Lurbinectedin as second-line treatment for patients with small-cell lung cancer: a single-arm, open-label, phase 2 basket trial

Angiogenesis Inhibitors in Small Cell Lung Cancer

Inhibition of angiogenesis has been demonstrated to be an efficacious strategy in treating several tumors. Vascular endothelial growth factor (VEGF) is the most important protein with proangiogenic functions and it is overexpressed in small cell lung cancer (SCLC). Bevacizumab, a monoclonal antibody directed against VEGF, showed a promising activity in combination with etoposide and cisplatin as first-line treatment of patients with extended stage (ES)-SCLC and two randomized studies confirmed that bevacizumab improved PFS, but failed to prolong OS. Instead, disappointing results have been observed with endostar, sunitinib, sorafenib, vandetanib, and thalidomide in combination with chemotherapy in the first-line setting, with sunitinib in the maintenance setting, with sunitinib, cediranib and nintedanib as single agents or ziv-aflibercept in combination with topotecan in second-line setting. Only anlotinib improved OS and PFS as third-line therapy in Chinese patients with SCLC, and it was approved with this indication in China. Future challenges are the evaluation of the role of angiogenesis inhibitors in combination with immune- checkpoint inhibitors and chemotherapy in SCLC patients and the identification of predictive biomarkers of response to both agents.

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.

A Phase II Trial of Prexasertib (LY2606368) in Patients With Extensive-Stage Small-Cell Lung Cancer

BACKGROUND

This study assessed the checkpoint kinase 1 inhibitor prexasertib in patients with extensive-stage small-cell lung cancer (ED-SCLC).

PATIENTS AND METHODS

This was a parallel-cohort phase II study of 105 mg/m² prexasertib once every 14 days for patients who progressed after no more than two prior therapies and had platinum-sensitive (Cohort 1) or platinum-resistant/platinum-refractory (Cohort 2) disease. The primary endpoint was objective response rate (ORR). Secondary endpoints included disease control rate (DCR), progression-free survival (PFS), overall survival (OS), safety, and pharmacokinetics. Exploratory endpoints included biomarker identification and assessment of an alternative regimen (Cohort 3: 40 mg/m² days 1-3, 14-day cycle).

RESULTS

In Cohort 1 (n = 58), ORR was 5.2%; DCR, 31%; median PFS, 1.41 months (95% confidence interval [CI], 1.31-1.64); and median OS, 5.42 months (95% CI, 3.75-8.51). In Cohort 2 (n = 60), ORR was 0%; DCR, 20%; median PFS, 1.36 months (95% CI, 1.25-1.45); and median OS, 3.15 months (95% CI, 2.27-5.52). The most frequent all-grade, related, treatment-emergent adverse events were decreased neutrophil count (Cohort 1, 69.6%; Cohort 2, 73.3%), decreased platelet count (Cohort 1, 51.8%; Cohort 2, 50.0%), decreased white blood cell count (Cohort 1, 28.6%; Cohort 2, 40.0%), and anemia (Cohort 1, 39.3%; Cohort 2, 28.3%). Eleven patients (19.6%) in Cohort 1 and one patient (1.7%) in Cohort 2 experienced grade ≥3 febrile neutropenia. Prexasertib pharmacokinetics were consistent with prior studies. Cohort 3 outcomes were similar to those of Cohorts 1 and 2. No actionable biomarkers were identified.

CONCLUSION

Prexasertib did not demonstrate activity to warrant future development as monotherapy in ED-SCLC.

[Small Cell Lung Cancer]

Small cell lung cancer is an aggressive cancer entity and characterized by rapid progression, early distant metastasis and poor prognosis. Only the minority of patients presents with a non-metastatic stage disease where chemo-radiotherapy or - in very selected cases - even surgical resection may be discussed. For most patients, the efficacy of systemic therapy is crucial. However, although most patients respond to platinum doublet chemotherapy, virtually all patients with metastatic disease eventually develop tumor progression for which there are limited treatment options. Recently and for the first time since decades, the systemic approaches have been enriched by the implementation of immunotherapy. Moreover, novel therapeutic approaches such as new cytotoxic agents or further immune modulatory strategies are being tested in clinical studies that might broaden our treatment options in the future even further.

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.

An update of new small-molecule anticancer drugs approved from 2015 to 2020

A high incidence of cancer has given rise to the development of more anti-tumor drugs. From 2015 to 2020, fifty-six new small-molecule anticancer drugs, divided into ten categories according to their anti-tumor target activities, have been approved. These include TKIs (30 drugs), MAPK inhibitors (3 drugs), CDK inhibitors (3 drugs), PARP inhibitors (3 drugs), PI3K inhibitors (3 drugs), SMO receptor antagonists (2 drugs), AR antagonists (2 drugs), SSTR inhibitors (2 drugs), IDH inhibitors (2 drugs) and others (6 drugs). Among them, PTK inhibitors (30/56) have led to a paradigm shift in cancer treatment with less toxicity and more potency. Each of their structures, approval statuses, applications, SAR analyses, and original research synthesis routes have been summarized, giving us a more comprehensive map for further efforts to design more specific targeted agents for reducing cancer in the future. We believe this review will help further research of potential antitumor agents in clinical usage.

A year in pharmacology: new drugs approved by the US Food and Drug Administration in 2020

While the COVID-19 pandemic also affected the work of regulatory authorities, the US Food and Drug Administration approved a total of 53 new drugs in 2020, one of the highest numbers in the past decades. Most newly approved drugs related to oncology (34%) and neurology (15%). We discuss these new drugs by level of innovation they provide, i.e., first to treat a condition, first using a novel mechanisms of action, and "others." Six drugs were first in indication, 15 first using a novel mechanism of action, and 32 other. This includes many drugs for the treatment of orphan indications and some for the treatment of tropical diseases previously neglected for commercial reasons. Small molecules continue to dominate new drug approvals, followed by antibodies. Of note, newly approved drugs also included small-interfering RNAs and antisense oligonucleotides. These data show that the trend for declines in drug discovery and development has clearly been broken.

A rational targeted therapy for platinum-resistant small-cell lung cancer

Small-cell lung cancer (SCLC) is initially sensitive to platinum doublet chemotherapy, providing dramatic clinical benefit. Unfortunately, most SCLCs relapse and become resistant to further therapy. In this issue of Cancer Cell, Thomas et al. show that some platinum-resistant SCLCs benefit from combination therapy with topotecan plus the ATR (ataxia telangiectasia-mutated and rad3-related) inhibitor berzosertib.

Therapeutic targeting of ATR yields durable regressions in small cell lung cancers with high replication stress

Small cell neuroendocrine cancers (SCNCs) are recalcitrant cancers arising from diverse primary sites that lack effective treatments. Using chemical genetic screens, we identified inhibition of ataxia telangiectasia and rad3 related (ATR), the primary activator of the replication stress response, and topoisomerase I (TOP1), nuclear enzyme that suppresses genomic instability, as synergistically cytotoxic in small cell lung cancer (SCLC). In a proof-of-concept study, we combined M6620 (berzosertib), first-in-class ATR inhibitor, and TOP1 inhibitor topotecan in patients with relapsed SCNCs. Objective response rate among patients with SCLC was 36% (9/25), achieving the primary efficacy endpoint. Durable tumor regressions were observed in patients with platinum-resistant SCNCs, typically fatal within weeks of recurrence. SCNCs with high neuroendocrine differentiation, characterized by enhanced replication stress, were more likely to respond. These findings highlight replication stress as a potentially transformative vulnerability of SCNCs, paving the way for rational patient selection in these cancers, now treated as a single disease.

Small Cell Lung Cancer: State of the Art of the Molecular and Genetic Landscape and Novel Perspective

Simple Summary

Small cell lung cancer (SCLC) continues to carry a poor prognosis with a five-year survival rate of 3.5% and a 10-year survival rate of 1.8%. The pathogenesis remains unclear, and there are no known predictive or diagnostic biomarkers. The current SCLC classification as a single entity hinders effective targeted therapies against this heterogeneous neoplasm. Despite dedicated decades of research and clinical trials, there has been no change in the SCLC treatment paradigm. This review summarizes the body of literature available on SCLC’s genomic landscape to describe SCLC’s molecular/genetic aspects, regardless of therapeutic strategy.

Abstract

Small cell lung cancer (SCLC) is a highly proliferative lung cancer that is not amenable to surgery in most cases due to the high metastatic potential. Precision medicine has not yet improved patients’ survival due to the lack of actionable mutations. Intra- and intertumoral heterogeneity allow the neoplasms to adapt to various microenvironments and treatments. Further studying this heterogeneous cancer might yield the discovery of actionable mutations. First-line SCLC treatment has added immunotherapy to its armamentarium. There has been renewed interest in SCLC, and numerous clinical trials are underway with novel therapeutic approaches. Understanding the molecular and genetic landscape of this heterogeneous and lethal disease will pave the way for novel drug development.

Immune checkpoint inhibitors for treatment of small-cell lung cancer: a systematic review and meta-analysis

Background

Small cell lung cancer (SCLC) is a very aggressive and proliferative disease, with little progress being having made for its treatment in decades. Our goal was to evaluate the effect of immune checkpoint inhibitors (ICIs) and identify optimal first-line interventions for the treatment of SCLC.

Methods

A systematic literature search of the Cochrane Library, PubMed and oncology conference proceedings were conducted. Randomized trials evaluating ICIs for SCLC were included. We use the risk of bias tool in RevMan 5.3 to assess the quality of studies. We used Stata version 15.0 to carry out data direct comparison and R version 4.0.2 to conduct the Bayesian network analysis.

Results

A total of 16 relevant clinical trials comprising 4,476 patients were included. We found the magnitude of efficacy for ICIs as first-line therapy conferred a statistically significant benefit in overall survival (OS) and progression-free survival compared to chemotherapy alone. The results were 0.82 (95% CI, 0.76–0.89, P<0.001) and 0.80 (95% CI, 0.74–0.86, P<0.001). For objective response rate (ORR), the result (1.13, 95% CI, 0.97–1.31, P=0.109) was not significant. In the second-line and maintenance treatment, no additional benefit was observed. With regard to safety, results showed that for all grades of AEs and grades 3–4 AEs, the pooled results were 1.36 (95% CI: 0.50–3.70; P=0.543) and 1.35 (95% CI: 0.58–3.15; P=0.484) respectively. In addition, the indirect comparison results showed that nivolumab combined with chemotherapy led to the most significant improvement in OS, while durvalumab combined with chemotherapy was a more efficacious therapy for improving ORR compared with the other interventions; the probability were the best treatments was 73.93% and 81% respectively.

Discussion

Our results showed ICIs combined with etoposide and platinum-based drugs as first-line treatment of SCLC have benefits for patients and there was no evidence of a significant difference in efficacy among the different ICI drugs used for the first-line therapy. As for toxicity, the ICIs did not increase the frequency AEs for patients. However, as some studies are ongoing and the full data have still not been reported, our conclusions may not be completely representative.

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.

Lurbinectedin in the treatment of relapsed small cell lung cancer

Lurbinectedin is a marine-derived drug that inhibits transcription, a process that is frequently dysregulated in small cell lung cancer. The activity of lurbinectedin has been studied in many solid tumors, showing not only promising results but also a favorable safety profile. In relapsed small cell lung cancer, the drug has shown encouraging activity both as a single agent and in combination with doxorubicin, paclitaxel or irinotecan. The USA FDA has recently granted accelerated approval to lurbinectedin monotherapy in this setting. This article provides an update on available data and ongoing studies of lurbinectedin in small cell lung cancer, including Phase I combination trials, the basket Phase II trial and the ATLANTIS Phase III trial.

Efficacy and safety of lurbinectedin and doxorubicin in relapsed small cell lung cancer. Results from an expansion cohort of a phase I study

Background A phase I study found remarkable activity and manageable toxicity for doxorubicin (bolus) plus lurbinectedin (1-h intravenous [i.v.] infusion) on Day 1 every three weeks (q3wk) as second-line therapy in relapsed small cell lung cancer (SCLC). An expansion cohort further evaluated this combination. Patients and methods Twenty-eight patients with relapsed SCLC after no more than one line of cytotoxic-containing chemotherapy were treated: 18 (64%) with sensitive disease (chemotherapy-free interval [CTFI] ≥90 days) and ten (36%) with resistant disease (CTFI <90 days; including six with refractory disease [CTFI ≤30 days]). Results Ten patients showed confirmed response (overall response rate [ORR] = 36%); median progression-free survival (PFS) = 3.3 months; median overall survival (OS) = 7.9 months. ORR was 50% in sensitive disease (median PFS = 5.7 months; median OS = 11.5 months) and 10% in resistant disease (median PFS = 1.3 months; median OS = 4.6 months). The main toxicity was transient and reversible myelosuppression. Treatment-related non-hematological events (fatigue, nausea, decreased appetite, vomiting, alopecia) were mostly mild or moderate. Conclusion Doxorubicin 40 mg/m² and lurbinectedin 2.0 mg/m² on Day 1 q3wk has shown noteworthy activity in relapsed SCLC and a manageable safety profile. The combination is being evaluated as second-line therapy for SCLC in an ongoing, randomized phase III trial. Clinical trial registration www.ClinicalTrials.gov code: NCT01970540. Date of registration: 22 October, 2013.

Novel Cytotoxic Chemotherapies in Small Cell Lung Carcinoma

Small cell lung cancer (SCLC) is one of the deadliest thoracic neoplasms, in part due to its fast doubling time and early metastatic spread. Historically, cytotoxic chemotherapy consisting of platinum-etoposide or anthracycline-based regimens has demonstrated a high response rate, but early chemoresistance leads to a poor prognosis in advanced SCLC. Only a fraction of patients with limited-disease can be cured by chemo-radiotherapy. Given the disappointing survival rates in advanced SCLC, new cytotoxic agents are eagerly awaited. Unfortunately, few novel chemotherapy drugs have been developed in the latest decades. This review describes the results and potential application in the clinical practice of novel chemotherapy agents for 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.

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

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.

Anticancer Potential of Compounds from the Brazilian Blue Amazon

"Blue Amazon" is used to designate the Brazilian Economic Exclusive Zone, which covers an area comparable in size to that of its green counterpart. Indeed, Brazil flaunts a coastline spanning 8000 km through tropical and temperate regions and hosting part of the organisms accredited for the country's megadiversity status. Still, biodiversity may be expressed at different scales of organization; besides species inventory, genetic characteristics of living beings and metabolic expression of their genes meet some of these other layers. These metabolites produced by terrestrial creatures traditionally and lately added to by those from marine organisms are recognized for their pharmaceutical value, since over 50% of small molecule-based medicines are related to natural products. Nonetheless, Brazil gives a modest contribution to the field of pharmacology and even less when considering marine pharmacology, which still lacks comprehensive in-depth assessments toward the bioactivity of marine compounds so far. Therefore, this review examined the last 40 years of Brazilian natural products research, focusing on molecules that evidenced anticancer potential-which represents ~ 15% of marine natural products isolated from Brazilian species. This review discusses the most promising compounds isolated from sponges, cnidarians, ascidians, and microbes in terms of their molecular targets and mechanisms of action. Wrapping up, the review delivers an outlook on the challenges that stand against developing groundbreaking natural products research in Brazil and on a means of surpassing these matters.

Surgery in Small-Cell Lung Cancer

Simple Summary

Small-cell lung cancer (SCLC) accounts for approximately 15% of all lung cancers and is one of the most aggressive tumors, with poor prognosis and limited therapeutic options. This review summarizes the main results observed with surgery in SCLC, discussing the critical issues related to the use of this approach. Following two old randomized clinical trials showing no benefit with surgery, several prospective, retrospective, and population-based studies have demonstrated the feasibility of a multimodality approach including surgery in addition to chemotherapy and radiotherapy in patients with selected stage I SCLC. Currently, the International Guidelines recommend a surgical approach in selected stage I SCLC patients, after adequate staging within a multimodal approach and after a multidisciplinary evaluation.

Abstract

Small-cell lung cancer (SCLC) is one of the most aggressive tumors, with a rapid growth and early metastases. Approximately 5% of SCLC patients present with early-stage disease (T1,2 N0M0): these patients have a better prognosis, with a 5-year survival up to 50%. Two randomized phase III studies conducted in the 1960s and the 1980s reported negative results with surgery in SCLC patients with early-stage disease and, thereafter, surgery has been largely discouraged. Instead, several subsequent prospective studies have demonstrated the feasibility of a multimodality approach including surgery before or after chemotherapy and followed in most studies by thoracic radiotherapy, with a 5-year survival probability of 36–63% for patients with completely resected stage I SCLC. These results were substantially confirmed by retrospective studies and by large, population-based studies, conducted in the last 40 years, showing the benefit of surgery, particularly lobectomy, in selected patients with early-stage SCLC. On these bases, the International Guidelines recommend a surgical approach in selected stage I SCLC patients, after adequate staging: in these cases, lobectomy with mediastinal lymphadenectomy is considered the standard approach. In all cases, surgery can be offered only as part of a multimodal treatment, which includes chemotherapy with or without radiotherapy and after a proper multidisciplinary evaluation.

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.

Current Status and Future Perspectives of Liquid Biopsy in Small Cell Lung Cancer

Approximately 19% of all cancer-related deaths are due to lung cancer, which is the leading cause of mortality worldwide. Small cell lung cancer (SCLC) affects approximately 15% of patients diagnosed with lung cancer. SCLC is characterized by aggressiveness; the majority of SCLC patients present with metastatic disease, and less than 5% of patients are alive at 5 years. The gold standard of SCLC treatment is platinum and etoposide-based chemotherapy; however, its effects are short. In recent years, treatment for SCLC has changed; new drugs have been approved, and new biomarkers are needed for treatment selection. Liquid biopsy is a non-invasive, rapid, repeated and alternative tool to the traditional tumor biopsy that could allow the most personalized medicine into the management of SCLC patients. Circulating tumor cells (CTCs) and cell-free DNA (cfDNA) are the most commonly used liquid biopsy biomarkers. Some studies have reported the prognostic factors of CTCs and cfDNA in SCLC patients, independent of the stage. In this review, we summarize the recent SCLC studies of CTCs, cfDNA and other liquid biopsy biomarkers, and we discuss the future utility of liquid biopsy in the clinical management of SCLC.

Petasis adducts of tryptanthrin – synthesis, biological activity evaluation and druglikeness assessment

The first example of a tryptanthrin-based Petasis multicomponent reaction is reported, with one of the new derivatives showing moderate fungicidal activity.

Targeted therapy for upper gastrointestinal tract cancer: current and future prospects

Gastric and oesophageal carcinoma remain major causes of worldwide mortality and morbidity. Despite incredible progress in understanding tumour biology, few targeted treatment options have proved effective in prolonging survival, and adjuvant therapy is largely interchangeable in these carcinomas. Through large-scale sequencing by the Cancer Genome Atlas and the Asian Cancer Research Group, numerous potential molecular targets have been discovered. Of the approved targeted therapies for gastric and oesophageal cancer, pathologists play a role in patient selection for the majority of them. Trastuzumab has been approved as a first-line therapy in conjunction with standard treatment in adenocarcinomas with either 3+ HER2/neu expression by immunohistochemistry or ERBB2 amplification by FISH. PD-L1 immunohistochemistry showing a combined positive score of 1 or greater qualifies patients for third-line pembrolizumab therapy, and identification of microsatellite instability-high carcinomas may qualify patients for second-line pembrolizumab. Ramucirumab, targeting VEGFR2, has also been approved for second-line therapy in gastric carcinoma. Non-surgical therapy for gastrointestinal stromal tumours relies mainly upon tyrosine kinase inhibitors, while new targeted therapy options for neuroendocrine neoplasms have recently emerged. Potential future options for targeted therapy in all these malignancies are being investigated in clinical trials, as this review will discuss.

Myelopreservation with Trilaciclib in Patients Receiving Topotecan for Small Cell Lung Cancer: Results from a Randomized, Double-Blind, Placebo-Controlled Phase II Study

INTRODUCTION

Multilineage myelosuppression is an acute toxicity of cytotoxic chemotherapy, resulting in serious complications and dose modifications. Current therapies are lineage specific and administered after chemotherapy damage has occurred. Trilaciclib is a cyclin-dependent kinase 4/6 inhibitor that is administered prior to chemotherapy to preserve hematopoietic stem and progenitor cells and immune system function during chemotherapy (myelopreservation).

METHODS

In this randomized, double-blind, placebo-controlled phase II trial, patients with previously treated extensive-stage small cell lung cancer (ES-SCLC) were randomized to receive intravenous trilaciclib 240 mg/m2 or placebo before topotecan 1.5 mg/m2 on days 1-5 of each 21-day cycle. Primary endpoints were duration of severe neutropenia (DSN) in cycle 1 and occurrence of severe neutropenia (SN). Additional endpoints were prespecified to further assess the effect of trilaciclib on myelopreservation, safety, patient-reported outcomes (PROs), and antitumor efficacy.

RESULTS

Thirty-two patients received trilaciclib, and 29 patients received placebo. Compared with placebo, administration of trilaciclib prior to topotecan resulted in statistically significant and clinically meaningful decreases in DSN in cycle 1 (mean [standard deviation] 2 [3.9] versus 7 [6.2] days; adjusted one-sided P < 0.0001) and occurrence of SN (40.6% versus 75.9%; adjusted one-sided P = 0.016), with numerical improvements in additional neutrophil, red blood cell, and platelet measures. Patients receiving trilaciclib had fewer grade ≥ 3 hematologic adverse events than patients receiving placebo, particularly neutropenia (75.0% versus 85.7%) and anemia (28.1% versus 60.7%). Myelopreservation benefits extended to improvements in PROs, specifically in those related to fatigue. Antitumor efficacy was comparable between treatment arms.

CONCLUSIONS

Compared with placebo, the addition of trilaciclib prior to topotecan for the treatment of patients with previously treated ES-SCLC improves the patient experience of receiving chemotherapy, as demonstrated by a reduction in chemotherapy-induced myelosuppression, improved safety profile, improved quality of life and no detrimental effects on antitumor efficacy.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02514447.

Lurbinectedin: A New Treatment Option for Relapsed/Refractory Small-Cell Lung Cancer

OBJECTIVE

To assess the clinical application of lurbinectedin and its role in the therapy of small-cell lung cancer (SCLC).

DATA SOURCES

PubMed database and ClincialTrials.gov were utilized to perform a comprehensive literature search from August 2011 to mid-November 2020 with the terms lurbinectedin and PM01183.

STUDY SELECTION AND DATA EXTRACTION

English-language clinical trials of lurbinectedin were evaluated.

DATA SYNTHESIS

Lurbinectedin, as second-line therapy in SCLC, demonstrated an overall response (OR) rate of 35.2% and median overall survival of 9.3 months. Phase II studies in multiple cancers revealed myelosuppression (>95%), increased liver enzymes (>70%), nausea (up to 80%), vomiting (54%), and fatigue (>50%) as the most common adverse events associated with lurbinectedin. CYP3A4 drug interactions affect lurbinectedin exposure (severe pancytopenia occurred after coadministration with aprepitant), and protein binding can affect its clearance. Patients with cardiac comorbidities were not included in published lurbinectedin trials because of cardiotoxicity associated with trabectedin.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Lurbinectedin is an option in SCLC after failure of a platinum-based regimen. Dose adjustments, drug interactions, antiemetic regimen choice, and patient comorbidities are important clinical considerations with lurbinectedin use. Likewise, its place in therapy in the era of immune checkpoint inhibitors requires further exploration.

CONCLUSIONS

With a promising OR compared with other second-line options, lurbinectedin should be considered in patients who have failed first-line therapy. Studies are ongoing with lurbinectedin in combination with other agents in SCLC, and a phase III trial is assessing use in combination with doxorubicin compared with other second-line regimens.

Thomas O, Barraja P, Gaudêncio SP, Bertoni F. Marine Anticancer Agents: An Overview with a Particular Focus on Their Chemical Classes

The marine environment is a rich source of biologically active molecules for the treatment of human diseases, especially cancer. The adaptation to unique environmental conditions led marine organisms to evolve different pathways than their terrestrial counterparts, thus producing unique chemicals with a broad diversity and complexity. So far, more than 36,000 compounds have been isolated from marine micro- and macro-organisms including but not limited to fungi, bacteria, microalgae, macroalgae, sponges, corals, mollusks and tunicates, with hundreds of new marine natural products (MNPs) being discovered every year. Marine-based pharmaceuticals have started to impact modern pharmacology and different anti-cancer drugs derived from marine compounds have been approved for clinical use, such as: cytarabine, vidarabine, nelarabine (prodrug of ara-G), fludarabine phosphate (pro-drug of ara-A), trabectedin, eribulin mesylate, brentuximab vedotin, polatuzumab vedotin, enfortumab vedotin, belantamab mafodotin, plitidepsin, and lurbinectedin. This review focuses on the bioactive molecules derived from the marine environment with anticancer activity, discussing their families, origin, structural features and therapeutic use.

A look around the West Indies: The spices of life are secondary metabolites

Natural products possess a wide range of bioactivities with potential for therapeutic usage. While the distribution of these molecules can vary greatly there is some correlation that exists between the biodiversity of an environment and the uniqueness and concentration of natural products found in that region or area. The Caribbean and pan-Caribbean area is home to thousands of species of endemic fauna and flora providing huge potential for natural product discovery and by way, potential leads for drug development. This can especially be said for marine natural products as many of are rapidly diluted through diffusion once released and therefore are highly potent to achieve long reaching effects. This review seeks to highlight a small selection of marine natural products from the Caribbean region which possess antiproliferative, anti-inflammatory and antipathogenic properties while highlighting any synthetic efforts towards bioactive analogs.

Systemic therapy options following first-line chemoimmunotherapy in small-cell lung cancer

Nearly all patients with extensive-stage small-cell lung cancer (ES-SCLC) relapse following first-line etoposide plus platinum (EP) with or without immune checkpoint inhibition. Topotecan and amrubicin are chemotherapies approved for these patients. The toxicities of these chemotherapies are significant and survival when treated with these regimens is minimal. The programmed death-1 (PD-1) inhibitors nivolumab and pembrolizumab are unlikely to be effective for patients who develop progressive disease on first-line chemoimmunotherapy. Newer systemic therapies (e.g., lurbinectedin and temozolomide plus poly-ADP ribose polymerase inhibition) have demonstrated greater response rates than topotecan, amrubicin or PD-1 inhibitors. The data on these newer systemic therapies and other agents that may soon enter clinic are reviewed in this manuscript. Additionally, some of the key questions arising following clinical trials of these newer agents are highlighted.

Impact of Lineage Plasticity to and from a Neuroendocrine Phenotype on Progression and Response in Prostate and Lung Cancers

Intratumoral heterogeneity can occur via phenotype transitions, often after chronic exposure to targeted anticancer agents. This process, termed lineage plasticity, is associated with acquired independence to an initial oncogenic driver, resulting in treatment failure. In non-small cell lung cancer (NSCLC) and prostate cancers, lineage plasticity manifests when the adenocarcinoma phenotype transforms into neuroendocrine (NE) disease. The exact molecular mechanisms involved in this NE transdifferentiation remain elusive. In small cell lung cancer (SCLC), plasticity from NE to nonNE phenotypes is driven by NOTCH signaling. Herein we review current understanding of NE lineage plasticity dynamics, exemplified by prostate cancer, NSCLC, and SCLC.

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.

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.

Specific Effects of Trabectedin and Lurbinectedin on Human Macrophage Function and Fate-Novel Insights

BACKGROUND

Tumor-associated macrophages (TAMs) play a crucial role in suppressing the immunosurveillance function of the immune system that prevents tumor growth. Indeed, macrophages can also be targeted by different chemotherapeutic agents improving the action over immune checkpoints to fight cancer. Here we describe the effect of trabectedin and lurbinectedin on human macrophage cell viability and function.

METHODS

Blood monocytes from healthy donors were differentiated into macrophages and exposed to different stimuli promoting functional polarization and differentiation into tumor-associated macrophages. Cells were challenged with the chemotherapeutic drugs and the effects on cell viability and function were analyzed.

RESULTS

Human macrophages exhibit at least two different profiles in response to these drugs. One-fourth of the blood donors assayed (164 individuals) were extremely sensitive to trabectedin and lurbinectedin, which promoted apoptotic cell death. Macrophages from other individuals retained viability but responded to the drugs increasing reactive oxygen production and showing a rapid intracellular calcium rise and a loss of mitochondrial oxygen consumption. Cell-membrane exposure of programmed-death ligand 1 (PD-L1) significantly decreased after treatment with therapeutic doses of these drugs, including changes in the gene expression profile of hypoxia-inducible factor 1 alpha (HIF-1α)-dependent genes, among other.

CONCLUSIONS

The results provide evidence of additional onco-therapeutic actions for these drugs.

Antitumor activity of lurbinectedin in second-line small cell lung cancer patients who are candidates for re-challenge with the first-line treatment

INTRODUCTION

The National Comprehensive Cancer Network guidelines recommend re-challenge with the first-line treatment for relapsed small cell lung cancer (SCLC) with chemotherapy-free interval (CTFI)≥180 days. A phase II study (NCT02454972) showed remarkable antitumor activity in SCLC patients treated with lurbinectedin 3.2 mg/m² 1 -h intravenous infusion every 3 weeks as second-line therapy. We report results for the pre-planned subset of patients with CTFI ≥ 180 days.

MATERIAL AND METHODS

Twenty patients aged ≥18 years with pathologically proven SCLC diagnosis, pretreated with only one prior platinum-containing line, no CNS metastases, and with CTFI ≥ 180 days were evaluated. The primary efficacy endpoint was the overall response rate (ORR) assessed by the Investigators according to RECIST v1.1.

RESULTS

ORR was 60.0 % (95 %CI, 36.1-86.9), with a median duration of response of 5.5 months (95 %CI, 2.9-11.2) and disease control rate of 95.0 % (95 %CI, 75.1-99.9). Median progression-free survival was 4.6 months (95 %CI, 2.6-7.3). With a censoring of 55.0 %, the median overall survival was 16.2 months (95 %CI, 9.6-upper level not reached). Of note, 60.9 % and 27.1 % of patients were alive at 1 and 2 years, respectively. The most common grade 3/4 adverse events and laboratory abnormalities were hematological disorders (neutropenia, 55.0 %; anemia; 10.0 % thrombocytopenia, 10.0 %), fatigue (10.0 %) and increased liver function tests (GGT, 10 %; ALT and AP, 5.0 % each). No febrile neutropenia was reported.

CONCLUSION

Lurbinectedin is an effective treatment for platinum-sensitive relapsed SCLC, especially in patients with CTFI ≥ 180 days, with acceptable safety and tolerability. These encouraging results suggest that lurbinectedin can be another valuable therapeutic option rather than platinum re-challenge.

Drugs in development for small cell lung cancer

Small cell lung cancer (SCLC) is a particularly lethal subtype of lung cancer whose treatment landscape has been relatively devoid of advance. The recent integration of immunotherapy in the first-line treatment of SCLC has improved overall survival (OS), prompting the first major paradigm shift for this disease in decades. Despite this improvement in outcomes, most patients with SCLC will relapse after initial response. Standard salvage systemic therapy for SCLC remains disappointing, with few approved agents and consistently poor outcomes. The need for novel agents to combat this disease remains pressing. Fortunately, there are several agents in various stages of development that hold potential as novel treatments for advanced SCLC. Lurbinectedin, which targets active transcription, has shown activity in platinum-sensitive and platinum-resistant SCLC as monotherapy and in combination with doxorubicin. Aurora A kinase (AAK) inhibitors showed initial activity when given with paclitaxel but in randomized studies, failed to improve outcomes over paclitaxel plus placebo. However, in the subset of patients with MYC expression, targeting AAK was effective. Similarly, agents targeting poly-ADP ribose (PARP) pair well with other DNA damaging drugs but in the subset of patients whose tumors express Schlafen-11 (SLFN-11), efficacy appeared greater. CDK 4/6 inhibition is being explored, primarily as a means to protect myeloid cells during cytotoxic chemotherapy in a strategy expected to be uniquely effective in SCLC. Ongoing trials are also studying are novel formulations of established cytotoxic agents. Delta-like protein 3 (DLL3) is an appealing therapeutic target given its selective expression on SCLC cells, but after initial exciting results, the antibody-drug conjugate (ADC) Rovalpituzumab tesirine (Rova-T) did not have a favorable efficacy to toxicity profile in randomized trials. Other agents targeting DLL3 are under study. Targeting angiogenesis has yielded modest improvements in the past but newer agents such as anlotinib are renewing interest. While the current therapeutic landscape beyond chemo-immunotherapy remains the same as it was decades ago, drug development for SCLC is rapidly moving forward and promises to deliver the needed novel agents in the very near future.

Immunotherapy in Small Cell Lung Cancer

Simple Summary

Small cell lung cancer (SCLC) accounts for about 15% of lung cancers and it has limited therapeutic options and poor prognosis. There has been no real progress for over 30 years in the treatment of this aggressive tumor type and platinum based chemotherapy represented the cornerstone of therapy. Immune checkpoint inhibitors are the first agents in the last decades to determine an improvement in outcomes of patients with extensive stage (ES) SCLC patients. In the IMpower 133 and CASPIAN studies, the addition of atezolizumab or durvalumab, respectively, to first-line chemotherapy produced a significant improvement in overall survival with an acceptable safety profile in previously untreated patients with ES-SCLC, leading to a new standard of care. This review summarizes the main results observed with checkpoint inhibitors in SCLC, discussing the critical issues related to the use of novel checkpoint inhibitors and the future research with immunotherapy agents in SCLC.

Abstract

Small-cell lung cancer (SCLC) is an aggressive tumor type with limited therapeutic options and poor prognosis. Chemotherapy regimens containing platinum represent the cornerstone of treatment for patients with extensive disease, but there has been no real progress for 30 years. The evidence that SCLC is characterized by a high mutational burden led to the development of immune-checkpoint inhibitors as single agents or in combination with chemotherapy. Randomized phase III trials demonstrated that the combination of atezolizumab (IMpower-133) or durvalumab (CASPIAN) with platinum-etoposide chemotherapy improved overall survival of patients with extensive disease. Instead, the KEYNOTE-604 study demonstrated that the addition of pembrolizumab to chemotherapy failed to significantly improve overall survival, but it prolonged progression-free survival. The safety profile of these combinations was similar with the known safety profiles of all single agents and no new adverse events were observed. Nivolumab and pembrolizumab single agents showed anti-tumor activity and acceptable safety profile in Checkmate 032 and KEYNOTE 028/158 trials, respectively, in patients with SCLC after platinum-based therapy and at least one prior line of therapy. Future challenges are the identification predictive biomarkers of response to immunotherapy in SCLC and the definition of the role of immunotherapy in patients with limited stage SCLC, in combination with radiotherapy or with other biological agents.

Emerging drugs for small cell lung cancer: a focused review on immune checkpoint inhibitors

INTRODUCTION

Small cell lung cancer (SCLC) is an aggressive malignancy that accounts for 15% of all lung cancers. It is characterized by initial responsiveness to therapy followed by rapid disease progression that is relatively resistant to further treatment. Recently, the addition of an immune checkpoint inhibitor (ICI) to chemotherapy has improved survival in patients with advanced disease, the first advance in systemic therapy in SCLC in over 30 years.

AREAS COVERED

In this review, we present an overview of SCLC with a focus on the scope of the problem and standard treatment, followed by a critical assessment of scientific rationale for immunotherapy in SCLC and the clinical trials that have been performed with ICIs in SCLC. Finally, we address ongoing hurdles for the development of ICIs in SCLC and potential avenues for further study.

EXPERT OPINION

Despite solid biological rationale, the results of clinical trials of ICIs in SCLC have yielded modest benefits. A small subset of patients does achieve long-term benefit, but further development of ICIs in SCLC will depend on the identification of predictive biomarkers and the design of combination regimens that take advantage of the molecular alterations that drive the immune-avoidance mechanisms and survival of SCLC cells.

Opportunities and obstacles of targeted therapy and immunotherapy in small cell lung cancer

Small cell lung cancer (SCLC) is an aggressive malignant tumour which accounts for approximately 13-15% of all newly diagnosed lung cancer cases. To date, platinum-based chemotherapy are still the first-line treatments for SCLC. However, chemotherapy resistance and systemic toxicity limit the long-term clinical outcome of first-line treatment in SCLC. Recent years, targeted therapy and immunotherapy have made great breakthrough in cancer therapy, and researchers aim to exploit both as a single agent or in combination with chemotherapy to improve the survival of SCLC patients, but limited effectiveness and the adverse events remain the major obstacles in the treatment of SCLC. To overcome these challenges for SCLC therapies, prevention and early diagnosis for this refractory disease is very important. At the same time, we should reveal more information about the pathogenesis of SCLC and the mechanism of drug resistance. Finally, new treatment strategies should also be taken into considerations, such as repurposing drug, optimising of targets, combination therapy strategies or prognostic biomarkers to enhance therapeutic effects and decrease the adverse events rates in SCLC patients. This article will review the molecular biology characteristics of SCLC and discuss the opportunities and obstacles of the current therapy for SCLC patients.

Lurbinectedin: an FDA-approved inducer of immunogenic cell death for the treatment of small-cell lung cancer

Lurbinectedin is a DNA-binding inhibitor of transcription that potently induces immunogenic cell death (ICD). In June 2020, the Federal Drug Administration (FDA) approved lurbinectedin for the salvage treatment of small-cell lung cancer that has relapsed from platinum compound-based first-line chemotherapy. Thus, the clinical activity of lurbinectedin may originate, at least in part, from the induction of ICD.

Systemic Therapy of Extensive Stage Small Cell Lung Cancer in the Era of Immunotherapy

OPINION STATEMENT

In March 2019, the FDA approved the use of the anti-programmed death ligand 1 (PD-L1) antibody atezolizumab, as a first-line treatment option in combination with platinum-etoposide (PE) for patients with extensive stage small cell lung cancer (ED SCLC) based upon the results of the IMpower133 trial. More recently, the FDA approved the anti-PD-L1 antibody durvalumab in March 2020 , also in the frontline setting for SCLC based upon the results of the CASPIAN trial. Both these trials demonstrated a small, but significant overall survival (OS) benefit with the addition of a PD-L1 antibody to standard chemotherapy in the treatment of ED SCLC, thereby altering the treatment paradigm for this aggressive disease. Previously, the FDA had approved the anti-PD1 antibodies nivolumab and pembrolizumab as single-agent third-line treatment options based upon encouraging phase 1/2 data in patients with relapsed SCLC who had not received prior immunotherapy (IO). Despite these recent advances, the overall benefit of IO in SCLC remains somewhat disappointing in comparison with the results seen in non-small cell lung cancer (NSCLC). To date, no reliable biomarkers exist to predict responsiveness to IO in SCLC, and the utility of second- or third-line immunotherapy is questionable in patients who have received IO as part of first-line treatment. There has also been minimal success in identifying targetable mutations in SCLC. Novel approaches include combination approaches with IO, including PARP inhibitors and CDK inhibitors. Few ongoing trials, however, have enrolled patients who have received frontline immunotherapy given the only recent change in standard of care. Consequently, the results of current trials evaluating second- and third-line therapies need to be interpreted and translated into clinical practice with caution. The most significant challenge in SCLC remains the identification of molecular targets for which drugs can be developed that can improve survival over the current standard of care.