Pembrolizumab After Two or More Lines of Previous Therapy in Patients With Recurrent or Metastatic SCLC: Results From the KEYNOTE-028 and KEYNOTE-158 Studies

Advances in novel molecular typing and precise treatment strategies for small cell lung cancer

Small cell lung cancer (SCLC) is a high-grade neuroendocrine (NE) cancer characterized by high circulating tumor-cell burden and early extensive metastasis. Considering the complexity of SCLC genes and the immune microenvironment, their unique molecular heterogeneity profiles have been continuously explored. The understanding of SCLC subtypes has recently changed from traditional "classical" and "variant" types to "NE" and "non-NE" phenotypes and to the subtypes defined by major transcriptional regulators, which indicates the gradual revelation of high intratumoral heterogeneity and plasticity characteristics of SCLCs. Advances in genomics as well as the development of single-cell sequencing analysis and new preclinical models have helped investigators gain many new insights into SCLCs and the development of targeted therapy and immunotherapy strategies. This article provides an overview of changes in molecular typing, tumor heterogeneity, and plasticity and that of advances in the precise treatment of different subtypes of SCLC.

Small cell lung cancer transformation during antitumor therapies: A systematic review

Lung cancer is the most common cause of cancer-related death. Non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) are the two major histological categories of lung cancers. Drug resistance is a great challenge for cancer treatment, and histological transformation from NSCLC to SCLC is one of the mechanisms underlying drug resistance in NSCLC patients. SCLC-transformed patients show combined characteristics of NSCLC and SCLC; however, they lack timely diagnoses and effective treatment strategies. Thus, we reviewed the clinical characteristics of SCLC transformation patients with a literature search to enhance clinical consciousness, diagnosis, and personalized treatment for patients with it.

Immune checkpoint inhibitors: a new landscape for extensive stage small cell lung cancer treatment

Introduction: Landscape of Extensive Stage (ES)-SCLC treatment has been unchanged over the years. Chemotherapy, mostly based on cisplatin and etoposide, remained the standard-of-care for patients with ES-SCLC for almost 40 years. Recently, immune check points inhibitors have emerged marking a turning point for ES-SCLC treatmentAreas covered: Aim of the paper is to discuss ICIs impact on ES-SCLC treatment algorithms, review current clinical trials, and explore future perspectives.Expert opinion: A growing body of evidence supports ICI-containing regimens as a new mainstay of ES-SCLC treatment. Whether subgroups of SCLC patients may have greater survival benefits from ICIs treatment needs to be better defined. Understanding the impact of tumor microenvironment and identifying reliable predictive and/or prognostic biomarkers will be fundamental to move toward a personalized treatment approach leading to improved survival.

Anlotinib vs placebo as third- or further-line treatment for patients with small cell lung cancer: a randomised, double-blind, placebo-controlled Phase 2 study

BACKGROUND

This study aimed to evaluate the efficacy and safety of anlotinib as a third-line and subsequent treatment for patients with small cell lung cancer (SCLC).

METHODS

We conducted this Phase 2 trial at 11 institutions in China. Patients with pathologically confirmed SCLC who failed at least two lines of chemotherapy were enrolled. Subjects were randomly assigned in a 2:1 ratio to receive either anlotinib 12 mg orally once daily for 14 days every 3 weeks or placebo. The primary endpoint was progression-free survival (PFS).

RESULTS

Between March 30, 2017 and June 8, 2018, a total of 82 and 38 patients were randomly assigned to receive anlotinib and placebo. The median PFS was significantly longer in the anlotinib group compared with the placebo group (4.1 months [95% confidence interval (CI), 2.8-4.2] vs 0.7 months [95% CI, 0.7-0.8]; hazard ratio (HR) 0.19 [95% CI, 0.12-0.32], p < 0.0001). Overall survival (OS) was significantly longer with anlotinib than placebo (7.3 months [95% CI, 6.1-10.3] vs 4.9 months [95% CI, 2.7-6.0]; HR 0.53 [95% CI, 0.34-0.81], p = 0.0029).

CONCLUSIONS

Anlotinib as a third-line or subsequent treatment for Chinese patients with SCLC showed improved PFS and OS than placebo with favourable safety profile.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, number NCT03059797.

Evidence to Date: Evaluating Pembrolizumab in the Treatment of Extensive-Stage Small-Cell Lung Cancer

Small-cell lung cancer (SCLC) is an aggressive subtype of lung cancer characterized by a rapid initial response and early development of resistance to systemic therapy and radiation. The management of SCLC significantly changed for the first time in decades with the introduction of immune checkpoint inhibitors. Pembrolizumab, a humanized IgG4 isotype antibody, targets the programmed cell death protein 1 (PD-1) pathway to restore anti-tumor immunity. Prospective trials of pembrolizumab in patients with previously treated SCLC showed significant durability of responses. These results led to the U.S. Food and Drug Administration (FDA) granting pembrolizumab accelerated approval as second- or third-line monotherapy for patients with extensive-stage (ES) SCLC. In a recent clinical trial that included patients with previously untreated ES-SCLC, pembrolizumab in combination with platinum/etoposide met its progression-free survival endpoint, but overall survival (OS) did not cross the threshold for superiority. With the therapeutic landscape for SCLC rapidly evolving, we review prior experience and future directions of pembrolizumab in ES-SCLC.

Notch signaling and efficacy of PD-1/PD-L1 blockade in relapsed small cell lung cancer

Immune checkpoint blockade (ICB) benefits only a small subset of patients with small cell lung cancer (SCLC), yet the mechanisms driving benefit are poorly understood. To identify predictors of clinical benefit to ICB, we performed immunogenomic profiling of tumor samples from patients with relapsed SCLC. Tumors of patients who derive clinical benefit from ICB exhibit cytotoxic T-cell infiltration, high expression of antigen processing and presentation machinery (APM) genes, and low neuroendocrine (NE) differentiation. However, elevated Notch signaling, which positively correlates with low NE differentiation, most significantly predicts clinical benefit to ICB. Activation of Notch signaling in a NE human SCLC cell line induces a low NE phenotype, marked by increased expression of APM genes, demonstrating a mechanistic link between Notch activation, low NE differentiation and increased intrinsic tumor immunity. Our findings suggest Notch signaling as a determinant of response to ICB in SCLC.

Immune checkpoint blockade (ICB) benefits only a small subset of patients with small cell lung cancer (SCLC) and the mechanisms driving benefit are poorly understood. Here, the authors show that elevated Notch signaling predicts clinical benefit in ICB in relapsed SCLC.

Prognostic Role of Lung Immune Scores for Prediction of Survival in Limited-stage Small Cell Lung Cancer

BACKGROUND/AIM

Previous studies have suggested the prognostic value of the Lung Immune Prediction Index (LIPI) and the Gustave Roussy Score (GRIM) as prognostic markers in advanced small cell lung cancer (SCLC). However, LIPI and GRIM score have not been evaluated in patients with limited stage SCLC (LS-SCLC).

PATIENTS AND METHODS

Pretreatment LIPI and GRIM score of 33 (43%) patients out of 77 LS-SCLC patients treated with chemoradiotherapy (CRT) during 2004-2015 were included.

RESULTS

The median overall survival (OS) time in the good, intermediate, and poor LIPI subgroups were 14, 17 and 3 months (p=0.973) and 14, 17 and 17 months in the GRIM subgroups. In univariate analysis, patients age <65 years (p=0.008), concurrent chemotherapy (p=0.028), and administering prophylactic cranial irradiation (PCI) (p=0.031) were associated with improved OS. Using Cox regression analysis, age remained significant (HR=3.299, p=0.031) and PCI showed a trend (HR=2.801, p=0.06).

CONCLUSION

Independent predictors of overall survival were identified and can contribute to improved treatment personalization. Concurrent chemotherapy and PCI after CRT were associated with improved OS compared to LIPI- and GRIM-score, which had no prognostic impact in LS-SCLC.

Immunotherapy in small cell lung cancer: one step at a time: a narrative review

Chemotherapy with or without radiotherapy has been the standard of care for many years for patients with small cell lung cancer (SCLC). Despite exceptionally high responses (up to 80%) with chemotherapy, the majority of patients relapse rapidly within weeks to months after treatment completion. Therefore, new and better treatment options are necessary. Recently, synergistic activity has been reported for the addition of immune checkpoint inhibitors (ICI) to standard platinum-based chemotherapy in the therapeutic strategy of advanced SCLC. For the first time after several decades, a significant survival improvement was achieved for this population. However, the overwhelming majority of patients do not respond to ICI, or relapse rapidly. There is need for better knowledge about the biology, histopathologic features, and molecular pathways of SCLC. This can probably help to identify the optimal predictive biomarkers, which are warranted to develop an individual therapeutic strategy including the rational use of a combination of immunotherapeutic agents. Here, we provide an overview of the rationale for and clinical results of the completed and ongoing trials using different strategies of immunotherapy in SCLC. In addition, opportunities for further improvement of therapies will be discussed, including the addition of radiotherapy, co-stimulatory antibodies, and other immune modifying agents.

Beyond the Androgen Receptor: The Sequence, the Mutants, and New Avengers in the Treatment of Castrate-Resistant Metastatic Prostate Cancer

Targeting the androgen receptor by depriving testosterone with gonadotropin-releasing hormone agonists or antagonists, or surgical castration, has been the backbone of metastatic prostate cancer treatment. Although most prostate cancers initially respond to androgen deprivation, metastatic castration-resistant prostate cancer evolves into a heterogeneous disease with diverse drivers of progression and mechanisms of therapeutic resistance. Development of castrate resistance phenotype is associated with lethality despite the recent noteworthy strides gained via increase in therapeutic options. Identification of novel therapeutics to further improve survival and achieve durable responses in metastatic castration-resistant prostate cancer is a clinical necessity. In this review, we outline the existing avengers for treatment of metastatic castration-resistant prostate cancer by clinical presentation, placing into context the clinical state of the patient, such as burden of disease and symptoms. Doing so might aid in the ability to optimize the sequence of agents and allow for maximal exposure to life-prolonging therapeutics. Realizing the limitations of the androgen signaling inhibition, we explore the androgen-indifferent prostate cancer: the mutants. Classically, these subtypes have been associated with variant histology, but androgen-indifferent prostate cancer features are now frequently observed in association with heterogeneous morphologies, including double-negative prostate cancers, lacking both androgen receptor and neuroendocrine features, or clinicopathologic criteria, such as the aggressive variant prostate cancer criteria. The framework of new avengers against metastatic castration-resistant prostate cancer based on mechanism, including DNA repair, immune checkpoint inhibition, PTEN/PI3K/AKT pathway, prostate-specific membrane antigen targets, bispecific T-cell engagers, and radionuclide therapies, is summarized in this review.

Novel patterns of progression upon immunotherapy in other thoracic malignancies and uncommon populations

In the immunotherapy era, considering the prolonged survival benefit and responses observed with immunecheckpoint inhibitors (ICI) in many cancer types, the identification of patients with rapid progression (PD) and deaths upon ICI has found some skepticism and resistance among the scientific community. Nevertheless, an acceleration of tumour during ICI, defined as hyperprogressive disease (HPD), has been recognized across different cancer types and evidence regarding rapid PDs and deaths are emerging in patients with malignant pleural mesothelioma (MPM), small cell lung cancer (SCLC) and thymic malignancies and in uncommon non-small cell lung cancer (NSCLC) populations. Of note, PD and early deaths (ED) rates upon single agent ICI were up to 60% and 30% in MPM and 70% and 38% in SCLC patients, respectively. Similarly, rapid PDs and deaths were observed in clinical trials and retrospective studies including patients with poor performance status (PS), HIV infection and rare NSCLC histologies. Atypical patterns of response, such as pseudoprogression (PsPD) may also occur in other thoracic malignancies (MPM) and in some uncommon populations (i.e., HIV patients), however probably at lower rate compared to HPD. The characterizations of HPD and PsPD mechanisms and the identification of common definition criteria are the next future challenges in this area of cancer research.

Toxicities of Immunotherapy for Small Cell Lung Cancer

Small cell lung cancer (SCLC), composing 15–20% of lung cancer, is a fatal disease with extremely poor prognosis. In the past two decades, etoposide platinum doublet chemotherapy remained the only choice of therapy, with disappointing overall survival ≤1 year for the metastatic disease. Novel treatments including immunotherapy are urgently needed and extensively explored. Recently, in two phase III trials, atezolizumab and durvalumab were shown to bring survival benefit to patients. While immunotherapy brings better outcome, it is accompanied by adverse events different from traditional treatments. Although these immune-related adverse events (irAEs) are generally mild and can be managed, some irAEs (myocarditis, pneumonitis) may be severe and even life-threatening. Accompanying with the increasing application of immunotherapy in clinical practice, the irAEs should not be overlooked. In this review, the irAEs profile in clinical trials of immunotherapy for SCLC will be summarized, also its unique features compared with irAEs in other malignancies will be explored. This review may be helpful for the appropriate clinical use of immunotherapy for SCLC.

Safety, pharmacokinetics, and efficacy of budigalimab with rovalpituzumab tesirine in patients with small cell lung cancer

BACKGROUND

Agents targeting programmed cell death protein 1 (PD-1) have been approved as monotherapy for patients with small cell lung cancer (SCLC). In preclinical models, the combined targeting of PD-1 and delta-like protein 3 resulted in enhanced antitumor activity. Herein, we report results from the expansion arm of study NCT03000257 evaluating the combination of the anti-PD-1 antibody budigalimab and the targeted antibody-drug conjugate rovalpituzumab tesirine (Rova-T) in patients with previously treated SCLC.

MATERIALS AND METHODS

This expansion arm of a multicenter, open-label, multi-arm, first-in-human phase 1 clinical trial enrolled adult patients with progressive SCLC. The primary objective was to assess safety and tolerability. Patients received budigalimab 375 mg via intravenous infusion every 3 weeks, and Rova-T was administered as a dose of 0.3 mg/kg intravenously, on day 1 of the first and third 3-week cycle.

RESULTS

As of October 2019, 31 patients with SCLC were enrolled and treated with budigalimab plus Rova-T. The combination was tolerated, with the most common treatment-emergent adverse events (in >30%) being pleural effusion, fatigue, and cough. The overall response rate was 24.1%, with one confirmed complete response and six confirmed partial responses. The overall response rate in patients with high delta-like protein 3 expression was similar (21.1%). The median progression-free survival was 3.48 months.

CONCLUSION

Combination therapy with budigalimab and Rova-T had promising efficacy and appeared to be tolerated in patients with SCLC. Although Rova-T development has been discontinued, development of budigalimab combined with other anticancer agents is ongoing.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03000257 Statement on originality of the work The manuscript represents original work and has not been submitted for publication elsewhere nor previously published. Statement of prior presentation Data from this study were previously presented at the European Society for Medical Oncology (ESMO) Congress 2019.

Biomarkers or factors for predicting the efficacy and adverse effects of immune checkpoint inhibitors in lung cancer: achievements and prospective

Immune checkpoint inhibitors (ICIs) are widely used in lung cancer therapy due to their effectiveness and minimal side effects. However, only a few lung cancer patients benefit from ICI therapy, driving the need to develop alternative biomarkers. Programmed death-ligand 1 (PD-L1) molecules expressed in tumor cells and immune cells play a key role in the immune checkpoint pathway. Therefore, PD-L1 expression is a prognostic biomarker in evaluating the effectiveness of programmed death-1 (PD-1)/PD-L1 inhibitors. Nevertheless, adverse predictive outcomes suggest that other factors are implicated in the response. In this review, we present a detailed introduction of existing biomarkers concerning tumor abnormality and host immunity. PD-L1 expression, tumor mutation burden, neoantigens, specific gene mutations, circulating tumor DNA, human leukocyte antigen class I, tumor microenvironment, peripheral inflammatory cells, and microbiome are discussed in detail. To sum up, this review provides information on the current application and future prospects of ICI biomarkers.

The puzzle of gynecologic neuroendocrine carcinomas: State of the art and future directions

Primary gynecologic neuroendocrine carcinomas (gNECs) are a heterogeneous spectrum of rare and highly aggressive neoplasms, accounting for about 2% of all gynecologic malignancies, which mostly resemble the small cell lung carcinoma (SCLC). Due to the lack of standardized treatment guidelines, their management poses a noteworthy clinical challenge. Currently, cumulative data retrieved from the management of SCLC and from retrospective studies supports a multimodality strategy, based on surgery, chemotherapy, and radiotherapy. Nevertheless, the prognosis remains poor and recurrences are extremely frequent. Hence, there is an urgent need for novel treatment options and promising molecular targets. Recently, there has been an increasing interest on the potential role of immune checkpoint inhibitors, especially in the recurrent setting. However, only scant evidence exists and there is still a long road ahead. A solid collaboration between gynecologists and oncologists worldwide is required to improve the treatment of these puzzling tumors.

Platinum-doublet chemotherapy as second-line treatment for relapsed patients with small-cell lung cancer: A systematic review and meta-analysis

OBJECTIVE

Optimal second-line chemotherapy for patients with relapsed small-cell lung cancer remains debatable. In addition to topotecan or amrubicin monotherapy, re-challenge with first-line platinum-doublets have been commonly used. In this study, we investigated whether platinum-doublets are suitable as second-line treatment for relapsed small-cell lung cancer.

MATERIALS AND METHODS

Studies that enrolled relapsed small-cell lung cancer and compared platinum-doublets with non-platinum-based regimens for second-line treatment were identified using PubMed and EMBASE. A meta-analysis was conducted to calculate the relative risk of objective response rate and disease control rate of the second-line chemotherapy. Subgroup analyses were conducted to focus on comparison with standard second-line regimens and sensitive relapse. Progression-free and overall survival, and adverse events were systematically reviewed.

RESULTS

Ten studies published between 2011 and 2020 were included in our analysis with a total of 1222 patients: 438 treated with platinum-doublets and 784 with non-platinum-based regimens. The objective response rates for second-line platinum-doublet and non-platinum regimens were 47.3 % [95 % CI: 40.5-54.0] and 31.5 % [95 % CI: 22.2-40.8], respectively.　Patients treated with platinum-doublets had a significantly higher objective response rate than patients with non-platinum-based regimens (RR [95 % CI]: 1.527 [1.100-2.121], p = 0.011), as well as disease control rate (RR [95 % CI]: 1.152 [1.052-1.262], p = 0.002). In a subgroup analysis comparing platinum-doublets with topotecan or amrubicin, patients treated with platinum-doublets had significantly higher objective response rate and disease control rate (RR [95 % CI]: 1.663 [1.055-2.619], p = 0.028 and 1.170 [1.021-1.340], p = 0.023 respectively). Progression-free and overall survival appeared consistent with the tumor responses. Adverse events associated with platinum-doublets appeared acceptable compared with the monotherapies.

CONCLUSION

Platinum-doublet chemotherapy as second-line treatment for patients with relapsed small-cell lung cancer can be considered as a reasonable option in comparison with non-platinum regimens.

Comparison of atezolizumab, durvalumab, pembrolizumab, and nivolumab as first-line treatment in patients with extensive-stage small cell lung cancer: A systematic review and network meta-analysis

BACKGROUND

In recent years, immune checkpoint inhibitors (ICIs) including atezolizumab, durvalumab, pembrolizumab, and nivolumab have reported their efficacy and safety profile in patients with extensive-stage small cell lung cancer (ES-SCLC). However, given the diverse efficacy and inconsistent safety among the ICIs, with the absence of head-to-head researches designed to evaluate the efficacy among them, it might bring with confusion on selection in clinical practice.

OBJECTIVES

The present systematic review and network meta-analysis was performed to conduct indirect comparisons on efficacy and safety profile among ICIs, including atezolizumab, durvalumab, pembrolizumab, and nivolumab as first-line treatment in patients with ES-SCLC.

DESIGN

Several databases were retrieved with established criteria until June 20, 2020, with the main MeSH Terms and their similarities. Hazard ratios of overall survival (OS) and progression-free survival (PFS), odds ratios (ORs) of disease control rate (DCR), objective response rate (ORR), and adverse events (AEs) were compared indirectly with network meta-analysis.

DATA SOURCES

Medline, Cochrane library, and Embase.

ELIGIBILITY CRITERIA

Prospective, randomized, controlled clinical studies, which reported PFS, OS, and AEs.

DATA EXTRACTION AND SYNTHESIS

Clinical characteristics were extracted by the 2 authors independently. Comparisons of HRs were calculated for PFS and OS by random effect model. ORR, DCR, and AEs were presented with ORs. Based on surface under the cumulative ranking curve, and forest plots, efficacy and safety of the treatments were ranked, with predicted histogram described.

RESULTS

In total, there were 4 studies including 1547 patients who met the eligibility criteria and enrolled. For indirect comparisons, no significant difference on PFS was observed between atezolizumab and durvalumab (HR 0.96, 95% CI, 0.72-1.29), or between atezolizumab and pembrolizumab (HR 1.05, 95% CI, 0.78-1.43), or between atezolizumab and nivolumab (HR 1.18, 95% CI, 0.79-1.79), or between durvalumab and pembrolizumab (HR 1.10, 95% CI, 0.84-1.43). or between durvalumab and nivolumab (HR 1.23, 95% CI, 0.83-1.82), or between pembrolizumab and nivolumab (HR 1.12, 95% CI, 0.76-1.66), nor significant difference on OS observed between atezolizumab and durvalumab (HR 0.93, 95% CI, 0.67-1.30), or between atezolizumab and pembrolizumab (HR 0.88, 95% CI, 0.62-1.24), or between atezolizumab and nivolumab (HR 1.04, 95% CI, 0.66-1.66), or between durvalumab and pembrolizumab (HR 0.94, 95% CI, 0.70-1.25), or between durvalumab and nivolumab (HR 1.12, 95% CI, 0.73-1.71), or between pembrolizumab and nivolumab (HR 1.19, 95% CI, 0.77-1.84). However, durvalumab was shown statistical superiority on ORR when compared with atezolizumab (HR 0.79, 95% CI, 0.64-0.98), also with significantly higher risk on immune-related AEs when compared with atezolizumab (OR 0.22, 95% CI, 0.10-0.50), and pembrolizumab (OR 3.12, 95% CI, 1.27-7.64).

CONCLUSIONS

Results of the study revealed that there was no statistical difference on PFS or OS among agents of atezolizumab, durvalumab, pembrolizumab, and nivolumab as first-line treatment in patients with ES-SCLC. However, durvalumab was shown superiority on ORR when compared with atezolizumab, also with significantly higher risk on immune-related AEs.

Molecular profiles of small cell lung cancer subtypes: therapeutic implications

Small cell lung cancer (SCLC; accounting for approximately 13%-15% of all lung cancers) is an exceptionally lethal malignancy characterized by rapid doubling time and high propensity to metastasize. In contrast to the increasingly personalized therapies in other types of lung cancer, SCLC is still regarded as a homogeneous disease and the prognosis of SCLC patients remains poor. Recently, however, substantial progress has been made in our understanding of SCLC biology. Advances in genomics and development of new preclinical models have facilitated insights into the intratumoral heterogeneity and specific genetic alterations of this disease. This worldwide resurgence of studies on SCLC has ultimately led to the development of novel subtype-specific classifications primarily based on the neuroendocrine features and distinct molecular profiles of SCLC. Importantly, these biologically distinct subtypes might define unique therapeutic vulnerabilities. Herein, we summarize the current knowledge on the molecular profiles of SCLC subtypes with a focus on their potential clinical implications.

Immune Check Point Inhibitors and Immune-Related Adverse Events in Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a malignant solid tumor. In recent years, although immune check point inhibitors (ICIs) have achieved important advances in the treatment of SCLC, immune-related adverse events (irAEs) have occurred at the same time during the therapeutic period. Some irAEs lead to dose reduction or treatment rejection. The immune microenvironment of SCLC is complicated, therefore, understanding irAEs associated with ICIs is of great importance and necessity for the clinical management of SCLC. However, the lack of comprehensive understanding of irAEs in patients with SCLC remains remarkable. This review aims to provide an up-to-date overview of ICIs and their associated irAEs in patients with SCLC based on present clinical data.

Small cell lung cancer: a slightly less orphan disease after immunotherapy

Small cell lung cancer (SCLC) is an aggressive malignancy accounting for 15% of all diagnosed cases of lung cancer. After >15 years without any clinically relevant therapeutic advances, extensive-disease SCLC has become the second thoracic malignancy for which immune checkpoint inhibitors (ICIs) have shifted the treatment paradigm to improve overall survival. Today, atezolizumab or durvalumab in combination with platinum-etoposide chemotherapy is considered the new standard of care in the first-line setting in SCLC. However, the magnitude of benefit with this immune-chemotherapy strategy in SCLC is more modest than that observed in metastatic non-small-cell lung cancer patients. The immunosuppressive phenotype of SCLC plays an important role in hampering ICI efficacy and may explain the differences in outcomes between these two types of lung cancer. In this review, we provide a summary of recent therapeutic advances in SCLC in light of ICIs, as well as current challenges of this strategy in patients who are elderly, have poor performance status or brain metastases. We also address future perspectives of immunotherapeutic strategies currently in clinical development for these patients.

Patterns of transcription factor programs and immune pathway activation define four major subtypes of SCLC with distinct therapeutic vulnerabilities

Despite molecular and clinical heterogeneity, small cell lung cancer (SCLC) is treated as a single entity with predictably poor results. Using tumor expression data and non-negative matrix factorization, we identify four SCLC subtypes defined largely by differential expression of transcription factors ASCL1, NEUROD1, and POU2F3 or low expression of all three transcription factor signatures accompanied by an Inflamed gene signature (SCLC-A, N, P, and I, respectively). SCLC-I experiences the greatest benefit from the addition of immunotherapy to chemotherapy, while the other subtypes each have distinct vulnerabilities, including to inhibitors of PARP, Aurora kinases, or BCL-2. Cisplatin treatment of SCLC-A patient-derived xenografts induces intratumoral shifts toward SCLC-I, supporting subtype switching as a mechanism of acquired platinum resistance. We propose that matching baseline tumor subtype to therapy, as well as manipulating subtype switching on therapy, may enhance depth and duration of response for SCLC patients.

Nivolumab and Ipilimumab as Maintenance Therapy in Extensive-Disease Small-Cell Lung Cancer: CheckMate 451

In extensive-disease small-cell lung cancer (ED-SCLC), response rates to first-line platinum-based chemotherapy are robust, but responses lack durability. CheckMate 451, a double-blind phase III trial, evaluated nivolumab plus ipilimumab and nivolumab monotherapy as maintenance therapy following first-line chemotherapy for ED-SCLC.

New Therapies and Biomarkers: Are We Ready for Personalized Treatment in Small Cell Lung Cancer?

Small cell lung cancer (SCLC) is an aggressive form of lung cancer with a 5-year survival rate of less than 7%. In contrast to non-small cell lung cancer, SCLC has long been treated as a homogeneous disease without personalized treatment options. In recent years, the incorporation of immunotherapy into the treatment paradigm has brought moderate benefit to patients with SCLC; however, more effective therapies are urgently needed. In this article, we describe the current treatment standards and emerging therapeutic approaches for the treatment of SCLC. We also discuss promising biomarkers in SCLC and the recently discovered four subtypes of SCLC, each with its unique therapeutic vulnerability. Lastly, we discuss the advances in radiation therapy for the treatment of SCLC.

History of Extensive Disease Small Cell Lung Cancer Treatment: Time to Raise the Bar? A Review of the Literature

Simple Summary

Small cell lung cancer (SCLC) remains the most aggressive form of neuroendocrine tumor of the lung, for which treatment options remain limited. The introduction of immune checkpoint inhibitors has modified for the first time the therapeutic strategies in patients with extensive disease after decades. New therapeutic approaches are required. Deeper knowledge of tumor biology is required to gain new insights into this complex disease.

Abstract

Several trials have tried for decades to improve the outcome of extensive disease small cell lung cancer (ED-SCLC) through attempts to modify the standard treatments. Nevertheless, platinum/etoposide combination and topotecan have remained respectively the first and the second line standard treatments for the last 40 years. With the advent of immunotherapy, this scenario has finally changed. Our review aims to provide an overview of the primary studies on the actual therapeutic strategies available for ED-SCLC patients, and to highlight emerging evidence supporting the use of immunotherapy in SCLC patients.

Clinicopathological and molecular characteristics of patients with hypermutant lung cancer: A retrospective cohort study

Tumor mutation burden (TMB) is an independent indicator used to select patients sensitive to immunotherapy. The present study aimed to investigate the clinicopathological and molecular characteristics of patients with hypermutant lung cancer to identify an economical, simple and complementary method for predicting TMB and immunotherapy responses. In total, 1,000 patients with lung cancer were randomly selected, and their samples were submitted to next-generation sequencing, with their TMB status reviewed. The threshold of hypermutation was set to 17.24 mutations (muts)/Mb. The proportion of smokers was higher in the hypermutant cohort (n=67) compared with in the non-hypermutant cohort (n=933; 85.1 vs. 46.6%; P<0.0001). Compared with in the non-hypermutant cohort, the proportion of squamous cell carcinoma cases and small cell lung cancer cases was higher in the hypermutant cohort (22.4 vs. 13.1% and 6.0 vs. 2.6%, respectively). In addition, compared with in the non-hypermutant cohort, mutations in the low-density lipoprotein receptor-related protein 1B were more frequently observed in the hypermutant cohort (67.2 vs. 14.3%; P<0.0001). A similar trend was obtained for all genes tested, except for the EGFR gene. Furthermore, in the hypermutant cohort, the prevalence of microsatellite instability was extremely high (9.0%). The mutation frequency in DNA damage response (DDR) genes was notably higher in the hypermutant cohort, where several DDR-associated genes were enriched, compared with in the non-hypermutant cohort. The enrichment analysis revealed a strong association between mutations in Notch signaling and high TMB. To the best of our knowledge, the present study is the first to comprehensively investigate the clinical and genetic characteristics of patients with hypermutant lung cancer in a Chinese population. The results of the current study suggested that hypermutant lung cancer exerted distinctive clinical and genetic features, which may be used as complementary indicators for screening patients sensitive to immunotherapy.

The Synergistic Effect of PARP Inhibitors and Immune Checkpoint Inhibitors

Poly (ADP-ribose) polymerase (PARP) inhibitors have demonstrated great promise for treating cancers with homologous recombination (HR) defects, such as germline BRCA1/2 mutation. Further studies suggest that PARP inhibitors (PARPi) can also exhibit efficacy in HR-competent cancers, by amplifying the DNA damage and inducing immunogenic cell death, and PARPi lead to increasing tumor neoantigen, upregulation of interferons and PD-L1, and modulation of the tumor microenvironment, which may facilitate a more profound antitumor immune response. Immune checkpoint inhibitors (ICIs) targeting PD-1/PD-L1 or CTLA-4 have achieved impressive success in the treatment of different malignancies. However, only a subset of populations derive clinical benefit, and the biomarkers and resistance mechanisms are not fully understood. Therefore, given that PARPi could potentiate the therapeutic effect of ICIs, PARPi combined with ICIs are becoming an alternative for patients who cannot benefit from ICI monotherapy. In this review, we focus on the mechanisms and immune role of PARPi and discuss the rationale and clinical studies of this combined regimen.

PD-L1 as a biomarker of response to immune-checkpoint inhibitors

Immune-checkpoint inhibitors targeting PD-1 or PD-L1 have already substantially improved the outcomes of patients with many types of cancer, although only 20-40% of patients derive benefit from these new therapies. PD-L1, quantified using immunohistochemistry assays, is currently the most widely validated, used and accepted biomarker to guide the selection of patients to receive anti-PD-1 or anti-PD-L1 antibodies. However, many challenges remain in the clinical use of these assays, including the necessity of using different companion diagnostic assays for specific agents, high levels of inter-assay variability in terms of both performance and cut-off points, and a lack of prospective comparisons of how PD-L1⁺ disease diagnosed using each assay relates to clinical outcomes. In this Review, we describe the current role of PD-L1 immunohistochemistry assays used to inform the selection of patients to receive anti-PD-1 or anti-PD-L1 antibodies, we discuss the various technical and clinical challenges associated with these assays, including regulatory issues, and we provide some perspective on how to optimize PD-L1 as a selection biomarker for the future treatment of patients with solid tumours.

Dendritic Cell-Based Immunotherapy in Lung Cancer

Lung cancer remains the leading cause of cancer-related death worldwide. The advent of immune checkpoint inhibitors has led to a paradigm shift in the treatment of metastatic non-small cell and small cell lung cancer. However, despite prolonged overall survival, only a minority of the patients derive clinical benefit from these treatments suggesting that the full anti-tumoral potential of the immune system is not being harnessed yet. One way to overcome this problem is to combine immune checkpoint blockade with different strategies aimed at inducing or restoring cellular immunity in a tumor-specific, robust, and durable way. Owing to their unique capacity to initiate and regulate T cell responses, dendritic cells have been extensively explored as tools for immunotherapy in many tumors, including lung cancer. In this review, we provide an update on the nearly twenty years of experience with dendritic cell-based immunotherapy in lung cancer. We summarize the main results from the early phase trials and give an overview of the future perspectives within this field.

PARP Inhibitors in Small-Cell Lung Cancer: Rational Combinations to Improve Responses

Simple Summary

Small-cell lung cancer carries a dismal prognosis with few long-term treatment options. The enzyme poly-(ADP)-ribose polymerase (PARP), which functions to repair DNA breaks, has emerged as a promising therapeutic target, with modest response rates in early clinical trials prompting investigation of predictive biomarkers and therapeutic combinations. This review summarizes the development and testing of PARP inhibitors in small-cell lung cancer with an emphasis on developing treatment combinations. These combinations can be divided into three categories: (1) contributing to DNA damage; (2) inhibiting the DNA damage response; and (3) activating the immune system. An evolving classification of small-cell lung cancer subtypes and gene expression patterns will guide PARP inhibitor biomarker identification to improve treatments for this challenging cancer.

Abstract

Despite recent advances in first-line treatment for small-cell lung cancer (SCLC), durable responses remain rare. The DNA repair enzyme poly-(ADP)-ribose polymerase (PARP) was identified as a therapeutic target in SCLC using unbiased preclinical screens and confirmed in human and mouse models. Early trials of PARP inhibitors, either alone or in combination with chemotherapy, showed promising but limited responses, suggesting that selecting patient subsets and treatment combinations will prove critical to further clinical development. Expression of SLFN11 and other components of the DNA damage response (DDR) pathway appears to select for improved responses. Combining PARP inhibitors with agents that damage DNA and inhibit DDR appears particularly effective in preclinical and early trial data, as well as strategies that enhance antitumor immunity downstream of DNA damage. A robust understanding of the mechanisms of DDR in SCLC, which exhibits intrinsic replication stress, will improve selection of agents and predictive biomarkers. The most effective combinations will target multiple nodes in the DNA damage/DDR/immune activation cascade to minimize toxicity from synthetic lethality.

First-line immune checkpoint inhibitors for extensive stage small-cell lung cancer: clinical developments and future directions

Small-cell lung cancer (SCLC) is an aggressive and rapidly growing disease with poor prognosis. Despite intense efforts to improve clinical outcomes, platinum/etoposide chemotherapy has remained the most effective regimen for first-line extensive disease SCLC for decades. The addition of immune checkpoint inhibitors, and specifically programmed death-ligand 1 inhibitors, to standard platinum/etoposide, significantly improves survival and represents a promising advance in this field. However, identification of a predictive biomarker to refine patient selection is an area of unmet need. Further understanding of tumour immunity and mechanism of resistance is required to design novel strategies that improve survival. In this review, we describe recent developments and future directions on first-line immune checkpoint blockade for extensive disease-SCLC.

The cutting-edge progress of immune-checkpoint blockade in lung cancer

Great advances in immune checkpoint blockade have resulted in a paradigm shift in patients with lung cancer. Immune-checkpoint inhibitor (ICI) treatment, either as monotherapy or combination therapy, has been established as the standard of care for patients with locally advanced/metastatic non-small cell lung cancer without EGFR/ALK alterations or extensive-stage small cell lung cancer. An increasing number of clinical trials are also ongoing to further investigate the role of ICIs in patients with early-stage lung cancer as neoadjuvant or adjuvant therapy. Although PD-L1 expression and tumor mutational burden have been widely studied for patient selection, both of these biomarkers are imperfect. Due to the complex cancer-immune interactions among tumor cells, the tumor microenvironment and host immunity, collaborative efforts are needed to establish a multidimensional immunogram to integrate complementary predictive biomarkers for personalized immunotherapy. Furthermore, as a result of the wide use of ICIs, managing acquired resistance to ICI treatment remains an inevitable challenge. A deeper understanding of the underlying biological mechanisms of acquired resistance to ICIs is helpful to overcome these obstacles. In this review, we describe the cutting-edge progress made in patients with lung cancer, the optimal duration of ICI treatment, ICIs in some special populations, the unique response patterns during ICI treatment, the emerging predictive biomarkers, and our understanding of primary and acquired resistance mechanisms to ICI treatment.

Second-line nivolumab in relapsed small-cell lung cancer: CheckMate 331☆

BACKGROUND

Patients with relapsed small-cell lung cancer (SCLC) have few treatment options and dismal survival. Phase I/II data show activity of nivolumab in previously treated SCLC.

PATIENTS AND METHODS

CheckMate 331 is a randomized, open-label, phase III trial of nivolumab versus standard chemotherapy in relapsed SCLC. Patients with relapse after first-line, platinum-based chemotherapy were randomized 1 : 1 to nivolumab 240 mg every 2 weeks or chemotherapy (topotecan or amrubicin) until progression or unacceptable toxicity. Primary endpoint was overall survival (OS).

RESULTS

Overall, 284 patients were randomized to nivolumab and 285 to chemotherapy. Minimum follow-up was 15.8 months. No significant improvement in OS was seen with nivolumab versus chemotherapy [median OS, 7.5 versus 8.4 months; hazard ratio (HR), 0.86; 95% confidence interval (CI), 0.72-1.04; P = 0.11]. A survival benefit with nivolumab was suggested in patients with baseline lactate dehydrogenase ≤ upper limit of normal and in those without baseline liver metastases. OS (nivolumab versus chemotherapy) was similar in patients with programmed death-ligand 1 combined positive score ≥1% versus <1%. Median progression-free survival was 1.4 versus 3.8 months (HR, 1.41; 95% CI, 1.18-1.69). Objective response rate was 13.7% versus 16.5% (odds ratio, 0.80; 95% CI, 0.50-1.27); median duration of response was 8.3 versus 4.5 months. Rates of grade 3 or 4 treatment-related adverse events were 13.8% versus 73.2%.

CONCLUSION

Nivolumab did not improve survival versus chemotherapy in relapsed SCLC. No new safety signals were seen. In exploratory analyses, select baseline characteristics were associated with improved OS for nivolumab.

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.

Meta-analysis of the Efficacy and Tolerability of Immune Checkpoint Inhibitors Combined With Chemotherapy in First-line Treatment of Small Cell Lung Cancer

PURPOSE

The present study was conducted to evaluate the efficacy and tolerability of using an immune checkpoint inhibitor (ICI; programmed cell death protein 1/ligand 1 [PD-1/PD-L1] inhibitor or cytotoxic T-lymphocyte antigen [CTLA]-4 inhibitor) combined with chemotherapy in the first-line treatment of small cell lung cancer.

METHODS

Potential articles and studies were identified using Web of Science, Cochrane Library, and ClinicalTrials.gov. The end points included overall survival, progression-free survival, objective response rate, and adverse events. Significant heterogeneity was represented by a P value (P_h) of <0.05 or an I² value of ≥50%, and the random-effects model was applied for pooled analysis. Otherwise, the fixed-effects model was used. Subgroup analysis was performed based on the type of ICI. Potential publication bias was evaluated via funnel plot and the Egger test.

FINDINGS

Five eligible articles were included. Both overall survival (hazard ratio [HR] = 0.83; 95% CI, 0.75-0.91; P < 0.001) and progression-free survival (HR = 0.80; 95% CI, 0.73-0.86; P < 0.001) were significantly prolonged by joint ICI + chemotherapy treatment. Additionally, the rates of tolerable grade ≥3 adverse events were similar between the ICI combination regimens and conventional chemotherapy (relative risk = 1.05; 95% CI, 0.98-1.12; P = 0.17). Subanalysis demonstrated that patient survival and objective response rate were more efficiently improved with a combination of anti-PD-1/PD-L1, but not anti-CTLA-4, + chemotherapy.

IMPLICATIONS

Based on data from the available literature, clinical efficacy (as measured by patient survival and objective response rate) was improved with a combination of anti-PD-1/PD-L1 + chemotherapy as first-line treatment compared with chemotherapy alone in patients with small cell lung cancer.

Small-cell lung cancer

Small-cell lung cancer (SCLC) represents about 15% of all lung cancers and is marked by an exceptionally high proliferative rate, strong predilection for early metastasis and poor prognosis. SCLC is strongly associated with exposure to tobacco carcinogens. Most patients have metastatic disease at diagnosis, with only one-third having earlier-stage disease that is amenable to potentially curative multimodality therapy. Genomic profiling of SCLC reveals extensive chromosomal rearrangements and a high mutation burden, almost always including functional inactivation of the tumour suppressor genes TP53 and RB1. Analyses of both human SCLC and murine models have defined subtypes of disease based on the relative expression of dominant transcriptional regulators and have also revealed substantial intratumoural heterogeneity. Aspects of this heterogeneity have been implicated in tumour evolution, metastasis and acquired therapeutic resistance. Although clinical progress in SCLC treatment has been notoriously slow, a better understanding of the biology of disease has uncovered novel vulnerabilities that might be amenable to targeted therapeutic approaches. The recent introduction of immune checkpoint blockade into the treatment of patients with SCLC is offering new hope, with a small subset of patients deriving prolonged benefit. Strategies to direct targeted therapies to those patients who are most likely to respond and to extend the durable benefit of effective antitumour immunity to a greater fraction of patients are urgently needed and are now being actively explored.

Updated Overall Survival and PD-L1 Subgroup Analysis of Patients With Extensive-Stage Small-Cell Lung Cancer Treated With Atezolizumab, Carboplatin, and Etoposide (IMpower133)

IMpower133 (ClinicalTrials.gov identifier: NCT02763579), a randomized, double-blind, phase I/III study, demonstrated that adding atezolizumab (anti-programmed death-ligand 1 [PD-L1]) to carboplatin plus etoposide (CP/ET) for first-line (1L) treatment of extensive-stage small-cell lung cancer (ES-SCLC) resulted in significant improvement in overall survival (OS) and progression-free survival (PFS) versus placebo plus CP/ET. Updated OS, disease progression patterns, safety, and exploratory biomarkers (PD-L1, blood-based tumor mutational burden [bTMB]) are reported.

Mechanisms of small cell lung cancer metastasis

Metastasis is a major cause of morbidity and mortality in cancer patients. However, the molecular and cellular mechanisms underlying the ability of cancer cells to metastasize remain relatively poorly understood. Among all solid tumors, small cell lung cancer (SCLC) has remarkable metastatic proclivity, with a majority of patients diagnosed with metastatic disease. Our understanding of SCLC metastasis has been hampered for many years by the paucity of material from primary tumors and metastases, as well as the lack of faithful pre-clinical models. Here, we review recent advances that are helping circumvent these limitations. These advances include methods that employ circulating tumor cells from the blood of SCLC patients and the development of diverse genetically engineered mouse models of metastatic SCLC. New insights into the cellular mechanisms of SCLC metastasis include observations of cell fate changes associated with increased metastatic ability. Ongoing studies on cell migration and organ tropism promise to expand our understanding of SCLC metastasis. Ultimately, a better molecular understanding of metastatic phenotypes may be translated into new therapeutic options to limit metastatic spread and treat metastatic SCLC.

Durvalumab and tremelimumab with or without stereotactic body radiation therapy in relapsed small cell lung cancer: a randomized phase II study

Background

Immune checkpoint blockade (ICB) targeting programmed cell death protein 1 and cytotoxic T lymphocyte-associated protein 4 has achieved modest clinical activity as salvage therapy in relapsed small cell lung cancer (SCLC). We conducted this signal-finding study to assess the efficacy of ICB with or without radiation in relapsed SCLC.

Methods

Patients with relapsed SCLC and ≤2 previous lines of therapy were randomized to (1) arm A: durvalumab (D) 1500 mg/tremelimumab (T) 75 mg (intravenously every 4 weeks without stereotactic body radiation therapy (SBRT)) or (2) arm B: immune-sensitizing SBRT to one selected tumor site (9 Gy × 3 fractions) followed by D/T. Treatment continued until progression or a maximum of 12 months. The co-primary endpoints of the study were overall response rate (ORR) and progression-free survival (PFS). We evaluated circulating lymphocyte repertoire in serial peripheral blood samples and tumor infiltrating lymphocytes (TILs) from on-treatment biopsies as pharmacodynamic markers.

Results

Eighteen patients were randomized to arms A and B (n=9 each): median age 70 years; 41.2% women. The median PFS and ORR were 2.1 months and 0% in arm A and 3.3 months and 28.6% in arm B. The median overall survival (OS) was 2.8 months in arm A and 5.7 months in arm B (p=0.3772). Pooled efficacy of D/T±SBRT in 15 Response evaluation criteria in solid tumors (RECIST) evaluable patients across both arms showed the best ORR in terms of partial response in 13.3%, stable disease in 26.6% and progressive disease in 60.0%; the overall median PFS and OS were 2.76 and 3.9 months. The most common adverse events were grade 1 fatigue (66%) and grade 1 elevated amylase (56%) in arm A, and grade 1 fatigue (56%) and pain (44%) in arm B. There was a significant increase in activated CD8(+)ICOS+ T cells (p=0.048) and a reduction in naïve T cells (p=0.0454) in peripheral blood following treatment, along with a significant amount of activated CD8+ICOS+ T cells in TILs from responders.

Conclusions

The D/T combination with and without SBRT was safe but did not show sufficient efficacy signal in relapsed SCLC. Changes in peripheral blood lymphocyte and TILs were consistent with an immunologic response.

Trial registration number NCT02701400.

Chemo-immunotherapy as first-line treatment for small-cell lung cancer

Small-cell lung cancer (SCLC) is a highly lethal subtype of lung cancer. Despite concerted efforts over the past several decades, there have been limited therapeutic advances. Traditional chemotherapy offers a high response rate and rapid symptomatic improvement, but its benefit is fleeting, and relapse is quick and unforgiving. Immunotherapy has delivered improved outcomes for patients with many cancers and there was compelling rationale for development in SCLC. While initial efforts with cytotoxic T-lymphocyte protein-4 inhibitors failed to improve upon chemotherapy alone, the addition of programmed death ligand-1 (PD-L1) inhibitors to first-line chemotherapy finally provided long-awaited gains in survival. Atezolizumab, when added to carboplatin and etoposide, improved both progression-free survival and overall survival. Durvalumab, when added to platinum plus etoposide, similarly improved OS. Biomarker development has stalled as PD-L1 expression and tumor mutational burden have not been useful predictive biomarkers. However, based on the significant survival improvements, both atezolizumab and durvalumab were approved by the US Food and Drug Administration to be given with first-line chemotherapy, and these regimens represent the new standards of care for SCLC.

First-line immune-checkpoint inhibitor plus chemotherapy versus chemotherapy alone for extensive-stage small-cell lung cancer: a meta-analysis

Introduction

Platin-based chemotherapy (CT) has long been the first-line standard-of-care for patients with extensive-stage small-cell lung cancer (ES-SCLC). Adding immune-checkpoint inhibitor(s) to CT (ICI+CT) in this setting is an option of interest, although its benefit is apparently modest.

Methods

This meta-analysis was conducted on randomized trials comparing first-line ICI+CT versus CT alone for ES-SCLC. Outcomes included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), response at 12 months and adverse events (AEs). Subgroup analyses were computed according to the immunotherapy used, performance status (PS), age, platinum salt, liver metastases and brain metastases at diagnosis.

Results

The literature search identified one randomized phase II (ECOG-ACRIN-5161) and four phase III trials (CASPIAN, IMPOWER-133, KEYNOTE-604 and Reck et al. 2016) that included 2775 patients (66% males, 95% smokers, median age: 64 years, PS = 0 or 1). ICI+CT was significantly associated (hazard ratio [95% confidence interval]) with prolonged OS [0.82 (0.75-0.89); p <  0.00001] and PFS [0.81 (0.75-0.87); p <  0.00001], with OS benefits for anti-PD-L1 [0.73 (0.63-0.85); p < 0.0001] or anti-PD-1 [0.76 (0.63-0.93); p < 0.006] but not for anti-CTLA-4 [0.90 (0.80-1.01), p = 0.07]. ORRs for ICI+CT or CT alone were comparable [odds ratio 1.12 (0.97-1.00); p = 0.12], but responses at 12 months favored ICI+CT [4.16 (2.81-6.17), p < 0.00001]. Serious grade-3/4 AEs were more frequent with ICI+CT [odds ratio 1.18 (1.02-1.37); p = 0.03]. Compared with CT, no ICI+CT benefit was found for ES-SCLC with brain metastases at diagnosis [HR 1.14 (0.87-1.50); p = 0.34].

Conclusions

First-line ICI+CT appears to be superior to CT alone for ES-SCLC except for patients with brain metastases at diagnosis.

Systematic Review and Network Meta-Analysis of Immune Checkpoint Inhibitors in Combination with Chemotherapy as a First-Line Therapy for Extensive-Stage Small Cell Carcinoma

Patients with extensive-stage small cell lung cancer (ED-SCLC) have a very short survival time even if they receive standard cytotoxic chemotherapy with etoposide and platinum (EP). Several randomized controlled trials have shown that patients with ED-SCLC who received a combination of EP plus immune checkpoint inhibitors (ICIs) had superior survival compared with those who received EP alone. We conducted a systematic review and network meta-analysis to provide a ranking of ICIs for our primary endpoints in terms of overall survival (OS), progression free survival (PFS), and objective response rate (ORR), as well as our secondary endpoint in terms of adverse events. The fractional polynomial model was used to evaluate the adjusted hazard ratios for the survival indicators (OS and PFS). Treatment rank was estimated using the surface under the cumulative ranking curve (SUCRA), as well as the probability of being best (Prbest) reference. EP plus nivolumab, atezolizumab or durvalumab had significant benefits compared with EP alone in terms of OS (Hazard Ratio HR = 0.67, 95% Confidence Interval CI = 0.46-0.98 for nivolumab, HR = 0.70, 95% CI = 0.54-0.91 for atezolizumab, HR = 0.73, 95% CI = 0.59-0.90 for durvalumab) but no significant differences were observed for pembrolizumab or ipilimumab. The probability of nivolumab being ranked first among all treatment arms was highest (SCURA = 78.7%, Prbest = 46.7%). All EP plus ICI combinations had a longer PFS compared with EP alone (HR = 0.65, 95% CI = 0.46-0.92 for nivolumab, HR = 0.77, 95% CI = 0.61-0.96 for atezolizumab, HR = 0.78, 95% CI = 0.65-0.94 for durvalumab, HR = 0.75, 95% CI = 0.61-0.92 for pembrolizumab), and nivolumab was ranked first in terms of PFS (SCURA = 85.0%, Prbest = 66.8%). In addition, nivolumab had the highest probability of grade 3-4 adverse events (SUCRA = 84.8%) in our study. We found that nivolumab had the best PFS and OS in all combinations of ICIs and EP, but nivolumab also had the highest probability of grade 3-4 adverse events in our network meta-analysis. Further head-to head large-scale phase III randomized controlled studies are needed to verify our conclusions.

The Immune Checkpoint PD-1 in Natural Killer Cells: Expression, Function and Targeting in Tumour Immunotherapy

In the last years, immunotherapy with antibodies against programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) has shown remarkable efficacy in the treatment of different types of tumours, representing a true revolution in oncology. While its efficacy has initially been attributed only to unleashing T cell responses, responsivity to PD-1/PD-L1 blockade was observed in some tumours with low Human Leukocyte Antigen (HLA) I expression and increasing evidence has revealed PD-1 surface expression and inhibitory function also in natural killer (NK) cells. Thus, the contribution of anti-PD-1/PD-L1 therapy to the recovery of NK cell anti-tumour response has recently been appreciated. Here, we summarize the studies investigating PD-1 expression and function in NK cells, together with the limitations and perspectives of immunotherapies. A better understanding of checkpoint biology is needed to design next-generation therapeutic strategies and to improve the clinical protocols of current therapies.

Camrelizumab Plus Apatinib in Extensive-Stage SCLC (PASSION): A Multicenter, Two-Stage, Phase 2 Trial

INTRODUCTION

Treatment options in the second-line extensive-stage SCLC (ED-SCLC) setting are limited. The PASSION study (ClinicalTrials.gov identifier: NCT03417895) was a phase 2 study of camrelizumab plus apatinib in ED-SCLC after platinum-based chemotherapy.

METHODS

In stage I of the study, patients were randomized (1:1:1) to receive camrelizumab 200 mg every 2 weeks plus apatinib 375 mg once daily (QD), 5 days on and 2 days off, or 7 days on and 7 days off (six patients each cohort). On the basis of tolerability during the first 28-day cycle and efficacy data at stage I, one cohort was chosen to expand to 45 patients at stage II. The primary end point was objective response rate (ORR).

RESULTS

From April 20, 2018 to March 12, 2019, a total of 59 patients were enrolled, with 47 patients in the QD cohort. In the QD cohort, confirmed ORR reached 34.0% (95% confidence interval: 20.9‒49.3), the median progression-free survival was 3.6 months, and the median overall survival was 8.4 months. Chemotherapy-sensitive and chemotherapy-resistant patients (defined as patients with disease relapse at ≥90 and <90 d after platinum-based chemotherapy, respectively) had comparable confirmed ORR (37.5% versus 32.3%), median progression-free survival (3.6 versus 2.7 mo), and median overall survival (9.6 versus 8.0 mo). Treatment-related adverse events of grade 3 or higher were reported in 43 of 59 patients (72.9%). Five patients (8.5%) discontinued because of treatment-related adverse events.

CONCLUSIONS

Camrelizumab plus apatinib exhibited potential antitumor activity in patients with both chemotherapy-sensitive and chemotherapy-resistant ED-SCLC who had failed platinum-based chemotherapy with an acceptable toxicity profile. This phase 2 data warrant further clinical studies of camrelizumab plus apatinib in SCLC.

Immunotherapy and potential predictive biomarkers in the treatment of neuroendocrine neoplasia

Neuroendocrine neoplasias (NENs) are a heterogeneous group of rare tumors scattered throughout the body. Surgery, locoregional or ablative therapies as well as maintenance treatments are applied in well-differentiated, low-grade NENs, whereas cytotoxic chemotherapy is usually applied in high-grade neuroendocrine carcinomas. However, treatment options for patients with advanced or metastatic NENs are limited. Immunotherapy has provided new treatment approaches for many cancer types, including neuroendocrine tumors, but predictive biomarkers of immune checkpoint inhibitors (ICIs) in the treatment of NENs have not been fully reported. By reviewing the literature and international congress abstracts, we summarize the current knowledge of ICIs, potential predicative biomarkers in the treatment of NENs, implications and efficacy of ICIs as well as biomarkers for NENs of gastroenteropancreatic system, lung NENs and Merkel cell carcinoma in clinical practice.

Efficacy and Safety of Anlotinib for Elderly Patients with Previously Treated Extensive-Stage SCLC and the Prognostic Significance of Common Adverse Reactions

Background

This study was to investigate the efficacy and safety of anlotinib for elderly patients with previously treated extensive-stage small cell lung cancer (ES-SCLC) and the prognostic significance of common adverse reactions.

Patients and Methods

A total of 79 elderly patients (≥60 years) with ES-SCLC who failed after at least two lines of previous systemic therapy were included. Baseline characteristics of the patients were collected. Follow-up was conducted regularly. Adverse reactions were documented. Survival curves were drawn using Kaplan–Meier method. Univariate analysis was assessed using log rank test, and multivariate analysis was adjusted by Cox regression analysis. Additionally, the prognostic significance of common adverse reactions was performed.

Results

All of the 79 patients were available for evaluation of efficacy. Partial response (PR) was observed in 7 patients, stable disease (SD) was noted in 48 patients and progressive disease (PD) was confirmed in 24 patients. Consequently, the objective response rate (ORR) was 8.9% and disease control rate (DCR) was 69.6%. The median progression-free survival (PFS) of the 79 elderly patients with ES-SCLC was 3.0 months [95% confidence interval (CI): 2.02–3.98]. The median overall survival (OS) was 7.1 months (95% CI: 5.07–9.13). Safety profile demonstrated that the relatively common adverse reactions of the elderly patients with ES-SCLC receiving anlotinib treatment were hypertension (40.5%), hand-foot syndrome (HFS, 31.6%), diarrhea (27.8%), decreased appetite (20.3%), fatigue (17.7%) and weight loss (17.7%). Interestingly, the prognostic significance of common adverse reactions indicated that the median PFS of patients with hypertension and without hypertension was 4.35 and 2.95 months, respectively (P=0.01), and the median PFS of patients with HFS and without HFS was 4.20 and 2.95 months, respectively (P=0.03).

Conclusion

The preliminary efficacy and safety of anlotinib in the treatment for elderly patients with previously treated ES-SCLC was satisfactory, and patients with hypertension and hand-foot syndrome might confer superior prognosis.

Advances and Therapeutic Perspectives in Extended-Stage Small-Cell Lung Cancer

Extended small cell lung cancer (ED-SCLC) is a very aggressive disease, characterized by rapid growth and an early tendency to relapse. In contrast to non-small cell lung cancer, no therapeutic innovation has improved survival in patients with ED-SCLC over the past 20 years. Recently, immunotherapy has shown an important role in the management of these patients, emerging as the treatment of first choice in combination with chemotherapy and completely changing the therapeutic paradigm. However, patients' selection for this strategy is still challenging due to a lack of reliable predictive biomarkers. Conversely, the immunotherapy efficacy beyond the first line is pretty disappointing and innovative chemotherapies or target agents seem to be more promising in this setting. Some of them are also under evaluation as an upfront strategy and they will probably change the treatment algorithm in the next future. This proposal provides a comprehensive overview of available treatment strategies for ED-SCLC patients, highlighting their strengths and weaknesses.