MA15.02 Long-Term Safety and Clinical Activity Results from a Phase Ib Study of Erlotinib Plus Atezolizumab in Advanced NSCLC

Mechanisms of resistance to tyrosine kinase inhibitor-targeted therapy and overcoming strategies

Tyrosine kinase inhibitor (TKI)-targeted therapy has revolutionized cancer treatment by selectively blocking specific signaling pathways crucial for tumor growth, offering improved outcomes with fewer side effects compared with conventional chemotherapy. However, despite their initial effectiveness, resistance to TKIs remains a significant challenge in clinical practice. Understanding the mechanisms underlying TKI resistance is paramount for improving patient outcomes and developing more effective treatment strategies. In this review, we explored various mechanisms contributing to TKI resistance, including on-target mechanisms and off-target mechanisms, as well as changes in the tumor histology and tumor microenvironment (intrinsic mechanisms). Additionally, we summarized current therapeutic approaches aiming at circumventing TKI resistance, including the development of next-generation TKIs and combination therapies. We also discussed emerging strategies such as the use of dual-targeted antibodies and PROteolysis Targeting Chimeras. Furthermore, we explored future directions in TKI-targeted therapy, including the methods for detecting and monitoring drug resistance during treatment, identification of novel targets, exploration of dual-acting kinase inhibitors, application of nanotechnologies in targeted therapy, and so on. Overall, this review provides a comprehensive overview of the challenges and opportunities in TKI-targeted therapy, aiming to advance our understanding of resistance mechanisms and guide the development of more effective therapeutic approaches in cancer treatment.

Safety and clinical activity of atezolizumab plus erlotinib in patients with non-small-cell lung cancer

BACKGROUND

Acquired resistance limits long-term epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) efficacy in patients with EGFR mutation-positive non-small-cell lung cancer (NSCLC) in whom anti-programmed death-ligand 1 (PD-L1) efficacy is also limited. We hypothesized that combining atezolizumab with erlotinib could enhance antitumor immunity and extend efficacy in these patients.

PATIENTS AND METHODS

This open-label phase Ib trial was conducted in adults aged ≥18 years who had advanced, unresectable NSCLC. Stage 1 (safety evaluation) enrolled EGFR TKI-naive patients regardless of EGFR status. Stage 2 (expansion) enrolled patients with EGFR-mutant NSCLC treated with ≤1 prior non-EGFR TKI therapy. Patients received 150 mg erlotinib orally once daily. After a 7-day erlotinib run-in, atezolizumab 1200 mg was administered intravenously every 3 weeks. The primary endpoint was the safety and tolerability of the combination in all patients; secondary endpoints included antitumor activity per RECIST 1.1 in stage 2 patients.

RESULTS

At the data cut-off on 7 May 2020, 28 patients (8 in stage 1, 20 in stage 2) were assessable for safety. No dose-limiting toxicities or grade 4 or 5 treatment-related adverse events occurred. Grade 3 treatment-related adverse events occurred in 46% of patients; the most common were increased alanine aminotransferase, diarrhea, pyrexia, and rash (each in 7% of patients). Serious adverse events occurred in 50% of patients. Pneumonitis (grade 1) was reported in a single patient (4%). The objective response rate was 75% [95% confidence interval (CI) 50.9% to 91.3%]), median response duration was 18.9 months (95% CI 9.5-40.5 months), median progression-free survival was 15.4 months (95% CI 8.4-39.0 months), and median overall survival was not estimable (NE) (95% CI 34.6-NE).

CONCLUSIONS

Atezolizumab combined with erlotinib demonstrated a tolerable safety profile and encouraging, durable clinical activity in patients with advanced EGFR mutation-positive NSCLC.

At the crossroads of immunotherapy for oncogene-addicted subsets of NSCLC

Non-small-cell lung cancer (NSCLC) has become a paradigm of precision medicine, with the discovery of numerous disease subtypes defined by specific oncogenic driver mutations leading to the development of a range of molecularly targeted therapies. Over the past decade, rapid progress has also been made in the development of immune-checkpoint inhibitors (ICIs), especially antagonistic antibodies targeting the PD-L1-PD-1 axis, for the treatment of NSCLC. Although many of the major oncogenic drivers of NSCLC are associated with intrinsic resistance to ICIs, patients with certain oncogene-driven subtypes of the disease that are highly responsive to specific targeted therapies might also derive benefit from immunotherapy. However, the development of effective immunotherapy approaches for oncogene-addicted NSCLC has been challenged by a lack of predictive biomarkers for patient selection and limited knowledge of how ICIs and oncogene-directed targeted therapies should be combined. Therefore, whether ICIs alone or with chemotherapy or even in combination with molecularly targeted agents would offer comparable benefit in the context of selected oncogenic driver alterations to that observed in the general unselected NSCLC population remains an open question. In this Review, we discuss the effects of oncogenic driver mutations on the efficacy of ICIs and the immune tumour microenvironment as well as the potential vulnerabilities that could be exploited to overcome the challenges of immunotherapy for oncogene-addicted NSCLC.

Treatment Strategies for Non-Small Cell Lung Cancer with Common EGFR Mutations: A Review of the History of EGFR TKIs Approval and Emerging Data

The development of targeted therapies over the past two decades has led to a dramatic change in the management of EGFR-mutant non-small cell lung cancer (NSCLC). While there are currently five approved EGFR tyrosine kinase inhibitors (TKIs) for treating EGFR-mutant NSCLC in the first-line setting, therapy selection after progression on EGFR TKIs remains complex. Multiple groups are investigating novel therapies and drug combinations to determine the optimal therapy and treatment sequence for these patients. In this review, we summarize the landmark trials and history of the approval of EGFR TKIs, their efficacy and tolerability, and the role of these therapies in patients with central nervous system metastasis. We also briefly discuss the mechanisms of resistance to EGFR TKIs, ongoing attempts to overcome resistance and improve outcomes, and finalize by offering treatment sequencing recommendations.

The toxicity associated with combining immune check point inhibitors with tyrosine kinase inhibitors in patients with non-small cell lung cancer

Latest advances in non-small cell lung cancer (NSCLC) therapies have revolutionized the treatment regimens utilized for NSCLCs with or without a driver mutation. Molecular targeted treatments such as tyrosine kinase inhibitors (TKIs) are utilized to prevent tumor progression and improve survival. Despite the great benefit of immunotherapy in NSCLC tumors with no driver mutation, the use of immune checkpoint inhibitors (ICIs) in NSCLC tumors harboring a driver mutation has been under debate. Furthermore, several trials have been conducted investigating the use of these therapies with TKIs. A few trials were halted due to growing concerns of increased toxicity with the combination of TKI and immunotherapy. The adverse events ranged from low grade dermatologic complaints to fatal interstitial lung diseases. These toxicities occur with both concurrent and sequential administration of treatment. Thus, recommendations for the safest method of combination treatment have not yet been described. This review paper discusses recent views on combination treatment, previous clinical trials reporting grade 3-4 toxicities, and guidelines for a safe timeline of administration of treatment based on past evidence.

Crosstalk between the B7/CD28 and EGFR pathways: Mechanisms and therapeutic opportunities

Somatic activating mutations in the epidermal growth factor receptor (EGFR) are one of the most common oncogenic drivers in cancers such as non-small-cell lung cancer (NSCLC), metastatic colorectal cancer, glioblastoma, head and neck cancer, pancreatic cancer, and breast cancer. Molecular-targeted agents against EGFR signaling pathways have shown robust clinical efficacy, but patients inevitably experience acquired resistance. Although immune checkpoint inhibitors (ICIs) targeting PD-1/PD-L1 have exhibited durable anti-tumor responses in a subset of patients across multiple cancer types, their efficacy is limited in cancers harboring activating gene alterations of EGFR. Increasing studies have demonstrated that upregulation of new B7/CD28 family members such as B7-H3, B7x and HHLA2, is associated with EGFR signaling and may contribute to resistance to EGFR-targeted therapies by creating an immunosuppressive tumor microenvironment (TME). In this review, we discuss the regulatory effect of EGFR signaling on the PD-1/PD-L1 pathway and new B7/CD28 family member pathways. Understanding these interactions may inform combination therapeutic strategies and potentially overcome the current challenge of resistance to EGFR-targeted therapies. We also summarize clinical data of anti-PD-1/PD-L1 therapies in EGFR-mutated cancers, as well as ongoing clinical trials of combination of EGFR-targeted therapies and anti-PD-1/PD-L1 immunotherapies.

Third-generation EGFR and ALK inhibitors: mechanisms of resistance and management

The discoveries of EGFR mutations and ALK rearrangements as actionable oncogenic drivers in non-small-cell lung cancer (NSCLC) has propelled a biomarker-directed treatment paradigm for patients with advanced-stage disease. Numerous EGFR and ALK tyrosine kinase inhibitors (TKIs) with demonstrated efficacy in patients with EGFR-mutant and ALK-rearranged NSCLCs have been developed, culminating in the availability of the highly effective third-generation TKIs osimertinib and lorlatinib, respectively. Despite their marked efficacy, resistance to these agents remains an unsolved fundamental challenge. Both 'on-target' mechanisms (largely mediated by acquired resistance mutations in the kinase domains of EGFR or ALK) and 'off-target' mechanisms of resistance (mediated by non-target kinase alterations such as bypass signalling activation or phenotypic transformation) have been identified in patients with disease progression on osimertinib or lorlatinib. A growing understanding of the biology and spectrum of these mechanisms of resistance has already begun to inform the development of more effective therapeutic strategies. In this Review, we discuss the development of third-generation EGFR and ALK inhibitors, predominant mechanisms of resistance, and approaches to tackling resistance in the clinic, ranging from novel fourth-generation TKIs to combination regimens and other investigational therapies.

Immunotherapy for EGFR-mutant advanced non-small-cell lung cancer: Current status, possible mechanisms and application prospects

Immune checkpoint inhibitors (ICIs) are effective against advanced and even perioperative non-small-cell lung cancer (NSCLC) and result in durable clinical benefit, regardless of programmed death ligand-1 (PD-L1) expression status in cancer. Existing clinical evidence shows that the effect of immunotherapy in patients with EGFR-mutant NSCLC after the development of tyrosine kinase inhibitor (TKI) resistance is not satisfactory. However, compared with monotherapy, ICIs combined with chemotherapy can improve the efficacy. Encouragingly, compared with that of patients with sensitive mutations, the progression-free survival of patients with rare mutations who were treated with ICIs was increased. Adequately maximizing the efficacy of ICIs in EGFR-mutant NSCLC patients is worth exploring. In this review, we described preclinical and clinical studies of ICIs or combined therapy for EGFR-mutant NSCLC. We further focused on EGFR mutations and the cancer immune response, with particular attention given to the role of EGFR activation in the cancer-immunity cycle. The mechanisms for the natural resistance to ICIs were explored to identify corresponding countermeasures that made more EGFR-mutant NSCLC patients benefit from ICIs.

Efficacy and safety of immune checkpoint inhibitors in post-TKI NSCLC patients harboring EGFR mutations

OBJECTIVE

Immune checkpoint inhibitors (ICIs) have been validated in epidermal growth factor receptor (EGFR) wild-type advanced non-small cell lung cancer (NSCLC) patients. However, there exists no evidence regarding NSCLC patients harboring EGFR mutations, experiencing EGFR-TKI (tyrosine kinase inhibitor) treatment failure. We collected clinical information from real world and conducted a time series-based meta-analysis to determine the efficacy and safety of ICIs in patients harboring EGFR mutations and experienced EGFR-TKIs resistance.

METHODS

Twenty-two NSCLC patients with EGFR mutations after TKI resistance were included from two hospitals. PubMed, Embase and Cochrane Library were searched for relevant literature published until December 31, 2021. Endpoint outcomes included mortality and progression-free survival (PFS) at different times of follow-up.

RESULTS

In total, 22 patients showed that the median PFS was 5.6 months (range 2.0-9.0 months). According to treatment strategies, the median PFS was 2.4 months (range 2.0-5.3 months) in the ICI monotherapy group and 5.9 months (range 2.8-9.0 months) in the ICI combined Chemotherapy group. Additionally, sixteen studies, including 5 trials, 10 controlled cohorts and 1 real-world study, were assessed, involving a total of ICI-treated NSCLC patients with EGFR mutation after TKI failure. The 6-month survival and PFS rate were 0.82 (95% CI 0.36-0.97) and 0.55 (95% CI 0.34-0.74), respectively. ICI combined chemotherapy showed the best survival outcome among these groups, as demonstrated by the 12-month survival rate and PFS. No new safety signals were identified with the combination therapy. The frequency of treatment-related adverse events was similar to that in previously reported studies of chemotherapy combined with checkpoint inhibitors.

CONCLUSIONS

The addition of ICIs plus chemotherapy may significantly improve progression-free survival among patients with locally advanced or metastatic non-squamous NSCLC who EGFR-TKIs resistance.

Durvalumab as Consolidation Therapy in Post-Multimodal Interventional Treatment for Patients with Advanced Solid Tumors: A Preliminary Study

With 2.1 million unique cases of lung tumors and 1.8 million mortalities in China, advanced solid tumors continue to be the primary source of cancer mortality rates. Nearly two-thirds of lung cancer individuals display advanced-stage tumors at the time of testing, with a 5-year survival ratio of 7%. People with advanced solid tumors have an appalling outcome, with a 5-year total survival ratio of roughly 15%. Immunotherapy inhibitors, like those for programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1), have ushered in a novel period in cancer diagnosis and therapy. Three resistant medications were authorized for advanced solid tumors: nivolumab, pembrolizumab, and atezolizumab. Durvalumab, an anti-PD-L1 antigen, is currently being researched. Durvalumab's pharmacologic characteristics, clinical efficacy, and security as consolidation therapy in post-multimodal interventional therapies for people with advanced solid tumors are discussed in this paper. We have also shared details of two patients who were identified with advanced solid tumors and were provided with durvalumab medication. The performance measures like Progression-Free Survival (PFS), Overall Survival (OS), and Overall Response Rate (ORR) are also contrasted for different antibodies. The research findings imply that durvalumab consolidation therapy is a cost-efficient therapy, while health policymakers should address the financial consequences.

Immunological effect of tyrosine kinase inhibitors on the tumor immune environment in non‑small cell lung cancer (Review)

Acquired resistance to tyrosine kinase inhibitors (TKIs) limits the duration of antitumor effects and impairs the survival of patients with oncogene-driven non-small cell lung cancer (NSCLC). At present, little is known about the immunomodulatory ability of TKIs during the entire treatment period, including the drug-sensitive and drug-resistant periods. The present review aimed to comprehensively explore the dynamic changes in the tumor microenvironment (TME) during TKI treatment in NSCLC. Previous clinical and preclinical studies from medical and health databases related to NSCLC are reviewed. During the response period, cytotoxic immune cells accumulate in the TME and contribute to the formation of an inflammatory microenvironment. During the resistance period, the number of immunosuppressive cells increases, as does the expression of immune checkpoint proteins, which are critical mechanisms for tumor progression. The combination of targeted therapy and immunotherapy has been explored in multiple studies, and preliminary data showed controversial results. Extensive studies are needed to confirm the criteria of the selected patient subgroups and the toxicity profiles of EGFR TKIs and immune checkpoint inhibitors (ICIs). At present, the reagents targeting other immune cells, cytokines and related pathways remain underexplored compared with the revolutionary effect of ICIs in lung cancer. In the future, the precisely selected regimens for combination treatment should be further investigated in carefully designed xenograft models and clinical trials.

Case Report: Opportunities and Challenges of Immunotherapy in Heavily-Treated EGFR-Mutant Advanced Squamous Cell Lung Carcinoma After Progression on EGFR-TKIs and Chemotherapy

Background

Epidermal growth factor receptor (EGFR) mutations have a low incidence in squamous cell lung cancer (SqCLC), and the clinical efficacy of EGFR tyrosine kinase inhibitors (TKIs) in EGFR-mutated SqCLC is far less than that in EGFR-mutated lung adenocarcinoma. The treatment strategy for patients with EGFR-mutated non-small cell lung cancer who are refractory to EGFR TKIs has become a current dilemma and challenge.

Case Presentation

A case of a 69-year-old male patient suffering from intermittent cough and hemoptysis was diagnosed with EGFR-mutated advanced SqCLC (stage cT2bN2M1). The patient was treated with camrelizumab alone after five courses of different systemic therapies and achieved a partial response, with an eminent progression-free survival of more than 24 months. Grade 1 to 2 reactive cutaneous capillary endothelial proliferation and mild pruritus were observed during the treatment. No other immune-related adverse events were observed.

Conclusion

Monotherapy of immune-checkpoint inhibitors may be considered as a later-line option for EGFR-mutated advanced SqCLC patients with PD-L1 expression.

Risk factors for immune-related adverse events: what have we learned and what lies ahead?

Immune checkpoint inhibitors (ICIs) have heralded the advent of a new era in oncology by holding the promise of prolonged survival in severe and otherwise treatment-refractory advanced cancers. However, the remarkable antitumor efficacy of these agents is overshadowed by their potential for inducing autoimmune toxic effects, collectively termed immune-related adverse events (irAEs). These autoimmune adverse effects are often difficult to predict, possibly permanent, and occasionally fatal. Hence, the identification of risk factors for irAEs is urgently needed to allow for prompt therapeutic intervention. This review discusses the potential mechanisms through which irAEs arise and summarizes the existing evidence regarding risk factors associated with the occurrence of irAEs. In particular, we examined available data regarding the effect of a series of clinicopathological and demographic factors on the risk of irAEs.

Immunotherapy in Treating EGFR-Mutant Lung Cancer: Current Challenges and New Strategies

Lung cancer is the leading cause of cancer-related deaths worldwide. Immune checkpoint inhibitors, including monoclonal antibodies against programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1), have dramatically improved the survival and quality of life of a subset of non-small cell lung cancer (NSCLC) patients. Multiple predictive biomarkers have been proposed to select the patients who may benefit from the immune checkpoint inhibitors. EGFR-mutant NSCLC is the most prevalent molecular subtype in Asian lung cancer patients. However, patients with EGFR-mutant NSCLC show poor response to anti-PD-1/PD-L1 treatment. While small-molecule EGFR tyrosine kinase inhibitors (TKIs) are the preferred initial treatment for EGFR-mutant NSCLC, acquired drug resistance is severely limiting the long-term efficacy. However, there is currently no further effective treatment option for TKIs-refractory EGFR-mutant NSCLC patients. The reasons mediating the poor response of EGFR-mutated NSCLC patients to immunotherapy are not clear. Initial investigations revealed that EGFR-mutated NSCLC has lower PD-L1 expression and a low tumor mutational burden, thus leading to weak immunogenicity. Moreover, the use of PD-1/PD-L1 blockade prior to or concurrent with osimertinib has been reported to increase the risk of pulmonary toxicity. Furthermore, emerging evidence shows that PD-1/PD-L1 blockade in NSCLC patients can lead to hyperprogressive disease associated with dismal prognosis. However, it is difficult to predict the treatment toxicity. New biomarkers are urgently needed to predict response and toxicity associated with the use of PD-1/PD-L1 immunotherapy in EGFR-mutated NSCLC. Recently, promising data have emerged to suggest the potentiation of PD-1/PD-L1 blockade therapy by anti-angiogenic agents and a few other novel therapeutic agents. This article reviews the current investigations about the poor response of EGFR-mutated NSCLC to anti-PD-1/PD-L1 therapy, and discusses the new strategies that may be adopted in the future.

Checkpoint Blockade in Lung Cancer With Driver Mutation: Choose the Road Wisely

Immune checkpoint blockade with PD-(L)1 antibodies has revolutionized the treatment of advanced non-small cell lung cancer (NSCLC). Similarly, the identification and targeting of oncogene drivers in metastatic NSCLC has dramatically improved patient outcomes with an expanding list of potentially actionable alterations and targeted therapies. Many of these molecular aberrations are more common in patients with little or no smoking history and adenocarcinoma histology. Certain molecular subsets of NSCLC, though gaining greatly from targeted therapy approaches, may derive less benefit from immune checkpoint blockade. The optimal identification, targeting, and sequencing of targeted therapies, immunotherapy, and chemotherapy are essential to continue to improve patient outcomes in advanced NSCLC. Herein, we review the role of immunotherapy in locally advanced and metastatic disease for patients with actionable driver alterations. Never-smoking patients have a high probability of having lung cancer that harbors one of these molecular aberrations that can be matched to a tyrosine kinase inhibitor with greatly improved clinical outcomes. Some of these patients with driver mutations may derive less benefit from immune checkpoint inhibitor approaches (either alone or combined with chemotherapy), especially compared with smoking-associated NSCLC. Given that PD-1 blockade alone or with platinum-based chemotherapy is the de facto first-line therapy (depending on level of PD-L1 expression) for nontargetable metastatic NSCLC, we also review treatment in never-smoking patients for whom molecular testing results are pending and the likelihood of identifying a driver mutation is high.

Immune checkpoint inhibitors in driver mutation-positive nonsmall cell lung cancer: is there a role?

PURPOSE OF REVIEW

Despite advances in immunotherapy for nonsmall cell lung cancer patients, the clinical efficacy of drugs for patients with oncogenic driver mutations remains limited. This article aimed to comprehensively review the currently available data on the efficacy and safety of immune checkpoint blockade (ICB) for patients with driver mutation-positive lung cancer.

RECENT FINDINGS

Despite the positive interaction between activation of oncogenic pathways and upregulated PD-L1 expression demonstrated in preclinical studies, the efficacy of single-agent ICB in patients with oncogenic mutation has largely been discouraging, except for those with KRAS mutations. The combination therapies using ICB with tyrosine kinase inhibitors (TKIs) for EGFR/ALK alteration raised a concern for the high incidence of treatment-related adverse events, notably hepatotoxicity and interstitial lung disease. A novel combination with bevacizumab demonstrated promising efficacy with tolerable safety profiles.

SUMMARY

Other than patients with the KRAS mutation who demonstrate relatively favorable response to ICB, a single-agent ICB therapy should be considered for those who retain good performance status but have no other therapeutic options available. Further studies on the combination of ICB and TKI are needed to identify the most viable pair regarding safety. Additional studies using novel combination partners, such as anti-VEGF inhibitors, are also warranted.

Optimal Management of Patients with Advanced NSCLC Harboring High PD-L1 Expression and Driver Mutations

OPINION STATEMENT

Patients with stage IV or recurrent/metastatic non-small cell lung cancer (NSCLC) whose tumors harbor high PD-L1 expression and driver mutations with approved targeted treatments (EGFR, ALK, BRAF^V600E, ROS1) should receive initial therapy with targeted therapy based on impressive clinical activity. PD-(L)1 inhibitors have demonstrated minimal activity in many driver mutation subsets including EGFR and ALK and appears to have more benefit in smoking-associated oncogenic drivers (KRAS, BRAF). For KRAS-driven tumors, co-mutations such as STK11/LKB1 are negative predictive markers of immunotherapy with or without chemotherapy. Therefore, driver mutations need to be evaluated before pursuing immunotherapy independent of PD-L1 expression level. Caution should be used with TKIs following or concurrent with immunotherapy owing to potentially increased toxicity. New immunotherapy combinations are needed especially for oncogene-driven tumors associated with never or light smoking history.

Tumour Microenvironment and Immune Evasion in EGFR Addicted NSCLC: Hurdles and Possibilities

In the last few years, the treatment strategy in Non-Small Cell Lung Cancer (NSCLC) patients has been heavily modified by the introduction of the immune-checkpoint inhibitors. Anti-programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) therapy has improved both progression-free and the overall survival in almost all subgroups of patients, with or without PDL1 expression, with different degrees of responses. However, there are patients that are not benefitting from this treatment. A defined group of immune-checkpoint inhibitors non-responder tumours carry EGFR (epidermal growth factor receptor) mutations: nowadays, anti-PD-1/PD-L1 clinical trials often do not involve this type of patient and the use of immune-checkpoint inhibitors are under evaluation in this setting. Our review aims to elucidate the mechanisms underlying this resistance: we focused on evaluating the role of the tumour microenvironment, including infiltrating cells, cytokines, secreted factors, and angiogenesis, and its interaction with the tumour tissue. Finally, we analysed the possible role of immunotherapy in EGFR mutated tumours.

Immune checkpoint inhibitors of PD-L1 as cancer therapeutics

Since the discovery of immune checkpoint proteins, there has been a special interest in developing antibodies that block programmed cell death 1 receptor (PD-1) and programmed cell death receptor ligand 1 (PD-L1) for a subset of cancer patients. PD-1 signaling negatively regulates T cell-mediated immune responses and serves as a mechanism for tumors to evade an antigen-specific T cell immunologic response. It plays a role in promoting cancer development and progression by enhancing tumor cell survival. With this background, PD-1 signaling represents a valuable therapeutic target for novel and effective cancer immunotherapy. Clinical data shows that blockade of this PD-1 signaling significantly enhance antitumor immunity, produce durable clinical responses, and prolong survival. Currently, there are three FDA-approved PD-L1 inhibitors for various malignancies ranging from non-small cell lung cancer to Merkel cell carcinoma. This review is to summarize many ongoing phase II/III trials of atezolizumab, durvalumab, avelumab, and new PD-L1 inhibitors in clinical developments. In particular, we focus on key trials that paved the pathway to FDA-approved indications for atezolizumab, durvalumab, and avelumab. Despite the popularity and accelerated FDA approval of PD-L1 inhibitors, further considerations into predictive biomarkers, mechanisms of resistance, treatment duration, immune-related toxicities, and PD-L1 expression threshold are needed to optimize anticancer potential in this class of immunotherapy.

Advanced-Stage Non-Small Cell Lung Cancer: Advances in Thoracic Oncology 2018

In 2018 research in the field of advanced NSCLCs led to an expanded reach and impact of immune checkpoint inhibitors (ICIs) as part of a frontline treatment strategy, regardless of histologic subtype, with ICI use extended to include stage III disease, shifting the prognosis of all these patients. This new standard first-line approach opens a gap in standard second-line treatment, and older combinations may again become standard of care after progression during treatment with an ICI. The characterization of predictive biomarkers, patient selection, the definition of strategies with ICI combinations upon progression during treatment with ICIs, as well as prospective evaluation of the efficacy of ICIs in subpopulations (such as patients with poor performance status or brain metastases) represent upcoming challenges in advanced thoracic malignancies. In oncogene-addicted NSCLC three major steps were taken during 2018: next-generation tyrosine kinase inhibitors have overtaken more established agents as the new standard of care in EGFR and ALK receptor tyrosine kinase gene (ALK)-positive tumors. Mechanisms of acquired resistance have been reported among patients treated with next-generation EGFR tyrosine kinase inhibitors, reflecting the diversity of the landscape. One major step forward was the approval of personalized treatment in very uncommon genomic alterations, mainly fusions. This raises a new question about the challenge of implementation of next-generation sequencing in daily clinical practice to detect new and uncommon genomic alterations and to capture the heterogeneity of the mechanisms of acquired resistance during treatment, as well as the need to extend research into new therapeutic strategies to overcome them.