Pembrolizumab in Patients With Extensive-Stage Small-Cell Lung Cancer: Results From the Phase Ib KEYNOTE-028 Study

Tumor-Targeted Drug Conjugates as an Emerging Novel Therapeutic Approach in Small Cell Lung Cancer (SCLC)

There are few effective therapies for small cell lung cancer (SCLC), a highly aggressive disease representing 15% of total lung cancers. With median survival <2 years, SCLC is one of the most lethal cancers. At present, chemotherapies and radiation therapy are commonly used for SCLC management. Few protein-targeted therapies have shown efficacy in improving overall survival; immune checkpoint inhibitors (ICIs) are promising agents, but many SCLC tumors do not express ICI targets such as PD-L1. This article presents an alternative approach to the treatment of SCLC: the use of drug conjugates, where a targeting moiety concentrates otherwise toxic agents in the vicinity of tumors, maximizing the differential between tumor killing and the cytotoxicity of normal tissues. Several tumor-targeted drug conjugate delivery systems exist and are currently being actively tested in the setting of SCLC. These include antibody-drug conjugates (ADCs), radioimmunoconjugates (RICs), small molecule-drug conjugates (SMDCs), and polymer-drug conjugates (PDCs). We summarize the basis of action for these targeting compounds, discussing principles of construction and providing examples of effective versus ineffective compounds, as established by preclinical and clinical testing. Such agents may offer new therapeutic options for the clinical management of this challenging disease in the future.

What is the role of radiotherapy for extensive-stage small cell lung cancer in the immunotherapy era?

Small cell lung cancer has been a difficult disease to treat with poor survival and few significant improvements in outcomes in the last three decades. Most recently the addition of atezolizumab to chemotherapy in the first-line treatment of extensive-stage small cell lung cancer (ES-SCLC) resulted in improved overall survival and progression-free survival compared to chemotherapy alone. Recent randomized studies examining both consolidative thoracic radiotherapy and prophylactic cranial irradiation (PCI) in ES-SCLC have impacted the utilization of these interventions. The approval of immune checkpoint inhibitors (ICIs) to platinum/etoposide chemotherapy for the treatment of ES-SCLC in the front-line setting may also further impact the role of radiotherapy in this disease. In this article, we review the current evidence supporting thoracic radiotherapy in ES-SCLC and discuss the promising therapeutic implications of thoracic radiation in light of the inclusion of ICIs. We also address how the increasing routine use of surveillance brain magnetic resonance imaging (MRI) and ICIs may diminish the use of PCI in ES-SCLC.

Next-Generation Sequencing May Discriminate Extreme Long-term versus Short-term Survival in Patients with Metastatic Small Cell Lung Cancer (SCLC)

BACKGROUND: Molecular underpinnings that may prognosticate survival could increase understanding of small cell lung cancer (SCLC) tumor behavior. Here, we report the clinicopathological characteristics and biomarker profiles of short-term (ST) versus long-term (LT) survival in patients with metastatic SCLC. METHODS: Of the 876 consecutive metastatic SCLC patients receiving standard of care therapy, 44 met the definition of LT and 91 for ST, respectively. Available FFPE tumor tissue blocks were analyzed by next-generation sequencing (NGS). Analysis included gene mutations, copy number variations, mRNA expression, and protein expression by immunohistochemistry, followed by correlation with clinicopathological characteristics. RESULTS: There were no statistically significant and clinically relevant differences in cases with or without FFPE according to major clinicopathological variables in ST and LT. However, according to NGS, five mutually exclusive gene mutations were identified (E1A binding protein P300 [EP300] p.N217S; p.E152K; human epidermal growth factor receptor 4 [ERBB4] p.E317K; BRCA1, DNA repair associated [BRCA1] p.E1661N, and epidermal growth factor receptor [EGFR] p.V742A). Comparing LT vs. ST survivals, a twofold increase was found in the average predicted number of drugs per patient off compendium. We found high SSTR2 mRNA expressions in all LT patients (vs. two [20%] ST patients), which may reflect more benign neuroendocrine tumor characteristics. CONCLUSIONS: Consolidation radiation therapy and higher predicted drug sensitivity for off compendium were associated with LT compared to ST patients in SCLC. NGS profiling of extreme survivals may improve classification of SCLC and possibly identify clinically relevant new targets.

Analyzing the percentage of different PD-1+ T cell subsets in peripheral blood and bronchoalveolar lavage fluid of small cell lung cancer patients: A prospective study

The present study was designed to evaluate the percentage of different programmed cell death-1 (PD-1)⁺ T cell subsets in peripheral blood and bronchoalveolar lavage fluid (BALF) of small cell lung cancer (SCLC) patients. The percentages of PD-1⁺ T cell subsets in peripheral blood and BALF samples obtained from 52 lung cancer and 20 pneumonia patients, and 20 healthy controls were examined by flow cytometry. In addition, clinical parameters, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels, were also determined using Spearman's correlation test to assess their association with PD-1⁺ T cell subsets. These present results revealed that the percentage of circulating PD-1⁺ Tfh and peripheral helper T cells (Tph) cells significantly increased in peripheral blood of SCLC patients, when compared to non-small cell lung cancer (NSCLC) pneumonia patients and healthy controls. In addition, PD-1⁺ Tfh cells were also significantly enhanced in patients in the extensive-stage group. In contrast, the BALF samples of SCLC patients exhibited a significant decrease in percentage of Tph cells. An overall imbalance was observed between PD-1⁺ Tfh and Tph cells in both compartments. Furthermore, SCLC patients exhibited a significant decrease in the percentage of circulating PD-1⁺ Tfh and Tph cells following chemotherapy, and the in vitro analysis revealed that the concentration of IL-2 and IFN-γ derived from PD-1 + Tfh cells in SCLC were significantly lower than that from NSCLC. However, this had no significant correlation with disease severity. The present study indicated that elevated circulating PD-1⁺ T cells can primarily be used as a biomarker for disease diagnosis and a potential therapeutic target.

A phase II study of pembrolizumab and paclitaxel in patients with relapsed or refractory small-cell lung cancer

OBJECTIVE

Patients with etoposide/platinum-refractory extensive disease (ED) small-cell lung cancer (SCLC) have a dismal prognosis. We aimed to evaluate the efficacy and safety of pembrolizumab and paclitaxel combination therapy in these patients.

METHODS

In this multi-center, phase II study, ED-SCLC patients who showed progression after etoposide/platinum chemotherapy received paclitaxel 175 mg/m² every 3 weeks for up to six cycles. Pembrolizumab 200 mg was added from the second cycle and continued until disease progression or unacceptable toxicity. The primary endpoint was the objective response rate (ORR) and the secondary endpoints were progression-free survival (PFS), overall survival (OS), safety, and biomarker analyses including programmed death-ligand 1 (PD-L1) expression, next-generation sequencing, and flow cytometric analysis of peripheral blood cells.

RESULTS

Of the 26 patients enrolled, the confirmed ORR was 23.1% (95%CI: 6.9%-39.3%); complete response: 3.9%, confirmed partial response [PR]: 19.2%, stable disease: 57.7%, progressive disease: 7.7%, and not evaluable: 11.5%. Including 4 cases of unconfirmed PRs, 38.5% of patients were responding and the disease control rate was 80.7%. The median PFS and OS were 5.0 months (95% CI: 2.7-6.7) and 9.1 months (95% CI: 6.5-15.0), respectively. The grade 3 or 4 adverse events observed included febrile neutropenia (7.7%), neutropenia (7.7%), asthenia (7.7%), hyponatremia (7.7%), and type I diabetes (7.7%). Targeted gene sequencing identified no specific genetic alterations correlated with the treatment, except for theMET copy number gain (PFS 10.5 versus 3.4 months, p = 0.019).

CONCLUSIONS

Pembrolizumab and paclitaxel combination therapy showed a moderate activity with acceptable toxicity in patients with refractory ED-SCLC.

Immune checkpoint blockade in small cell lung cancer

Despite the highly immunogenic potential of small cell lung cancer (SCLC), progress in evaluating the therapeutic value of immune checkpoint agents has lagged behind that of non-small cell lung cancer. Results from a number of phase I-III clinical trials that specifically address the use of anti-PD-1, anti-PD-L1 and anti-CTLA-4 agents in SCLC have now been reported. This review will focus on the available evidence for immune checkpoint blockade in SCLC and review current biomarker strategies with the aim of providing perspective and interpretation of this data for clinical practice.

Immunotherapy in small-cell lung cancer: from molecular promises to clinical challenges

Management of small cell lung cancer (SCLC) has not changed over the last decades. In more recent years, alterations of DNA repair machinery and other molecular pathways have been identified in SCLC and preclinical data suggest that dysregulation of these pathways might offer new therapeutic opportunities.While immune checkpoint inhibitors (ICIs) have had a major impact on the clinical outcome of several solid tumors, including non-small cell lung cancer, the potential role of ICIs is currently under investigation in SCLC and some promising data are available. However, several clinical and biological hurdles have to be overcome and predictive markers are still eagerly needed. Knowledge of molecular pathways specifically involved in SCLC growth and treatment resistance is essential for a more rational planning of new combinations including ICIs.The present manuscript summarizes the current clinical evidence on immunotherapy in SCLC, describes the molecular bases underlying treatment resistance and discusses the potentialities and the rationale of different therapeutic combinations.

Current Diagnosis and Management of Small-Cell Lung Cancer

Small-cell lung cancer (SCLC) is an aggressive disease with distinct pathological, clinical, and molecular characteristics from non-small-cell lung cancer. SCLC has high metastatic potential, resulting in a clinically poor prognosis. Early concurrent chemo-radiation is the standard of care for limited-stage SCLC (LS-SCLC). Prophylactic cranial irradiation (PCI) is recommended for patients with LS-SCLC without progression of disease after initial therapy. A combination of etoposide and cisplatin or carboplatin remains the mainstay of first-line treatment for ES-SCLC, with the addition of atezolizumab, now becoming standard. Most SCLCs initially respond to therapy but almost invariably recur. Topotecan and amrubicin (in Japan) remain the primary chemotherapy options for relapsed SCLC. Immunotherapy, including nivolumab with or without ipilimumab, is now available for refractory disease. In general, the poor prognosis of SCLC has not improved significantly for more than 3 decades. Recently, next-generation molecular profiling studies have identified new therapeutic targets for SCLC. A variety of proapoptotic agents, compounds capitalizing on DNA-repair defects, immunotherapy agents, and antibody-drug conjugates are being evaluated in SCLC, with a number of them showing early promise.

Immune Checkpoint Inhibitors in Small Cell Lung Cancer: A Partially Realized Potential

Small cell lung cancer (SCLC) is a highly lethal subtype of lung cancer that has seen few therapeutic advances, despite ongoing concerted efforts. Immunotherapy has been an effective option in other carcinogen-related cancers and has shown modest activity in SCLC. Monotherapy with the anti-PD-1 antibody nivolumab in patients with at least two prior lines of therapy was associated with a response rate of 11.9% and a median duration of response of 17.9 months, leading to accelerated approval by the Food and Drug Administration (FDA) as third-line therapy for SCLC. Second-line checkpoint inhibitors have not performed well enough to change the standard of care, and maintenance immunotherapy has not shown significant benefit. However, the incorporation of concurrent immunotherapy in the first-line treatment of SCLC has improved outcomes. The addition of the anti-PD-L1 antibody atezolizumab to standard carboplatin plus etoposide led to an improvement in progression free survival (PFS) and overall survival, the first such improvement in over 30 years leading to the approval of atezolizumab as part of first-line therapy for advanced SCLC. While these landmark approvals offer promising novel treatment options for this recalcitrant disease, more work is needed to optimize their delivery and to build upon these important advances.

Maintenance with lanreotide in small-cell lung cancer expressing somatostatine receptors: A multicenter, randomized, phase 3 trial

OBJECTIVES

Considering the frequent expression of somatostatine receptors, we designed the G04.2011 trial to investigate the efficacy of the somatostatine analogue lanreotide in maintenance for SCLC patients after response to standard treatment.

MATERIALS AND METHODS

A multicenter, randomized, phase 3 trial was conducted in SCLC expressing somatostatine receptors at baseline Octreoscan, responding after platinum-based chemotherapy with/without radiotherapy. Patients were randomized 1:1 to receive maintenance lanreotide 120 mg subcutaneously every 28 days, up to 1 year or progression versus observation. Randomization was stratified according to stage (limited/extended, LD/ED). The primary end-point was progression-free survival (PFS). Secondary endpoints were overall survival (OS) and safety.

RESULTS

Seventy-one patients were randomly assigned (39 to lanreotide, 32 to observation) in 9 Italian institutions. Median PFS was 3.6 (95% CI 3.2-3.9) with lanreotide versus 2.3 months (95% CI 1.7-2.9) with observation (HR 1.51, 95% CI 0.90-2.50; P = 0.11). Stage was an independent predictor for PFS (HR 3.14, 95% CI 1.77-5.57; P < 0.0001). Median PFS was 7.0 (95% CI <1-13.5) with lanreotide versus 3.8 months (95% CI <1-8.6) with observation in LD (P = 0.21), and 3.0 (95% CI 2.2-3.8) versus 2.2 (95% 1.7-2.7) in ED (P = 0.19). Median OS was 9.5 (95% CI 4.8-14.3) with lanreotide versus 4.7 months (95% CI <1-16.6) with observation (P = 0.47). Treatment-related adverse events occurred in 28% of patients with lanreotide (grade 3 in two patients).

CONCLUSION

Although survival outcomes were not significantly prolonged with lanreotide as a maintenance in SCLC expressing somatostatin receptors after response to standard treatment, lanreotide showed a slight PFS benefit in LD SCLC deserving further investigations.

Novel Delivery Systems for Checkpoint Inhibitors

Checkpoint inhibition (CPI) therapies have been proven to be powerful clinical tools in treating cancers. FDA approvals and ongoing clinical development of checkpoint inhibitors for treatment of various cancers highlight the immense potential of checkpoint inhibitors as anti-cancer therapeutics. The occurrence of immune-related adverse events, however, is a major hindrance to the efficacy and use of checkpoint inhibitors as systemic therapies in a wide range of patients. Hence, methods of sustained and tumor-targeted delivery of checkpoint inhibitors are likely to improve efficacy while also decreasing toxic side effects. In this review, we summarize the findings of the studies that evaluated methods of tumor-targeted delivery of checkpoint inhibitors, review their strengths and weaknesses, and discuss the outlook for therapeutic use of these delivery methods.

Treatment-Related Adverse Events of PD-1 and PD-L1 Inhibitors in Clinical Trials: A Systematic Review and Meta-analysis

IMPORTANCE

Programmed cell death (PD-1) and programmed cell death ligand 1 (PD-L1) inhibitors have been increasingly used in cancer therapy. Understanding the treatment-related adverse events of these drugs is critical for clinical practice.

OBJECTIVE

To evaluate the incidences of treatment-related adverse events of PD-1 and PD-L1 inhibitors and the differences between different drugs and cancer types.

DATA SOURCES

PubMed, Web of Science, Embase, and Scopus were searched from October 1, 2017, through December 15, 2018.

STUDY SELECTION

Published clinical trials on single-agent PD-1 and PD-L1 inhibitors with tabulated data on treatment-related adverse events were included.

DATA EXTRACTION AND SYNTHESIS

Trial name, phase, cancer type, PD-1 and PD-L1 inhibitor used, dose escalation, dosing schedule, number of patients, number of all adverse events, and criteria for adverse event reporting data were extracted from each included study, and bayesian multilevel regression models were applied for data analysis.

MAIN OUTCOMES AND MEASURES

Incidences of treatment-related adverse events and differences between different drugs and cancer types.

RESULTS

This systematic review and meta-analysis included 125 clinical trials involving 20 128 patients; 12 277 (66.0%) of 18 610 patients from 106 studies developed at least 1 adverse event of any grade (severity), and 2627 (14.0%) of 18 715 patients from 110 studies developed at least 1 adverse event of grade 3 or higher severity. The most common all-grade adverse events were fatigue (18.26%; 95% CI, 16.49%-20.11%), pruritus (10.61%; 95% CI, 9.46%-11.83%), and diarrhea (9.47%; 95% CI, 8.43%-10.58%). The most common grade 3 or higher adverse events were fatigue (0.89%; 95% CI, 0.69%-1.14%), anemia (0.78%; 95% CI, 0.59%-1.02%), and aspartate aminotransferase increase (0.75%; 95% CI, 0.56%-0.99%). Hypothyroidism (6.07%; 95% CI, 5.35%-6.85%) and hyperthyroidism (2.82%; 95% CI, 2.40%-3.29%) were the most frequent all-grade endocrine immune-related adverse events. Nivolumab was associated with higher mean incidences of all-grade adverse events compared with pembrolizumab (odds ratio [OR], 1.28; 95% CI, 0.97-1.79) and grade 3 or higher adverse events (OR, 1.30; 95% CI, 0.89-2.00). PD-1 inhibitors were associated with a higher mean incidence of grade 3 or higher adverse events compared with PD-L1 inhibitors (OR, 1.58; 95% CI, 1.00-2.54).

CONCLUSIONS AND RELEVANCE

Different PD-1 and PD-L1 inhibitors appear to have varying treatment-related adverse events; a comprehensive summary of the incidences of treatment-related adverse events in clinical trials provides an important guide for clinicians.

Potential immune escape mechanisms underlying the distinct clinical outcome of immune checkpoint blockades in small cell lung cancer

Small cell lung cancer (SCLC) is one of the deadliest cancer types in the world. Despite the high response rate to frontline platinum-containing doublets, relapse is inevitable for the majority of patients and the prognosis is poor. Topotecan, which has limited efficacy, has remained the standard second-line therapy for approximately three decades. Although SCLC has a high mutation burden, the clinical efficacy of immune checkpoint blockades (ICBs) in SCLC is far less pronounced than that in non-small cell lung cancer (NSCLC). Only atezolizumab in combination with chemotherapy improved overall survival over chemotherapy alone in the phase III CheckMate 133 trial and has recently received FDA approval as first-line therapy. Most studies concerning ICBs in SCLC are limited to early-phase studies and found that ICBs were not superior to traditional chemotherapy. Why is there such a large difference between SCLC and NSCLC? In this review, comparative analyses of previous studies indicate that SCLC is even more immunodeficient than NSCLC and the potential immune escape mechanisms in SCLC may involve the low expression of PD-L1 and the downregulation of major histocompability complex (MHC) molecules and regulatory chemokines. In consideration of these immune dysfunctions, we speculate that chemotherapy and radiotherapy prior to immunotherapy, the combination of ICBs with antiangiogenic treatment, and selecting tumor mutation burden in combination with PD-L1 expression as biomarkers could be promising strategies to improve the clinical efficacy of immunotherapy for SCLC.

Immune checkpoint inhibitors for small cell lung cancer: opportunities and challenges

Lung cancer is the most common cancer and the leading cause of cancer death worldwide, with an estimated 2.1 million new cases and 1.8 million deaths in 2018. Although small cell lung cancer (SCLC) is the most aggressive type of lung cancer, it shows high response rates to chemotherapy in early lines of therapy. Unfortunately, it is associated with rapid recurrence and relatively poor prognosis. Over the last few years, considerable progress has been made in cancer immunotherapy. One of the most promising ways to activate therapeutic antitumor immunity is via blockade of immune checkpoints, such as cytotoxic T lymphocyte-associated protein-4 (CTLA-4) and programmed cell death protein-1/programmed cell death ligand-1 (PD-1/PD-L1). Immune checkpoint inhibitors show promise as SCLC therapeutics. The overall expectation for immuno-oncology is high, and the outcomes of trials will hopefully reveal a variety of treatment options for SCLC patients. In this review, we discuss the discovery of new immune inhibitory and stimulatory pathways and rational combination strategies to explain the role of immunotherapy in SCLC and its future opportunities and challenges.

Immunotherapy in Small Cell Lung Cancer

Small-cell lung cancer (SCLC) is extremely sensitive to standard treatments, including conventional cytotoxic chemotherapies and radiotherapy, and has poor prognosis and short survival. Standard therapies have reached a plateau of effectiveness and new therapeutic strategies are needed to improve SCLC patient outcomes going forward. Immunotherapy has revolutionised the treatment of solid malignancies, offering a novel way to harness the host immune system to target malignant cells in patients whose disease may no longer respond to cytotoxic therapy. This review describes the available data for the checkpoint inhibitors, such as anti-cytotoxic T-lymphocyte antigen-4 protein (CTLA-4), anti-programmed cell death-1 protein receptor (PD-1), and ligands (PD-L1 and PD-L2) alone or in combination with first-line chemotherapy or in relapsed SCLC. Several trials investigating immunotherapy in SCLC patients are ongoing and the results are awaited soon. Moreover, further immune checkpoint inhibitors directed against other targets, such as the killer-cell immunoglobulin-like receptor and lymphocyte-activation gene-3, are in clinical development. Overall, the high expectations from the oncology community are that the drugs under development will offer new and improved treatment options for SCLC patients.

Improved Prognosis and Increased Tumor-Infiltrating Lymphocytes in Patients Who Have SCLC With Neurologic Paraneoplastic Syndromes

BACKGROUND

Approximately 10% of patients with SCLC develop a paraneoplastic syndrome (PNS). Neurologic PNS are thought to improve prognosis, which we hypothesized is related to increased tumor-infiltrating lymphocytes and immune recognition.

METHODS

We queried 2,512,042 medical records from a single institution to identify patients who have SCLC with and without PNS and performed manual, retrospective chart review. We then performed multiplexed fluorescence immunohistochemistry and automated quantitative analysis (AQUA Technology) on tumors to assess CD3, CD4, and CD8 T cell infiltrates and programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) interactions. T cell infiltrates and PD-1/PD-L1 interaction scores were compared among patients with neurologic PNS, endocrinologic PNS, and a control group without PNS. Clinical outcomes were analyzed using the Kaplan-Meier method and Cox proportional hazards models.

RESULTS

We evaluated 145 SCLC patients: 55 with PNS (25 neurologic and 30 endocrinologic) and 90 controls. Patients with neurologic PNS experienced improved overall survival compared to patients with endocrinologic PNS and controls (median overall survival of 24 months versus 12 months versus 13 months, respectively). Of the 145 patients, we identified tumor tissue from 34 patients that was adequate for AQUA analysis. Among 37 specimens from these 34 patients, patients with neurologic PNS had increased T cell infiltrates (p = 0.033) and PD-1/PD-L1 interaction (p = 0.014) compared to tumors from patients with endocrinologic PNS or controls.

CONCLUSIONS

Tumor tissue from patients with SCLC with neurologic PNS showed increased tumor-infiltrating lymphocytes and PD-1/PD-L1 interaction consistent with an inflamed tumor microenvironment.

Fluorodeoxyglucose uptake is associated with low tumor-infiltrating lymphocyte levels in patients with small cell lung cancer

OBJECTIVES

Positron emission tomography (PET) using 2-deoxy-2-[¹⁸F] fluoro-D-glucose (¹⁸F-FDG) is a clinically useful modality for cancer evaluation. The mechanism of ¹⁸F-FDG uptake within cancer cells involves the glucose transporter 1 (GLUT1) and hypoxia-inducible factor-1 α (HIF-1α). Although recent research has shown its clinical efficacy in small-cell lung cancer (SCLC), no suitable biomarker has been identified. We conducted a clinicopathological study to examine the relationship between tumor immunity and ¹⁸F-FDG uptake in patients with SCLC.

MATERIALS AND METHODS

Tumor sections were stained by immunohistochemistry for GLUT1, HIF-1α, PD-L1, CD4, CD8, and Foxp3. The relationship between clinicopathological features and ¹⁸F-FDG uptake was analyzed. Student's t-test, χ2 test, non-parametric Spearman's rank test, and Kaplan-Meier method were used to evaluate associations between the variables.

RESULTS

A total of 98 patients 78 men and 20 women who underwent ¹⁸F-FDG PET, were enrolled in this study. PD-L1 was expressed in 36.7% (36/98) of all patients; this was significantly associated with GLUT1 expression (p = 0.04). The accumulation of ¹⁸F-FDG was significantly higher in patients with low CD8 and CD4 TILs than in those with high TILs (p = 0.03 and p = 0.01, respectively). The uptake of ¹⁸F-FDG was not significantly associated with the expression of either Foxp3 or PD-L1. Multivariate analysis demonstrated that advanced stage, poor ECOG-PS, and high SUV_max were independent predictors of poor OS. Among patients with limited-stage disease, multivariate analysis confirmed high PD-L1 expression and a high SUV_max to be independent predictors of poor OS. However, only ECOG-PS was found to be an independent predictor of poor OS among patients with extensive-stage tumors.

CONCLUSION

High SUV_max on ¹⁸F-FDG-PET is correlated with low expression of CD8(+) and CD4(+) TILs, but is an independent prognostic factor for OS, particularly in those with limited disease. Further studies are warranted to validate our findings.

Novel targeted strategies to overcome resistance in small-cell lung cancer: focus on PARP inhibitors and rovalpituzumab tesirine

Introduction: Small-cell lung cancer (SCLC) is a highly aggressive neuroendocrine tumour, and its outcome is strongly conditioned by the rapid onset of resistance to conventional chemotherapeutics. First-line treatment with a combination of platinum agents and topoisomerase inhibitors has been the standard of care for over 30 years, with disappointing clinical outcome caused by early-acquired chemoresistance. In this disheartening scenario, novel treatment strategies are being implemented in order to either revert or bypass resistance mechanisms. Areas covered: The general mechanism of action of the standard frontline treatment regimens for SCLC, as well as the known resistance mechanisms to these drugs, is reviewed. Moreover, we focus on the current preclinical and clinical evidence on the potential role of PARP inhibitors and rovalpituzumab tesirine (Rova-T) to tackle chemoresistance in SCLC. Expert opinion: Preliminary evidence supports PARP inhibitors and Rova-T as two promising approaches to either revert or bypass chemoresistance in SCLC, respectively. The identification of potential predictive biomarkers of response to these innovative treatments (SLFN11 and DLL3) has shortened the gap between SCLC and personalized targeted therapy. Further large-scale clinical studies are urgently needed for a better designation of PARP inhibitors and Rova-T in the therapeutic algorithm of SCLC patients.

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

The introduction of programmed death receptor ligand-1 (PD-L1) and programmed death receptor-1 (PD-1) inhibitors into the field of non-small cell lung cancer (NSCLC) was practice changing. The pivotal trials consistently showed a clinically meaningful improvement in overall survival (OS) for patients with driver mutation-negative NSCLC, a field in which outcomes had been stagnant for decades. The success of immune checkpoint inhibitor (ICI) therapy in NSCLC has led to enthusiasm to expand the reach of these drugs into other thoracic malignancies such as thymic epithelial tumors (TETs), mesothelioma, and small cell lung cancer (SCLC). Unfortunately, the improvement in outcomes with ICI therapy in these rarer thoracic tumors has been somewhat modest, and in the case of thymoma, rates of adverse events are too high to routinely justify their use. Although the response rates seen in ICI therapy in these tumor types are similar to those seen with other available single-agent therapies for advanced disease, ICIs do present another option for clinicians treating patients with mesothelioma, small cell carcinoma, and thymic carcinoma (TC), diseases in which approved treatment options are limited. Here we review the latest trials of ICI therapy in mesothelioma, SCLC, and TETs.

Clinical utility of pembrolizumab in the management of advanced solid tumors: an evidence-based review on the emerging new data

Pembrolizumab is a full-length human immunoglobulin G4 (IgG4) monoclonal antibody directed against the immune checkpoint PD-1 to remove its binding with PD-L1 and thus to restore an anti-tumor immune response of T cells. Pembrolizumab is one of the most advanced immune checkpoint inhibitors for cancer care. Apart from rare and serious adverse effects, its favorable tolerance profile enables to treat fragile patients who have often no other choice than best supportive care. The effective retained dose of pembrolizumab is a venous administration of 200 mg every 3 weeks until disease progression, intolerance or up to 24 months. Pembrolizumab has already proven its efficacy and thus obtained marketing authorization in so-called hot or hypermutated tumors or tumors expressing PD-L1 such as melanomas, non-small cell lung cancers, urothelial carcinomas, cervical cancer, etc. Pembrolizumab is also authorized in the United States in the treatment of mismatch repair-deficient tumors or with microsatellite instability. The current challenge is to expand its use in tumor types that are supposed to be less immunogenic, for example, by attempting to warm up the tumor microenvironment, or by combining pembrolizumab with other molecules. An acceptable toxicity profile of such combinations remains to explore. We review here the current indications of this drug, the main prognostic and predictive factors of its efficacy as well as the potential forthcoming indications.

PD-L1 Expression and Immune Cell Infiltration in Gastroenteropancreatic (GEP) and Non-GEP Neuroendocrine Neoplasms With High Proliferative Activity

The potential of neuroendocrine neoplasms (NEN) to respond to checkpoint inhibitors is largely unknown and full of great expectations. Immunohistochemical (IHC) studies of programmed cell death ligand 1 (PD-L1) expression in the tumor microenvironment and its implications in predicting the response to checkpoint inhibition is a very active subject. Currently, the combined analysis of PD-L1 expression and tumor-associated immune cell (TAIC) infiltration is considered the best predictive marker of therapeutic response. Here we investigated the expression of PD-L1 on tumor cells (TC) and tumor-infiltrating immune cells (IC) by IHC in 68 NEN samples with a high proliferation rate (Ki-67 >20%) from 57 patients and in 22 samples we correlated it with TAIC density by assessing intratumoral infiltration of CD3+, CD8+, and CD68+ cells. Furthermore, the tumor microenvironment was evaluated according to the classification of Teng et al. We detected PD-L1 expression in 31.6% of NEN G3. Its expression usually was weak and more IC than TC expressed PD-L1. The proportion of tumors positive for PD-L1 was comparable in NEN from different sites of origin but varied depending on tumor differentiation and disease extension. No positive IHC staining was found in 3 well-differentiated neuroendocrine tumors (NETs) with a proliferation rate above 20% (NET G3). When analyzing TAIC, we rarely (18.2%) detected intratumoral CD8+ cells, whereas infiltration by CD3+ and CD68+ cells was more common (45.5 and 59.1%, respectively). By combining CD3+ cells and PD-L1 status, we identified the immune ignorant phenotype of tumor microenvironment as being the most common phenotype, supporting the concept of a preferably combined immunotherapeutic approach in neuroendocrine carcinoma (NEC).

Durvalumab in Combination with Olaparib in Patients with Relapsed SCLC: Results from a Phase II Study

PURPOSE

Despite high tumor mutationburden, immune checkpoint blockade has limited efficacy in SCLC. We hypothesized that poly (ADP-ribose) polymerase inhibition could render SCLC more susceptible to immune checkpoint blockade.

METHODS

A single-arm, phase II trial (NCT02484404) enrolled patients with relapsed SCLC who received durvalumab, 1500 mg every 4 weeks, and olaparib, 300 mg twice a day. The primary outcome was objective response rate. Correlative studies included mandatory collection of pretreatment and during-treatment biopsy specimens, which were assessed to define SCLC immunephenotypes: desert (CD8-positive T-cell prevalence low), excluded (CD8-positive T cells in stroma immediately adjacent/within tumor), and inflamed (CD8-positive T cells in direct contact with tumor).

RESULTS

A total of 20 patients were enrolled. Their median age was 64 years, and most patients (60%) had platinum-resistant/refractory disease. Of 19 evaluable patients, two were observed to have partial or complete responses (10.5%), including a patient with EGFR-transformed SCLC. Clinical benefit was observed in four patients (21.1% [95% confidence interval: 6.1%-45.6%]) with confirmed responses or prolonged stable disease (≥8 months). The most common treatment-related adverse events were anemia (80%), lymphopenia (60%), and leukopenia (50%). Nine of 14 tumors (64%) exhibited an excluded phenotype; 21% and 14% of tumors exhibited the inflamed and desert phenotypes, respectively. Tumor responses were observed in all instances in which pretreatment tumors showed an inflamed phenotype. Of the five tumors without an inflamed phenotype at baseline, no during-treatment increase in T-cell infiltration or programmed death ligand 1 expression on tumor-infiltrating immune cells was observed.

CONCLUSIONS

The study combination did not meet the preset bar for efficacy. Pretreatment and during-treatment biopsy specimens suggested that tumor immune phenotypes may be relevant for SCLC responses to immune checkpoint blockade combinations. The predictive value of preexisting CD8-positive T-cell infiltrates observed in this study needs to be confirmed in larger cohorts.

Emerging therapies for small cell lung cancer

Currently, chemotherapy remains the standard treatment for first- and second-line management of small cell lung cancer (SCLC). Immunotherapy has made progress in the treatment of SCLC, and nivolumab, pembrolizumab, atezolizumab, and durvalumab have led to significant improvements in clinical outcomes of SCLC. Regarding options in other classes of therapy, the cytotoxic drug lurbinectedin was granted orphan drug status based on a remarkable objective response rate of 39.3%. In addition, an increase in progression-free survival (PFS) was achieved in a phase II study of anlotinib (ALTER 1202). Future prospects for even better outcomes in SCLC lie in novel ways to integrate immunotherapy and small-molecule TKI drugs. Innovative clinical trial designs are needed to efficiently explore the increasing number of options with new drugs and new combinations thereof for SCLC.

Molecular subtypes of small cell lung cancer: a synthesis of human and mouse model data

Small cell lung cancer (SCLC) is an exceptionally lethal malignancy for which more effective therapies are urgently needed. Several lines of evidence, from SCLC primary human tumours, patient-derived xenografts, cancer cell lines and genetically engineered mouse models, appear to be converging on a new model of SCLC subtypes defined by differential expression of four key transcription regulators: achaete-scute homologue 1 (ASCL1; also known as ASH1), neurogenic differentiation factor 1 (NeuroD1), yes-associated protein 1 (YAP1) and POU class 2 homeobox 3 (POU2F3). In this Perspectives article, we review and synthesize these recent lines of evidence and propose a working nomenclature for SCLC subtypes defined by relative expression of these four factors. Defining the unique therapeutic vulnerabilities of these subtypes of SCLC should help to focus and accelerate therapeutic research, leading to rationally targeted approaches that may ultimately improve clinical outcomes for patients with this disease.

Postoperative adjuvant therapy for resectable esophageal cancer: A protocol of a systematic review and meta-analysis

BACKGROUND

Esophageal cancer is one of the most common malignant tumors, characterized by early metastasis and high degree of malignancy. Its morbidity ranks 7th among all malignant tumors and its mortality ranks 6th. Postoperative adjuvant therapy after esophagectomy can significantly improve the overall survival rate of patients with locally resectable esophageal cancer. With the breakthrough and progress of immunotherapy, the possibility of cure of esophageal cancer is greatly improved. Some clinical trials have reported that programmed death 1 (PD1) and programmed death ligand 1 (PDL1) inhibitors alone, compared with traditional platinum-based chemotherapy, can benefit patients and effectively extend the overall survival period of patients. We will conduct a systematic review and meta-analysis on the comparison of the efficacy of immunotherapy (PD1 and PDL1 inhibitors) alone and traditional platinum-based chemotherapy, so as to provide a reliable basis for clinicians to formulate the best chemotherapy regimen for patients with esophageal cancer after esophagectomy.

METHODS

We will search Pubmed, Medline, Embase, Web of Science, Cancerlit, Google Scholar, and the Cochrane Central Register of Controlled Trials for related studies published before December 1, 2019 without language restrictions. Two review authors will search and assess relevant studies independently. Randomized controlled trials (RCTs) or quasi-RCTs, and prospective cohort studies will be included. We will perform subgroup analysis in sex, age, ethnicity, and tumor stage of esophageal cancer patients.

RESULTS

The results of this study will be published in a peer-reviewed journal.

CONCLUSION

The results of this systematic review and meta-analysis will provide a basis for clinicians to formulate the best chemotherapy regimen for patients, as well as a research clue for clinical researchers in this field. The results of this study will expand the treatment options for esophageal patients, but due to the nature of the disease and intervention, large sample clinical trials are not abundant, so we will include some high-quality small sample trials, which may cause high heterogeneity.PROSPERO registration number: CRD42019125000.

Targeting DNA Damage Response Promotes Antitumor Immunity through STING-Mediated T-cell Activation in Small Cell Lung Cancer

Despite recent advances in the use of immunotherapy, only a minority of patients with small cell lung cancer (SCLC) respond to immune checkpoint blockade (ICB). Here, we show that targeting the DNA damage response (DDR) proteins PARP and checkpoint kinase 1 (CHK1) significantly increased protein and surface expression of PD-L1. PARP or CHK1 inhibition remarkably potentiated the antitumor effect of PD-L1 blockade and augmented cytotoxic T-cell infiltration in multiple immunocompetent SCLC in vivo models. CD8+ T-cell depletion reversed the antitumor effect, demonstrating the role of CD8+ T cells in combined DDR-PD-L1 blockade in SCLC. We further demonstrate that DDR inhibition activated the STING/TBK1/IRF3 innate immune pathway, leading to increased levels of chemokines such as CXCL10 and CCL5 that induced activation and function of cytotoxic T lymphocytes. Knockdown of cGAS and STING successfully reversed the antitumor effect of combined inhibition of DDR and PD-L1. Our results define previously unrecognized innate immune pathway-mediated immunomodulatory functions of DDR proteins and provide a rationale for combining PARP/CHK1 inhibitors and immunotherapies in SCLC. SIGNIFICANCE: Our results define previously unrecognized immunomodulatory functions of DDR inhibitors and suggest that adding PARP or CHK1 inhibitors to ICB may enhance treatment efficacy in patients with SCLC. Furthermore, our study supports a role of innate immune STING pathway in DDR-mediated antitumor immunity in SCLC.See related commentary by Hiatt and MacPherson, p. 584.This article is highlighted in the In This Issue feature, p. 565.

[Clinical Research Progress of Immune Checkpoint Inhibitors in the Treatment of Small Cell Lung Cancer]

With the in-depth study of tumor immunity, immunotherapy represented by immune checkpoint inhibitors has made a great breakthrough in solid tumors. Small cell lung cancer (SCLC) accounts for about 15%-20% of all lung cancers, with high malignancy, early metastasis and lack of effective treatment strategy. The appearance of immune checkpoint inhibitors brings new hope for SCLC. Several clinical trials have demonstrated the persistent efficacy and clinical activity of the programmed death receptor/ligand 1 (PD-1/L1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4) in the treatment of SCLC. However, its efficacy and safety are not very accurate, and the markers that can effectively predict the efficacy of immunotherapy have not been concluded. In this paper, for further changing the treatment strategy of SCLC clinical practice and providing theoretical basis of research, we reviewed the progress of immune checkpoint inhibitors, related markers in the treatment of SCLC by exploring the value, problems and challenges of immunotherapy in SCLC.
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Personalized Dendritic Cell Vaccines-Recent Breakthroughs and Encouraging Clinical Results

With the advent of combined immunotherapies, personalized dendritic cell (DC)-based vaccination could integrate the current standard of care for the treatment of a large variety of tumors. Due to their proficiency at antigen presentation, DC are key coordinators of the innate and adaptive immune system, and have critical roles in the induction of antitumor immunity. However, despite proven immunogenicity and favorable safety profiles, DC-based immunotherapies have not succeeded at inducing significant objective clinical responses. Emerging data suggest that the combination of DC-based vaccination with other cancer therapies may fully unleash the potential of DC-based cancer vaccines and improve patient survival. In this review, we discuss the recent efforts to develop innovative personalized DC-based vaccines and their use in combined therapies, with a particular focus on ovarian cancer and the promising results of mutanome-based personalized immunotherapies.

Recent progress in systemic treatment for lung cancer

PURPOSE OF REVIEW

We intend to highlight progress made in 2017 to lung cancer molecular nosology and application of new knowledge to treatment.

RECENT FINDINGS

Studies have shown that agents targeting specific molecular defects in lung cancers such as epidermal growth factor receptor(egfr) mutations, alk or ros1 gene rearrangements, are more effective than conventional combination chemotherapy as primary treatment for various lung cancer subgroups. Identification of mechanisms of drug resistance has guided development of improved agents and effective salvage regimens. Progress in reversing tumor-induced immunosuppression has led to further improvements in response rates (RR) including some patients with prolonged durable remissions.

SUMMARY

State-of-the-art management of patients with lung cancer requires information derived from tumor molecular analysis, obtained either directly from the tumor or from tumor-derived circulating DNA. Empiric combination chemotherapy is no longer uniformly the best available treatment for all patients. Therapeutic decisions should be guided by an understanding of molecular features of an individual patient's tumor. The future gains will likely emerge from finding optimal ways of combining targeted therapy, immunotherapy, and chemotherapy.

Unexpected Synergy Reveals New Therapeutic Strategy in SCLC

DNA damage repair (DDR) inhibition and immune checkpoint blockade (ICB) have each individually shown modest clinical activity in small cell lung cancer (SCLC). Recently, Sen and colleagues (Cancer Discov. 2019;https://doi.org/10.1158/2159-8290.CD-18-1020) demonstrated that DDR inhibition can activate the stimulator of interferon genes (STING) innate immune pathway, providing strong rationale for combining DDR inhibition and ICB to treat SCLC.

Use of targeted next generation sequencing to characterize tumor mutational burden and efficacy of immune checkpoint inhibition in small cell lung cancer

BACKGROUND

Clinically-available biomarkers to identify the fraction of patients with small cell lung cancer (SCLC) who respond to immune-checkpoint inhibitors (ICIs) are lacking. High nonsynonymous tumor mutational burden (TMB), as assessed by whole exome sequencing, correlates with improved clinical outcomes for patients with SCLC treated with ICIs. Whether TMB as assessed by targeted next generation sequencing (NGS) is associated with improved efficacy of ICIs in patients with SCLC is currently unknown. Here we determined whether TMB by targeted NGS is associated with efficacy of ICIs in patients with SCLC.

METHODS

We collected clinicopathologic data from patients with relapsed or refractory SCLC which underwent targeted NGS with TMB assessment by the Dana-Farber Cancer Institute OncoPanel platform. The relationship between TMB and clinical outcomes after treatment with ICIs was investigated.

RESULTS

Among the 52 patients treated with ICIs, we found no significant difference in the objective response rate (ORR) between patients with a TMB above the 50th percentile ("TMB high") and those with a TMB at or below the 50th percentile ("TMB low"). The median progression-free survival (mPFS) and median overall survival (mOS) were significantly longer in patients with a high TMB compared to those with a low TMB (mPFS: 3.3 versus 1.2 months, HR: 0.37 [95% CI: 0.20-0.69], P < 0.01; mOS: 10.4 versus 2.5 months, HR: 0.38 [95% CI: 0.19-0.77], P < 0.01). The one-year PFS and OS rates improved with increasing mutational load when TMB was divided into tertiles.

CONCLUSIONS

These findings show that targeted NGS, a readily available clinical diagnostic test, can be used to identify patients with SCLC who are most likely to benefit from treatment with immune checkpoint inhibitors.

Serum cytokine levels as predictive biomarkers of benefit from ipilimumab in small cell lung cancer

Background. Immunotherapy has shown efficacy in small cell lung cancer (SCLC), but only a subset of patients benefits. Surrogate biomarkers are urgently needed. Our aim was to evaluate serum Th1, Th2, and proinflammatory cytokines in two cohorts of SCLC patients before and during treatment with chemotherapy with or without ipilimumab and to correlate them with survival. Patients and methods. Two cohorts of SCLC patients were studied: patients treated with chemotherapy (n = 47), and patients treated with chemotherapy plus ipilimumab (n = 37). Baseline, on-treatment and after-treatment serum samples were evaluated for the presence of IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IFN-gamma, TNF-alpha, GM-CSF, and Mip-1alpha using a Luminex assay. Differential changes in cytokines between cohorts were analyzed. Associations between cytokine levels and their changes with overall survival were evaluated. Results. Patients treated with ipilimumab showed a global increase of all cytokines after treatment initiation. A high level of IL-8 at baseline was associated with worse prognosis regardless of treatment. Baseline increased IL-2 levels predicted sensitivity to ipilimumab, while high IL-6 and TNF-alpha predicted resistance. An on-treatment increase in IL-4 levels in patients treated with immune-chemotherapy was associated with a better overall survival. Conclusions. The addition of ipilimumab to standard chemotherapy in SCLC modulates the serum levels of cytokines. Baseline levels and their change over time relate to overall survival. Blood-based biomarkers are convenient for patients, and our results support prospective validation of cytokines as predictive biomarkers for ipilimumab in SCLC.

A case of small-cell lung cancer with adrenocorticotropic hormone deficiency induced by nivolumab

Anti-programmed death-1 (anti-PD-1) monoclonal antibodies, such as nivolumab, have been used for the treatment of various types of cancers, and excellent efficacy has been shown in some patients. The adverse effects of anti-PD-1 antibodies relating to autoimmunity are different from traditional chemotherapeutic drugs and may involve many organs including the endocrine system. We herein describe a case of adrenocorticotropic hormone deficiency during the treatment of advanced small-cell lung cancer, probably caused by nivolumab-induced hypophysitis. The case showed nonspecific, insidious, as well as potentially life-threatening characters of immune-related adverse effects. It is important for physicians to acknowledge clinical features of the rare side effect and take appropriate and prompt treatment.

Expression and clinical significance of PD-L1, B7-H3, B7-H4 and TILs in human small cell lung Cancer (SCLC)

Background

Small cell lung cancer (SCLC) accounts for 10–15% of all lung malignancies and its prognosis is dismal. Although early studies have shown promising clinical activity of immune checkpoint blockers, the immune composition and expression of potentially actionable immunostimulatory targets in this malignancy are poorly understood.

Methods

Using multiplexed quantitative immunofluorescence (QIF), we measured the levels of 3 different B7 family ligands PD-L1, B7-H3, B7-H4 and major tumor infiltrating lymphocyte (TIL) subsets in 90 SCLC samples represented in tissue microarray format. Associations between the marker levels, clinicopathological variables and survival were studied.

Results

PD-L1 protein was detected in 7.3%, B7-H3 in 64.9% and B7-H4 in 2.6% of SCLC cases. The markers showed limited co-expression and were not associated with the level of TILs, age, gender and stage. Elevated B7-H4 was associated with shorter 5-year overall survival. The levels of CD3+, CD8+ and CD20+ TILs and the ratio of total/effector T-cells were significantly lower in SCLC than in non-small cell lung cancer. High levels of CD3+, but not CD8+ or CD20+ TILs were significantly associated with longer survival.

Conclusions

Taken together, our study indicate variable expression and clinical role of B7-family ligands in SCLC with predominant expression of the candidate target B7-H3 and the presence of a limited cytotoxic anti-tumor immune response. These results support the evaluation of B7-H3 blockers and/or pro-inflammatory therapies in SCLC.

Randomized-controlled phase II trial of salvage chemotherapy after immunization with a TP53-transfected dendritic cell-based vaccine (Ad.p53-DC) in patients with recurrent small cell lung cancer

Small cell lung cancer TP53 mutations lead to expression of tumor antigens that elicits specific cytotoxic T-cell immune responses. In this phase II study, dendritic cells transfected with wild-type TP53 (vaccine) were administered to patients with extensive-stage small cell lung cancer after chemotherapy. Patients were randomized 1:1:1 to arm A (observation), arm B (vaccine alone), or arm C (vaccine plus all-trans-retinoic acid). Vaccine was administered every 2 weeks (3 times), and all patients were to receive paclitaxel at progression. Our primary endpoint was overall response rate (ORR) to paclitaxel. The study was not designed to detect overall response rate differences between arms. Of 69 patients enrolled (performance status 0/1, median age 62 years), 55 were treated in stage 1 (18 in arm A, 20 in arm B, and 17 in arm C) and 14 in stage 2 (arm C only), per 2-stage Simon Minimax design. The vaccine was safe, with mostly grade 1/2 toxicities, although 1 arm-B patient experienced grade 3 fatigue and 8 arm-C patients experienced grade 3 toxicities. Positive immune responses were obtained in 20% of arm B (95% confidence interval [CI], 5.3-48.6) and 43.3% of arm C (95% CI 23.9-65.1). The ORRs to the second-line chemotherapy (including paclitaxel) were 15.4% (95% CI 2.7-46.3), 16.7% (95% CI 2.9-49.1), and 23.8% (95% CI 9.1-47.5) for arms A, B, and C, with no survival differences between arms. Although our vaccine failed to improve ORRs to the second-line chemotherapy, its safety profile and therapeutic immune potential remain. Combinations with the other immunotherapeutic agents are reasonable options.

Solvent-based paclitaxel or nab-paclitaxel for heavily treated relapsed/refractory small cell lung cancer: Retrospective single-institution observational study

Treatment options for patients with relapsed/refractory small cell lung cancer (R/R SCLC) are limited, and the efficacy of salvage therapies for heavily treated patients should be assessed. Here, we evaluated the efficacy of paclitaxel (PTX) in R/R SCLC patients.A single-institute retrospective chart review was conducted. The primary endpoint was overall survival (OS), whereas the secondary endpoints were progression-free survival (PFS), overall response rate, disease control rate (DCR), and safety.Thirty-one patients (median age, 69 [range, 56-80] years) were analyzed. The median follow-up period was 122 (range, 28-1121) days. The median OS and PFS were 4.4 and 2.2 months, respectively. Adverse events of grade 3 or higher, other than hematological toxicity, were febrile neutropenia and neuropathy. Multivariate analyses identified the following independent predictors of poor OS: performance status and lactate dehydrogenase at the upper limit of normal.PTX monotherapy showed moderate efficacy with acceptable toxicity in heavily treated patients with R/R SCLC patients.

Prevalence and prognostic value of PD-L1 expression in molecular subtypes of metastatic large cell neuroendocrine carcinoma (LCNEC)

BACKGROUND

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a rare tumor with high mutational burden. Two subtypes of LCNEC are recognized, the co-mutated TP53 and RB1 group and the TP53 and STK11/KEAP1 group. We investigated PD-L1 and CD8 expression in a well characterized stage IV LCNEC cohort and compared expression in the two subtypes.

METHODS

Immunohistochemical (IHC) analysis for PD-L1 and CD8 was performed on pathological reviewed pretreatment tumor samples for 148 stage IV LCNEC. Data about targeted next generation sequencing (TNGS) (TP53, RB1, STK11, KEAP1) and IHC for RB1 were available for most tumors. IHC staining for PD-L1 (DAKO 28-8) was performed and scored positive if tumors showed ≥1% membranous staining. CD8 was scored for intra-tumor T-cells and stromal cells.

RESULTS

PD-L1 IHC expression data could be generated in 98/148 confirmed LCNEC samples along with RB1 IHC (n = 97) of which 77 passed quality control for TNGS. PD-L1 expression was positive in 16/98 cases (16%); 5 (5%) with ≥50%. PD-L1 expression was equal in RB1 mutated and RB1 wildtype tumors. None of STK11 mutated tumors (n = 7) expressed PD-L1. PD-L1 expression was correlated with superior overall survival (OS), hazard ratio 0.55 ((95% Confidence Interval 0.31-0.96), p = 0.038). Intra-tumor CD8 was associated with PD-L1 expression (p = 0.021) and stromal and intra-tumor CD8 were correlated with improved OS (p = 0.037 and p = 0.026 respectively).

CONCLUSIONS

PD-L1 expression was positive in 16% of stage IV LCNEC tumors. This was independent of molecular subtype but associated with CD8 expression. In LCNEC patients with PD-L1 and/or CD8 expression superior OS was observed.

Checkpoint Kinase 1 Inhibition Enhances Cisplatin Cytotoxicity and Overcomes Cisplatin Resistance in SCLC by Promoting Mitotic Cell Death

INTRODUCTION

Platinum-based chemotherapy remains the standard treatment for patients with SCLC, but the benefit of the treatment is often hampered by rapid development of drug resistance. Thus far, there is no targeted therapy available for SCLC. More than 90% of SCLC tumors harbor mutations in the tumor suppressor gene tumor protein p53 (p53), an important DNA damage checkpoint regulator, and these tumor cells rely predominantly on the checkpoint kinases to control DNA damage response.

METHODS

We examined whether and how inhibition of checkpoint kinase 1 (Chk1) affects cisplatin cytotoxicity in SCLC cells with and without p53 mutations, and evaluated the effect of Chk1 inhibitor and cisplatin combination in cisplatin-sensitive and -resistant preclinical models.

RESULTS

Inhibition of Chk1 synergized with cisplatin to induce mitotic cell death in the p53-deficeint SCLC cells. The effect was regulated in part through activation of caspase 2 and downregulation of E2F transcription factor 1 (E2F1). Furthermore, Chk1 inhibitors prexasertib and AZD7762 enhanced cisplatin antitumor activity and overcame cisplatin resistance in SCLC preclinical models in vitro an in vivo. We also observed that higher expression of Chk1 was associated with poorer overall survival of patients with SCLC.

CONCLUSIONS

Our data account Chk1 as a potential therapeutic target in SCLC, and rationalize clinical development of Chk1 inhibitor and cisplatin combinational strategy for the treatment of SCLC.

2017-2018 Scientific Advances in Thoracic Oncology: Small Cell Lung Cancer

SCLC remains an aggressive, deadly cancer with only modest effect on survival from standard chemotherapy. However, with the advent of immunotherapy and comprehensive genomic and transcriptomic profiling, multiple new targets are showing promise in the clinical arena, and just recently programmed death ligand 1 inhibition has been shown to improve the efficacy of standard chemotherapy in extended-disease SCLC. Our increasing understanding of the interactions between different pathways will enable more tailored immunotherapy and targeted therapies based on specific biomarkers and rational combinations. Here we discuss the preclinical and clinical strides in 2017 and 2018 that put us on the threshold of a new era in therapeutics and will, it is hoped, translate into significant improvements in survival.

Surgical Resection of SCLC: Prognostic Factors and the Tumor Microenvironment

INTRODUCTION

Surgery in SCLC is limited to very early stages, but several reports suggest a potential broader role. Little is known of the influence of microenvironment on the biology of SCLC.

METHODS

We assessed the clinical prognostic factors in a large series of resected SCLC patients. The prognostic value of programmed cell death ligand 1 (PD-L1) expression in tumor cells and tumor infiltrating lymphocytes (TILs) and the percentage of CD3-, CD20-, CD45- and CD68-positive cells, were also investigated.

RESULTS

Two hundred five SCLC cases were resected between 2005 and 2015 and the median follow-up was 29 months (range: 2 to 135 months). Median survival of all patients was 69 months, and 5-year survival rates were 63.8%, 65.5%, 34.9%, and 0% for pathologic stages I, II, III, and IV, respectively. By multivariate analysis complete resection, cigarette index, lymph node metastatic rate, percentage of CD3-positive cells, PD-L1 expression in tumor cells, and TILs were independent prognostic factors. High PD-L1 expression was present in 3.2% and 33.5% of all tumor samples in tumor cells and TILs, respectively. High PD-L1 expression in tumor cells or TILs correlated with shorter survival, whereas high expression of CD3, CD20, and CD45 correlated with better survival.

CONCLUSIONS

Resected stage II SCLC patients have similar survival as stage I, suggesting that surgery could be extended to patients with hilar lymph node involvement. Survival was better in tumors with a higher percentage of T cells and B cells, whereas PD-L1 expression in tumor cells and TILs correlated with worse survival, which suggests a potential role of immunotherapy in resected SCLC.

Retrospect and Prospect for Lung Cancer in China: Clinical Advances of Immune Checkpoint Inhibitors

Lung cancer is the most commonly diagnosed cancer and the leading cause of cancer-related deaths in China. The recent emergence of immunotherapy treatment options, such as the use of programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) checkpoint inhibitors, has also led to a paradigm shift in the treatment of non-small cell lung cancer, and has provided promising directions for the treatment of small cell lung cancer. This review provides a summary of the developmental process of immunotherapy, especially immune checkpoint inhibitors in lung cancer, ongoing international and domestic clinical trials in this field, and the challenges and considerations related to the use of immunotherapy in Chinese patients with lung cancer, with the aim of providing detailed information for future immunotherapy-related clinical trials in China. Research regarding immune checkpoint inhibitors in China is several years behind similar research in several developed countries. However, although PD-1/PD-L1 inhibitor-related clinical trials remain in their early stages in China, increased efforts by Chinese clinicians, researchers, and government staff have been directed toward trying to introduce novel drugs into the clinical setting. Because of the specific characteristics of Chinese patients with lung cancer (such as high epidermal growth factor receptor mutation rates, later disease stages, and different toxicity profiles), large-scale clinical trials targeting the Chinese population or Chinese participation in multinational trials should be promoted. IMPLICATIONS FOR PRACTICE: As the leading cause of cancer-related morbidity and mortality, lung cancer is a major public health problem in China. Immunotherapy based on programmed cell death protein 1/programmed death-ligand 1 checkpoint inhibitors may result in new treatment directions and a paradigm shift for Chinese patients with lung cancer. Although checkpoint inhibitor-related clinical trials remain in their early stages in China, increased efforts by Chinese clinicians, researchers, and government staff have been directed toward trying to introduce novel drugs into the clinical setting by encouraging the development of large-scale clinical trials targeting the Chinese population and promoting Chinese patients with lung cancer to participate in international trials.

Intestinal microbiota predicts lung cancer patients at risk of immune-related diarrhea

AIM

Previous studies showed that some patients after the treatment of anti-programmed cell death protein-1 (anti-PD-1) antibodies experienced immune-related diarrhea. In this study, we aim to explore the association between intestinal microbiota and immune-related diarrhea.

METHODS

We obtained the fecal samples of 26 advanced lung cancer patients before the first dose of anti-PD-1 antibodies.

RESULTS

Eight of 26 patients experienced diarrhea after the treatment of anti-PD-1 antibodies. At the phylum level, our study demonstrated that Bacteroidetes were higher in diarrhea-free (D-F) patients, while Firmicutes were lower. Bacteroides and Parabacteroides belonging to Bacteroidetes phylum and Phascolarctobacterium of Firmicutes phylum were more abundant in D-F patients. Whereas, Veillonella of Proteobacteria phylum was lower in D-F patients.

CONCLUSION

Our study highlights that intestinal microbiota variation is correlated with the subsequent development of immune-related diarrhea.