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Immunotherapy; Lung neoplasms; Tumor biomarkers Immunoteràpia; Càncer de pulmó; Biomarcadors tumorals Inmunoterapia; Cáncer de pulmón; Biomarcadores tumorales Background Immune checkpoint inhibitors (ICIs) targeting the programmed cell death 1/programmed death-ligand 1 axis have transformed the management of advanced non-small cell lung cancer (NSCLC). However, many patients do not benefit from this type of treatment, and thus several molecular biomarkers of benefit have been explored. The value of somatic copy number alterations (SCNAs) burden remains elusive. Patients and methods We assembled a cohort of 109 patients with NSCLC treated with ICIs and available tumor samples. We performed shallow whole-genome sequencing on 89 patients to determine genome-wide SCNAs and targeted gene expression analysis on 63 patients to study immune infiltration. We analyzed SCNAs burden in different ways (ie, the fraction of the genome altered or number of events) and studied their association with ICIs benefit based on survival analysis. We correlated SCNAs burden and immune infiltration on 35 patients of our cohort and on patients with lung adenocarcinoma from The Cancer Genome Atlas (TCGA). Results High SCNAs burden, computed in diverse ways, is negatively associated with ICIs progression-free survival (PFS), with the fraction of the genome altered (FGA) by arm and chromosome events showing the strongest association with PFS (p=0.002) (n=77). Nevertheless, we found differences in SCNAs across some clinicopathological features (sample site origin). A multivariate analysis adjusted for relevant characteristics showed that the FGA of arm and chromosome alterations was strongly associated with PFS (HR=2.21, p=3.3 x 10−5). Finally, we confirmed that SCNAs burden negatively correlates with tumor immune infiltration (n=35), although this correlation was not found for the males studied. Similar results were observed in the TCGA cohort. Conclusions SCNAs burden is a potential biomarker of benefit to ICIs in patients with NSCLC, although there appear to be some nuances worth consideration. Further studies will be needed to establish its role as a biomarker of benefit to ICIs. This work was supported by Merck Healthcare KGaA, Darmstadt, Germany (Grant for Oncology Innovation to the Vall d’Hebron Institute of Oncology (VHIO), Barcelona, Spain), Fundación Cientifica Asociación Española Contra el Cancer-AECC (grant number GCB14142170 to EF); the Catalan Government/AGAUR (2017–SGR–1738 to EF). Merck Healthcare KGaA reviewed the manuscript for medical accuracy only before journal submission.

BackgroundMalignant pleural mesothelioma (MPM) is an aggressive malignancy without curative treatment. Standard of care (SOC) include pemetrexed/cisplatin and nivolumab/ipilimumab with median overall survival in unresectable disease of 12.1 months and 18.1 months respectively.1 2 ONCOS-102 is a granulocyte-macrophage colony stimulating factor (GM-CSF) expressing oncolytic adenovirus (Ad5/3-D24-GMCSF) with a unique ability to both prime and boost immune responses. The aim of the study was to assess efficacy and safety of ONCOS-102 in combination with SOC chemotherapy in 1st and 2nd line unresectable MPM.MethodsTwenty patients (experimental arm) were allocated to receive ONCOS-102 given intratumorally under CT or US guidance at a dose of 3 x 1011 VP on Day 1, 4, 8, 36, 78 and 120 plus six cycles of SOC starting on Day 22. Eleven patients (control group) received SOC. Imaging was done at baseline, Day 43–64 and 127–148 with regular monitoring of blood and biopsy based immune markers. Primary objective was safety and tolerability. Secondary objectives were ORR, PFS and OS as well as immunological activation. An analysis of 24 month survival data compared randomised only patients excluding six patients in the single-arm safety lead-in.Results24-month survival rate for 1st line pts was 50% in the experimental group and 0% in the control group with mOS of 25.0 months and 13.5 months respectively (N.S). Based on censoring, mOS in the experimental group will be within 21.9 – 25.0 months range. mOS across both 1st and 2nd line was 19.3 and 18.3 months for experimental and control patients (N.S). mPFS was 9.8 months in the experimental group and 7.6 in the control group (N.S.).ConclusionsThe survival rate of patients receiving ONCOS-102 in combination with SOC was seen to be numerically higher than previously reported for SOC or nivolumab/ipilimumab. Improved survival was associated with ONCOS-102 induced immune activation with a favourable TME modulation providing scientific rationale for combination with check point inhibition.Trial RegistrationClinicalTrials.gov NCT02879669ReferencesVogelzang, et al, Phase III study of pemetrexed in combination with cisplatin versus cisplatin alone in patients with malignant pleural mesothelioma. J Clin Oncol 2003;21: 2636–44.Baas P, et al, First-line nivolumab plus ipilimumab in unresectable pleural mesothelioma (CheckMate 743): a multicentre, randomised, open-label, phase 3 trial. The Lancet 2021; 397: 375–386.Ethics ApprovalThis study was approved by the IRBs of all the participating sites in Madrid, Barcelona, Rennes and Poitiers.

Background Tumour heterogeneity impacts the efficacy of metastatic cancer treatment even if actionable mutations are identified. Clinicians need to understand if assessing one lesion provides reliable information to drive a therapeutic decision in non-small-cell lung cancer (NSCLC) patients. Methods We analysed inter-tumour heterogeneity from five autopsied individuals with NSCLC-harbouring mutations in the epidermal growth factor receptor (EGFR), treated with EGFR tyrosine kinase inhibitors (TKIs). Through a comprehensive next-generation sequencing (NGS) oncopanel, and an EGFR panel for digital droplet PCR (ddPCR), we compared metastases within individuals, longitudinal biopsies from the same lesions and, whenever possible, the primary naive tumour. Results Analysis of 22 necropsies from five patients revealed homogeneity in pathogenic mutations and TKI-resistance mechanisms within each patient in four of them. In-depth analysis by whole-exome sequencing from patient 1 confirmed homogeneity in clonal mutations, but heterogeneity in passenger subclonal alterations. Different resistance mechanisms were detected depending on the patient and line of treatment. Three patients treated with a c-MET inhibitor in combination with TKI lost MET amplification upon progression. Conclusion At a given point and under selective TKI pressure, a single metastasis biopsy in disseminated tumours from EGFR-mutated NSCLC patients could provide a reasonable assessment of actionable alterations useful for therapeutic decisions.

Immune checkpoint inhibitors (ICIs) have transformed non-small cell lung cancer (NSCLC) treatment. Unfortunately, only some patients benefit from these therapies. Thus, certain clinicopathological characteristics of the patients have been proposed as biomarkers of ICIs response. We assembled a retrospective cohort of 262 NSCLC patients treated with ICIs, compiled relevant clinicopathological characteristics, and studied their associations with treatment outcome using Cox proportional-hazards survival models. Additionally, we investigated the interrelations between clinicopathological features and devised a method to create a compendium associated with ICIs response by selecting those that provide non-redundant information. In multivariate analyses, ECOG performance status (hazard ratio (HR) 1.37 (95% CI 1.11 to 1.68), p &lt, 0.005), LDH (HR 1.24 (95% CI 1.03 to 1.48), p = 0.02)) and PD-L1 negativity were associated with decreased PFS (HR 1.92 (95% CI 1.03 to 3.58), p &lt, 0.04), whereas presentation of immune-related adverse events (irAEs) (HR 0.35 (95% CI 0.22 to 0.55, p &lt, 0.005) or females (HR 0.52 (95% CI 0.33 to 0.80, p &lt, 0.005) had longer progression-free survival. Additionally, numerous clinicopathological indicators were found to be interrelated. Thus, we searched for features that provide non-redundant information, and found the combination of LDH levels, irAEs, and gender to have a better association with ICIs treatment response (cross-validated c-index = 0.66). We concluded that several clinicopathological features showed prognostic value in our real-world cohort. However, some are interrelated, and compendiums of features should therefore consider these interactions. Joint assessment of LDH, irAEs, and gender may be a good prognostic compendium.

Mesothelioma is a rare and aggressive tumour with dismal prognosis arising in the pleura and associated with asbestos exposure. Its incidence is on the rise worldwide. In selected patients with early-stage MPM, a maximal surgical cytoreduction in combination with additional antitumour treatment may be considered in selected patients assessed by a multidisciplinary tumor board. In patients with unresectable or advanced MPM, chemotherapy with platinum plus pemetrexed is the standard of care. Currently, no standard salvage therapy has been approved yet, but second-line chemotherapy with vinorelbine or gemcitabine is commonly used. Novel therapeutic approaches based on dual immunotherapy or chemotherapy plus immunotherapy demonstrated promising survival benefit and will probably be incorporated in the future., E. Nadal thanks the support of Health Institute Carlos III-FEDER (ISCIII) [PI14/01109 and PI18/00920].

Background Malignant pleural mesothelioma (MPM) is a rare and aggressive tumour. For patients with inoperable disease, few treatment options are available after first line chemotherapy. The combination of ipilimumab and nivolumab has recently shown increased survival compared to standard chemotherapy, but most patients do not respond and improvements are called for. Telomerase is expressed in mesothelioma cells, but only sparsely in normal tissues and is therefore an attractive target for therapeutic vaccination. Vaccination against telomerase is tolerable and has shown to induce immune responses associated with increased survival in other cancer types. There is a well-founded scientific rationale for the combination of a telomerase vaccine and checkpoint inhibition to improve treatment response in MPM patients. Methods NIPU is a randomized, multi-centre, open-label, phase II study comparing the efficacy and safety of nivolumab and ipilimumab with or without telomerase vaccine in patients with inoperable malignant pleural mesothelioma after first-line platinum-based chemotherapy. Participants (n = 118) are randomized 1:1 into two treatment arms. All participants receive treatment with nivolumab (240 mg every 2 weeks) and ipilimumab (1 mg/kg every 6 weeks) until disease progression, unacceptable toxicity or for a maximum of 2 years. Patients randomised to the experimental arm receive 8 intradermal injections of UV1 vaccine during the first three months of treatment. Tumour tissue, blood, urine, faeces and imaging will be collected for biomarker analyses and exploration of mechanisms for response and resistance to therapy. Discussion Checkpoint inhibition is used for treatment of mesothelioma, but many patients still do not respond. Increasing therapy response to immunotherapy is an important goal. Possible approaches include combination with chemotherapy, radiotherapy, targeted therapy and other immunotherapeutic agents. Predictive biomarkers are necessary to ensure optimal treatment for each patient and to prevent unnecessary side effects. This trial seeks to improve treatment response by combining checkpoint inhibition with a telomerase vaccine and also to explore mechanisms for treatment response and resistance. Knowledge gained in the NIPU study may be transferred to the first line setting and to other cancers with limited benefit from immunotherapy. Trial registration: ClinicalTrials.gov: NCT04300244, registered March 8th, 2020, https://clinicaltrials.gov/ct2/show/NCT04300244?term=NIPU&draw=2&rank=1.

8561 Background: MPM is an aggressive malignancy without curative treatment. ONCOS-102 is an oncolytic adenovirus expressing GM-CSF (Ad5/3-D24-GMCSF) with a clinically documented ability to stimulate local and systemic immune responses and re-modulate the tumor microenvironment, both as a monotherapy and in combination with anti-PD1 blockade. The study objectives included determining safety and tolerability, efficacy and immunological activation in repeat tumor biopsies, and correlations with clinical outcomes. Methods: Following a safety run-in of n = 6 pts, 25 patients were randomized to receive ONCOS-102 intratumorally under CT or US guidance at a dose of 3 x 1011 Virus Particles on Day 1, 4, 8, 36, 78 and 120, plus six cycles of P/C starting on Day 22, or control comprising six cycles of P/C only. Both treatment-naïve (1L) and previously treated patients (2L) were enrolled. Imaging was done at baseline, Day 43-64 and 127-148 and tumor biopsy were collected at baseline and at Day 36. Final survival analysis (n = 25) was performed after 30 mo follow up. Multiplex immunofluorescence for immune cell subsets, RNASeq and qPCR was performed on repeat tumor samples. Results: The most frequent adverse events were anaemia, neutropenia and asthenia reported by > 50% in both groups with more frequent reports of pyrexia and nausea in the experimental (exp) group. No difference in the rate of severe events (Gr 3/4 acc to NCI CTCAE vs 4.0) were observed. 30-month survival rate (n = 25) was 34.3 % vs 18.2 % (NS) with mOS of 19.3 mo (95% CI: 4.6, NA) vs 18.3 mo (95% CI: 3.1, 28.9) in the exp group vs control. For patients treated in the 1L setting, 30 mo survival was 33.3 % in the exp group (n = 8) and 0% in the control group (n = 6) with mOS of 25.0 months and 13.5 months, respectively (NS). mPFS was unchanged from prior cut-offs; 9.8 months in the exp group and 7.6 in the control (NS). ONCOS-102 + P/C induced a pronounced increase in tumor infiltration by CD4+, CD8+ and granzyme B expressing CD8+ T-cells as well as M1:M2 macrophage polarization in patients with disease control (n = 13) vs progressing patients (n = 3). The data from RNAseq and qPCR analysis will be presented. Conclusions: The addition of ONCOS-102 to P/C was well tolerated by MPM patients and resulted in numerically improved 30-month survival rate in the overall population, and improved mOS in chemotherapy-naïve patients, albeit not statistically significant. Substantial immunological activation in tumor associated with ONCOS-102 was demonstrated, correlating with clinical benefit. Further exploration of ONCOS-102 as a treatment option in MPM is warranted Clinical trial information: NCT02879669.

e20595 Background: MPM is an aggressive cancer associated with asbestos exposure. Chemotherapy has been a mainstay of therapy and recently immunotherapy has been associated with survival improvements. Chemotherapy and immunotherapy influence the tumor microenvironment and some reports have shown increased of TIL after chemotherapy in MPM. The purpose of this study was to determine dynamic changes in the tumor immune environment during mesothelioma evolution and after systemic therapies in paired samples. Methods: We examined 20 matched formalin-fixed paraffin embedded tissue samples from 10 patients (p) with MPM taken at diagnosis and at disease progression (follow-up), including untreated and treated with chemotherapy or immunotherapy. Tissue densities (number of cells/mm2) of key immune effector cells such as total lymphocytes (CD3), cytotoxic T cells (CD8), regulatory T cells (FOXP3) and monocytes/macrophages (CD163) were quantified by image analysis using multiplexed immunohistochemistry (IHC). PD-L1 expression in both tumor cells and immune cells was analysed by singleplex IHC and quantified using the CPS score. Results: Median age was 62 years (range 53-84), 7 p were male and all p presented epithelioid histology. Three matched samples belong to patients that did not receive any systemic treatment between biopsies and the other 7 pair of samples belong to patients treated with chemotherapy +/- immunotherapy. The median interval between paired biopsies was 12 m (3-33 m). Median overall survival was 27.8 months (1 m-NR). Median densities of T cells and macrophages in diagnostic and matched follow-up samples were: CD3+:982 vs 712; CD8+:422 vs 334, FOXP3+: 22 vs 25 and CD163+: 2086 vs 1706. Median PD-L1 CPS was 2.5 and 4 in diagnostic and follow-up samples, respectively. In p receiving treatment between sample pairs, the median densities in diagnostic and follow-up matched samples were: CD3+:979 vs 407; CD8+:467 vs 225, FOXP3+: 25 vs 15, CD163+: 1583 vs 1508, and PD-L1: 2 and 1. In p without any systemic treatment between sample pairs, the median densities were CD3+:1645 vs 2397; CD8+:376 vs 1605, FOXP3+: 19 vs 121, CD163+: 2102 vs 2377, and PD-L1: 3 vs 25. Conclusions: In our small series with paired samples from MPM p, we observed immune cells infiltration changes during MPM evolution with a trend towards a decrease after systemic therapy. Further investigation in tumor microenvironment in MPM to define the most appropriate time for immunotherapy is needed.

Background Malignant pleural mesothelioma (MPM) is a rare, aggressive malignancy without curative treatment. Majority of patients receive pemetrexed/cisplatin as standard of care (SoC). Median overall survival in unresectable disease is 12 months. ONCOS-102 is a granulocyte-macrophage colony stimulating factor (GM-CSF) expressing oncolytic adenovirus (Ad5/3-D24-GMCSF) with a unique ability to both prime and boost immune responses. The aim of the study was to assess immune and clinical responses as well as safety in patients with 1st and 2nd line unresectable MPM. Methods Eligible patients (experimental arm, n=20) received ONCOS-102 given intratumorally under CT or US guidance at a dose of 3 × 10 × 11 on Day 1, 4, 8, 36, 78 and 120 plus six cycles of SoC starting on Day 22. The control group (n=11) received only SoC. Imaging was done at baseline, Day 43–64 and 127–148. Patients were monitored regularly for immunological assessment including lesional biopsies (baseline and Day 36). Primary objective was safety and tolerability. Secondary objectives were immunological activation, ORR, PFS and OS as well as correlation between immunological activation and clinical outcome. Results There were no safety concerns nor DLTs. In 1st line patients ORR/DCR was 30%/90% in the experimental group and 33%/83% in the control group. 2nd line patients had ORR/DCR of 11%/67% in the experimental group and 60%/80% in the control group. 12-month survival rate for the 1st line pts was 64% in the experimental group and 50% in the control group. PFS and OS are still to be reported. The treatment with ONCOS-102 induced strong upregulation of multiple genes associated with immune activation in tumor lesions. Profound innate and adaptive immune activation was observed in the experimental vs control group that was associated with better clinical outcome. In addition to an increase in intra-tumoral cytotoxic T-cells (10/15 pts), the treatment with ONCOS-102 resulted in polarization from M2 to M1 macrophages. An upregulation of PD-L1 was reported in 9/15 pts in the experimental group vs 2/5 pts in the control arm, highlighting the potential of ONCOS-102 as an immunosensitizing agent for combinatory therapies with checkpoint inhibitors. Conclusions ONCOS-102 treated patients benefited from superior immune activation compared to patients receiving SoC with preliminary signals of clinical efficacy. Upregulation of adaptive immunity and cytotoxicity related gene expression, PD-L1 level and M2 to M1 macrophage polarization indicate that ONCOS-102 can induce a favourable TME modulation thus providing a scientific rationale for combination with check point inhibition. Trial Registration ClinicalTrials. gov NCT02879669 Ethics Approval This study was approved by the IRBs of all the sites in Madrid, Barcelona, Rennes and Poitiers.

Introduction Uncommon epidermal growth factor receptor (EGFR) mutations (u-EGFRm) are a heterogeneous group of molecular alterations and have also been reported as comutations with other EGFR mutations (complex mutations) in non–small-cell lung cancer (NSCLC). Afatinib has shown activity against some u-EGFRm, and we examined its efficacy in Spanish clinical practice. Patients and Methods Data of 67 patients with advanced NSCLC with u-EGFRm treated with afatinib between 2012 and 2017 at 23 Spanish institutions were reviewed. u-EGFRm were analyzed as complex mutations (group A), EGFR exon 20 insertions (ins20; group B), or single mutations (group C). Efficacy was evaluated in terms of overall survival (OS) and tumor response. Results Group A complex u-EGFRm consisted of double mutations of G719X+E709F, G719X+S768I, G719X+L861Q, L858R+T790M, L858R+S768I, L858R+S765I, del19+S768I, del19+L747S, or R776C+L861Q. No differences in clinical characteristics were found between groups A (n = 20), B (n = 23), and C (n = 24). Afatinib was administered as first-line therapy in 80% of patients. Median time of receipt of therapy was 4.2 months (range, 2.0–12.9 months). Median OS for the entire cohort was 19.9 months (95% confidence interval, 9.7, 30.1). Hazard ratios for OS were 0.26 (95% confidence interval, 0.10, 0.71; P = .008) and 0.40 (95% confidence interval, 0.17, 0.95; P = .037) for groups A and C compared to B, respectively. Response was significantly higher in groups A (70%) and C (54%) compared to B (13%; pairwise comparison P Conclusion In clinical practice, afatinib was active in patients with u-EGFRm NSCLC, particularly in complex and single mutations. Further strategies are needed for patients with ins20, a subgroup u-EGFRm with a lower clinical benefit with afatinib.

Cáncer de pulmón; Inmunoterapia Càncer de pulmó; Immunoteràpia Lung cancer; Immunotherapy

Heat shock proteins (HSPs) are molecular chaperones that maintain proteins in their correct conformation to ensure stability and protect carcinoma cells from apoptosis. HSP90 inhibitors (HSP90i) block multiple targets simultaneously, and despite responses in a selected population, no HSP90i have yet been approved. We present a patient with a lung tumor with an exceptional response to cisplatin/gemcitabine in combination with HSP90i, which nowadays continues with HSP90i maintenance after three years. Whole-exome sequencing of the lung tumor unveiled a BRCA1/2 deficiency mutational signature, and mutation analysis confirmed a germline BRCA1 mutation. The striking efficacy of HSP90i plus chemotherapy vs chemotherapy alone was reproduced in a patient-derived xenograft (PDX) model from a breast cancer patient with a BRCA1 mutation (mean tumor volume [SD], No. of tumors: vehicle 8.38 [7.07] mm3, n = 3; HSP90i 4.18 [1.93] mm3, n = 5; cisplatin plus gemcitabine 3.31 [1.95] mm3, n = 5; cisplatin plus gemcitabine plus HSP90i 0.065 [0.076] mm3, n = 6). This case and the PDX demonstrate the efficacy for therapeutic inhibition of HSP90 in a BRCA-mutated patient, opening a new potential avenue for better identifying patients who might benefit most from HSP90i.

Antibody targeting of the immune checkpoint receptor PD1 produces therapeutic activity in a variety of solid tumors, but most patients exhibit partial or complete resistance to treatment for reasons that are unclear. In this study, we evaluated tumor specimens from 65 patients with melanoma, lung nonsquamous, squamous cell lung or head and neck cancers who were treated with the approved PD1-targeting antibodies pembrolizumab or nivolumab. Tumor RNA before anti-PD1 therapy was analyzed on the nCounter system using the PanCancer 730-Immune Panel, and we identified 23 immune-related genes or signatures linked to response and progression-free survival (PFS). In addition, we evaluated intra- and interbiopsy variability of PD1, PD-L1, CD8A, and CD4 mRNAs and their relationship with tumor-infiltrating lymphocytes (TIL) and PD-L1 IHC expression. Among the biomarkers examined, PD1 gene expression along with 12 signatures tracking CD8 and CD4 T-cell activation, natural killer cells, and IFN activation associated significantly with nonprogressive disease and PFS. These associations were independent of sample timing, drug used, or cancer type. TIL correlated moderately (∼0.50) with PD1 and CD8A mRNA levels and weakly (∼0.35) with CD4 and PD-L1. IHC expression of PD-L1 correlated strongly with PD-L1 (0.90), moderately with CD4 and CD8A, and weakly with PD1. Reproducibility of gene expression in intra- and interbiopsy specimens was very high (total SD

Immune checkpoint inhibitors are considered standard second-line treatment in advanced non-small cell lung cancer patients. This strategy has also become standard in first-line setting for a subgroup of patients with strongly positive PD-L1 tumors; therefore, PD-L1 status might be considered a new biomarker that deserves upfront testing. New combinations of immune checkpoint inhibitors and with chemotherapy have been tested in first-line treatment. However, some questions remain unanswered such as the best treatment strategy or the real upfront efficacy of these therapeutic strategies in the whole lung cancer population. In this review we summarize the main results in the first-line setting of recent phase III trials with immune checkpoint inhibitors in advanced non-small cell lung cancer patients.

New therapeutic strategies for malignant mesothelioma are urgently needed. In the DETERMINE study, we investigated the effects of the cytotoxic-T-lymphocyte-associated antigen 4 (CTLA-4) monoclonal antibody tremelimumab in patients with previously treated advanced malignant mesothelioma.DETERMINE was a double-blind, placebo-controlled, phase 2b trial done at 105 study centres across 19 countries in patients with unresectable pleural or peritoneal malignant mesothelioma who had progressed after one or two previous systemic treatments for advanced disease. Eligible patients were aged 18 years or older with Eastern Cooperative Oncology Group performance status of 0 or 1 and measurable disease as defined in the modified Response Evaluation Criteria In Solid Tumors (RECIST) version 1.0 for pleural mesothelioma or RECIST version 1.1 for peritoneal mesothelioma. Patients were randomly assigned (2:1) in blocks of three, stratified by European Organisation for Research and Treatment of Cancer status (low risk vs high risk), line of therapy (second line vs third line), and anatomic site (pleural vs peritoneal), by use of an interactive voice or web system, to receive intravenous tremelimumab (10 mg/kg) or placebo every 4 weeks for 7 doses and every 12 weeks thereafter until a treatment discontinuation criterion was met. The primary endpoint was overall survival in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of study drug. The trial is ongoing but no longer recruiting participants, and is registered with ClinicalTrials.gov, number NCT01843374.Between May 17, 2013, and Dec 4, 2014, 571 patients were randomly assigned to receive tremelimumab (n=382) or placebo (n=189), of whom 569 patients received treatment (two patients in the tremelimumab group were excluded from the safety population because they did not receive treatment). At the data cutoff date (Jan 24, 2016), 307 (80%) of 382 patients had died in the tremelimumab group and 154 (81%) of 189 patients had died in the placebo group. Median overall survival in the intention-to-treat population did not differ between the treatment groups: 7·7 months (95% CI 6·8-8·9) in the tremelimumab group and 7·3 months (5·9-8·7) in the placebo group (hazard ratio 0·92 [95% CI 0·76-1·12], p=0·41). Treatment-emergent adverse events of grade 3 or worse occurred in 246 (65%) of 380 patients in the tremelimumab group and 91 (48%) of 189 patients in the placebo group; the most common were dyspnoea (34 [9%] patients in the tremelimumab group vs 27 [14%] patients in the placebo group), diarrhoea (58 [15%] vs one [1%]), and colitis (26 [7%] vs none). The most common serious adverse events were diarrhoea (69 [18%] patients in the tremelimumab group vs one [1%] patient in the placebo group), dyspnoea (29 [8%] vs 24 [13%]), and colitis (24 [6%] vs none). Treatment-emergent events leading to death occurred in 36 (9%) of 380 patients in the tremelimumab group and 12 (6%) of 189 in the placebo group; those leading to the death of more than one patient were mesothelioma (three [1%] patients in the tremelimumab group vs two [1%] in the placebo group), dyspnoea (three [1%] vs two [1%]); respiratory failure (one [1%] vs three [2%]), myocardial infarction (three [1%] vs none), lung infection (three [1%] patients vs none), cardiac failure (one [1%] vs one [1%]), and colitis (two [1%] vs none). Treatment-related adverse events leading to death occurred in five (1%) patients in the tremelimumab group and none in the placebo group. The causes of death were lung infection in one patient, intestinal perforation and small intestinal obstruction in one patient; colitis in two patients, and neuritis and skin ulcer in one patient.Tremelimumab did not significantly prolong overall survival compared with placebo in patients with previously treated malignant mesothelioma. The safety profile of tremelimumab was consistent with the known safety profile of CTLA-4 inhibitors. Investigations into whether immunotherapy combination regimens can provide greater efficacy than monotherapies in malignant mesothelioma are ongoing.AstraZeneca.

Promising results have been reported with immune checkpoint inhibitors (ICI) in a small proportion of MPM patients. MMR deficiency (dMMR) has been well described in several malignancies and was approved as a biomarker for anti-PD-1 inhibitors. Next generation sequencing (NGS) data demonstrated that 2% of MPM harbor microsatellite instability. The aim of this study is to characterize MMR by immunohistochemistry (IHC) in a series of MPM including a subset of patients treated with immunotherapy. Tumors of 159 MPM p diagnosed between 2002 and 2017 were reviewed. Formalin-fixed, paraffin-embedded tissue was stained for MLH1, MSH2, MSH6 and PMS2 and tumors were classified as dMMR (MMR protein expression negative) and MMR intact (all MMR proteins positively expressed). We retrospectively collected clinical outcomes under standard chemotherapy and experimental immunotherapy in the entire cohort. MMR protein expression was analyzed in 158 samples with enough tissue and was positive in all of the cases. Twenty two patients received ICI with anti-CTLA4 or anti-PD-1 blockade in clinical trials, 58% had a response or stable disease for more than 6 m, with median progression-free survival (PFS) of 5.7 m (2.1–26.1 m). The median overall survival (mOS) in all population was 15 months (m) (13.5–18.8 m). In a multivariable model factors associated to improved mOS were PS 0, neutrophil–lymphocyte ratio (NLR)

Background Nintedanib targets VEGF receptors 1-3, PDGF receptors alpha and beta, FGF receptors 1-3, and Src and Abl kinases, which are all implicated in malignant pleural mesothelioma pathogenesis. Here, we report the final results of the phase 3 part of the LUME-Meso trial, which aimed to investigate the efficacy and safety of pemetrexed plus cisplatin combined with nintedanib or placebo in unresectable malignant pleural mesothelioma. Methods This double-blind, randomised, placebo-controlled phase 3 trial was done at 120 academic medical centres and community clinics in 27 countries across the world. Chemotherapy-naive adults (aged >= 18 years) with unresectable epithelioid malignant pleural mesothelioma and ECOG performance status 0-1 were randomly assigned 1:1 via an independently verified random number-generating system to receive up to six 21-day cycles of pemetrexed (500 mg/m(2)) plus cisplatin (75 mg/m(2)) on day 1, then nintedanib (200 mg twice daily) or matched placebo on days 2-21. Patients without disease progression after six cycles received nintedanib or placebo maintenance on days 1-21 of each cycle. The primary endpoint was progression-free survival (investigator-assessed according to mRECIST) in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of their assigned study drug. This study is registered with ClinicalTrials.gov, number NCT01907100. Findings Between April 14, 2016, and Jan 5, 2018, 541 patients were screened and 458 were randomly assigned to either the nintedanib group (n=229) or the placebo group (n=229). Median treatment duration was 5.3 months (IQR 2.8-7.3) in the nintedanib group and 5.1 months (2.7-7.8) in the placebo group. After 250 events, progression-free survival was not different between the nintedanib group (median 6.8 months [95% CI 6.1-7.0]) and the placebo group (7.0 months [6.7-7.2]; HR 1.01 [95% CI 0.79-1.30], p=0.91). The most frequently reported grade 3 or worse adverse event in both treatment groups was neutropenia (73 [32%] in the nintedanib group vs 54 [24%] in the placebo group). Serious adverse events were reported in 99 (44%) patients in the nintedanib group and 89 (39%) patients in the placebo group. The only serious adverse event occurring in at least 5% of patients in either group was pulmonary embolism (13 [6%] vs seven [3%]). Interpretation The primary progression-free survival endpoint of the phase 3 part of LUME-Meso was not met and phase 2 findings were not confirmed. No unexpected safety findings were reported. Copyright (C) 2019 Elsevier Ltd. All rights reserved.

e20563 Background: MPM is a highly aggressive pleural tumor associated with asbestos exposure and with limited survival despite systemic therapy. Histology is a prognostic factor and recently CheckMate 743 trial demonstrated survival benefit of immunotherapy in first line with some differences in the efficacy of chemotherapy according to histology. However, randomized trials who led to the approval of antifolate in mesothelioma did not include analysis of outcomes by histology. The objective of this study is to characterize the impact of chemotherapy according to histology in p with MPM at our institution. Methods: We review 189 MPM p diagnosed at Vall d´Hebron University Hospital between November 2002 and April 2020. Associations between clinical variables and outcome were assessed with Cox regression models and survival data were calculated by the Kaplan-Meier method. Results: Patient’s characteristics: median age 68 years (y) (45-88 y), males: 70%, performance status (PS)1: 69%, asbestos exposure: 75%, epithelioid subtype: 76%. First line chemotherapy was offered to 85% of p (66% cisplatin-pemetrexed and 27% carboplatin-pemetrexed). Median overall survival (OS) in overall population was 21.3 m (95%CI17.2-24.3). Epithelioid histology, PS 0, neutrophil-lymphocyte ratio

Malignant pleural mesothelioma (MPM) frequently express elevated AKT/mTOR activity. Previous reports in gliomas, colon, breast and prostate cancer suggest that PTEN/PI3K pathway may be important for the induction of PD-L1 expression. This study explored the expression of PTEN/PI3K pathway and PD-L1 in MPM and its relationship with the patient́s prognosisTwenty seven consecutive MPM patients were reviewed. Formalin-fixed, paraffin-embedded tissue biopsies were used for immunohistochemical analysis of PTEN/PI3K pathway and PD-L1 RESULTS: Expression of PTEN, mTOR, pAKT, p4EBP1, peif4E, pS6 and FOXO3a was found in 88.5%, 92.3%, 78.3%, 38.5%, 100%, 52.2% and 100% of tumors and PD-L1 in 23%. We found a significant correlation between pAKT, FOXO3a and PD-L1 expression and longer overall survival (p 0.05). We did not identify significant association between the level of PD-L1 expression and alterations in PI3K pathwayThis study shows PTEN/PI3K pathway and PD-L1 in MPM are frequently activated. Our results suggests that there is not association between PD-L1 and the involvement of the PI3K pathway in MPM.

e21524 Background: In metastatic NSCLC, identification of biomarkers of response to immune checkpoint inhibitors (ICI) is still an unmet need. Liquid biopsy, including the detection of circulating tumor DNA (ctDNA) in patients’ bloodstream, is an emerging tool for detecting and monitoring genetic alterations. Mutations in specific genes as KRAS or STK11, in combination with PDL1, have been suggested as potential biomarkers to select responders to ICI. Methods: Digital NGS of ctDNA was analyzed by Guardant360 in samples from 89 patients with advanced NSCLC treated with ICI between 2017 to 2019. Plasma samples after progression to ICI were obteined from 40 patients and we focus in this subgroup to explore mutations of genes commonly alterated in lung cancer and correlate them with clinical outcomes. Results: Forty patients were included in the analysis with a median age of 64.5 years and 62.5% were diagnosed with adenocarcinoma. Fourteen patients were treated with single agent ICI as first line, 19 patients as second line and 7 in third line. A median of 4 mutations per patient were detected (range 0-13). Mutations (mut) in TP53 were found in 85% of the patients, KRAS in 34%, STK11 in 22% and both genes KRAS and STK11 were alterated in 12.5% of the patients. Globally, median PFS (mPFS) of the patients treated with ICI was 7.5 months. mPFS in patients harboring KRAS mutations was 4.9 m ( vs 10.1 m in patients without KRASmut, logrank test p-value = 0.031) and 4.1 m in those patients with STK11 mutations (vs 9.5 m in patients without STK11mut, logrank test p-value = 0.034). Additionally, mutations in both genes were also associated to statistically significant shorter mPFS 3.9 m vs 9.5 m (logrank test p-value < 0.01). Conclusions: Our results support the idea that tumor alterations identified by liquid biopsy panels can potentially contribute as biomarkers of response to ICI in NSCLC. When analyzing the mutational panorama after ICI treatment, we find that those patients exhibiting KRAS and/or STK11 mutations in their ctDNA have a shorter PFS.

BACKGROUND: Third-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as osimertinib are the last line of targeted treatment of metastatic non-small-cell lung cancer (NSCLC) EGFR-mutant harboring T790M. Different mechanisms of acquired resistance to third-generation EGFR-TKIs have been proposed. It is therefore crucial to identify new and effective strategies to overcome successive acquired mechanisms of resistance. METHODS: For Amplicon-seq analysis, samples from the index patient (primary and metastasis lesions at different timepoints) as well as the patient-derived orthotopic xenograft tumors corresponding to the different treatment arms were used. All samples were formalin-fixed paraffin-embedded, selected and evaluated by a pathologist. For droplet digital PCR, 20 patients diagnosed with NSCLC at baseline or progression to different lines of TKI therapies were selected. Formalin-fixed paraffin-embedded blocks corresponding to either primary tumor or metastasis specimens were used for analysis. For single-cell analysis, orthotopically grown metastases were dissected from the brain of an athymic nu/nu mouse and cryopreserved at -80°C. RESULTS: In a brain metastasis lesion from a NSCLC patient presenting an EGFR T790M mutation, we detected MET gene amplification after prolonged treatment with osimertinib. Importantly, the combination of capmatinib (c-MET inhibitor) and afatinib (ErbB-1/2/4 inhibitor) completely suppressed tumor growth in mice orthotopically injected with cells derived from this brain metastasis. In those mice treated with capmatinib or afatinib as monotherapy, we observed the emergence of KRAS G12C clones. Single-cell gene expression analyses also revealed intratumor heterogeneity, indicating the presence of a KRAS-driven subclone. We also detected low-frequent KRAS G12C alleles in patients treated with various EGFR-TKIs. CONCLUSION: Acquired resistance to subsequent EGFR-TKI treatment lines in EGFR-mutant lung cancer patients may induce genetic plasticity. We assess the biological insights of tumor heterogeneity in an osimertinib-resistant tumor with acquired MET-amplification and propose new treatment strategies in this situation. This work was supported by the Spanish Ministries of Health and Fondo de Investigación Sanitaria-Fondo Europeo de Desarrollo Regional (FEDER) (PI14/01248, PI13-01339, PIE13/00022, PI16/01898); AECC Scientific Foundation (GCB14-2170); and Fundación Mutua Madrileña (AP150932014). HGP and HH are Miguel Servet researchers funded by the Spanish Institute of Health Carlos III (CPII14/00037, CP14/00229). PN laboratory is funded by the Tumor Biomarker Research Program of the Banco Bilbao Vizcaya Argentaria Foundation (FBBVA)

Non-small-cell lung cancer (NSCLC) represents approximately 85% of all lung cancer cases, with a world-wide annual incidence of around 1.3 million. Surgery remains the corner stone of treatment in early-stage NSCLC when feasible, and the addition of adjuvant cisplatin-based chemotherapy has improved these results in resected NSCLC patients. For those patients with non-metastatic NSCLC not suitable for complete surgical resection, chemotherapy plus radiotherapy remains the best treatment option. For patients with metastatic NSCLC, molecular targeted agents have become part of the therapeutic arsenal in recent years. However, to date no targeted agent has been approved for patients with early or locally-advanced stages of NSCLC. Here, we review the rationale, literature and studies addressing the role of targeted agents used in the adjuvant setting or as part of chemoradiotherapy regimens.

Background WNT pathway mutations (mut) are uncommon in NSCLC. Recent preclinical studies suggest that APC/CTNNB1 mut induce immune resistance in lung adenocarcinoma but how they may impact on immunotherapy response in the clinics remains unclear. Objective: our aim is to describe the clinical outcomes - Overall survival (OS) and progression-free-survival (PFS) and response rate (RR) - of a metastatic NSCLC cohort with APC/CTNNB1 mut treated with immunotherapy. Methods We selected those patients with metastatic NSCLC and APC or CTNNB1 mut detected through Amplicon-Seq (tissue), Foundation (plasma), Guardant (plasma) or exome sequencing (tissue) performed from 2014 to 2018. Results Incidence of APC/CTNNB1 mut in NSCLC in our hospital has been 1,26% and 0,7% respectively by Amplicon-Seq (tissue) and 10.4% and 1.04% respectively by exome sequencing (tissue). We identified 27 patients with APC (81%) or CTNNB1 (19%) mutations. The median age of the patients was 59 years (44-74), 72% of them were male and most frequent histology was adenocarcinoma (66%). Fifteen of the patients received ICI, 27% as a first line treatment and 47% as a second line. Interestingly, 1 patient had EGFR mut (exon 19 and 20) and 4 patients had KRAS mut. Median OS of the whole cohort from date of diagnosis was 24.5 months (CI95% 13.7-NA). Median OS was 23.5 months (CI95% 10.4-NA) for those patients who harboured CTNNB1 mut and 57.3 months (CI95% 13.7-NA) for those patients with APC mut (HR 1.8, CI95% 0.32-10, p = 0.5). Median PFS with ICI was 6.6 months (CI95% 0.9-NA). Median PFS was 0.7 months (CI95% 0.5-NA) for those patients with CTNNB1 mut and 8.9 months (CI95% 1.8-NA) with APC mut (HR 6.7, CI95% 1.1-41, p = 0.04). None of the 2 CTNNB1 mut patients responded to ICI, while RR in the APC mut cohort was 30% (4 out of 13). Conclusions In our cohort, APC mut did not show to impair clinical outcomes. Few CTNNB1 mut cases hinder conclusive analyses. Correlation with other predictive biomarkers such as tumor mutation burden and PDL1 expression is ongoing. Legal entity responsible for the study Vall d´Hebron Institute of Oncology (VHIO). Funding Grant from: Carlos III Institute of Health, Madrid, Spain: PI14/01248 and PI17/00938. Disclosure P. Iranzo: Advisory / Consultancy, Travel / Accommodation / Expenses: BMS; Advisory / Consultancy, Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Travel / Accommodation / Expenses: Merck; Advisory / Consultancy, Travel / Accommodation / Expenses: Boehringer; Advisory / Consultancy, Travel / Accommodation / Expenses: MSD; Advisory / Consultancy: Rovi; Advisory / Consultancy: Kyowa Kirin; Advisory / Consultancy, Travel / Accommodation / Expenses: Grunental. A. Callejo: Advisory / Consultancy, Travel / Accommodation / Expenses: BMS; Advisory / Consultancy, Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer; Advisory / Consultancy, Travel / Accommodation / Expenses: Boehringer; Advisory / Consultancy, Travel / Accommodation / Expenses: MSD; Advisory / Consultancy: Kyowa kirin; Travel / Accommodation / Expenses: Celgene. N. Pardo: Advisory / Consultancy: BMS; Advisory / Consultancy, Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer; Advisory / Consultancy: Boehringer. A. Martinez: Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: BMS; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: MSD; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Pfizer; Advisory / Consultancy, Speaker Bureau / Expert testimony, Travel / Accommodation / Expenses: Boehringer. A. Navarro: Advisory / Consultancy, Travel / Accommodation / Expenses: BMS; Advisory / Consultancy, Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer; Advisory / Consultancy, Travel / Accommodation / Expenses: Boehringer; Advisory / Consultancy: Oryzon Genomics; Travel / Accommodation / Expenses: MSD. S. Cedres: Advisory / Consultancy: BMS; Advisory / Consultancy, Travel / Accommodation / Expenses: Roche; Advisory / Consultancy, Travel / Accommodation / Expenses: Pfizer ; Advisory / Consultancy, Travel / Accommodation / Expenses: Boehringer; Advisory / Consultancy: MSD; Advisory / Consultancy: Amphera. R. Dienstmann: Advisory / Consultancy, Speaker Bureau / Expert testimony: Roche; Speaker Bureau / Expert testimony: Symphogen; Speaker Bureau / Expert testimony: Ipsen; Speaker Bureau / Expert testimony: Amgen; Speaker Bureau / Expert testimony: Sanofi; Speaker Bureau / Expert testimony: MSD; Speaker Bureau / Expert testimony: Servier; Research grant / Funding (institution): Merck. H.G. Palmer: Research grant / Funding (institution): Bayer; Research grant / Funding (institution): Blueprint; Research grant / Funding (institution): Merus; Research grant / Funding (institution): Cellestia. A. Vivancos: Advisory / Consultancy, Research grant / Funding (institution): SYSMEX; Advisory / Consultancy, Research grant / Funding (institution): Novartis; Advisory / Consultancy: MERCK; Advisory / Consultancy, Research grant / Funding (institution): Roche; Advisory / Consultancy, Research grant / Funding (institution): BMS; Advisory / Consultancy: Guardant Health; Licensing / Royalties, Technology Transfer DX Field: Ferrer; Research grant / Funding (institution): DEBIO; Research grant / Funding (institution): Cellestia; Research grant / Funding (institution): Chittern. E. Felip: Advisory / Consultancy: Abbvie; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Blueprint Medicines; Advisory / Consultancy: Boehringer Ingelheim,; Advisory / Consultancy: Bristol-Myers Squibb; Advisory / Consultancy: Celgene; Advisory / Consultancy: Eli Lilly; Advisory / Consultancy: Guardant Health; Advisory / Consultancy: Janssen; Advisory / Consultancy: Medscape; Advisory / Consultancy: Merck KGaA; Advisory / Consultancy: Merck Sharp & Dohme; Advisory / Consultancy: Novartis; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Roche; Advisory / Consultancy: Takeda; Advisory / Consultancy: Touchtime; Research grant / Funding (institution): Fundacion Merck Salud; Research grant / Funding (institution): Grant for Oncology Innovation EMD Serono. All other authors have declared no conflicts of interest.

9071 Background: ICIs have significantly changed the therapeutic landscape of advanced NSCLC. As such, characterizing predictive markers of long-term clinical benefit is a critical objective. TMB quantification using targeted gene panels associates with long-term response to ICIs in NSCLC patients (Rizvi H ASCO 18). Although TMB quantified by targeted NGS correlates with that of WES, caution may be needed when using smaller panels. Methods: Here we analyzed WES of tumors and matched normal tissue from 67 NSCLC patients including 42 treated with ICIs. We correlated TMB with clinico-pathological features and outcomes. TMB was categorized as high vs. low according to the upper quartile of cohort distribution. Results: The median TMB was 2.68 non-synonymous variants (nSNVs)/Mb, ranging from 0 to 15.6 nSNVs/Mb, with upper quartile at 5.42 nSNVs/Mb. TMB was higher for smoker/current smoker (median 3.51) compared to never smokers (median 0.94, p = 0.0048) but no differences were seen in elderly ( > 70 years) vs. young patients or across histologies (squamous, adeno and other) and stages at diagnosis. In patients treated with ICIs, median TMB was 5.44 for those achieving complete response, 3.87 for patients with partial response and 2.42 for patients with progressive disease (PD) (p = 0.04). Moreover, improved clinical outcomes were associated with higher TMB (Table). In patients treated with ICIs, TMB as continuous variable had an impact on progression free survival (PFS) (p = 0.03). Median PFS was 22.3 months (mo) (14-not reached) for those with high TMB and 6.4 mo (3-16) for those with low TMB (HR 0.34, 0.13-0.9, p = 0.03). Median overall survival was not reached for those patients with high TMB and 32 mo (22-43) for those with low TMB (HR 0.29, 0.1-0.86, p = 0.02). Conclusions: High TMB correlates with long-term ICI benefit in NSCLC patients. Mutations in individual genes potentially linked to long-term benefit or resistance to ICIs will be presented. [Table: see text]

Background: Tumor Treating Fields (TTFields), an anti-mitotic, regional treatment approved for glioblastoma utilizes low intensity, alternating electric fields delivered non-invasively to the tumor using a portable medical device. In-vitro, human mesothelioma cells were highly susceptible to TTFields. Methods: The trial accrued 80 patients with unresectable, previously untreated mesothelioma. Patients were treated with continuous 150 kHz TTFields (>18h/day) in combination with pemetrexed and cisplatin or carboplatin. Inclusion criteria included ECOG PS of 0-1 and pathologically proven mesothelioma. The primary endpoint was overall survival (OS). A visual analog scale was used to assess EOCG performance status and cancer-related pain assessed until disease progression. The sample size provided 80% power with two-sided alpha of 0.05 to detect an increase in median OS of 5.5 months compared to historical controls (Vogelzang, JCO 2003). Results: All 80 patients had a minimum follow up of 12 months. Median age was 67 (range 27-78), 84% were male and 44% (35 patients) had an ECOG PS of 1. 66% (53 patients) had epithelioid histology, similar to the Vogelzang study. Median OS was 18.2 months (95% CI 12.1-25.8) versus 12.1 months in the historical control. Median OS for epithelioid patients was 21.2 months (95% CI 13.2-25.8). ECOG score was stable during the first year of follow up. Median time to deterioration in performance status was 13.1 months. Average score of pain was lower compared to baseline during the first 7 months of the treatment and was higher later on the study, with a median time to a clinical significant 33% increase in pain of 8.4 months. No device-related serious adverse events (AEs) were reported. Expected TTFields-related dermatitis was reported in 46% (37 patients). Four patients (5%) had grade 3 dermatitis. Conclusions: The study met primary endpoint of significant extension of overall survival in previously untreated mesothelioma patients. TTFields was not associated with a decrease in performance status or an increase in pain for the duration of TTFields use. TTFields in combination with chemotherapy is efficacious in malignant pleural mesothelioma compared to historical data.

Nodal categories for malignant pleural mesothelioma are derived from the lung cancer staging system and have not been adequately validated. The International Association for the Study of Lung Cancer developed a multinational database to generate evidence-based recommendations to inform the eighth edition of the TNM classification of malignant pleural mesothelioma.Data from 29 centers were entered prospectively (n = 1566) or by transfer of retrospective data (n = 1953). Survival according to the seventh edition N categories was evaluated using Kaplan-Meier survival curves and Cox proportional hazards regression analysis. Survival was measured from the date of diagnosis.There were 2432 analyzable cases: 1603 had clinical (c) staging, 1614 had pathologic (p) staging, and 785 had both. For clinically staged tumors there was no separation in Kaplan-Meier curves between cN0, cN1 or cN2 (cN1 versus cN0 hazard ratio [HR] = 1.06, p = 0.77 and cN2 versus cN1 HR = 1.04, p = 0.85). For pathologically staged tumors, patients with pN1 or pN2 tumors had worse survival than those with pN0 tumors (HR = 1.51, p 0.0001) but no survival difference was noted between those with pN1 and pN2 tumors (HR = 0.99, p = 0.99). Patients with both pN1 and pN2 nodal involvement had poorer survival than those with pN2 tumors only (HR = 1.60, p = 0.007) or pN0 tumors (HR = 1.62, p0.0001).A recommendation to collapse both clinical and pN1 and pN2 categories into a single N category comprising ipsilateral, intrathoracic nodal metastases (N1) will be made for the eighth edition staging system. Nodes previously categorized as N3 will be reclassified as N2.