Efficacy and safety of pembrolizumab in patients with advanced mesothelioma in the open-label, single-arm, phase 2 KEYNOTE-158 study

Pembrolizumab-induced vasculitis demonstrated by FDG-PET/CT

A 76-year-old man with a history of malignant pleural mesothelioma treated with pembrolizumab underwent FDG-PET/CT for restaging. The images demonstrated FDG uptake overlying the right hepatic and splenic artery, which were new from the previous FDG-PET/CT 2.5 years prior before the patient started pembrolizumab, suspicious for vasculitis. A follow-up MRI supported the diagnosis with evidence of celiac, splenic, common hepatic, and right hepatic artery involvement. Pembrolizumab was discontinued and the patient received a short course of oral glucocorticoids. Subsequent FDG-PET/CT performed 14 months after initiation of treatment for vasculitis demonstrated resolution of vasculitis. Immune checkpoint inhibitors can cause vasculitis, which can be recognized on FDG-PET/CT and lead to appropriate treatment.

Emerging biomarkers for immunotherapy response in biliary tract cancers: a comprehensive review of immune checkpoint inhibitor strategies

Biliary tract cancers (BTCs) have rising incidence and mortality rates. Chemotherapy's limited efficacy has led to exploring new treatments like immunotherapy. which offers modest benefits. Moreover, the identification of reliable predictive biomarkers for immune checkpoint therapy in BTCs remains elusive, hindering personalized treatment strategies. This review provides an overview of the current landscape of emerging biomarkers for immunotherapy response in BTCs. We discuss the incremental benefits of combination therapy and the evolving role of immunotherapy in managing advanced BTC. Additionally, we highlight the need for robust predictive biomarkers to optimize treatment outcomes and foster a more individualized approach to patient care. We aim to identify promising research avenues and strategies to enhance therapeutic efficacy and patient survival in BTCs.

Genomic and T cell repertoire biomarkers associated with malignant mesothelioma survival

BACKGROUND

Malignant mesothelioma (MM) is an exceedingly rare tumor with poor prognosis due to the limited availability of effective treatment. Immunotherapy has emerged as a novel treatment approach for MM, but less than 40% of the patients benefit from it. Thus, it is necessary to identify accurate and effective biomarkers that can predict the overall survival (OS) and immunotherapy efficacy for MM.

METHODS

DNA sequencing was used to identify the genomic landscape based on the data from 86 Chinese patients. T cell receptor (TCR) sequencing was used to characterize MM TCR repertoires of 28 patients between October 2016 and April 2023.

RESULTS

Patients with TP53, NF2, or CDKN2A variants at the genomic level, as well as those exhibiting lower Shannon index (<6.637), lower evenness (<0.028), or higher clonality (≥0.194) according to baseline tumor tissue TCR indexes, demonstrated poorer OS. Furthermore, patients with TP53, CDKN2A, or CDKN2B variants and those with a lower evenness (<0.030) in baseline tumor tissue showed worse immunotherapy efficacy. The present study is the first to identify five special TCR Vβ-Jβ rearrangements associated with MM immunotherapy efficacy.

CONCLUSIONS

The present study reported the largest-scale genomic landscape and TCR repertoire of MM in Chinese patients and identified genomic and TCR biomarkers for the prognosis and immunotherapy efficacy in MM. The study results might provide new insights for prospective MM trials using specific genes, TCR indexes, and TCR clones as biomarkers and offer a reference for future antitumor drugs based on TCR-specific clones.

Brief Report: Real-World Toxicity and Survival of Combination Immunotherapy in Pleural Mesothelioma-RIOMeso

BACKGROUND

Australia has one of the highest rates of asbestos-associated diseases. Mesothelioma remains an area of unmet need with a 5-year overall survival of 10%. First-line immunotherapy with ipilimumab and nivolumab is now a standard of care for unresectable pleural mesothelioma following the CheckMate 743 trial, with supportive data from the later line single-arm MAPS2 trial. RIOMeso evaluates survival and toxicity of this regimen in real-world practice.

METHODS

Demographic and clinicopathologic data of Australian patients treated with ipilimumab and nivolumab in first- and subsequent-line settings for pleural mesothelioma were collected retrospectively. Survival was reported using the Kaplan-Meier method and compared between subgroups with the log-rank test. Toxicity was investigator assessed using Common Terminology Criteria for Adverse Events version 5.0.

RESULTS

A total of 119 patients were identified from 11 centers. The median age was 72 years, 83% were male, 92% had Eastern Cooperative Oncology Group less than or equal to 1, 50% were past or current smokers, and 78% had known asbestos exposure. In addition, 50% were epithelioid, 19% sarcomatoid, 14% biphasic, and 17% unavailable. Ipilimumab and nivolumab were used first line in 75% of patients. Median overall survival (mOS) was 14.5 months (95% confidence interval [CI]: 13.0-not reached [NR]) for the entire cohort. For patients treated first line, mOS was 14.5 months (95% CI: 12.5-NR) and in second- or later-line patients was 15.4 months (95% CI: 11.2-NR). There was no statistically significant difference in mOS for epithelioid patients compared with nonepithelioid (19.1 mo [95% CI: 15.4-NR] versus 13.0 mo [95% CI: 9.7-NR], respectively, p = 0.064). Furthermore, 24% of the patients had a Common Terminology Criteria for Adverse Events grade greater than or equal to 3 adverse events, including three treatment-related deaths. Colitis was the most frequent adverse event.

CONCLUSIONS

Combination immunotherapy in real-world practice has poorer survival outcomes and seems more toxic compared with clinical trial data. This is the first detailed report of real-world survival and toxicity outcomes using ipilimumab and nivolumab treatment of pleural mesothelioma.

Immunotherapy of mesothelioma: the evolving change of a long-standing therapeutic dream

Pleural mesothelioma (PM) is an aggressive and rare disease, characterized by a very poor prognosis. For almost two decades, the world standard treatment regimen for unresectable PM has consisted of a platinum-based drug plus pemetrexed, leading to an overall survival of approximately 12 months. The dramatic therapeutic scenario of PM has recently changed with the entry into the clinic of immune checkpoint inhibition, which has proven to be an effective approach to improve the survival of PM patients. The aim of the present review is to provide a comprehensive overview of the most promising immunotherapeutic-based strategies currently under investigation for advanced PM.

Malignant Pleural Mesothelioma: Staging and Radiological Response Criteria in Patients Treated with Immune Checkpoint Inhibitors

Malignant pleural mesothelioma (MPM) is a rare and challenging cancer associated with asbestos fiber exposure, which offers limited treatment options. Historically, platinum-based chemotherapy has been the primary approach, but recent developments have introduced immunotherapy as a promising alternative for the treatment of this disease. Nevertheless, the unique growth patterns and occasionally ambiguous progressive characteristics of MPM make the interpretation of radiological assessments complex. Immunotherapy further complicates matters by introducing unconventional treatment response patterns such as hyperprogression and pseudoprogression. Consequently, there is a growing imperative to integrate the standard RECIST criteria with the mesothelioma-specific mRECIST criteria (version 1.1), as outlined in iRECIST. This comprehensive review is driven by the intent to provide a valuable resource for radiologists and clinicians engaged in the diagnosis, treatment, and monitoring of MPM in the era of immunotherapy. Specifically, the current imaging methods employed for staging and follow-up will be exposed and discussed, with a focus on the technical specificities and the mRECIST 1.1 methodology. Furthermore, we will provide a discussion about major clinical trials related to the use of immunotherapy in MPM patients. Finally, the latest advancements in radiomics, the applications of artificial intelligence in MPM, and their potential impact on clinical practice for prognosis and therapy, are discussed.

Current State-of-the-Art Therapy for Malignant Pleural Mesothelioma and Future Options Centered on Immunotherapy

Malignant pleural mesothelioma (MPM) is a locally aggressive disease related to asbestos exposure with a median survival for untreated patients of 4-8 months. The combination of chemotherapy based on platinum and antifolate is the standard treatment, and the addition of bevacizumab adds two months to median survival. Recently, in first-line treatment, immunotherapy combining nivolumab with ipilimumab has been shown to be superior to chemotherapy in the CheckMate-743 study in terms of overall survival (18.1 months), leading to its approval by the FDA and EMA. The positive results of this study represent a new standard of treatment for patients with MPM; however, not all patients will benefit from immunotherapy treatment. In an effort to improve the selection of patient candidates for immunotherapy for different tumors, biomarkers that have been associated with a greater possibility of response to treatment have been described. MPM is a type of tumor with low mutational load and neo-antigens, making it a relatively non-immunogenic tumor for T cells and possibly less susceptible to responding to immunotherapy. Different retrospective studies have shown that PD-L1 expression occurs in 20-40% of patients and is associated with a poor prognosis; however, the predictive value of PD-L1 in response to immunotherapy has not been confirmed. The purpose of this work is to review the state of the art of MPM treatment in the year 2023, focusing on the efficacy results of first-line or subsequent immunotherapy studies on patients with MPM and possible chemo-immunotherapy combination strategies. Additionally, potential biomarkers of response to immunotherapy will be reviewed, such as histology, PD-L1, lymphocyte populations, and TMB.

A first-in-human phase 1 study of nofazinlimab, an anti-PD-1 antibody, in advanced solid tumors and in combination with regorafenib in metastatic colorectal cancer

BACKGROUND

We assessed nofazinlimab, an anti-PD-1 antibody, in solid tumors and combined with regorafenib in metastatic colorectal cancer (mCRC).

METHODS

This phase 1 study comprised nofazinlimab dose escalation (phase 1a) and expansion (phase 1b), and regorafenib dose escalation (80 or 120 mg QD, days 1-21 of 28-day cycles) combined with 300-mg nofazinlimab Q4W (part 2a) to determine safety, efficacy, and RP2D.

RESULTS

In phase 1a (N = 21), no dose-limiting toxicity occurred from 1 to 10 mg/kg Q3W, with 200 mg Q3W determined as the monotherapy RP2D. In phase 1b (N = 87), 400-mg Q6W and 200-mg Q3W regimens were found comparable. In part 2a (N = 14), both regimens were deemed plausible RP2Ds. Fatigue was the most frequent treatment-emergent adverse event (AE) in this study. Any-grade and grade 3/4 nofazinlimab-related AEs were 71.4% and 14.3%, 56.3% and 5.7%, and 57.1% and 21.4% in phases 1a, 1b, and part 2a, respectively. ORRs were 14.3% and 25.3% in phases 1a and 1b, respectively. In part 2a, no patients had radiological responses.

CONCLUSIONS

Nofazinlimab monotherapy was well tolerated and demonstrated preliminary anti-tumor activity in multiple tumor types. Regorafenib plus nofazinlimab had a manageable safety profile but was not associated with any response in mCRC.

CLINICAL TRIAL REGISTR ATION

Clinicaltrials.gov (NCT03475251).

Zimberelimab plus chemotherapy as the first-line treatment of malignant peritoneal mesothelioma: A case report and review of literature

BACKGROUND

Malignant peritoneal mesothelioma (MPeM) is a rare cancer with a poor prognosis at advanced stage, and the standard first-line treatment for inoperable patients is chemotherapy. Although combining programmed cell death 1 (PD-1) inhibitors with chemotherapy is generally considered safe and effective in several malignant solid tumors, there are few reports regarding initial immunochemotherapy in advanced MPeM.

CASE SUMMARY

Here, to our knowledge, we present the first case of a patient with epithelioid subtype MPeM, who was treatment-naïve and benefited from initial PD-1 inhibitor plus standard chemotherapy with a prolonged progression-free survival (PFS) and good tolerance. A 49-year-old man was admitted to our hospital for a persistent burning sensation in the abdomen. Computed tomography revealed a solid mass in the lower abdomen, which was subsequently diagnosed histologically as epithelioid subtype MPeM by core needle biopsy. The patient received eight cycles of pemetrexed 800 mg (day 1), cisplatin 60/50 mg (day 1–2), and zimberelimab (PD-1 inhibitor) 240 mg (day 1) every 3 wk. He achieved significant reduction of peritoneal tumors with remarkable improvement in symptoms. The best tumor response was partial remission with a final PFS of 7 mo. No immune-related adverse event occurred during the combination treatment.

CONCLUSION

The outcome of the present case demonstrates the promising anti-tumor activity of immunochemotherapy to treat inoperable MPeM in the future.

Zimberelimab plus chemotherapy as the first-line treatment of malignant peritoneal mesothelioma: A case report and review of literature

BACKGROUND

Malignant peritoneal mesothelioma (MPeM) is a rare cancer with a poor prognosis at advanced stage, and the standard first-line treatment for inoperable patients is chemotherapy. Although combining programmed cell death 1 (PD-1) inhibitors with chemotherapy is generally considered safe and effective in several malignant solid tumors, there are few reports regarding initial immunochemotherapy in advanced MPeM.

CASE SUMMARY

Here, to our knowledge, we present the first case of a patient with epithelioid subtype MPeM, who was treatment-naïve and benefited from initial PD-1 inhibitor plus standard chemotherapy with a prolonged progression-free survival (PFS) and good tolerance. A 49-year-old man was admitted to our hospital for a persistent burning sensation in the abdomen. Computed tomography revealed a solid mass in the lower abdomen, which was subsequently diagnosed histologically as epithelioid subtype MPeM by core needle biopsy. The patient received eight cycles of pemetrexed 800 mg (day 1), cisplatin 60/50 mg (day 1-2), and zimberelimab (PD-1 inhibitor) 240 mg (day 1) every 3 wk. He achieved significant reduction of peritoneal tumors with remarkable improvement in symptoms. The best tumor response was partial remission with a final PFS of 7 mo. No immune-related adverse event occurred during the combination treatment.

CONCLUSION

The outcome of the present case demonstrates the promising anti-tumor activity of immunochemotherapy to treat inoperable MPeM in the future.

ARIH1 activates STING-mediated T-cell activation and sensitizes tumors to immune checkpoint blockade

Despite advances in cancer treatment, immune checkpoint blockade (ICB) only achieves complete response in some patients, illustrating the need to identify resistance mechanisms. Using an ICB-insensitive tumor model, here we discover cisplatin enhances the anti-tumor effect of PD-L1 blockade and upregulates the expression of Ariadne RBR E3 ubiquitin-protein ligase 1 (ARIH1) in tumors. Arih1 overexpression promotes cytotoxic T cell infiltration, inhibits tumor growth, and potentiates PD-L1 blockade. ARIH1 mediates ubiquitination and degradation of DNA-PKcs to trigger activation of the STING pathway, which is blocked by the phospho-mimetic mutant T68E/S213D of cGAS protein. Using a high-throughput drug screen, we further identify that ACY738, less cytotoxic than cisplatin, effectively upregulates ARIH1 and activates STING signaling, sensitizing tumors to PD-L1 blockade. Our findings delineate a mechanism that tumors mediate ICB resistance through the loss of ARIH1 and ARIH1-DNA-PKcs-STING signaling and indicate that activating ARIH1 is an effective strategy to improve the efficacy of cancer immunotherapy.

Improvements in Systemic Therapies for Advanced Malignant Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare and aggressive malignancy associated with poor prognosis and a 5-year survival rate of 12%. Many drugs have been tested over the years with conflicting results. The aim of this review is to provide an overview of current therapies in MPM and how to best interpret the data available on these drugs. Furthermore, we focused on promising treatments under investigation, such as immunotherapy with targets different from anti-PD-1/PD-L1 inhibitors, vaccines, target therapies, and metabolism-based strategies.

A Novel Two-Gene Expression-Based Prognostic Score in Malignant Pleural Mesothelioma

BACKGROUND

Malignant pleural mesothelioma (MPM) is a rare cancer type with an increasing incidence worldwide. We aimed to develop a rational gene expression-based prognostic score in MPM using publicly available datasets.

METHODS

We developed and validated a two-gene prognostic score (2-PS) using three independent publicly available gene expression datasets. The 2-PS was built using the Robust Likelihood-Based Survival Modeling with Microarray Data method.

RESULTS

We narrowed down the model building to the analysis of 179 genes, which have been shown previously to be of importance to MPM development. Our statistical approach showed that a model including two genes (GOLT1B and MAD2L1) was the best predictor for overall survival (OS) (p < 0.0001). The binary score based on the median of the continuous score stratified the patients into low and high score groups and also showed statistical significance in uni- and multivariate models. The 2-PS was validated using two independent transcriptomic datasets. Furthermore, gene set enrichment analysis using training and validation datasets showed that high score patients had distinct gene expression profiles. Our 2-PS also showed a correlation with the estimated infiltration by some immune cell fractions such as CD8+ T cells and M1/2 macrophages. Finally, 2-PS correlated with sensitivity or resistance to some commonly used chemotherapeutic drugs.

CONCLUSION

This is the first study to demonstrate good performance of only two-gene expression-based prognostic scores in MPM. Our initial approach for features selection allowed for an increased likelihood for the predictive value of the developed score, which we were also able to demonstrate.

Immunotherapy vs. Chemotherapy in Subsequent Treatment of Malignant Pleural Mesothelioma: Which Is Better?

(1) Background: Malignant pleural mesothelioma (MPM) is a rare but aggressive tumor arising from the pleural surface. For relapsed MPM, there is no accepted standard of- are for subsequent treatment. Thus, we aimed to compare the efficacy of chemotherapy, targeting drugs, and immune-checkpoint inhibitors (ICIs) as subsequent therapy for relapsed MPM. (2) Methods: The study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We searched several acknowledged databases. Primary outcomes were defined as overall median progressive survival (mPFS) and median overall survival (mOS) in different treatment groups. Secondary outcomes were defined as objective response rate (ORR), the proportion of stable disease (SD), and progressive disease (PD). (3) Results: Ultimately, 43 articles were selected for the meta-analysis. According to the results of a pooled analysis of single-arm studies, ICIs showed a slight advantage in mOS, while chemotherapy showed a slight advantage in mPFS (mOS: 11.2 m vs. 10.39 m and mPFS: 4.42 m vs. 5.08 m for ICIs group and chemotherapy group, respectively). We identified only a few studies that directly compared the efficacy of ICIs with that of chemotherapy, and ICIs did not show significant benefits over chemotherapy based on mOS. (4) Conclusions: Based on current evidence, we considered that immunotherapy might not be superior to chemotherapy as a subsequent therapy for relapsed MPM. Although several studies investigated the efficacy of ICIs, targeting drugs, and chemotherapy in relapsed MPM, there was still no standard of care. Further randomized control trials with consistent criteria and outcomes are recommended to guide subsequent therapy in relapsed MPM and identify patients with certain characteristics that might benefit from such subsequent therapy.

Immunotherapies in rare cancers

Cancer remains a leading cause of death worldwide, placing a significant burden on healthcare systems as well as the global economy. Rare cancers comprise a group of about 200 cancers that individually occur at extremely low frequencies. In the United States (US), their frequency is approximately 15 cases per 100,000 people, and it is even lower in Europe with approximately 6 cases per 100,000 people. However, combined their frequency of occurrence is much higher than any singular cancer. Cancer treatment and management has tremendously improved in the last decade, particularly with the administration of immune-based therapies. The four most prevalent immune-based therapies are (1) the use of immune-checkpoint inhibitors, (2) macrophage therapy, (3) Chimeric Antigen Receptor (CAR) T cell therapy, and (4) neoantigen-based therapies. In our review, we discuss these various aproaches and their implementation in the treatment of a variety of rare cancers. Furthermore, we discuss their limitations and potential strategies to overcome them to enhance the therapeutic efficacy of these approaches. Finally, our article presents the future directions and other additional immune therapies that may be incorporated into the treatment of rare cancers.

Immunotherapy with immune checkpoint inhibitors and predictive biomarkers in malignant mesothelioma: Work still in progress

Malignant mesothelioma (MM) is a rare and aggressive neoplasm, usually associated with a poor prognosis (5 years survival rate <10%). For unresectable disease, platinum and pemetrexed chemotherapy has been the only standard of care in first line for more than two decades, while no standard treatments have been approved in subsequent lines. Recently, immunotherapy has revolutionized the therapeutic landscape of MM. In fact, the combination of ipilimumab plus nivolumab has been approved in first line setting. Moreover, immune checkpoint inhibitors (ICIs) showed promising results also in second-third line setting after platinum-based chemotherapy. Unfortunately, approximately 20% of patients are primary refractory to ICIs and there is an urgent need for reliable biomarkers to improve patient's selection. Several biological and molecular features have been studied for this goal. In particular, histological subtype (recognized as prognostic factor for MM and predictive factor for chemotherapy response), programmed death ligand 1 (PD-L1) expression, and tumor mutational burden (widely hypothesized as predictive biomarkers for ICIs in several solid tumors) have been evaluated, but with unconclusive results. On the other hand, the deep analysis of tumor infiltrating microenvironment and the improvement in genomic profiling techniques has led to a better knowledge of several mechanisms underlying the MM biology and a greater or poorer immune activation. Consequentially, several potential biomarkers predictive of response to immunotherapy in patients with MM have been identified, also if all these elements need to be further investigated and prospectively validated. In this paper, the main evidences about clinical efficacy of ICIs in MM and the literature data about the most promising predictive biomarkers to immunotherapy are reviewed.

Prognostic value of tumor mutation burden in patients with advanced gastric cancer receiving first-line chemotherapy

Background

Tumor mutation burden (TMB) is a promising biomarker positively associated with the benefit of immunotherapy and that might predict the outcome of chemotherapy. We described the prognostic value of TMB in advanced gastric cancer and explored the underlying mechanism.

Methods

We enrolled 155 TMB-evaluated advanced gastric cancer patients and analyzed the relationship between clinicopathological characteristics and both overall survival (OS) and progression-free survival (PFS) among 40 patients treated with first-line chemotherapy. We further verified the distribution of TMB and analyzed the potential mechanism underlying the prognosis based on The Cancer Genome Atlas (TCGA) database.

Results

Among the 155 patients, 29 (18.7%) were TMB-high (TMB ≥ 10), roughly the same as the proportion in the TCGA data. Of the 40 patients receiving first-line chemotherapy, the median OS (7.9 vs. 12.1 months; HR 3.18; p = 0.0056) and PFS (4.4 vs. 6.2 months; HR 2.94; p = 0.0099) of the tissue-tested TMB (tTMB)-high patients were inferior to those of the tTMB-low patients. Similarly, unfavorable median OS (9.9 vs. 12.1 months; HR 2.11; p = 0.028) and PFS (5.3 vs. 6.5 months; HR 2.49; p = 0.0054) were shown in the blood-tested TMB (bTMB)-high than in the bTMB-low patients. The Cox analysis demonstrated that both tTMB-high and bTMB-high were significant independent predictors of dreadful OS and PFS. The differentially expressed genes (DEGs) according to TMB status were most significantly enriched in the downregulated metabolic pathway among the TMB-high patients.

Conclusions

TMB-high advanced gastric cancer patients accounted for around one-sixth and had a poorer prognosis than TMB-low patients when treated with first-line chemotherapy. The potential mechanism might be the downregulated metabolic activity in TMB-high patients.

Focused ultrasound-mediated small-molecule delivery to potentiate immune checkpoint blockade in solid tumors

In the last decade, immune checkpoint blockade (ICB) has revolutionized the standard of treatment for solid tumors. Despite success in several immunogenic tumor types evidenced by improved survival, ICB remains largely unresponsive, especially in "cold tumors" with poor lymphocyte infiltration. In addition, side effects such as immune-related adverse events (irAEs) are also obstacles for the clinical translation of ICB. Recent studies have shown that focused ultrasound (FUS), a non-invasive technology proven to be effective and safe for tumor treatment in clinical settings, could boost the therapeutic effect of ICB while alleviating the potential side effects. Most importantly, the application of FUS to ultrasound-sensitive small particles, such as microbubbles (MBs) or nanoparticles (NPs), allows for precise delivery and release of genetic materials, catalysts and chemotherapeutic agents to tumor sites, thus enhancing the anti-tumor effects of ICB while minimizing toxicity. In this review, we provide an updated overview of the progress made in recent years concerning ICB therapy assisted by FUS-controlled small-molecule delivery systems. We highlight the value of different FUS-augmented small-molecules delivery systems to ICB and describe the synergetic effects and underlying mechanisms of these combination strategies. Furthermore, we discuss the limitations of the current strategies and the possible ways that FUS-mediated small-molecule delivery systems could boost novel personalized ICB treatments for solid tumors.

Immune Checkpoint Inhibitors in Malignant Pleural Mesothelioma: A Systematic Review and Meta-Analysis

Many clinical trials have investigated the role of ICIs in PM, with contrasting results. We performed a systematic review and meta-analysis of clinical trials testing single-agent anti-Programmed Death -1 (PD-1)/Programmed Death-Ligand 1 (PD-L1), anti-Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) or combined treatment in PM patients, analyzing response and survival rate as well as safety data. We selected 17 studies including 2328 patients. Both OS and PFS rates were significantly higher with combined ICI treatments than with single agent anti-PD-1/PD-L1 (p < 0.001 and p = 0.006, respectively) or anti CTLA-4 (p < 0.001) treatments. ORR and DCR for all ICI treatments were 20% (95% CI 13−27%) and 56% (95% CI 45−67%), respectively, and they did not significantly differ between combined and single agent treatments (p = 0.088 and p = 0.058, respectively). The 12-month OS and 6-month PFS rates did not differ significantly (p = 0.0545 and p = 0.1464, respectively) among pre-treated or untreated patients. Combined ICI treatments had a significantly higher rate of Adverse Events (AEs) (p = 0.01). PD-L1-positive patients had a higher probability of response and survival. In conclusion, combined ICI treatments have higher efficacy than single agents but are limited by higher toxicity. Efficacy was independent of treatment line, so a customized sequential strategy should still be speculated. PD-L1 expression could influence response to ICIs; however, reliable biomarkers are warranted.

Comparison of Survival by Multimodal Treatment Regimen Among Malignant Pleural Mesothelioma Patients in an Integrated Health System

BACKGROUND

Optimal therapy for malignant pleural mesothelioma (MPM) remains unclear. We compared overall survival in patients with MPM after various multimodal treatment regimens including combinations of immunotherapy, chemotherapy, and surgery.

PATIENTS AND METHODS

We examined MPM patients treated within our integrated health system from January 1, 2009 to December 31, 2020. Patients were grouped based on treatment regimen: chemotherapy alone (CT), immunotherapy with or without chemotherapy (iCT), surgery with chemotherapy (sCT), and surgery with immunotherapy and chemotherapy (siCT). We analyzed baseline characteristics and overall patient survival among these groups and several subgroups.

RESULTS

One hundred seventy-nine patients were included. Among the study groups, there was no difference in age, sex, race/ethnicity, Charlson Comorbidity Index, or Eastern Cooperative Oncology Group performance status. Patients treated with CT (N = 109), iCT (N = 35), sCT (N = 26), and siCT (N = 9) had median (95% confidence interval) survivals of 11.7 (9.9-16.3), 18.2 (14.5-29.8), 20.7 (11.6-37.2), and 22.6 (19.7-37.8) months, respectively (P < .001). Median survival among patients with and without immunotherapy was 19.7 (17.4-29.8) and 12.3 (10.6-17.3) months, respectively (P = .023). Median survival among patients with and without surgery was 21.7 (17.6-34.8) and 13.6 (11.5-17.3) months, respectively (P = .007). Patients with biphasic/sarcomatoid subtypes who received immunotherapy experienced 76.2% (55.8%-100.0%) 12 month survival vs. 13.6% (4.8%-39.0%) among those who did not (P < .001).

CONCLUSION

MPM patients receiving surgery and immunotherapy as part of multimodal treatment regimens experienced the longest survival. Surgery and immunotherapy are each associated with survival. Further investigations are warranted to assess the benefit of immunotherapy within multimodal treatment regimens for MPM.

Genomic landscape of pleural and peritoneal mesothelioma tumours

BACKGROUND

Malignant pleural and peritoneal mesotheliomas are rare malignancies with unacceptable poor prognoses and limited treatment options. The genomic landscape is mainly characterised by the loss of tumour suppressor genes and mutations in DNA repair genes. Currently, data from next-generation sequencing (NGS) of mesothelioma tumours is restricted to a limited number of cases; moreover, data comparing molecular features of mesothelioma from the pleural and peritoneal origin with NGS are lacking.

METHODS

We analysed 1113 pleural mesothelioma and 355 peritoneal mesothelioma samples. All tumours were sequenced with the FoundationOne® or FoundationOne®CDx assay for detection of substitutions, insertion-deletions, copy-number alterations and selected rearrangements in at least 324 cancer genes.

RESULTS

This analysis revealed alterations in 19 genes with an overall prevalence of at least 2%. Alterations in BAP1, CDKN2A, CDKN2B, NF2, MTAP, TP53 and SETD2 occurred with a prevalence of at least 10%. Peritoneal, compared to pleural mesothelioma, was characterised by a lower prevalence of alterations in CDKN2A, CDKN2B and MTAP. Moreover, we could define four distinct subgroups according to alterations in BAP1 and CDKN2A/B. Alterations in Hedgehog pathway-related genes (PTCH1/2 and SUFU) and Hippo pathway-related gene (NF2) as well as KRAS, EGFR, PDGFRA/B, ERBB2 and FGFR3 were detected in both cohorts.

CONCLUSION

Here, we report the molecular aberrations from the largest cohort of patients with mesothelioma. This analysis identified a proportion of patients with targetable alterations and suggests that molecular profiling can identify new treatment options for patients with mesothelioma.

What's Current and What's New in Mesothelioma?

Malignant mesothelioma is a rare disease with limited treatment options. In malignant pleural mesothelioma (MPM), radical trimodality approaches, including surgery, radiotherapy and systemic chemo- and immunotherapy, have been delivered in some countries but remain controversial due to a lack of randomised evidence. Even in the unresectable scenario, surgery and radiotherapy play an important role in managing pleural effusions and pain, which may optimise wellbeing and maintain performance status. From the systemic treatment point of view, the recent incorporation of anti-angiogenics and, more importantly, immunotherapy has changed the standard of care in a space where chemotherapy with platinum and pemetrexed was the only therapeutic intervention with demonstrated benefits in overall survival. Histology is essential in determining an initial treatment plan as non-epithelioid MPMs may have a higher substantial survival improvement with dual immunotherapy compared with chemotherapy, whereas chemotherapy remains an option for epithelioid MPM; however, predictive biomarkers for systemic therapy are not entirely validated to guide the selection, as a subgroup of MPM patients might not benefit from immunotherapy. This overview approaches how the overall management of mesothelioma is evolving to incorporate the recent changes in the standards of care.

Pulmonary adverse events following immune checkpoint inhibitors

PURPOSE OF REVIEW

Immune checkpoint inhibitors (ICIs) have rapidly become a mainstay of cancer treatment. However, immune modulation resulting from checkpoint inhibition can cause inflammation in any organ system, with pneumonitis being one of the most severe immune-related adverse events (irAEs). Here, we review the most recent literature on pulmonary adverse events following ICIs.

RECENT FINDINGS

Several systematic reviews and meta-analyses of data from trials of antiprogrammed death-1 (PD-1; nivolumab, pembrolizumab), anti-PD-ligand-1 (PD-L1; atezolizumab, avelumab, durvalumab) and anticytotoxic T lymphocyte antigen-4 (CTLA-4; ipilimumab or tremelimumab) in patients with advanced cancer have explored the relative risk and incidence of lung toxicity among different tumor types and therapeutic regimens. They have showed that the incidence of all-grade (1-4) and high-grade (3-4) pneumonitis is significantly higher in nonsmall cell lung cancer (NSCLC) compared with other tumor types. In addition, they have demonstrated that immunotherapy, especially monoimmunotherapy, has a significantly lower risk of irAEs compared to immune-chemotherapy. Treatment for lung cancer, preexisting interstitial lung disease, smoking history and male sex appear to increase the risk for ICI-related pneumonitis.

SUMMARY

Lung toxicity is an uncommon but potentially severe and even fatal complication of ICIs. Timely recognition is critically important but challenging, particularly in patients with lung cancer wherein drug toxicity can mimic disease progression or recurrence.

Immunotherapy approaches for malignant pleural mesothelioma

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.

Nivolumab plus ipilimumab in malignant pleural mesothelioma

INTRODUCTION

Unresectable pleural mesothelioma is a poor prognosis disease. Improvement in overall survival (OS) has been shown with PEMETREXED combined to CISPLATIN. BEVACIZUMAB combined with chemotherapy is associated with an improvement in OS, compared to chemotherapy alone, but is not supported by health insurance everywhere.

AREAS COVERED

Immune Checkpoint Inhibition (ICI) monotherapy seemed to be promising, but is controversial. ICI combination showed significant results. NIVOLUMAB, an anti-Programmed-Death-receptor 1, associated to IPILIMUMAB, an anti-Cytotoxic-T-Lymphocyte-Associated-protein 4, was evaluated in two phase II trials and a phase III trial, recently published. This combination led to a significant benefit in survival in first line compared to chemotherapy (OS 18.1 months (95%CI(16.8-21.4)) vs 14.1 (95%CI(12.4-16.2) HR 0.74 (95%CI 0.6-0.91) p=0.002).

EXPERT OPINION

These results represent a big step in unresectable pleural mesothelioma. The benefit in non-epithelioid subtype is impressive (OS 18.1 months (95%CI 12.2-22.8) vs 8.8 months 95%CI (7.4-10.2) HR 0.46 (95%CI(0.31-0.68)). Benefit in epithelioid subtype (OS 18.7 months 95%CI(16.9-22) vs 16.5 95%CI(14.9-20.5) HR 0.86 95%CI(0.69-1.08)) is similar to the benefit of the combination of BEVACIZUMAB and chemotherapy. Identification of predictive biomarkers is needed to identify patients who are most likely to benefit from each therapeutic strategy.

Pembrolizumab in Microsatellite Instability High or Mismatch Repair Deficient Cancers: Updated Analysis from the Phase 2 KEYNOTE-158 Study

BACKGROUND

Pembrolizumab demonstrated durable antitumor activity in 233 patients with previously treated advanced microsatellite instability high (MSI-H) or mismatch repair deficient (dMMR) advanced solid tumors in the phase 2 multicohort KEYNOTE-158 (NCT02628067) study. Herein, we report safety and efficacy outcomes with longer follow-up for more patients with previously treated advanced MSI-H/dMMR noncolorectal cancers who were included in cohort K of the KEYNOTE-158 (NCT02628067) study.

PATIENTS AND METHODS

Eligible patients with previously treated advanced noncolorectal MSI-H/dMMR solid tumors, measurable disease per RECIST v1.1, and ECOG performance status of 0 or 1 received pembrolizumab 200 mg Q3W for 35 cycles or until disease progression or unacceptable toxicity. The primary endpoint was ORR per RECIST v1.1 by independent central radiologic review.

RESULTS

Three hundred and fifty-one patients with various tumor types were enrolled in KEYNOTE-158 cohort K. The most common tumor types were endometrial (22.5%), gastric (14.5%), and small intestine (7.4%). Median time from first dose to database cutoff (October 5, 2020) was 37.5 months (range, 0.2‒55.6 months). ORR among 321 patients in the efficacy population (patients who received ≥1 dose of pembrolizumab enrolled ≥6 months before the data cutoff date) was 30.8% (95% CI, 25.8‒36.2). Median duration of response was 47.5 months (range, 2.1+ to 51.1+ months). Median progression-free survival was 3.5 months (95% CI, 2.3‒4.2 months) and median overall survival was 20.1 months (95% CI, 14.1‒27.1 months). Treatment-related AEs occurred in 227 patients (64.7%). Grade 3‒4 treatment-related AEs occurred in 39 patients (11.1%); three had (0.9%) grade 5 treatment-related AEs (myocarditis, pneumonia, and Guillain-Barre syndrome, n=1 each).

CONCLUSION

Pembrolizumab demonstrated clinically meaningful and durable benefit, with high ORR of 30.8%, long median duration of response of 47.5 months, and manageable safety across a range of heavily pretreated, advanced MSI-H/dMMR noncolorectal cancers, providing support for use of pembrolizumab in this setting.

Current status and progress in immunotherapy for malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare and aggressive malignant disease. Currently, the platinum doublet of pemetrexed and cisplatin is the standard first-line treatment for unresectable MPM. However, recent promising results of immunotherapy have markedly changed the landscape of MPM treatment. Further, the ongoing innovative therapeutic strategies are expected to expand the range of treatment options; however, several questions remain unanswered. First, establishing predictive biomarkers with high potency is urgently needed to optimize the patient selection process. Second, further exploration of the combination algorithm is expected to unveil more effective and safe regimens. Moreover, other dilemmas, such as the resistance mechanism of immunotherapy and the role of immunotherapy in perioperative settings, still warrant further exploration.

Current treatments for inoperable mesothelioma: indirect comparisons based on individual patient data reconstructed retrospectively from 4 trials

In inoperable pleural mesothelioma, pemetrexed + cisplatin as first line is considered the standard of care, but novel treatments have been recently proposed. Our objective was to comparatively examine the information on overall survival (OS) with these new agents. The Shiny technique was employed for reconstructing individual patient data. Cox statistics was run to estimate hazard ratios (HRs). After a standard literature search, four new treatments were identified (nivolumab + ipilimumab, bevacizumab + pemetrexed + cisplatin, pembrolizumab monotherapy, and durvalumab + pemetrexed + cisplatin). Pemetrexed + ciplatin was the treatment for controls. Nivolumab + ipilimumab and bevacizumab + pemetrexed + cisplatin showed a better OS compared with controls (HR, 0.79 and 0.79, respectively; p < 0.05). Pembrolizumab determined only a numerical improvement (p > 0.05). In contrast, OS worsened with durvalumab + pemetrexed + cisplatin. Our analysis indicates that the novel treatments for inoperable mesothelioma have similar efficacy and, in general, provide a small though significant survival benefit compared with standard of care. Further research is needed to identify agents determining a more substantial OS improvement.

Immune-Checkpoint Inhibitors for Malignant Pleural Mesothelioma: A French, Multicenter, Retrospective Real-World Study

Backgrounds: Malignant pleural mesothelioma (MPM) is a cancer with poor prognosis. Second-line and onward therapy has many options, including immune-checkpoint inhibitors with demonstrated efficacy: 10−25% objective response rate (ORR) and 40−70% disease-control rate (DCR) in clinical trials on selected patients. This study evaluated real-life 2L+ nivolumab efficacy in MPM patients and looked for factors predictive of response. Methods: This retrospective study included (September 2017−July 2021) all MPM patients managed in 11 French centers. Results: The 109 enrolled patients’ characteristics were: median age: 69 years; 67.9% men; 82.6% epithelioid subtype. Strictly, second-line nivolumab was given to 51.4%. Median PFS and OS were 3.8 (3.2−5.9) and 12.8 (9.2−16.4) months. ORR was 17/109 (15.6%); 34/109 patients had a stabilized disease (DCR 46.8%). Univariable analysis identified several parameters as significantly (p < 0.05) prognostic of OS [HR (95% CI)]: biphasic subtype: 3.3 (1.52−7.0), intermediate Lung Immune Prognostic Index score: 0.46 (0.22−0.99), progression on the line preceding nivolumab: 2.1 (1.11−3.9) and age > 70 years: 2.5 (1.5−4.0). Multivariable analyses retained only biphasic subtype: 3.57 (1.08−11.8) and albumin < 25 g/L: 10.28 (1.5−70.7) as significant and independent predictors. Conclusions: Second-line and onward nivolumab is effective against MPM in real life but with less effectiveness in >70 years. Ancillary studies are needed to identify the predictive factors.

An Update on Emerging Therapeutic Options for Malignant Pleural Mesothelioma

The treatment paradigm for malignant pleural mesothelioma (MPM) has changed little in the last 18 years. Radical intent treatment, consisting of surgical resection, radiotherapy and chemotherapy, has been offered to a highly select few; however, there is little randomised evidence to validate this approach. Prior to 2020 chemotherapy with platinum and an anti-folate was the only intervention with randomised evidence to demonstrate improved overall survival (OS) in MPM. No systemic therapy had been demonstrated to improve OS in the second line setting until 2020. The publication of the Checkmate 743 trial in 2021 demonstrated a survival benefit of combination immunotherapy over standard chemotherapy in newly diagnosed patients with MPM. This finding was shortly followed by the CONFIRM trial which demonstrates a modest but significant survival benefit of second line nivolumab versus placebo in patients having previously received standard chemotherapy. The results of these trials, recent biomarker directed therapy and chemotherapy adjuncts are discussed within this review. The integration of immunotherapy for the few patients in whom radical surgical therapy is intended is currently the subject of clinical trials and offers the prospect of improving outcomes in this rare but devastating disease.

Novel and Future Treatment Options in Mesothelioma: A Systematic Review

Mesothelioma is a rare tumor, frequently associated with asbestos exposure, arising from pleura and peritoneum. Traditionally, diagnosis and treatment have been difficult in a clinical setting. The treatment is based on a trimodal approach involving surgery, chemotherapy, and radiotherapy. The introduction of chemotherapy improved the overall survival. However, the regimen of pemetrexed/cisplatin doublet has not been changed as a standard treatment since 2004. Novel combinations of ipilimumab and nivolumab have only been approved for clinical use in late 2020. The aim of this review was to systematically summarize findings on novel treatment options in mesothelioma. We searched available medical databases online, such as PubMed and Clinicaltrials.gov, to systematically review the literature on novel approaches in immunotherapy, vaccines, and Chimeric Antigen Receptor (CAR)-T cell therapy in mesothelioma. We manually screened 1127 articles on PubMed and 450 trials on ClinicalTrials.gov, and 24 papers and 12 clinical trials published in the last ten years were included in this review. Immunotherapy that was swiftly introduced to treat other thoracic malignancies was slow to reach desirable survival endpoints in mesothelioma, possibly due to limited patient numbers. Novel treatment approaches, such as CAR-T cell therapy, are being investigated. As the incidence of mesothelioma is still rising globally, novel treatment options based on a better understanding of the tumor microenvironment and the genetic drivers that modulate it are needed to support future precision-based therapies.

G6PD functions as a metabolic checkpoint to regulate granzyme B expression in tumor-specific cytotoxic T lymphocytes

Background

Granzyme B is a key effector of cytotoxic T lymphocytes (CTLs), and its expression level positively correlates with the response of patients with mesothelioma to immune checkpoint inhibitor immunotherapy. Whether metabolic pathways regulate Gzmb expression in CTLs is incompletely understood.

Methods

A tumor-specific CTL and tumor coculture model and a tumor-bearing mouse model were used to determine the role of glucose-6-phosphate dehydrogenase (G6PD) in CTL function and tumor immune evasion. A link between granzyme B expression and patient survival was analyzed in human patients with epithelioid mesothelioma.

Results

Mesothelioma cells alone are sufficient to activate tumor-specific CTLs and to enhance aerobic glycolysis to induce a PD-1^hi Gzmb^lo CTL phenotype. However, inhibition of lactate dehydrogenase A, the key enzyme of the aerobic glycolysis pathway, has no significant effect on tumor-induced CTL activation. Tumor cells induce H3K9me3 deposition at the promoter of G6pd, the gene that encodes the rate-limiting enzyme G6PD in the pentose phosphate pathway, to downregulate G6pd expression in tumor-specific CTLs. G6PD activation increases acetyl-coenzyme A (CoA) production to increase H3K9ac deposition at the Gzmb promoter and to increase Gzmb expression in tumor-specific CTLs converting them from a Gzmb^lo to a Gzmb^hi phenotype, thus increasing CTL tumor lytic activity. Activation of G6PD increases Gzmb⁺ tumor-specific CTLs and suppresses tumor growth in tumor-bearing mice. Consistent with these findings, GZMB expression level was found to correlate with increased survival in patients with epithelioid mesothelioma.

Conclusion

G6PD is a metabolic checkpoint in tumor-activated CTLs. The H3K9me3/G6PD/acetyl-CoA/H3K9ac/Gzmb pathway is particularly important in CTL activation and immune evasion in epithelioid mesothelioma.

Comparative Analysis of Predictive Biomarkers for PD-1/PD-L1 Inhibitors in Cancers: Developments and Challenges

Simple Summary

The development of immune checkpoint inhibitors (ICIs) has greatly changed the treatment landscape of multiple malignancies. However, the wide administration of ICIs is mainly obstructed by the low response rate and several life-threatening adverse events. Thus, there is an urgent need to identify sets of biomarkers to predict which patients will respond to ICIs. In this review, we discuss the recently investigated molecular and clinical determinants of ICI response, from the aspects of tumor features, clinical features, as well as tumor microenvironment.

Abstract

Immune checkpoint inhibitors (ICIs) targeting programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) have dramatically changed the landscape of cancer therapy. Both remarkable and durable responses have been observed in patients with melanoma, non-small-cell lung cancer (NSCLC), and other malignancies. However, the PD-1/PD-L1 blockade has demonstrated meaningful clinical responses and benefits in only a subset of patients. In addition, several severe and life-threatening adverse events were observed in these patients. Therefore, the identification of predictive biomarkers is urgently needed to select patients who are more likely to benefit from ICI therapy. PD-L1 expression level is the most commonly used biomarker in clinical practice for PD-1/PD-L1 inhibitors. However, negative PD-L1 expression cannot reliably exclude a response to a PD-1/PD-L1 blockade. Other factors, such as tumor microenvironment and other tumor genomic signatures, appear to impact the response to ICIs. In this review, we examine emerging data for novel biomarkers that may have a predictive value for optimizing the benefit from anti-PD-1/PD-L1 immunotherapy.

Immunotherapy, the promise for present and future of malignant pleural mesothelioma (MPM) treatment

Due to occupational asbestosis exposure, the incidence of malignant pleural mesothelioma (MPM) has continuously increased over the last 30 years, with a plateau anticipated around the year 2030 in Western countries. Molecular MPM carcinogenesis involves alterations of NF2, RASSF1, LATS2WT1, p16, as well as BAP-1tumor-suppressor genes, which usually regulate apoptosis, cell invasion, motility, cell division, chromatin remodeling, as well as control of DNA repair. In few selected patients, debulking surgery consisting of pleurectomy-decortication is carried out, resulting in unsatisfactory long-term results. For about 15 years, first-line chemotherapy has been primarily based on a doublet of pemetrexed and cisplatin. Adding the monoclonal antibody bevacizumab (Avastin®), which targets vascular endothelial growth factor (VEGF), has been shown to improve overall survival (OS) by nearly 19 months. The emergence of immune check-point inhibitors (ICIs) in MPM treatment has recently been associated with substantial survival improvements in both second- and first-line settings. Similarly to non-small-cell lung cancer (NSCLC) patients, on-going trials are presently exploring the chemotherapy-ICI combination in MPM management, and depending on their results, this combination could represent a further major advance in this previously orphan disease. The current article reviews recent clinical trial results, as well as future clinical developments in this moving field.

Immune checkpoint inhibitor therapy for malignant pleural mesothelioma

Mesothelioma is a rare and universally fatal cancer linked to exposure to asbestos. Until recently, standard of care treatment was chemotherapy; a treatment resulting in a minimal survival extension, and not improved upon for almost twenty years. However, the advent of cancer immunotherapy - and in particular the immune checkpoint inhibitor class of drugs - has resulted in recently approved new treatment options, with more currently under investigation. Here, we review clinical trials of both single agent and combination checkpoint inhibitors in mesothelioma, plus studies investigating their combination with chemotherapy. We also describe current advances in biomarker identification regarding prediction of patient response to checkpoint inhibitors. Finally, we assess the probable future direction of the field; including where current and developing technologies are likely to lead - in terms of both biomarker discovery and treatment options.

Advances in Immunotherapy of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) represents the uncommon cancer originating from pleural mesothelial cells, which is associated with dismal prognostic outcome. According to CheckMate-743 results, nivolumab plus ipilimumab has been approved to treat the unresectable MPM in treatment-naive patients as a first-line therapy by the FDA in October 2020. Immunotherapy is expected to be the best choice for MPM treatment. In the following article, the past treatment plan and the progress of immunotherapy for MPM will be reviewed.

Pleural mesothelioma (PM) - The status of systemic therapy

Pleural mesothelioma (PM) remains a malignancy with poor prognosis. Despite initial disappointing response rates to single-agent chemotherapy, upfront platinum and anti-folate-based combination chemotherapy has remained the backbone of treatment for PM for the last three decades. The role of maintenance chemotherapy remains unclear; switch-maintenance gemcitabine has shown improvements in progression-free but not overall survival. The addition of antiangiogenic agents to chemotherapy yielded modest improvements in survival, both upfront in combination with platinum-pemetrexed, and in the relapsed setting. Immunotherapy, particularly PD-(L)1 inhibitors, has shown important but variable effectiveness in relapsed PM when used as monotherapy, and is an important salvage treatment after first-line chemotherapy. Furthermore, the randomized phase 3 trial of ipilimumab-nivolumab versus platinum-pemetrexed chemotherapy demonstrated improved overall survival favouring ipilimumab-nivolumab (HR 0.74, 96.6% CI 0.60-0.91; p = 0.0020), establishing this regimen as the new standard first-line treatment for PM, particularly in those with non-epithelioid histology. Increased interest in PM genomics has led to development of novel personalized therapeutics, such as those targeting DNA repair and EZH2 pathways, however with variable outcomes in trials. Targeting the membrane glycoprotein mesothelin and arginine deprivation are other important strategies under ongoing investigation. The field of PM is changing and new treatments bring hope to a largely lethal and poor prognostic malignancy. Despite these developments, current challenges include understanding the role of combination and multimodality treatments, drivers of resistance to treatment, and establishing predictive biomarkers to improve patient selection and treatment sequencing.

Oncological Frontiers in the Treatment of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare malignancy characterized by very poor prognosis and lack of treatment options. Immunotherapy has rapidly emerged as an effective tool for MPM, particularly for tumors of non-epithelioid histology. At the same time, comprehensive genomic sequencing may open the way to new-generation targeted-drugs able to hit specific MPM molecular vulnerabilities. These innovations will possibly enrich, but also dramatically complicate, the elucidation of treatment algorithms. Multidisciplinary integration is urgently needed.

Emerging biological therapies for the treatment of malignant pleural mesothelioma

Introduction: Malignant pleural mesothelioma (MPM) has limited treatment options with minimal new therapy approvals for unresectable disease in the past 15 years. However, considerable work has occurred to develop immunotherapies and biomarker driven therapy to improve patient outcomes over this period.Areas covered: This review examines current standard of care systemic therapy in the first- and second line setting. The last 12 months has seen 2 significant trials (Checkmate 743 and CONFIRM) which provide evidence supporting the role of immunotherapy in the management of MPM. Further trials are underway to assess the role of combination chemoimmunotherapy and personalized therapy. Additionally, a large number of clinical trials are ongoing to assess the efficacy of oncoviral, dendritic cell, anti-mesothelin and chimeric antigen receptor T cell therapy in the treatment of MPM.Expert opinion: Recent Phase III trial results have established a role for immunotherapy in the management of MPM. The optimal sequencing and combination of chemotherapy and immunotherapy remains to be determined. Novel therapies for MPM are promising however efficacy remains to be determined and issues remain regarding access to and delivery of these therapies.