First-Line Nivolumab Plus Ipilimumab in Advanced Non-Small-Cell Lung Cancer (CheckMate 568): Outcomes by Programmed Death Ligand 1 and Tumor Mutational Burden as Biomarkers

Tumor mutational burden quantification from targeted gene panels: major advancements and challenges

Tumor mutational burden (TMB), the total number of somatic coding mutations in a tumor, is emerging as a promising biomarker for immunotherapy response in cancer patients. TMB can be quantitated by a number of NGS-based sequencing technologies. Whole Exome Sequencing (WES) allows comprehensive measurement of TMB and is considered the gold standard. However, to date WES remains confined to research settings, due to high cost of the large genomic space sequenced. In the clinical setting, instead, targeted enrichment panels (gene panels) of various genomic sizes are emerging as the routine technology for TMB assessment. This stimulated the development of various methods for panel-based TMB quantification, and prompted the multiplication of studies assessing whether TMB can be confidently estimated from the smaller genomic space sampled by gene panels. In this review, we inventory the collection of available gene panels tested for this purpose, illustrating their technical specifications and describing their accuracy and clinical value in TMB assessment. Moreover, we highlight how various experimental, platform-related or methodological variables, as well as bioinformatic pipelines, influence panel-based TMB quantification. The lack of harmonization in panel-based TMB quantification, of adequate methods to convert TMB estimates across different panels and of robust predictive cutoffs, currently represents one of the main limitations to adopt TMB as a biomarker in clinical practice. This overview on the heterogeneous landscape of panel-based TMB quantification aims at providing a context to discuss common standards and illustrates the strong need of further validation and consolidation studies for the clinical interpretation of panel-based TMB values.

Recent Advances in Lung Cancer Immunotherapy: Input of T-Cell Epitopes Associated With Impaired Peptide Processing

Recent advances in lung cancer treatment are emerging from new immunotherapies that target T-cell inhibitory receptors, such as programmed cell death-1 (PD-1). However, responses to anti-PD-1 antibodies as single agents are observed in fewer than 20% of non-small-cell lung cancer (NSCLC) patients, and immune mechanisms involved in the response to these therapeutic interventions remain poorly elucidated. Accumulating evidence indicates that effective anti-tumor immunity is associated with the presence of T cells directed toward cancer neoepitopes, a class of major histocompatibility complex (MHC)-bound peptides that arise from tumor-specific mutations. Nevertheless, tumors frequently use multiple pathways to escape T-cell recognition and destruction. In this regard, primary and acquired resistance to immune checkpoint blockade (ICB) therapy was associated with alterations in genes relevant to antigen presentation by MHC-class I/beta-2-microglobulin (MHC-I/β2m) complexes to CD8 T lymphocytes. Among additional known mechanisms involved in tumor resistance to CD8 T-cell immunity, alterations in transporter associated with antigen processing (TAP) play a major role by inducing a sharp decrease in surface expression of MHC-I/β2m-peptide complexes, enabling malignant cells to evade cytotoxic T lymphocyte (CTL)-mediated killing. Therefore, development of novel immunotherapies based on tumor neoantigens, that are selectively presented by cancer cells carrying defects in antigen processing and presentation, and that are capable of inducing destruction of such transformed cells, is a major challenge in translational research for application in treatment of lung cancer. In this context, we previously identified a non-mutant tumor neoepitope, ppCT₁₆₋₂₅, derived from the preprocalcitonin (ppCT) leader sequence and processed independently of proteasomes/TAP by a mechanism involving signal peptidase (SP) and signal peptide peptidase (SPP). We also provided in vitro and in vivo proof of the concept of active immunotherapy based on ppCT-derived peptides capable of controlling growth of immune-escaped tumors expressing low levels of MHC-I molecules. Thus, non-mutant and mutant neoepitopes are promising T-cell targets for therapeutic cancer vaccines in combination with ICB. In this review, we summarize current treatments for lung cancer and discuss the promises that conserved neoantigens offer for more effective immunotherapies targeting immune-escaped tumor variants.

First-line immune checkpoint inhibitors for advanced non-small cell lung cancer with wild-type epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK): a systematic review and network meta-analysis

Background

To assess the comparative efficacy and safety of first-line immune checkpoint inhibitors (ICIs) for advanced non-small cell lung cancer (NSCLC) with wild-type epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK).

Methods

PubMed, Embase, Cochrane Library, Web of Science, and major international scientific meetings were searched for relevant randomized controlled trials. Overall survival (OS) and progression-free survival (PFS) were the primary outcomes and serious adverse events (SAEs) were the secondary outcome of interests and were reported as hazard ratio (HR) or odds ratio (OR) with 95% confidence intervals (CIs).

Results

Fourteen trials with 9,570 patients randomized to receive ten ICI-based treatments (including PD-1/PD-L1 and CTLA-4 antibodies and PD-1/PD-L1 with CTLA-4 combination therapies) were included in the meta-analysis. Pembrolizumab combined with chemotherapy (Pem + CT) (HR =0.56, 95% CI: 0.42-0.74) and Pem (HR =0.75, 95% CI: 0.62-0.91) were more effective than CT in terms of OS; Pem + CT was also superior to Pem (HR =0.74, 95% CI: 0.56-0.98), atezolizumab + CT (HR =0.65, 95% CI: 0.50-0.85), ipilimumab + CT (HR =0.65, 95% CI: 0.47-0.89), and nivolumab (HR =0.52, 95% CI: 0.31-0.87). In subgroup analyses, Pem + CT was more effective than CT regardless of PD-L1 expression, while Pem was superior to CT only for PD-L1 with expression ≥50%; Pem + CT showed significant OS advantage over other treatments in patients with non-squamous cell carcinoma (NSCC); ICIs had a comparable efficacy in younger vs. older patients. Based on treatment ranking in terms of OS, Pem + CT had the highest probability (98%) of being the most effective treatment, followed by Pem (70%), with acceptable toxicity limit.

Conclusions

Pem + CT seemed to be more effective first-line regimen for advanced NSCLC with wild-type EGFR or ALK, especially for patients with NSCC. However, limitations of the study including methodological quality and immature OS data need to be considered.

First-line immune checkpoint blockade for advanced non-small-cell lung cancer: Travelling at the speed of light

The development of PD-1, PD-L1 and CTLA-4 immune checkpoint inhibitors (CPI) has revolutionised the treatment of advanced non-small cell lung cancer (NSCLC). The potential of immunotherapy (IO) to induce durable responses for a subset of patients represents a therapeutic milestone. After the approval of front-line single agent pembrolizumab, IO-based combinations are rapidly entering clinical practice resulting in a fast change of treatment algorithms for advanced NSCLC. We hereby summarize the recent first-line phase 3 trials evaluating PD-(L)1 blockade plus chemotherapy (ChT) and PD-1 plus CTLA-4 CPI for advanced NSCLC and provide potential treatment recommendations.

Combination of CTLA-4 and PD-1 blockers for treatment of cancer

Targeting checkpoints of immune cell activation has been demonstrated to be the most effective approach for activation of anti-tumor immune responses. Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1), both inhibitory checkpoints commonly seen on activated T-cells have been found to be the most reliable targets for the treatment of cancer. Six drugs targeting PD-1 or its ligand PD-L1 and one drug targeting CTLA-4 have been approved for treatment of different types of cancers and several others are in advanced stages of development. The drugs when administered as monotherapy had dramatic increase in durable response rates and had manageable safety profile, but more than 50% of patients failed to respond to treatment. Combination of CTLA-4 and PD-1 blockers was then evaluated to increase the response rates in patients, and ipilimumab (anti-CTLA-4) plus nivolumab (anti-PD-1) combination was shown to significantly enhance efficacy in metastatic melanoma patients. Subsequently, ipilimumab plus nivolumab was approved for treatment of metastatic melanoma, advanced renal cell carcinoma and metastatic colorectal cancer with MMR/MSI-H aberrations. The success of combination encouraged multiple clinical studies in other cancer types. Efficacy of the combination has been shown in a number of published studies and is under evaluation in multiple ongoing studies. This review aims to support future research in combination immunotherapy by discussing the basic details of CTLA-4 and PD-1 pathways and the results from clinical studies that evaluated combination of CTLA-4 and PD-1/PD-L1 blockers.

Combination pembrolizumab plus chemotherapy: a new standard of care for patients with advanced non-small-cell lung cancer

Until recently, the treatment of patients with advanced non-small-cell lung cancer (NSCLC) whose tumors did not have a targetable genetic alteration was cytotoxic chemotherapy alone. This treatment provided only modest survival benefit. The introduction of immune checkpoint inhibitors targeting programmed cell death 1 protein (PD-1) signaling pathway in the treatment of patients with NSCLC has had significant effect on patient survival. Atezolizumab, nivolumab and pembrolizumab have been shown to be superior to chemotherapy in patients with recurrent NSCLC. Recently, pembrolizumab has been combined with chemotherapy in the front-line setting and has demonstrated an improvement in overall survival in NSCLC patients as compared to chemotherapy alone. In this review we will focus on the clinical trials that led to approval of combination pembrolizumab and chemotherapy as first-line treatment for patients with advanced NSCLC as well as discuss other combinations of immunotherapy and chemotherapy that have also been evaluated.

Nivolumab plus ipilimumab combination therapy for the first-line treatment NSCLC: evidence to date

Immune checkpoint inhibitors (ICI) as monotherapy in selected patients as well as in combination with chemotherapy have become the standard of care in the first-line treatment strategy of advanced non-small cell lung cancer (NSCLC) patients. Combination treatment with ICI, such as nivolumab and ipilimumab or durvaluamb and ipilimumab, has also been proposed as potential strategies in this setting in selected advanced NSCLC patients. Characterizing predictive markers of long-term clinical benefit with ICI is a critical objective. Tumor mutational burden has been proposed as a potential predictive biomarker. In this review, we discuss the efficacy of nivolumab and ipilimumab in advanced NSCLC patients as well as the clinical utility of tumor mutational burden in the efficacy of this combination. Ongoing clinical trials with nivolumab and ipilimumab, and the efficacy of this combination in subgroups of NSCLC patients, such as elderly patients and patients with brain metastases, are also discussed.

Nivolumab plus ipilimumab in non-small-cell lung cancer

Nivolumab and ipilimumab, two therapeutic immune checkpoint inhibitor antibodies that block PD-1 and CTLA-4, respectively, have indications in cancer as single agents and in combination. In this Review, we examine the potential role of dual immune checkpoint inhibition with nivolumab plus ipilimumab in the management of patients with previously untreated advanced non-small-cell lung cancer, based on results from the Phase III CheckMate 227 study. Immunotherapies with indications in the first-line treatment of non-small-cell lung cancer include pembrolizumab alone and combined with chemotherapy, and atezolizumab combined with bevacizumab and chemotherapy. CheckMate 227 is the first Phase III study evaluating first-line chemotherapy-sparing combination immunotherapy and including tumor mutational burden as a biomarker for patient selection.

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.