafenib and trametinib (n=6). We have collected 24 samples at baseline, 45 during follow-up and 9 at progressive disease (PD). ctDNA genotyping of 36 genes was performed using the Inivata InVisionFirst™ assay. Functional analyses of potentially resistant mutations and in vitro strategies to revert the resistant phenotype are ongoing. Results: Our preliminary analyses showed that BRAF mutations were detected at diagnosis in 16/24 pts, including 12 BRAF V600E mutations and 4 non-V600E mutations (i.e. G466V, G596R, G469A and K601E). 4/12 (34%) of BRAF V600E-mutated pts presented coexistent mutations, in FGFR2, CTNNB1, IDH1 or PI3KCA, whereas concomitant mutations in KRAS, NRAS or MYC were found in 3/4 (75%) of non-V600E cases. Analyses of response to treatment vs mutational profile will be presented. For the remaining 8/24 pts, TP53 mutations were found in 5 pts in absence of BRAF mutations, and no mutations were detected in 3 pts. Mechanisms of resistance were evaluated in 9 pts. One patient who progressed after 11 months on vemurafenib had MAP2K1 C121S and NFE2L2 p.31-32:GV/X mutations. In this patient, longitudinal ctDNA profiling revealed agreement between the %AF of BRAF and TP53 mutations and response to treatment, and detectable levels of the BRAF V600E and the MAP2K1 C121S mutations up to 6 months before the clinical confirmation of PD. Acquired PI3KCA H1047R and E545K mutations were seen in two pts, respectively, who progressed after 15 and 7 months of vemurafenib. Finally, a fourth patient who relapsed after 3 months on vemurafenib, presented a KRAS G12C mutation. All 4 cases also presented detectable levels of the BRAF V600E mutation at PD. In 3/8 pts, we detected the BRAF V600E mutation at PD but no other mutations; drivers of resistance may be present in genes outside this panel. ctDNA sequencing data on additional 7 pts at PD will be presented. Conclusion: Our results suggest that ctDNA genotyping might be an informative tool for monitoring disease response and resistance in NSCLC pts treated with BRAF-targeted therapies. Citation Format: Sandra Ortiz-Cuaran, Julien Mazières, Aurélie Swalduz, Washington René Chumbi Flores, Yohan Loriot, Virginie Westeel, Anne Pradines, Claire Tissot, Christelle Clement Duchene, Christine Raynaud, Xavier Quantin, Radj Gervais, Etienne Brain, Isabelle Monnet, Etienne Giroux Leprieur, Séverine Neymarc, Virginie Avrillon, Solène Marteau, Séverine Martinez, Gilles Clapisson, Nathalie Girerd-Chambaz, Celine Mahier, Nathalie Hoog-Labouret, Frank de Kievit, Karen Howarth, Emma Green, Clive Morris, Maurice Pérol, Jean-Yves Blay, Pierre Saintingy. Integrative analysis of resistance to BRAF-targeted therapies in lung adenocarcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1841.

Abstract 3693: Immunologic and clinical implications of polymerase δ (POLD) and Polymerase ϵ (POLE) gene mutations in non-small cell lung cancer (NSCLC)

Abstract POLD1 plays a role in proofreading the polymerase δ complex while POLE encodes the major catalytic and proofreading subunit of the polymerase ϵ complex. Mutations in POLD1 and POLE increase spontaneous somatic mutation rates which have been linked with favorable response to PD-1 inhibitor in NSCLC. However, little is known about its impact on the immune landscape and prognosis. We analyzed genomic, transcriptomic and clinical data from The Cancer Genome Atlas (TCGA) database using cBioPortal of patients with lung adenocarcinoma (ADC, 522 samples) and squamous cell carcinoma (SQCC, 504 samples). We compared patient samples with at least one mutation (M group) in POLD/E family genes (POLD1, POLD2, POLD3, POLD4, POLE, POLE2, POLE3, POLE4) with patient samples without any mutations in above mentioned gene set (N group). The tumor immune landscape was analyzed from RNA-seq z-scores of 812 ‘immune metagene' signatures (Angelova, M. et al, 2015) which were used to predict immune infiltration of 31 distinct immune cells for each tumor sample. POLD family gene mutation frequency was 0.5% (5/1026 samples) while POLE family gene mutation frequency was 2.0% (21/1026 samples). M group showed significantly higher tumor mutational burden (TMB) in both ADC (median mutation count M:475 N:149, t-test p=0.003) and SQCC (median mutation count M: 318 N:218, t-test p=0.01). In ADC, infiltration of activated CD8 T-cells (M:46% N:26%, chi square test p=0.11) and activated CD4 T-cells (M:46% N:29%, chi square test p=0.19) were not significant. In SQCC, M group showed significantly higher infiltration of activated CD8 T-cells (M:54% N:27%, chi square test p=0.03) while infiltration of activated CD4 T-cells (M:46% N:36%, chi square test p=0.44) was not significant. In terms of survival, in ADC, there was significantly worse survival in M group compared to N group (median M:21 N:50 months, log-rank test p<0.001), while in SQCC, there was no significant difference (median M:66 N:62 months, log-rank test p=0.70). This is the first comprehensive report describing the immunologic and clinical implication of POLD/E family gene mutation status in NSCLC. In summary, POLD/E family gene mutation was linked with higher TMB in NSCLC. In adenocarcinoma, mutational status of POLD/E was associated with an unfavorable survival outcome suggesting potential prognostic implications. Citation Format: Young Kwang Chae, Kyunghoon Rhee, Lee Chun Park, Anderson Cho, Sangmin Chang, Taeyeong Ko, Andrew Davis, Manali Bhave, Marcello Cruz, Wadw Iams. Immunologic and clinical implications of polymerase δ (POLD) and Polymerase ϵ (POLE) gene mutations in non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3693.

Diagnosing Lung Cancer: The Complexities of Obtaining a Tissue Diagnosis in the Era of Minimally Invasive and Personalised Medicine.

The role of the respiratory physician in diagnosing lung cancer has increased in complexity over the last 20 years. Adenocarcinoma is now the prevailing histopathological sub-type of non-small cell lung cancer (NSCLC) resulting in more peripheral cancers. Conventional bronchoscopy is often not sufficient to obtain adequate tissue samples for diagnosis. Radiologically guided transthoracic biopsy is a sensitive alternative, but carries significant risks. These limitations have driven the development of complimentary bronchoscopic navigation techniques for peripheral tumour localisation and sampling. Furthermore, linear endobronchial ultrasound with transbronchial needle aspiration (EBUS-TBNA) is increasingly being chosen as the initial diagnostic procedure for those with central lesions and/or radiological evidence of node-positive disease. This technique can diagnose and stage patients in a single, minimally invasive procedure with a diagnostic yield equivalent to that of surgical mediastinoscopy. The success of molecular targeted therapies and immune checkpoint inhibitors in NSCLC has led to the increasing challenge of obtaining adequate specimens for accurate tumour subtyping through minimally invasive procedures. This review discusses the changing epidemiology and treatment landscape of lung cancer and explores the utility of current diagnostic options in obtaining a tissue diagnosis in this new era of precision medicine.

Early prediction of outcomes to PD1 inhibitors in non-small cell lung cancer (NSCLC) using next generation sequencing (NGS) of plasma circulating tumor DNA (ctDNA).

9078Background: Patient selection for PD-1 inhibitors in NSCLC is still based on imperfect screening biomarkers, including PD-L1 tumor expression and tumor mutational burden. We hypothesized that p...

192P KRAS as predictive biomarker of response to checkpoint inhibitors in NSCLC

Background: AntiPD1/antiPDL1-based immunotherapy has changed dramatically the prognosis of non small cell lung cancer (NSCLC)pwith a substantial improvement of overall survival (OS) and even presenting long lasting responses in a subset of patients (pts). Several factors have been associated with the likelihood of better survival, which include the smoking exposure and the presence of KRAS-mutation according to data from randomized clinical trials that compared chemotherapy to these immunotherapeutic (IO) agents. Methods: We have collected all the cases of stage IV NSCLC pts treated with IO agents within our institution form January 2016 to december 2017 with particular interest to pts harbouring KRAS –mutation. We have assessed their clinical outcomes: disease control rate (DCR) Partial response (PR), progression free survival (PFS) and overall survival (OS). Results: 45 patients with advanced NSCLC were treated with anti PD1 or anti PDL1 (Nivolumab 71%, Pembrolizumab 22% and Atezolizumab 7%, respectively) from January 2016 to December 2018 within our Institution. Twenty (44%) pts were identified as Adenocarcinoma with KRAS-mutation. The subgroup included 39% of female, median age of 61 years, and all patients had PS0-1. The immunotherapy (IO) was administered as 1st, 2nd and ≥ 3rd therapy in 7%, 82% et 11% of the 45 pts, respectively: DCR was 74% with 49% PR and in 40% of pts the response lasted ≥12 months. Within the KRAS mutation group (20 pts) the DCR was 83.5% and the PR was 67%. Within this cohort the PFS was 9.5 months and OS was 42 months. At the time of analysis 7/45 pts were still receiving the immunotherapy treatment. Conclusions: Our retrospective analysis has showed that KRAS-mutation pts represent a subgroup of pts that seem to substantially benefit from IO agents in terms of both response rate, PFS and OS. This is in line with the literature and despite the limitations of a retrospective analysis, it confirms the possible strong correlation among KRAS mutation and response to IO. Further prospective studies are warranted to better define the role of KRAS mutation in this context. Legal entity responsible for the study: HUG Funding: Has not received any funding Disclosure: All authors have declared no conflicts of interest.

Estado da Arte dos Doentes com Cancro do Pulmão de Não Pequenas Células: Doença Avançada e Mutação EGFR Positiva

O aparecimento de terapêuticas dirigidas, trouxe na última década uma enorme esperança para os doentes com cancro do pulmão. Os inibidores dos recetores do fator de crescimento epidérmico (EGFR), erlotinib e gefitinib (inibidores de tirosina quinase TKI), estiveram na vanguarda das mudanças da prática de tratamento para doença avançada do cancro do pulmão de não pequenas células (CPNPC), nos últimos 10 anos, com a descoberta de mutações EGFR que conferem sensibilidade a inibidores da tirosina quinase no CPNPC.
 O ano de 2004, marcou o início da era da medicina de precisão para o cancro do pulmão. Os estudos randomizados de fase III investigaram o papel de dois inibidores de EGFR-TKI, gefitinib e erlotinib, como tratamento de primeira linha em comparação com a quimioterapia à base de platina, em doentes com CPNPC doença avançada com mutações de ativação do EGFR.
 Um TKI de segunda geração (afatinib) encontra-se já aprovado pela EMA com a mesma indicação após resultados dos clínicos do Lux Lung 3 e 6. No entanto, os doentes com mutação EGFR positiva, regra geral, progridem após 10-12 meses de tratamento, necessitando de novas opções terapêuticas. Inibidores de 3ª geração entretanto desenvolvidos (dirigidos à mutação de resistência do T790M, e outras, após rebiópsia), demostraram uma notável eficácia, em doentes já tratados e com um perfil de toxicidade ainda menor que os TKI de 1ª e 2ª geração.
 Recebido: 30/05/2016 - Aceite: 03/06/2016

Treatment with PD-1 inhibitors in NSCLC beyond disease progression: Impact on symptoms and cost.

174 Background: Immunotherapy with PD-1 axis inhibitors has become standard of care in the treatment of patients with advanced non-small cell lung cancer (NSCLC), with improved survival and less toxicity than chemotherapy. Response patterns to PD-1 axis inhibitors can be unconventional, including pseudoprogression. Identifying disease progression using RECIST has been challenging. We explored treatment past progression (TPP) with PD-1 inhibitors and its impact on patient symptoms and costs. Methods: Retrospective analysis of consecutive patients with advanced NSCLC that received single agent PD-1 inhibitors at the Princess Margaret Cancer Centre (PMH) between 2013 and 2017. Patient symptom burden was assessed by Edmonton Symptom Assessment Scale (ESAS) at outpatient clinic visits. Drug acquisition costs were calculated using hospital-based costs for the agents used and both actual and fixed dosing recommendations. Results: The study cohort included 89 patients with advanced NSCLC. Median age was 62, half were female and 75% had adenocarcinoma. Most, 70%, developed disease progression during treatment, 19% stopped due to toxicity. Twenty-one patients received TPP (23% of entire cohort, 34% of those with progression). Demographic characteristics except age and baseline symptom scores were similar between groups. Younger patients (p = 0.046), those with lower symptom burden upon RECIST progression (mean ESAS 14.7 vs. 27.2 non-TPP, p = 0.013) and greater symptom improvement from baseline (mean ESAS change -11.7 vs. -2.3 non-TPP, p = 0.11) were more likely to receive TPP. During TPP, only 1 patient achieved tumor response. TPP represented 29% of total treatment costs. This did not vary significantly between weight- based and fixed dosing. However, the costs of treatment of the entire cohort was 23% higher using fixed dosing compared to weight-based. Conclusions: : Treatment with immunotherapy beyond RECIST progression is common in advanced lung cancer, although patient benefit is rare. This can lead to substantial expenditure without clear value for most patients. Better methods for detecting early failure of immunotherapy in advanced NSCLC are needed, to allow patients to switch to more active treatment.

PD-L1 expression testing in non-small cell lung cancer.

In recent years, immunotherapy has revolutionized and changed the standard of care in patients with advanced non-small cell lung cancer (NSCLC). Immune checkpoint inhibitors, fundamentally those that act by blocking the programmed cell death receptor-1 (PD-1) and its ligand the programmed cell death ligand-1 (PD-L1) have emerged as novel treatment strategies in NSCLC, demonstrating undoubted superiority over chemotherapy in terms of efficacy. Several of these immune checkpoint modulators have recently gained regulatory approval for the treatment of advanced NSCLC, such as nivolumab, atezolizumab and pembrolizumab in first-line (only the latter) and second-line settings, and more recently, durvalumab as maintenance after chemoradiotherapy in locally advanced disease. There is consensus that PD-L1 expression on tumor cells predicts responsiveness to PD-1 inhibitors in several tumor types. Hence PD-L1 expression evaluated by immunohistochemistry (IHC) is currently used as a clinical decision-making tool to support the use of checkpoint inhibitors in NSCLC patients. However, the value of PD-L1 as the ‘definitive’ biomarker is controversial as its testing is puzzled by multiple unsolved issues such as the use of different staining platforms and antibodies, the type of cells in which PD-L1 is assessed (tumor versus immune cells), thresholds used for PD-L1-positivity, or the source and timing for sample collection. Therefore, newer biomarkers such as tumor mutation burden and neoantigens as well as biomarkers reflecting host environment (microbiome) or tumor inflamed microenvironment (gene expression signatures) are being explored as more reliable and accurate alternatives to IHC for guiding treatment selection with checkpoint inhibitors in NSCLC.

Tumor Immunology and Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer.

Lung cancer is one of the most commonly diagnosed cancers and the leading cause of cancer-related deaths worldwide. Although progress in the treatment of advanced non-small cell lung cancer (NSCLC) has been made over the past decade, the 5-year survival rate in patients with lung cancer remains only 10%–20%. Obviously, new therapeutic options are required for patients with advanced NSCLC and unmet medical needs. Cancer immunotherapy is an evolving treatment modality that uses a patient's own immune systems to fight cancer. Theoretically, cancer immunotherapy can result in long-term cancer remission and may not cause the same side effects as chemotherapy and radiation. Immuno-oncology has become an important focus of basic research as well as clinical trials for the treatment of NSCLC. Immune checkpoint inhibitors are the most promising approach for cancer immunotherapy and they have become the standard of care for patients with advanced NSCLC. This review summarizes basic tumor immunology and the relevant clinical data on immunotherapeutic approaches, especially immune checkpoint inhibitors in NSCLC.

Oxymatrine inhibits non-small cell lung cancer via suppression of EGFR signaling pathway.

Epidermal growth factor receptor (EGFR) plays a crucial role in human non–small cell lung cancer (NSCLC) tumorigenesis. In this study, oxymatrine was identified as an EGFR signaling pathway inhibitor in NSCLC. Oxymatrine inhibited anchorage‐dependent and independent growth of NSCLC cell lines but had no cytotoxicity in normal lung cells. We found that exposure to oxymatrine not only suppressed the activity of wild‐type EGFR but also inhibited the activation of exon 19 deletion and L858R/T790M mutated EGFR. Flow cytometry analysis suggested that oxymatrine‐induced cell cycle G0/G1 arrest was dependent on EGFR‐Akt signaling. Exogenous overexpression of Myr‐Akt rescued cyclin D1 expression in HCC827 cells. Moreover, oxymatrine prominently suppressed tumor growth in a xenograft mouse model. Thus, oxymatrine appears to be a novel therapeutic agent for NSCLC treatment.

Immune Checkpoint Inhibitors in Advanced-Stage Non-small Cell Lung Cancer.

More than half of non-small cell lung cancer (NSCLC) patients are at an advanced stage at the time of diagnosis, and they have a poor prognosis. Systemic treatment is the basic treatment approach for advanced-stage NSCLC, and chemotherapy and targeted treatments are commonly used based on the molecular characteristics. Although targeted therapies have led to a significant level of improvement in terms of survival, the results are still unsatisfactory. However, considerable attention has been focused to the immunotherapy with recent positive results reported by studies on this field. In this context, a certain portion of clinical studies have shown dramatic results, and these have involved inhibitors developed particularly against the immune checkpoint protein programmed death receptor-1 and its ligand (programmed death ligand-1). This review aims to present the significance of immune checkpoint inhibitors in NSCLC and to summarize the findings of relevant contemporary clinical studies.

MET inhibitors in advanced non-small-cell lung cancer: a meta-analysis and review.

The alterations of MET have been detected in non-small-cell lung cancer (NSCLC). However, survival benefit of MET inhibitors remains controversial. We performed this meta-analysis to evaluate the survival benefit of MET inhibitors combined with an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) or standard chemotherapy in patients with advanced or metastatic NSCLC. A systematic computerized search of the electronic databases was carried out. From seven studies, 2,577 patients were included in the meta-analysis. Compared with patients in the placebo group, patients who received an additional MET inhibitor did not show significantly improved progression-free survival (hazard ration (HR) = 0.92 [95% confidence interval (CI): 0.79–1.08], P = 0.33) and overall survival (HR = 1.0 [95% CI: 0.90–1.11], P = 0.97). In the subgroup analysis, patients with MET-high NSCLC tended to show longer survival when treated with an additional MET inhibitor than those in the placebo group (HR = 0.76, [95% CI: 0.58–1.01], P = 0.06). In conclusion, this meta-analysis indicates that the addition of a MET inhibitor to an EGFR TKI or chemotherapy has no survival benefit over placebo in patients with advanced or metastatic NSCLC. Although patients with MET-high tumor tended to show better survival, further studies to explore more specific biomarkers are warranted to identify ideal candidates for MET inhibitors in NSCLC.

Abstract 4719: MYC expression correlates with PD-L1 expression and related poor clinical outcome in non-small cell lung cancer

Abstract Background: Programmed death-ligand 1 (PD-L1) is widely used biomarker for the response prediction of immune checkpoint inhibitors, but its usefulness has been challenged. MYC, a transcriptional factor which is overexpressed in various cancers, plays critical roles in preventing immune cells from attacking tumor cells by inducing PD-L1 expression. We evaluated that MYC expression is positively related that of PD-L1 in non-small cell lung cancer (NSCLC) clinical specimens and that it has potential as a predictor of response to immune checkpoint inhibitors in NSCLC. Methods: Eighty-four cases who were diagnosed as NSCLC and underwent surgical resection were evaluated by immunohistochemistry (IHC). PD-L1 expression was evaluated by FDA-approved PD-L1, 22C3 PharmDxTM protocol using the Dako Automated Link 48 platform at Clarient Diagnostic Services, Inc (Aliso Viejo, CA, USA). Its expression was determined by using Tumor Proportion Score (TPS), which is the percentage of viable tumor cells showing partial or complete membrane staining. If TPS >= 50% of the viable tumor cells exhibit membrane staining at any intensity, it was considered positive. IHC of MYC was performed using anti-c-MYC antibody [Y69] (ab32072, Abcam, USA) and its expression was evaluated by scoring system using product of nuclear staining intensity and percentage of positive cells. Results: When MYC cDNA was transfected into KRAS-dependent lung cancer cell lines that did not express both MYC and PD-L1, the protein expression and mRNA of PD-L1 were induced in a dose-dependent manner. On the other hands, knockdown of MYC with siRNA inhibited protein expression and mRNA indicating MYC regulates PD-L1 at transcriptional level. Of 84 NSCLC tumor tissues, PD-L1 was expressed in 14 (16.7%) and MYC in 30 (35.7%) cases. Dual positive patients were 9 (10.7%) and dual negative patients were 49 (58.3%). When the relationship between PD-L1 and MYC expression was evaluated, significant positive correlation was observed between PD-L1 and MYC expression (γ=0.267, P=0.014). Dual positive patients showed significantly shorter disease free survival (16.1 vs. 62.5 months, P=0.004) and overall survival (24.9 vs. 70.9 months, P=0.002) than dual negative patients. Conclusion: MYC expression correlates with PD-L1 expression in the NSCLC and the patients with overexpression of both MYC and PD-L1 showed significantly poor survival. This suggest that it is worth of investigation of MYC expression as a surrogate predictive marker for treatment of immune checkpoint inhibitors in NSCLC. Citation Format: Eun Young Kim, Arum Kim, Se Kyu Kim, Yoon Soo Chang. MYC expression correlates with PD-L1 expression and related poor clinical outcome in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4719. doi:10.1158/1538-7445.AM2017-4719

Abstract 1774: Progression-free survival curves suggest a dichotomous determinant of PD-L1 inhibitor efficacy

Abstract Background: PD-L1 expression varies across tumors but does not accurately predict PD-L1 inhibitor efficacy. Some negative tumors respond and some positive tumors fail. PD-L1 inhibitor progression-free survival (PFS) curve shape in non-small cell lung cancer (NSCLC) suggests that a dichotomous (present vs absent) factor might drive sensitivity rather than it being driven by a continuous variable like PD-L1 expression. PFS curves may follow first order kinetics, with a straight line if log % PFS is plotted vs time. If the population had 2 distinct subgroups with differing rates of progression then one would expect an inflection point on the log-linear curve, and the curve would fit a 2-phase decay model in nonlinear regression analysis (NLRA). A more homogeneous population would not fit a 2-phase model. Methods: We used arohatgi.info/WebPlotDigitizer/app/ to digitize published PFS curves, then GraphPad Prism5 for 2-phase NLRA, with the constraints Y0=100, plateau=0. To generate standardized 2-phase curves, we utilized 1) unselected NSCLC patients treated with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) where we expected a high proportion of curves to fit a 2-phase model as only some patients would have a sensitizing EGFR mutation; 2) NSCLC EGFR mutant and wild type (WT) patients treated with EGFR TKIs, and patients treated with platinum-based chemotherapy, taxanes or placebo/best supportive care (BSC), where we expected a lower proportion of curves to fit 2-phase models; 3) PD-L1 PFS curves in NSCLC and other tumor types. Results: With EGFR TKIs in unselected patients, 58 of 79 (73%) curves were fit by 2-phase models, vs 5 of 37 (14%) with EGFR TKIs in EGFR mutant patients (p<0.0001), 13 of 27 (48%) in EGFR WT patients (p<0.02), 4 of 37 (11%) with platinum-based therapy (p<0.0001), 15 of 47 (32%) with a taxane (p<0.0001), and 6 of 22 (27%) with placebo/BSC (p=0.0001). With PD-L1 inhibitors in NSCLC, 30 of 32 (94%) curves fit 2-phase models (p<0.0001 vs each of EGFR TKIs in EGFR mutants, EGFR WTs, platinum and taxane chemotherapy and placebo/BSC). In other tumor types, 27 of 32 (84%) PD-L1 curves fit 2-phase models. Conclusions: Most PD-L1 inhibitor PFS curves fit a 2-phase model. This is similar to what we observed with EGFR TKIs in unselected patients and different from EGFR TKIs in EGFR mutant and WT patients, and from chemotherapy or placebo/BSC. This leads us to hypothesize the existence of a dichotomous (present vs absent) factor such as a gene mutation, deletion or silencing that sensitizes tumors to PD-1/PD-L1 inhibitors. If found, such a dichotomous factor could prove to be a highly useful biomarker that could permit accurate prediction of PD-1/PD-L1 inhibitor efficacy. Since PD-1/PD-L1 inhibitor efficacy is higher in tumors with high PD-L1 expression, any sensitizing dichotomous factor might also drive PD-L1 expression. Citation Format: David J. Stewart, Dominick Bosse, Stephanie Brule, Andrew G. Robinson, Michael Ong, John F. Hilton. Progression-free survival curves suggest a dichotomous determinant of PD-L1 inhibitor efficacy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1774. doi:10.1158/1538-7445.AM2017-1774

Therapeutic value of EGFR inhibition in CRC and NSCLC: 15 years of clinical evidence

Epidermal growth factor receptor (EGFR) plays a key role in tumour evolution, proliferation and immune evasion, and is one of the most important targets for biological therapy, especially for non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC). In the past 15 years, several EGFR antagonists have been approved for the treatment of NSCLC and metastatic CRC (mCRC). To optimise the use of anti-EGFR agents in clinical practice, various clinical and molecular biomarkers have been investigated, thus moving their indication from unselected to selected populations. Nowadays, anti-EGFR drugs represent a gold-standard therapy for metastatic NSCLC harbouring EGFR activating mutation and for RAS wild-type mCRC. Their clinical efficacy is limited by the presence of intrinsic resistance or the onset of acquired resistance. In this review, we provide an overview of the antitumour activity of EGFR inhibitors in NSCLC and CRC and of mechanisms of resistance, focusing on the development of a personalised approach through 15 years of preclinical and clinical research.

Overcoming Resistance to EGFR Inhibitors in NSCLC.

The clarification of several molecular pathways underlying the tumorigenesis has led to the development of several targeted drugs that have substantially improved the treatment of Non-Small-Cell Lung Cancer (NSCLC). The Epidermal Growth Factor Receptor (EGFR) is the target of several Tyrosine-Kinase Inhibitors (TKIs), some of them approved for treatment and others currently in clinical development. EGFR-TKIs markedly improve progression-free survival of patients with advanced NSCLC with EGFR mutations compared with chemotherapy. We undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question. Although first- and second-generation agents offer in target population (with EGFR mutations) a substantial improvement of outcomes compared with standard chemotherapy, unfortunately, drug resistance develops after initial benefit, through a variety of mechanisms. Novel- (third) generation EGFR inhibitors have a selective mechanism of action and are currently in advanced clinical development, producing encouraging results in patients with acquired resistance to previous generation agents. The search for new drugs or strategies to overcome the TKI resistance in patients with EGFR mutations is to be considered a priority for the improvement of outcomes in the treatment of advanced NSCLC, and third-generation EGFR inhibitors are the most promising approach to the issue.

Elucidation of Resistance Mechanisms to Second-Generation ALK Inhibitors Alectinib and Ceritinib in Non–Small Cell Lung Cancer Cells

Crizotinib is the first anaplastic lymphoma kinase (ALK) inhibitor to have been approved for the treatment of non–small cell lung cancer (NSCLC) harboring an ALK fusion gene, but it has been found that, in the clinic, patients develop resistance to it. Alectinib and ceritinib are second-generation ALK inhibitors which show remarkable clinical responses in both crizotinib-naive and crizotinib-resistant NSCLC patients harboring an ALK fusion gene. Despite their impressive activity, clinical resistance to alectinib and ceritinib has also emerged. In the current study, we elucidated the resistance mechanisms to these second-generation ALK inhibitors in the H3122 NSCLC cell line harboring the EML4-ALK variant 1 fusion in vitro. Prolonged treatment of the parental H3122 cells with alectinib and ceritinib led to two cell lines which are 10 times less sensitive to alectinib and ceritinib than the parental H3122 cell line. Although mutations of ALK in its kinase domain are a common resistance mechanism for crizotinib, we did not detect any ALK mutation in these resistant cell lines. Rather, overexpression of phospho-ALK and alternative receptor tyrosine kinases such as phospho-EGFR, phospho-HER3, and phospho-IGFR-1R was observed in both resistant cell lines. Additionally, NRG1, a ligand for HER3, is upregulated and responsible for resistance by activating the EGFR family pathways through the NRG1-HER3-EGFR axis. Combination treatment with EGFR inhibitors, in particular afatinib, was shown to be effective at overcoming resistance. Our study provides new mechanistic insights into adaptive resistance to second-generation ALK inhibitors and suggests a potential clinical strategy to combat resistance to these second-generation ALK inhibitors in NSCLC.