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Most patients with pleural mesothelioma (PM) present with symptomatic pleural effusion. In some patients, PM is only detectable on the pleural surfaces, providing a strong rationale for intrapleural anticancer therapy. In modern prospective studies involving expert radiological staging and specialist multidisciplinary teams, the population incidence of stage I PM (an approximate surrogate of pleura-only PM) is higher than in historical retrospective series. In this Viewpoint, we advocate for the expansion of intrapleural trials to serve these patients, given the paucity of data supporting licensed systemic therapies in this setting and the uncertainties involved in surgical therapy. We begin by reviewing the unique anatomical and physiological features of the PM-bearing pleural space, before critically appraising the evidence for systemic therapies in stage I PM and previous intrapleural PM trials. We conclude with a summary of key challenges and potential solutions, including optimal trial designs, repurposing of indwelling pleural catheters, and new technologies., Competing Interests: Declaration of interests KGB declares institutional grant funding from Rocket Medical and RS Oncology; lecture honoraria from Bristol-Myers Squibb; and the role of chief investigator of the PREDICT-Meso International Accelerator Network. PSA declares research funding from ATARA Biotherapeutics; patents, royalties, and intellectual property on therapies licensed to ATARA Biotherapeutics; and scientific advisory board membership and consulting fees from ATARA Biotherapeutics, Bayer, Bio4T2, Carisma Therapeutics, Imugene, ImmPactBio, Johnson & Johnson, Orion Pharma, and Outpace Bio. PA declares equipment loans for courses from Novatech, Wolf, and Olympus. LD declares lecture honoraria from Bristol-Myers Squibb. YCGL declares receipt of equipment from Rocket Medical for use in clinical trials. ASM declares institutional grant funding from Novartis and Verily; consulting fees from Rising Tide and TRIPTYCH Health Partners; institutional payments or honoraria from Janssen, BeiGene, Chugai Pharmaceutical (Roche), Ideology Health (formerly Health Media), Antoni van Leeuwenhoek Kanker Instituut, AXIS Medical Education, Johnson & Johnson Global Services, Intellisphere, Answers in CME, University of Miami International Mesothelioma Symposium, and Immunocore; support for attending meetings from Shanghai Roche; membership of scientific advisory boards for AbbVie, AstraZeneca, Bristol-Myers Squibb, Genentech/Roche, Takeda Oncology, and Sanofi Genzyme; and study funding from Bristol-Myers Squibb. SJM is co-principal investigator of the Engineering and Physical Sciences Research Council Interdisciplinary Research Collaboration in Targeted Delivery for Hard-to-Treat Cancers; he declares consulting fees from DefiniGEN, and support for attending meetings from Alpha-1 Foundation, Federation of American Societies for Experimental Biology, and Mesothelioma UK. NM declares consulting fees from Rocket Medical UK, Cook Medical UK, and Becton Dickinson. VP declares grant funding from the Danish Comprehensive Cancer Center and no conflicts of interest within the scope of this Viewpoint. NMR declares consulting fees from Rocket Medical UK, Cook Medical UK, and LTI USA. MGZ declares institutional grant funding from Medimmune, Precog, GSK, Epizyme, Polaris, Sellas Life Sciences, Bristol-Myers Squibb, Millenium, Curis, and Atara; consulting fees from Curis, Ikena, Takeda, GSK, and Novocure; and honoraria from PER and Medscape. DS declares support including research funding and consulting fees from AstraZeneca, Boehringer Ingelheim, Exigo Management, Flame Biosciences, HitchBio, Intuitive Surgical, Janssen, Johnson & Johnson, Medscape, Olympus Corporation of the Americas (also known as Spiration), Sensei Biotherapeutics, Trizell, Trustees of the University of Pennsylvania, Verismo, and Wolters Kluwer Health. DAF declares institutional grants from Aldeyra, Astex Therapeutics, Bayer Oncology, Bergen Bio, Boehringer Ingelheim, Clovis Oncology, Eli Lilly, Lovance, MSD, Owkin, Roche Oncology, and RS Oncology; consulting fees from Cambridge Clinical Laboratories and RS Oncology; honoraria from MSD and Bristol-Myers Squibb; support for attending meetings from RS Oncology; and participation on data monitoring or advisory boards for AstraZeneca and RS Oncology. TP declares no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Importance: Arginine deprivation using ADI-PEG20 (pegargiminase) combined with chemotherapy is untested in a randomized study among patients with cancer. ATOMIC-Meso (ADI-PEG20 Targeting of Malignancies Induces Cytotoxicity-Mesothelioma) is a pivotal trial comparing standard first-line chemotherapy plus pegargiminase or placebo in patients with nonepithelioid pleural mesothelioma., Objective: To determine the effect of pegargiminase-based chemotherapy on survival in nonepithelioid pleural mesothelioma, an arginine-auxotrophic tumor., Design, Setting, and Participants: This was a phase 2-3, double-blind randomized clinical trial conducted at 43 centers in 5 countries that included patients with chemotherapy-naive nonepithelioid pleural mesothelioma from August 1, 2017, to August 15, 2021, with at least 12 months' follow-up. Final follow-up was on August 15, 2022. Data analysis was performed from March 2018 to June 2023., Intervention: Patients were randomly assigned (1:1) to receive weekly intramuscular pegargiminase (36.8 mg/m2) or placebo. All patients received intravenous pemetrexed (500 mg/m2) and platinum (75-mg/m2 cisplatin or carboplatin area under the curve 5) chemotherapy every 3 weeks up to 6 cycles. Pegargiminase or placebo was continued until progression, toxicity, or 24 months., Main Outcomes and Measures: The primary end point was overall survival, and secondary end points were progression-free survival and safety. Response rate by blinded independent central review was assessed in the phase 2 portion only., Results: Among 249 randomized patients (mean [SD] age, 69.5 [7.9] years; 43 female individuals [17.3%] and 206 male individuals [82.7%]), all were included in the analysis. The median overall survival was 9.3 months (95% CI, 7.9-11.8 months) with pegargiminase-chemotherapy as compared with 7.7 months (95% CI, 6.1-9.5 months) with placebo-chemotherapy (hazard ratio [HR] for death, 0.71; 95% CI, 0.55-0.93; P = .02). The median progression-free survival was 6.2 months (95% CI, 5.8-7.4 months) with pegargiminase-chemotherapy as compared with 5.6 months (95% CI, 4.1-5.9 months) with placebo-chemotherapy (HR, 0.65; 95% CI, 0.46-0.90; P = .02). Grade 3 to 4 adverse events with pegargiminase occurred in 36 patients (28.8%) and with placebo in 21 patients (16.9%); drug hypersensitivity and skin reactions occurred in the experimental arm in 3 patients (2.4%) and 2 patients (1.6%), respectively, and none in the placebo arm. Rates of poststudy treatments were comparable in both arms (57 patients [45.6%] with pegargiminase vs 58 patients [46.8%] with placebo)., Conclusions and Relevance: In this randomized clinical trial of arginine depletion with pegargiminase plus chemotherapy, survival was extended beyond standard chemotherapy with a favorable safety profile in patients with nonepithelioid pleural mesothelioma. Pegargiminase-based chemotherapy as a novel antimetabolite strategy for mesothelioma validates wider clinical testing in oncology., Trial Registration: ClinicalTrials.gov Identifier: NCT02709512.

Introduction: Cytoreductive surgery has been used a part of multimodality treatment in patients with malignant pleural mesothelioma (MPM). The residual microscopic disease that remains will lead to disease progression in the majority of patients. Delivery of hyperthermic intrathoracic chemotherapy at the time of surgery has been used to address this microscopic disease, however it's effect and place in the multimodality treatment sphere is unknown. The aim of this systematic review was to assess the effect of surgery and hyperthermic intrathoracic chemotherapy in patients with MPM on overall survival and disease-free interval., Methods: Ovid MEDLINE, Embase, Web of Science and the Cochrane Database of Systematic Reviews were searched from database inception through to June 2021. Studies reporting overall survival and/or disease-free interval in patients with MPM undergoing cytoreductive surgery with hyperthermic intrathoracic chemotherapy were considered. Study quality was assessed using the Newcastle-Ottawa Scale. A narrative review was performed., Results: Fifteen studies were eligible for inclusion comprising 598 patients. Surgery with hyperthermic intrathoracic chemotherapy was associated with a median overall survival and disease-free interval ranging from 11 to 75 months and 7.2 to 57 months, respectively. These appeared to be superior to patients not receiving hyperthermic intrathoracic chemotherapy (overall survival: 5-36 months and disease-free interval: 12.1-21 months). A higher dose of hyperthermic intrathoracic chemotherapy was associated with an improvement in overall survival compared with a lower dose: 18-31 months versus 6-18 months, respectively. The most common morbidity was atrial fibrillation followed by renal complications., Conclusion: Surgery with hyperthermic intrathoracic chemotherapy offers a safe and effective therapy with an improvement in disease-free interval and overall survival, particularly when hyperthermic intrathoracic chemotherapy is administered at a higher dose., Prospero Registration Number: CRD42019129002., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Over the past decade, immune-checkpoint inhibitors (ICIs) have revolutionized the treatment of cancer. In mesothelioma, a rare cancer with a dismal prognosis generally caused by exposure to asbestos, treatment with single or dual ICIs results in robust improvements in overall survival over previous standard-of-care therapies, both in the first-line and relapsed disease settings. Predictive biological features that underpin response to ICIs remain poorly understood; however, insights into the immune microenvironment and genomic landscape of mesothelioma as well as into their association with response or acquired resistance to ICIs are emerging. Several studies of rational combinations involving ICIs with either another ICI or a different agent are ongoing, with emerging evidence of synergistic antitumour activity. Non-ICI-based immunotherapies, such as peptide-based vaccines and mesothelin-targeted chimeric antigen receptor T cells, have demonstrated promising efficacy. Moreover, results from pivotal trials of dendritic cell vaccines and viral cytokine delivery, among others, are eagerly awaited. In this Review, we comprehensively summarize the key steps in the development of immunotherapies for mesothelioma, focusing on strategies that have led to randomized clinical evaluation and emerging predictors of response. We then forecast the future treatment opportunities that could arise from ongoing research., (© 2022. Springer Nature Limited.)

Background: Malignant pleural mesothelioma (MPM) has a poor overall survival with few treatment options. Whole genome sequencing (WGS) combined with the immune features of MPM offers the prospect of identifying changes that could inform future clinical trials., Methods: We analysed somatic mutations from 229 MPM samples, including previously published data and 58 samples that had undergone WGS within this study. This was combined with RNA-seq analysis to characterize the tumour immune environment., Results: The comprehensive genome analysis identified 12 driver genes, including new candidate genes. Whole genome doubling was a frequent event that correlated with shorter survival. Mutational signature analysis revealed SBS5/40 were dominant in 93% of samples, and defects in homologous recombination repair were infrequent in our cohort. The tumour immune environment contained high M2 macrophage infiltrate linked with MMP2, MMP14, TGFB1 and CCL2 expression, representing an immune suppressive environment. The expression of TGFB1 was associated with overall survival. A small subset of samples (less than 10%) had a higher proportion of CD8 T cells and a high cytolytic score, suggesting a 'hot' immune environment independent of the somatic mutations., Conclusions: We propose accounting for genomic and immune microenvironment status may influence therapeutic planning in the future., (© 2022. The Author(s).)

Background: Genetically stratified therapy for malignant mesothelioma is unavailable. Mesotheliomas frequently harbour loss of the chromosome 9p21.3 locus (CDKN2A-MTAP), which is associated with shorter overall survival due to loss of the tumour suppressor p16ink4A, an endogenous suppressor of cyclin-dependent kinase (CDK)4 and CDK6. Genetic restoration of p16ink4A suppresses mesothelioma in preclinical models, underpinning the rationale for targeting CDK4 and CDK6 in p16ink4A-negative mesothelioma. We developed a multicentre, stratified, phase 2 trial to test this hypothesis., Methods: The MiST2 study was a single-arm, open-label, phase 2 clinical trial done two UK centres. Patients older than 18 years with any histologically confirmed subtype of mesothelioma (pleural or peritoneal) with radiological progression after at least one course of platinum-based chemotherapy were molecularly screened by immunohistochemistry for p16ink4A. Patients with p16ink4A-negative mesothelioma were eligible for inclusion in the study. Patients were required to have measurable disease by modified Response Evaluation Criteria in Solid Tumours version 1.1 for malignant mesothelioma, a predicted life expectancy of at least 12 weeks, and an Eastern Cooperative Oncology Group performance status score of 0-1. Patients received oral abemaciclib 200 mg twice daily, administered in 28-day cycles for 24 weeks. The primary endpoint was the disease control rate (patients with complete responses, partial responses, or stable disease) at 12 weeks. The null hypothesis could be rejected if at least 11 patients had disease control. The efficacy and safety populations were defined as all patients who received at least one dose of the study drug. The study is registered with ClinicalTrials.gov, NCT03654833, and is ongoing (but MiST2 is now closed)., Findings: Between Sept 31, 2019, and March 2, 2020, 27 eligible patients consented to molecular screening. The median follow-up was 18·4 weeks (IQR 6·7-23·9). One patient was excluded before treatment because of a serious adverse event before study drug allocation. 26 (100%) of 26 treated patients were p16ink4A deficient and received at least one dose of abemaciclib. Disease control at 12 weeks was reported in 14 (54%) of 26 patients (95% CI 36-71). Grade 3 or worse treatment-related adverse events (of any cause) occurred in eight (27%) of 26 patients (diarrhoea, dyspnoea, thrombocytopenia, vomiting, urinary tract infection, increased alanine aminotransferase, ascites, chest infection or suspected chest infection, neutropenic sepsis, alopecia, blood clot left calf, fall [broken neck and collar bone], haemoptysis, lower respiratory tract infection, and pulmonary embolism). Grade 3 or worse treatment-related adverse events occurred in three (12%) of 26 patients (diarrhoea, thrombocytopenia, vomiting, increased alanine aminotransferase, and pulmonary embolism). Serious adverse events occurred in six (23%) of 26 patients, leading to treatment discontinuation in one (4%) patient (diarrhoea, urinary tract infection, chest infection, neutropenic sepsis, fall [broken neck and collar bone], haemoptysis, lower respiratory tract infection, and pulmonary embolism). One patient had a serious adverse event related to abemaciclib (diarrhoea). One (4%) of 26 patients died from an adverse event (neutropenic sepsis)., Interpretation: This study met its primary endpoint, showing promising clinical activity of abemaciclib in patients with p16ink4A-negative mesothelioma who were previously treated with chemotherapy, and warrants its further investigation in a randomised study as a targeted stratified therapy., Funding: University of Leicester, Asthma UK and British Lung Foundation Partnership, and the Victor Dahdaleh Foundation., Competing Interests: Declaration of interests DAF reports grants from Astex Therapeutics, Boehringer Ingelheim, MSD, and Bayer; personal fees from Aldeyra, Inventiva, and Paredox; non-financial support from Clovis, Eli Lilly, and BMS; and personal fees and non-financial support from Roche, during the conduct of the study. AT reports personal fees from Amgen, outside the submitted work. All other authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Malignant Pleural Mesothelioma (MPM) is typically diagnosed 20-50 years after exposure to asbestos and evolves along an unknown evolutionary trajectory. To elucidate this path, we conducted multi-regional exome sequencing of 90 tumour samples from 22 MPMs acquired at surgery. Here we show that exomic intratumour heterogeneity varies widely across the cohort. Phylogenetic tree topology ranges from linear to highly branched, reflecting a steep gradient of genomic instability. Using transfer learning, we detect repeated evolution, resolving 5 clusters that are prognostic, with temporally ordered clonal drivers. BAP1/-3p21 and FBXW7/-chr4 events are always early clonal. In contrast, NF2/-22q events, leading to Hippo pathway inactivation are predominantly late clonal, positively selected, and when subclonal, exhibit parallel evolution indicating an evolutionary constraint. Very late somatic alteration of NF2/22q occurred in one patient 12 years after surgery. Clonal architecture and evolutionary clusters dictate MPM inflammation and immune evasion. These results reveal potentially drugable evolutionary bottlenecking in MPM, and an impact of clonal architecture on shaping the immune landscape, with potential to dictate the clinical response to immune checkpoint inhibition.

Introduction: Mesothelioma remains a lethal cancer. To date, systemic therapy with pemetrexed and a platinum drug remains the only licensed standard of care. As the median survival for patients with mesothelioma is 12.1 months, surgery is an important consideration to improve survival and/or quality of life. Currently, only two surgical trials have been performed which found that neither extensive (extra-pleural pneumonectomy) or limited (partial pleurectomy) surgery improved survival (although there was some evidence of improved quality of life). Therefore, clinicians are now looking to evaluate pleurectomy decortication, the only radical treatment option left., Methods and Analysis: The MARS 2 study is a UK multicentre open parallel group randomised controlled trial comparing the effectiveness and cost-effectiveness of surgery-(extended) pleurectomy decortication-versus no surgery for the treatment of pleural mesothelioma. The study will test the hypothesis that surgery and chemotherapy is superior to chemotherapy alone with respect to overall survival. Secondary outcomes include health-related quality of life, progression-free survival, measures of safety (adverse events) and resource use to 2 years. The QuinteT Recruitment Intervention is integrated into the trial to optimise recruitment., Ethics and Dissemination: Research ethics approval was granted by London - Camberwell St. Giles Research Ethics Committee (reference 13/LO/1481) on 7 November 2013. We will submit the results for publication in a peer-reviewed journal., Trial Registration Numbers: ISRCTN-ISRCTN44351742 and ClinicalTrials.gov-NCT02040272., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.)

The European Respiratory Society (ERS)/European Society of Thoracic Surgeons (ESTS)/European Association for Cardio-Thoracic Surgery (EACTS)/European Society for Radiotherapy and Oncology (ESTRO) task force brought together experts to update previous 2009 ERS/ESTS guidelines on management of malignant pleural mesothelioma (MPM), a rare cancer with globally poor outcome, after a systematic review of the 2009-2018 literature. The evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation approach. The evidence syntheses were discussed and recommendations formulated by this multidisciplinary group of experts. Diagnosis: pleural biopsies remain the gold standard to confirm the diagnosis, usually obtained by thoracoscopy but occasionally via image-guided percutaneous needle biopsy in cases of pleural symphysis or poor performance status. Pathology: standard staining procedures are insufficient in ∼10% of cases, justifying the use of specific markers, including BAP-1 and CDKN2A (p16) for the separation of atypical mesothelial proliferation from MPM. Staging: in the absence of a uniform, robust and validated staging system, we advise using the most recent 2016 8th TNM (tumour, node, metastasis) classification, with an algorithm for pretherapeutic assessment. Monitoring: patient's performance status, histological subtype and tumour volume are the main prognostic factors of clinical importance in routine MPM management. Other potential parameters should be recorded at baseline and reported in clinical trials. Treatment: (chemo)therapy has limited efficacy in MPM patients and only selected patients are candidates for radical surgery. New promising targeted therapies, immunotherapies and strategies have been reviewed. Because of limited data on the best combination treatment, we emphasize that patients who are considered candidates for a multimodal approach, including radical surgery, should be treated as part of clinical trials in MPM-dedicated centres., (© The article has been co-published with permission in the European Journal of Cardio-Thoracic Surgery and the European Respiratory Journal. All rights reserved in respect of European Journal of Cardio-Thoracic Surgery, © European Association for Cardio-Thoracic Surgery 2020 and European Respiratory Journal, © European Respiratory Society 2020. The articles are identical except for minor stylistic and spelling differences in keeping with each journal’s style. Either citation can be used when citing this article.)

The accurate diagnosis of mesothelioma is critical for the appropriate clinical management of this cancer. Many issues complicate making the diagnosis of mesothelioma including the presence of reactive mesothelial cells in benign pleural effusions, the heterogeneity of mesothelioma histopathology, the relatively high incidence of other epithelial malignancies that metastasize to the pleura, and primary sarcomas that arise within the pleura. Given the rapidly evolving field of molecular profiling and the need for translational correlates in mesothelioma clinical trials, the National Cancer Institute (NCI)-International Association for the Study of Lung Cancer-Mesothelioma Applied Research Foundation Clinical Trials Planning Meeting was convened in March 2017 to develop a consensus on standard pathology guidelines for future NCI-sponsored clinical trials in mesothelioma. This consensus statement covers recommendations for specimen handling, pathologic classification and diagnosis, biobanking, and tissue correlative studies., (Copyright © 2019 International Association for the Study of Lung Cancer. All rights reserved.)

Background: Nintedanib targets VEGF receptors 1-3, PDGF receptors α and β, 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., Funding: Boehringer Ingelheim., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Purpose: Inhibition of focal adhesion kinase has been shown to selectively kill mesothelioma cells that express low levels of moesin-ezrin-radixin-like protein (merlin). On this basis, we designed a randomized, phase II trial to investigate whether defactinib as maintenance therapy after standard first-line chemotherapy could improve progression-free survival (PFS) in patients with malignant pleural mesothelioma (MPM)., Methods: This global, double-blind, randomized, placebo-controlled trial was conducted in patients with advanced MPM and disease control after at least four cycles of first-line chemotherapy. Patients were stratified for merlin and then randomly assigned (in a 1:1 fashion) to receive either oral defactinib or placebo until disease progression, unacceptable toxicity, or withdrawal occurred. The coprimary end points were PFS and overall survival (OS). Quality of life (QoL) was assessed using the Lung Cancer Symptom Scale for Mesothelioma tool., Results: Three hundred forty-four patients were randomly assigned to receive either defactinib (n = 173) or placebo (n = 171). The median PFS was 4.1 months (95% CI, 2.9 to 5.6 months) for defactinib versus 4.0 months (95% CI, 2.9 to 4.2 months) for placebo. The median OS was 12.7 months (95% CI, 9.1 to 21 months) for defactinib versus 13.6 months (95% CI, 9.6 to 21.2 months) for placebo (hazard ratio, 1.0; 95% CI, 0.7 to 1.4). Although shorter survival for both defactinib- and placebo-treated patients was observed, in the patients who had merlin-low MPM compared with the patients who had merlin-high MPM, there were no statistical differences in response rate, PFS, OS, or QoL between the treatment groups. The most common grade 3 or worse adverse events were nausea, diarrhea, fatigue, dyspnea, and decreased appetite., Conclusion: Neither PFS nor OS was improved by defactinib after first-line chemotherapy in patients with merlin-low MPM. Defactinib cannot be recommended as maintenance therapy for advanced MPM.

Background: Mesothelioma is an incurable, apoptosis-resistant cancer caused in most cases by previous exposure to asbestos and is increasing in incidence. It represents a growing health burden but remains under-researched, with limited treatment options. Early promising signals of activity relating to both PD-L1- and PD-1-targeted treatment in mesothelioma implicate a dependency of mesothelioma on this immune checkpoint. There is a need to evaluate checkpoint inhibitors in patients with relapsed mesothelioma where treatment options are limited., Methods: The addition of 12 months of nivolumab (anti-PD1 antibody) to standard practice will be conducted in the UK using a randomised, placebo-controlled phase III trial (the Cancer Research UK CONFIRM trial). A total of 336 patients with pleural or peritoneal mesothelioma who have received at least two prior lines of therapy will be recruited from UK secondary care sites. Patients will be randomised 2:1 (nivolumab:placebo), stratified according to epithelioid/non-epithelioid, to receive either 240 mg nivolumab monotherapy or saline placebo as a 30-min intravenous infusion. Treatment will be for up to 12 months. We will determine whether the use of nivolumab increases overall survival (the primary efficacy endpoint). Secondary endpoints will include progression-free survival, objective response rate, toxicity, quality of life and cost-effectiveness. Analysis will be performed according to the intention-to-treat principle using a Cox regression analysis for the primary endpoint (and for other time-to-event endpoints)., Discussion: The outcome of this trial will provide evidence of the potential benefit of the use of nivolumab in the treatment of relapsed mesothelioma. If found to be clinically effective, safe and cost-effective it is likely to become the new standard of care in the UK., Trial Registration: EudraCT Number: 2016-003111-35 (entered on 21 July 2016); ClinicalTrials.gov, ID: NCT03063450 . Registered on 24 February 2017.

Competing Interests: Competing interests: LD has received funding from Irwin Mitchell and Lilly Oncology. DF has received funding from Roche, MSD, Lilly, BI, BMS, Bayer and Astex. SH has received from GSK, Chiesi, Astra Zeneca, Mediconf, Pfizer, Sandoz, Napp. KK has received funding from AZ, BI, BMS, Lilly, Merck, MSD, Novartis, Pfizer, Roche. NM has received funding from BD. NR has received funding from Rocket Medical.

Objectives: There is little evidence regarding the use of chemotherapy as part of multimodality treatment of malignant pleural mesothelioma (MPM). We aimed to determine whether, in those patients fit for chemotherapy, a delay in this treatment affected survival., Materials and Methods: We analysed postoperative variables of 229 patients undergoing either extrapleural pneumonectomy (EPP) (81 patients) or extended pleurectomy-decortication (EPD) (197 patients) for MPM at a single centre. There was no standard protocol for additional chemotherapy and varied with referral centre. Outcome was compared between 4 chemotherapy strategies: true adjuvant therapy, neo-adjuvant therapy, therapy reserved until evidence of disease progression in those otherwise fit in the post-operative setting, and those unfit for chemotherapy., Results: There was no effect of the timing of chemotherapy on overall or progression free survival in patients fit enough for treatment (p=0.39 and p=0.33 respectively). However delaying chemotherapy until evidence of disease progression in patients with non-epithelioid disease had a detrimental effect on overall survival (OS), and on progression free survival (PFS) in lymph node positive patients (15.6 vs. 8.2 months p=0.001, and 14.9 vs. 6.0 months p=0.016). Further analysis of 169 patients receiving platinum/pemetrexed as first line treatment, showed similar results; there was no effect of the timing of chemotherapy on OS or PFS (p=0.80 and p=0.53 respectively) and an improved OS in patients with non-epithelioid disease, and improved PFS in those with lymph node metastases, if chemotherapy was given in the immediate adjuvant setting (p=0.001 and 0.038) when therapy was not delayed until disease progression., Conclusion: Our results suggest that the timing of additional chemotherapy may be important in those with a poorer prognosis on the basis of cell type and nodal stage. In these patients additional postoperative chemotherapy should not be delayed., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Background: Response criteria have always been difficult to apply to malignant pleural mesothelioma (MPM), due to its unique pattern of growth. We developed some models to show that progression free survival rate (PFSR) could be a better predictor of overall survival (OS) than the response rate (RR) in MPM patients. The results were validated independently in the European Organisation for Research and Treatment of Cancer (EORTC) 08052, a phase II study in MPM., Methods: Individual patient data from 10 EORTC-Lung Cancer Group (LCG) studies of first-line chemotherapy in MPM were pooled. Response to therapy was assessed according to World Health Organisation (WHO) criteria in all except the two most recent trials, which used Response Evaluation Criteria in Solid Tumours (RECIST). Landmark analyses (LA) at 9 weeks and 18 weeks after registration/randomisation were performed to assess the association between PFSR and OS. Independent validation of the results was conducted in EORTC 08052 study (82 patients) employing the same LA., Results: All 10 studies (N=523 patients) were included in the LA of PFSR at 9 and 18 weeks (PFSR-9 and PFSR-18). PFSR-9 and PFSR-18 were confirmed as predictors of OS, with hazard ratio (HR) of 0.37 (95% confidence interval (CI), 0.30-0.47) and 0.50 (0.38-0.65) and C-index of 0.62 and 0.58, respectively. In the validation study, 28.4% achieved CR/PR and 77.8% had disease control (CR/PR/SD) as their best overall response. PFSR-9 and PFSR-18 weeks were both strongly correlated with OS (HR of 0.35 [80% CI, 0.25-0.49] and 0.46 (0.32-0.67) and C-index of 0.66 and 0.60, respectively)., Conclusion: PFSR-18 was strongly correlated and discriminated patients with better OS from the poorer prognosis patients. An earlier end-point, PFSR-9 was also strongly correlated to OS with better discriminating capacity. The results were independently validated., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Background: There is currently no early predictive marker of survival for patients receiving chemotherapy for malignant pleural mesothelioma (MPM). Tumour response may be predictive for overall survival (OS), though this has not been explored. We have thus undertaken a combined-analysis of OS, from a 42day landmark, of 526 patients receiving systemic therapy for MPM. We also validate published progression-free survival rates (PFSRs) and a progression-free survival (PFS) prognostic-index model., Methods: Analyses included nine MPM clinical trials incorporating six European Organisation for Research and Treatment of Cancer (EORTC) studies. Analysis of OS from landmark (from day 42 post-treatment) was considered regarding tumour response. PFSR analysis data included six non-EORTC MPM clinical trials. Prognostic index validation was performed on one non-EORTC data-set, with available survival data., Results: Median OS, from landmark, of patients with partial response (PR) was 12·8months, stable disease (SD), 9·4months and progressive disease (PD), 3·4months. Both PR and SD were associated with longer OS from landmark compared with disease progression (both p<0·0001). PFSRs for platinum-based combination therapies were consistent with published significant clinical activity ranges. Effective separation between PFS and OS curves provided a validation of the EORTC prognostic model, based on histology, stage and performance status., Conclusion: Response to chemotherapy is associated with significantly longer OS from landmark in patients with MPM., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Based on promising preclinical efficacy of bortezomib in mesothelioma, a single-arm phase II trial (Ireland Cooperative Oncology Research Group 05-10 study), with Simon's two-stage design, was undertaken to assess efficacy of bortezomib monotherapy in the first-line (poor performance status) and second-line settings. The Bcl-2 homology domain 3-only protein Noxa has been implicated as a key inducer of apoptosis by bortezomib. Thus, in a biomarker research substudy, we hypothesized that deficiency in Noxa expression might correlate with resistance. In the second-line setting, 23 patients were enrolled. Partial response was confirmed in one patient (4.8%) who received four cycles of bortezomib. One patient had stable disease; however, progression occurred in the majority of patients within the first two cycles. Median progression-free survival and overall survival were 2.1 and 5.8 months, respectively. In the first-line setting, ten patients were accrued, and there was no evidence of objective response. In the tumor analysis, expression of Noxa was seen in all biopsies. Bortezomib monotherapy exhibits insufficient activity to warrant further investigation in unselected patients with mesothelioma.

Therapeutic options for malignant pleural mesothelioma (MPM) are limited despite the increasing incidence globally. The vinca alkaloid vinorelbine exhibits clinical activity; however, to date, treatment optimization has not been achieved using biomarkers. BRCA1 regulates sensitivity to microtubule poisons; however, its role in regulating vinorelbine-induced apoptosis in mesothelioma is unknown. Here we demonstrate that BRCA1 plays an essential role in mediating vinorelbine-induced apoptosis, as evidenced by (1) the strong correlation between vinorelbine sensitivity and BRCA1 expression level; (2) induction of resistance to vinorelbine by BRCA1 using siRNA oligonucleotides; (3) dramatic down-regulation of BRCA1 following selection for vinorelbine resistance; and (4) the re-activation of vinorelbine-induced apoptosis following re-expression of BRCA1 in resistant cells. To determine whether loss of BRCA1 expression in mesothelioma was potentially relevant in vivo, BRCA1 immunohistochemistry was subsequently performed on 144 primary mesothelioma specimens. Loss of BRCA1 protein expression was identified in 38.9% of samples. Together, these data suggest that BRCA1 plays a critical role in mediating apoptosis by vinorelbine in mesothelioma, warranting its clinical evaluation as a predictive biomarker., (Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

Introduction: Malignant pleural mesothelioma (MPM) is a rapidly fatal malignancy that is increasing in incidence. The caspase 8 inhibitor FLIP is an anti-apoptotic protein over-expressed in several cancer types including MPM. The histone deacetylase (HDAC) inhibitor Vorinostat (SAHA) is currently being evaluated in relapsed mesothelioma. We examined the roles of FLIP and caspase 8 in regulating SAHA-induced apoptosis in MPM., Methods: The mechanism of SAHA-induced apoptosis was assessed in 7 MPM cell lines and in a multicellular spheroid model. SiRNA and overexpression approaches were used, and cell death was assessed by flow cytometry, Western blotting and clonogenic assays., Results: RNAi-mediated FLIP silencing resulted in caspase 8-dependent apoptosis in MPM cell line models. SAHA potently down-regulated FLIP protein expression in all 7 MPM cell lines and in a multicellular spheroid model of MPM. In 6/7 MPM cell lines, SAHA treatment resulted in significant levels of apoptosis induction. Moreover, this apoptosis was caspase 8-dependent in all six sensitive cell lines. SAHA-induced apoptosis was also inhibited by stable FLIP overexpression. In contrast, down-regulation of HR23B, a candidate predictive biomarker for HDAC inhibitors, significantly inhibited SAHA-induced apoptosis in only 1/6 SAHA-sensitive MPM cell lines. Analysis of MPM patient samples demonstrated significant inter-patient variations in FLIP and caspase 8 expressions. In addition, SAHA enhanced cisplatin-induced apoptosis in a FLIP-dependent manner., Conclusions: These results indicate that FLIP is a major target for SAHA in MPM and identifies FLIP, caspase 8 and associated signalling molecules as candidate biomarkers for SAHA in this disease., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Malignant pleural mesothelioma is an asbestos-related neoplasm with poor prognosis, refractory to current therapies, the incidence of which is expected to increase in the next decades. Female gender was identified as a positive prognostic factor among other clinical and biological prognostic markers for malignant mesothelioma, yet a role of estrogen receptors (ERs) has not been studied. Our goal was to investigate ERs expression in malignant mesothelioma and to assess whether their expression correlates with prognosis. Immunohistochemical analysis revealed intense nuclear ERbeta staining in normal pleura that was reduced in tumor tissues. Conversely, neither tumors nor normal pleura stained positive for ERalpha. Multivariate analysis of 78 malignant mesothelioma patients with pathologic stage, histologic type, therapy, sex, and age at diagnosis indicated that ERbeta expression is an independent prognostic factor of better survival. Moreover, studies in vitro confirmed that treatment with 17beta-estradiol led to an ERbeta-mediated inhibition of malignant mesothelioma cell proliferation as well as p21(CIP1) and p27(KIP1) up-regulation. Consistently cell growth was suppressed by ERbeta overexpression, causing a G(2)-M-phase cell cycle arrest, paralleled by cyclin B1 and survivin down-regulation. Our data support the notion that ERbeta acting as a tumor suppressor is of high potential relevance to prediction of disease progression and to therapeutic response of malignant mesothelioma patients.

Mesothelioma is a rare malignancy arising from mesothelial cells lining the pleura and peritoneum. Advances in modern technology have allowed the development of array based approaches to the study of disease allowing researchers the opportunity to study many genes or proteins in a high-throughput fashion. This review describes the current knowledge surrounding array based approaches with respect to mesothelioma research.

Malignant pleural mesothelioma is an aggressive thoracic malignancy associated with exposure to asbestos, and its incidence is anticipated to increase during the first half of this century. Chemotherapy is the mainstay of treatment, yet sufficiently robust evidence to substantiate the current standard of care has emerged only in the past 5 years. This Review summarizes the evidence supporting the clinical activity of chemotherapy, discusses the use of end points for its assessment and examines the influence of clinical and biochemical prognostic factors on the natural history of malignant pleural mesothelioma. Early-phase clinical trials of second-line and novel agents are emerging from an increased understanding of mesothelioma cell biology. Coupled with high-quality translational research, such developments have real potential to improve the outlook of patients at a time of increasing incidence.

Background: Malignant pleural mesothelioma (MPM) is a rapidly progressive lethal tumor. Treatment options remain limited and the outcome in recurrent disease is poor., Methods: A Phase II open-label noncomparative study was conducted to assess the safety and efficacy of the triplet combination irinotecan, cisplatin, and mitomycin-C (IPM) chemotherapy in untreated patients and in those with previous exposure to chemotherapy., Results: In 62 patients an objective response rate of 25% was observed. In the first-line setting progression-free survival measured 6.4 months (95% confidence interval [CI]: 4.5-7.3) and overall survival was 10.8 months (95% CI: 7.9-13.7). In the second-line setting progression-free survival was 7.3 months (95% CI: 3.4-11.2) and overall survival was also 7.3 months (95% CI: 4.8-9.8). Psychosocial well-being improved during chemotherapy and the main toxicity observed was neutropenia (40%)., Conclusions: IPM appeared to have a reasonable response rate with an acceptable toxicity profile in the first- and second-line treatment of MPM., ((c) 2006 American Cancer Society.)

Purpose: Malignant pleural mesothelioma (MPM) is an increasing health burden on many societies worldwide and, being generally resistant to conventional treatment, has a poor prognosis with a median survival of <1 year. Novel therapies based on the biology of this tumor seek to activate a proapoptotic cellular pathway. In this study, we investigated the expression and biological significance of argininosuccinate synthetase (AS), a rate-limiting enzyme in arginine production., Experimental Design: Initially, we documented down-regulation of AS mRNA in three of seven MPM cell lines and absence of AS protein in four of seven MPM cell lines. We confirmed that the 9q34 locus, the site of the AS gene, was intact using a 1-Mb comparative genomic hybridization array; however, there was aberrant promoter CpG methylation in cell lines lacking AS expression, consistent with epigenetic regulation of transcription. To investigate the use of AS negativity as a therapeutic target, arginine was removed from the culture medium of the MPM cell lines., Results: In keeping with the cell line data, 63% (52 of 82) of patients had tumors displaying reduced or absent AS protein, as assessed using a tissue microarray. Cell viability declined markedly in the AS-negative cell lines 2591 and MSTO but not in the AS-positive cell line, 28. This response was apparent by day 4 and maintained by day 9 in vitro. Arginine depletion induced BAX conformation change and mitochondrial inner membrane depolarization selectively in AS-negative MPM cells., Conclusions: In summary, we have identified AS negativity as a frequent event in MPM in vivo, leading to susceptibility to cytotoxicity following restriction of arginine. A phase II clinical trial is planned to evaluate the role of arginine depletion in patients with AS-negative MPM.

Malignant pleural mesothelioma (MPM) is a highly chemoresistant cancer with a poor prognosis. Hypoxia is a specific property of solid tumours, contributes to low apoptotic potential, and can be selectively targeted by bioreductive drugs. Hypoxia-inducible factor 1alpha (HIF-1alpha) is a subunit of a heterodimeric transcription complex that regulates several genes associated with tumour progression and anti-apoptosis. In this study, we measured for the first time the expression of HIF-1alpha in MPM. Our results show that HIF-1alpha is commonly expressed in MPM but not in normal mesothelium, consistent with the presence of hypoxia. HIF-1alpha does not appear to predict survival; however, this study suggests that bioreductive drugs should be investigated in clinical trials of MPM.

Prognostic factors can help clinicians and patients when deciding a treatment plan. Patients in the best prognostic groups can be considered for more intensive or experimental therapy. Alternatively, patients in the best prognostic groups might prefer a period of observation prior to commencement of therapy. For patients with mesothelioma prognostic factors are potentially especially important because of the lack of a widely applicable anatomical staging system. Both the International Mesothelioma Interest Group (IMIG) and Brigham staging systems are of limited relevance to patients not undergoing radical debulking surgery. Radiological prediction of IMIG or Brigham stage is of little value. Review of the best-known prognostic scoring systems from the EORTC and CALGB has shown that the most important predictors of poor prognosis are: poor performance status; non-epithelioid histology; male gender; low hemoglobin; high platelet count; high white blood cell count; and high lactate dehydrogenase (LDH). The EORTC model was validated at St Bartholomew's Hospital in a group of 145 patients treated in sequential phase II chemotherapy trials. For 70 patients treated with vinorelbine, those having the best EORTC prognosis had a median survival of 19.2 months [95% C.I.=14.7-23.7] compared to 9.9 months [95% C.I.=8.5-11.3] for those in the worst group. The suggestion is that all clinical and biological factors relevant to prognosis should be recorded prospectively in mesothelioma patients selected for clinical trials.

Unlabelled: The incidence of malignant pleural mesothelioma (MPM) is increasing. Treatment options are limited, although recently published data have offered cause for optimism. We reported a response rate of 24% with low toxicity for single agent vinorelbine. Here we report a phase II trial of vinorelbine with oxaliplatin (VO) in patients with untreated MPM. Chemotherapy consisted of vinorelbine 30 mg/m(2), days 1 and 8 of a 21-day-cycle, and oxaliplatin 130 mg/m(2), day 1. Treatment continued up to six cycles. The primary endpoint was objective response. Secondary endpoints were toxicity, progression-free and overall survival. Responses were assessed by modified RECIST criteria. Twenty-six patients were enrolled. There were six partial remissions, 17 patients with stable disease, and three patients with PD. Response rate was 23% (95% confidence interval 9-44%). Median number of cycles delivered was four. Progression-free survival from first treatment was 4.7 months, and overall survival was 8.8 months. One-year-survival was 27%. Toxicity (% of patients with at least one episode of grade 3 or 4 toxicity): neutropenia 18%, phlebitis 12%, malaise 12%, anorexia 12%, nausea and vomiting 12%, constipation 6%. Quality of life assessed by Rotterdam symptom checklist was associated with stabilization or improvement of psychological well-being and lung symptoms in the majority of patients, but deterioration in physical symptoms., Conclusion: VO has activity in MPM with most patients responding or having stable disease, although this doublet is associated with significant toxicity.

Purpose: Malignant pleural mesothelioma (MPM) carries a poor prognosis due to chemoresistance. The European Organisation for Research and Treatment of Cancer (EORTC) prognostic model was reported to predict survival in MPM. Our retrospective analysis set out to test the validity of the model as a prognostic tool in patients treated in three phase II trials at St Bartholomew's Hospital (London, United Kingdom) between 1999 and 2003., Patients and Methods: A total of 145 patients were treated in three phase II trials; vinorelbine (VIN; 70 patients), vinorelbine/oxaliplatin (VO; 26 patients), and irinotecan/cisplatin/mitomycin C (IPM; 49 patients). Two subgroups, high-risk and low-risk, were defined by EORTC prognostic score (EPS). EPS was determined by a five-parameter model incorporating age, sex, histology, probability of diagnosis, and leukocyte count. An EPS cutoff of less than 1.27 (low risk) or more than 1.27 (high risk) was used to stratify Kaplan-Meier survival curves. Each of the EPS variables exhibited either trends or significant stratification of overall survival (OS)., Results: Multivariate analysis confirmed leukocyte count, Eastern Cooperative Oncology Group performance status, and sarcomatous histology as independent prognostic variables. EPS stratified OS in both individual and pooled trial datasets. No association between objective tumor response and EPS classification was identified by multinomial logistic regression. EPS stratified progression-free survival for the VO and IPM cohorts, but not for VIN., Conclusion: This study validates the EPS system as a robust tool for stratifying small trials into low- and high-risk subgroups. EPS should facilitate patient selection and analysis in randomized clinical trials.

Because of a lack of effective treatments, survival from diffuse pleural mesothelioma remains poor. Many people do not think that treatments for this disease are effective. The understanding of the biology of mesothelioma relevant to the apoptosis-resistant phenotype has been slow to advance. However, this is now changing, and strategies for rational therapeutic drug development are emerging that have the potential to change the natural history and improve survival in the increasing number of patients that will be diagnosed in the next two decades. This review discusses recent developments in apoptosis biology that are specific to mesothelioma and the therapeutic implications for this aggressive cancer.