Role of Immunotherapy in Small Cell Lung Cancer, Thymic Epithelial Tumors, and Mesothelioma

Traditional Treatment Approaches and Role of Immunotherapy in Lung Malignancy and Mesothelioma

There is no denying that many revolutions took place in the fight against cancer during the last decades. However, cancers have always managed to find new ways to challenge humankinds. Variable genomic epidemiology, socio-economic differences and limitations of widespread screening are the major concerns in cancer diagnosis and early treatment. A multidisciplinary approach is essentially to manage a cancer patient efficiently. Thoracic malignancies including lung cancers and pleural mesothelioma are accountable for little more than 11.6% of the global cancer burden [4]. Mesothelioma is one of the rare cancers, but concern is the incidences are increasing globally. However, the good news is first-line chemotherapy with the combination of immune checkpoints inhibitors (ICIs) in non-small cell lung cancer (NSCLC) and mesothelioma has showed promising respond and improved overall survival (OS) in pivotal clinical trials [10]. ICIs are commonly referred as immunotherapy are antigens on the cancer cells, and inhibitors are the antibodies produce by the T cell defence system. By inhibiting immune checkpoints, the cancer cells become visible to be identified as abnormal cells and attack by the body's defence system [17]. The programmed death receptor-1 (PD-1) and programmed death receptor ligand-1 (PD-L1) inhibitors are commonly used immune checkpoint blockers for anti-cancer treatment. PD-1/PD-L1 are proteins produced by immune cells and mimic by cancer cells that are implicated in inhibiting T cell response to regulate our immune system, which results tumour cells escaping the defence mechanism to achieve immune surveillance. Therefore, inhibiting immune checkpoints as well as monoclonal antibodies can lead to effective apoptosis of tumour cells [17]. Mesothelioma is an industrial disease caused by significant asbestos exposure. It is the cancer of the mesothelial tissue which presents in the lining of the mediastinum of pleura, pericardium and peritoneum, most commonly affected sites are pleura of the lung or chest wall lining [9] as route of asbestos exposure is inhalation. Calretinin is a calcium binding protein, typically over exposed in malignant mesotheliomas and the most useful marker even while initial changes take place [5]. On the other hand, Wilm's tumour 1 (WT-1) gene expression on the tumour cells can be related to prognosis as it can elicit immune response, thereby inhibit cell apoptosis. A systematic review and meta-analysis study conducted by Qi et al. has suggested that expression of WT-1 in a solid tumour is fatal however, it gives the tumour cell a feature of immune sensitivity which then acts positively towards the treatment with immunotherapy. Clinical significance of WT-1 oncogene in treatment is still hugely debatable and needs further attention [21]. Recently, Japan has reinstated Nivolumab in patients with chemo-refractory mesothelioma. According to NCCN guidelines, the salvage therapies include Pembrolizumab in PD-L1 positive patients and Nivolumab alone or with Ipilimumab in cancers irrespective of PD-L1 expression [9]. The checkpoint blockers have taken over the biomarker-based research and demonstrated impressive treatment options in immune sensitive and asbestos-related cancers. It can be expected that in near future the immune checkpoint inhibitors will be considered as approved first-line cancer treatment universally.

A Drug Screening Revealed Novel Potential Agents against Malignant Pleural Mesothelioma

The lack of effective therapies remains one of the main challenges for malignant pleural mesothelioma (MPM). In this perspective, drug repositioning could accelerate the identification of novel treatments. We screened 1170 FDA-approved drugs on a SV40-immortalized mesothelial (MeT-5A) and five MPM (Mero-14, Mero-25, IST-Mes2, NCI-H28 and MSTO-211H) cell lines. Biological assays were carried out for 41 drugs, showing the highest cytotoxicity and for whom there were a complete lack of published literature in MPM. Cytotoxicity and caspase activation were evaluated with commercially available kits and cell proliferation was assayed using MTT assay and by clonogenic activity with standard protocols. Moreover, the five most effective drugs were further evaluated on patient-derived primary MPM cell lines. The most active molecules were cephalomannine, ouabain, alexidine, thonzonium bromide, and emetine. Except for alexidine, these drugs inhibited the clonogenic ability and caspase activation in all cancer lines tested. The proliferation was inhibited also on an extended panel of cell lines, including primary MPM cells. Thus, we suggest that cephalomannine, ouabain, thonzonium bromide, and emetine could represent novel candidates to be repurposed for improving the arsenal of therapeutic weapons in the fight against MPM.

A New Horizon of Liquid Biopsy in Thymic Epithelial Tumors: The Potential Utility of Circulating Cell-Free DNA

BACKGROUND

Thymic epithelial tumors (TETs) are rare thoracic malignancies, commonly divided into two different histopathological entities, thymoma (T) and thymic carcinoma (TC). To date, there are no specific biomarkers for monitoring the biological course of these rare tumors. We carried out a single center study aiming at the detection of circulating cell-free DNA (ccfDNA) and the correlation of its levels with metastatic dissemination and histological subtype in patients with TETs.

METHODS

From July 2018 to January 2020, 5-ml blood samples from 26 patients with advanced TET (aTET) (11 patients with TC and 15 patients with T) and from six patients with completely resected TET (cr-TET), were prospectively obtained before the initiation of systemic therapy. Blood samples from 10 healthy donors were used as control. The QIAamp MinElute ccfDNA Kits was used for ccfDNA isolation from plasma; real-time PCR was used for cfDNA quantification.

RESULTS

We found significantly higher ccfDNA amount in patients with T and TC compared to controls, with median ccfDNA level of 3.3 ng/µl, 11.4 ng/µl and 25.6 ng/µl, for healthy donors, T and TC patients, respectively (p<0.001). No significant difference was found between cr-TET and controls (p = 0.175). ccfDNA concentrations were higher in metastatic (M1a and M1b) compared to non-metastatic (M0) TETs (25.6 ng/µl versus 7.2 ng/µl; p= 0.037). No significant correlation was found either between ccfDNA and disease stage, according to both the Masaoka-Koga (p= 0.854) and the TNM 8th edition staging systems (p = 0.66), or between ccfDNA levels and overall tumor burden, estimated according RECIST 1.1 criteria (r = 0.07, p = 0.725).

CONCLUSIONS

To the best of our knowledge, this is the first study that prospectively explores detection and quantification of ccfDNA in TETs. Higher baseline cfDNA levels have been observed in both advanced T and TC comparing to the control group.

Old but gold: the role of drug combinations in improving response to immune check-point inhibitors in thoracic malignancies beyond NSCLC

The introduction of immune checkpoint inhibitors (ICIs) in non-oncogene addicted non-small cell lung cancer (NSCLC) has revolutionized the treatment scenario and led to a meaningful improvement in patient prognosis. Disappointingly, the success of ICI therapy in NSCLC has not been fully replicated in other thoracic malignancies as small cell lung cancer (SCLC), malignant pleural mesothelioma (MPM), and thymic epithelial tumors (TETs), due to the peculiar biological features of these disease and to the difficulties in the conduction of well-designed, biomarker-driven clinical trials. Therefore, combination strategies of ICIs plus conventional therapies (either chemotherapy, alternative ICIs or targeted agents) have been implemented. Although first approvals of ICI therapy have been recently granted in SCLC and MPM (in combination with chemotherapy and different ICIs), results remain somewhat modest and limited to a small proportion of patients. This work reviews the trial results of ICI therapy in mesothelioma, SCLC, and TETs and discusses the potential of combining ICIs with old drugs.

Clinical effectiveness outcomes and healthcare resource utilization of patients diagnosed with small-cell lung cancer

Background: Real-world data are lacking on patients with small-cell lung cancer (SCLC) with extensive-stage SCLC (eSCLC) and poor performance status (PS). Patients & methods: Eligible patients diagnosed with eSCLC between 1 January 2008 and 31 December 2017 were included in this retrospective, observational study. Results: The study included 406 patients, with 14.3% impaired PS. Progression-free survival and overall survival were not significantly different between impaired (Eastern Cooperative Oncology Group ≥2) and not impaired patients (median, 4.5 vs 5.3 months, and 7.2 vs 8.4 months, respectively). Impaired patients used more supportive care drugs (mean, 3.0 vs 2.0; p = 0.033). Conclusion: Effectiveness outcomes among patients with and without impaired PS did not differ in the real-world setting. Progression-free survival and overall survival were similar to data from clinical trials.

Autoimmune disorders and paraneoplastic syndromes in thymoma

Thymomas are counted among the rare tumour entities which are associated with autoimmune disorders (AIDs) and paraneoplastic syndromes (PNS) far more often than other malignancies. Through its complex immunological function in the context of the selection and maturation of T cells, the thymus is at the same time highly susceptible to disruptive factors caused by the development and growth of thymic tumours. These T cells, which are thought to develop to competent immune cells in the thymus, can instead adopt autoreactive behaviour due to the uncontrolled interplay of thymomas and become the trigger for AID or PNS affecting numerous organs and tissues within the human body. While myasthenia gravis is the most prevalent PNS in thymoma, numerous others have been described, be they related to neurological, cardiovascular, gastrointestinal, haematological, dermatological, endocrine or systemic disorders. This review article sheds light on the pathophysiology, epidemiology, specific clinical features and therapeutic options of the various forms as well as courses and outcomes of AID/PNS in association with thymomas. Whenever suitable and backed by the limited available evidence, the perspectives from both the thymoma and the affected organ/tissue will be highlighted. Specific issues addressed are the prognostic significance of thymectomy on myasthenia gravis and other thymoma-associated AID/PND and further the impact and safety of immunotherapies on AID and PND relating to thymomas.

Combinational immunotherapy based on immune checkpoints inhibitors in small cell lung cancer: is this the beginning to reverse the refractory situation?

Small cell lung cancer (SCLC), a particular neuroendocrine tumor, occupies 13% of lung cancers, with the highest mortality among cancers. Immune checkpoints inhibitors (ICIs) based on programmed cell death protein-1 (PD-1)/programmed cell death one ligand (PD-L1) inhibitors and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors have been one of the most favorable therapies in SCLC. Simultaneously, not all the patients respond to ICIs due to the lack of biomarkers to predict the immunotherapeutic effect. Multiple combinational approaches are under exploration, including the integrated or successive assessment of additional immunotherapeutic agents, chemotherapy, radiotherapy, and targeted therapy with ICIs. The current review offers a general view of the rationale for clinical studies exploring the experimental result of combinational immunotherapy based on ICIs, with both available results and ongoing trials. Moreover, the development of more predictive biomarkers, specific clinical trial designs, enhancement of the efficacy, and decreasing the financial toxicity will become the trend of future research and clinical applications of ICIs. Understanding the evolving immuno-oncology is increasingly relevant and crucial to solve those problems and define therapeutic strategies and potential target populations of combinational immunotherapy. Ultimately, emerging combinational immunotherapy will transform SCLC into a chronic disease to help patients survive from tumors.

Retrospective Evaluation of the Use of Pembrolizumab in Malignant Mesothelioma in a Real-World Australian Population

INTRODUCTION

We investigated the efficacy and toxicity of pembrolizumab in patients with mesothelioma from a real-world Australian population. We aimed to determine clinical factors and predictive biomarkers that could help select patients who are likely to benefit from pembrolizumab.

METHOD

Patients with mesothelioma who were treated with pembrolizumab as part of the Insurance and Care New South Wales compensation scheme were included. Clinical information was collected retrospectively. Tumor biomarkers such as programmed death-ligand 1 (PD-L1), BAP1, and CD3-positive (CD3+) tumor-infiltrating lymphocytes (TILs) were examined using archival formalin-fixed paraffin-embedded tumor samples.

RESULTS

A total of 98 patients were included with a median age of 70 years (range, 46-91 y); 92% were men; 76% had epithelioid subtype; 21% had an Eastern Cooperative Oncology Group (ECOG) performance status of 0. Pembrolizumab was used as second-line or subsequent-line treatment in 94 patients and as first-line treatment in four patients. The overall response rate was 18%, and the disease control rate was 56%. The median progression-free survival (PFS) was 4.8 months (95% confidence interval: 3.6-6.2), and the median overall survival (OS) was 9.5 months (95% confidence interval: 6.6-13.7). Immune-related adverse events occurred in 27% of patients, of which nine (9%) were of grade 3 or higher. In the multivariable analysis, factors independently associated with longer PFS included baseline ECOG status of 0 (median PFS: 12 mo versus 4 mo, p < 0.01) and PD-L1 tumor proportion score of greater than or equal to 1% (median PFS: 6 mo versus 4 mo, p < 0.01). Baseline platelet count of less than or equal to 400 × 109/liter was independently associated with longer PFS and OS (median PFS: 6 mo versus 2 mo, p = 0.05; median OS: 10 mo versus 4 mo, p = 0.01), whereas lack of pretreatment dexamethasone was independently associated with OS but not PFS (median OS: 10 mo versus 3 mo, p = 0.01). The odds of response were higher for patients with baseline ECOG status of 0 (p = 0.02) and with greater than or equal to 5% CD3+ TILs in the tumor (p < 0.01). PD-L1 expression, BAP1 loss, and CD3+ TILs in the stroma were not significantly associated with the overall response rate.

CONCLUSIONS

Immunotherapy is a reasonable treatment option for patients with mesothelioma. Our results are comparable to other clinical trials investigating pembrolizumab in mesothelioma in terms of response. Good performance status assessment remains the most robust predictor for patient outcomes. CD3+ TILs in the tumor may help select patients that are likely to respond to pembrolizumab, whereas factors such as PD-L1 expression, baseline platelet count, and lack of pretreatment dexamethasone may help predict survival outcomes from pembrolizumab treatment.

An update on the immune landscape in lung and head and neck cancers

Immunotherapy has dramatically changed the treatment landscape for patients with cancer. Programmed death-ligand 1/programmed death-1 checkpoint inhibitors have been in the forefront of this clinical revolution. Currently, there are 6 US Food and Drug Administration-approved checkpoint inhibitors for approximately 18 different histologic types of cancer. Lung cancer and head and neck squamous cell carcinoma (HNSCC) are 2 diseases that have led the way in the development of immunotherapy. Atezolizumab, durvalumab, nivolumab, and pembrolizumab are all currently used as part of standard-of-care treatment for different stages of lung cancer. Similarly, nivolumab and pembrolizumab have US regulatory approval as treatment for advanced metastatic HNSCC. This is significant because lung cancer represents the most common and most fatal cancer globally, and HNSCC is the sixth most common. Currently, most of the approvals for the use of immunotherapy agents are for patients diagnosed in the metastatic setting. However, research is ongoing to evaluate these drugs in earlier stage disease. There is plausible biological rationale to expect that pharmacologic activation of the immune system will be effective for early-stage and smaller tumors. In addition, selecting patients who are more likely to respond to immunotherapy and understanding why resistance develops are crucial areas of ongoing research. The objective of this review was to provide an overview of the current immune landscape and future directions in lung cancer and HNSCC.