Predictive Biomarkers for Immune Checkpoint Inhibitors in Advanced Non-Small Cell Lung Cancer: Current Status and Future Directions

Construction of a B cell-related gene pairs signature for predicting prognosis and immunotherapeutic response in non-small cell lung cancer

BACKGROUND

Accumulating evidence indicates that the B cells play important roles in anti-tumor immunity and shaping tumor development. This study aimed to explore the expression profiles of B cell marker genes and construct a B cell-related gene pairs (BRGPs) signature associated with the prognosis and immunotherapeutic efficiency in non-small cell lung cancer (NSCLC) patients.

METHODS

B cell-related marker genes in NSCLC were identified using single-cell RNA sequencing data. TCGA and GEO datasets were utilized to identify the prognostic BRGPs based on a novel algorithm of cyclically single pairing along with a 0-or-1 matrix. BRGPs signature was then constructed using Lasso-Cox regression model. Its prognostic value, associated immunogenomic features, putative molecular mechanism and predictive ability to immunotherapy were investigated in NSCLC patients.

RESULTS

The BRGPs signature was composed of 23 BRGPs including 28 distinct B cell-related genes. This predictive signature demonstrated remarkable power in distinguishing good or poor prognosis and can serve as an independent prognostic factor for NSCLC patients in both training and validation cohorts. Furthermore, BRGPs signature was significantly associated with immune scores, tumor purity, clinicopathological characteristics and various tumor-infiltrating immune cells. Besides, we demonstrated that the tumor mutational burden scores and TIDE scores were positively correlated with the risk score of the model implying immune checkpoint blockade therapy may be more effective in NSCLC patients with high-risk scores.

CONCLUSIONS

This novel BRGPs signature can be used to assess the prognosis of NSCLC patients and may be useful in guiding immune checkpoint inhibitor treatment in our clinical practice.

Prognostic scores including peripheral blood-derived inflammatory indices in patients with advanced non-small-cell lung cancer treated with immune checkpoint inhibitors

Peripheral blood inflammatory indices, like the neutrophil-to-lymphocyte ratio (NLR), may reflect the host's pro-inflammatory status and systemic immune response to cancer-related inflammation. We reviewed 22 combined prognostic scores based on peripheral blood-derived inflammatory indices for aNSCLC patients treated with single-agent or combination immune-checkpoint inhibitors (ICI) as first-line or subsequent therapy lines and attempted evidence strength assessment and scoring. The Lung Immune Prognostic Index (LIPI), consisting of derived NLR and LDH, was the most studied score with validated prognostic value in over five thousand aNSCLC ICI-naïve or pretreated patients. The combination of NLR and tumour programmed-cell-death-ligand1 (PD-L1) expression showed a predictive value. The Lung-Immune-Prognostic score (LIPS) might help identify patients with poor performance status but a favourable outcome following first-line ICI. These non-expensive scores can help clinicians discuss the prognosis with aNSCLC patients approaching ICI, identify those less likely to benefit from single-agent ICI and orient future clinical research.

Managing Resistance to Immune Checkpoint Inhibitors in Lung Cancer: Treatment and Novel Strategies

A proportion of patients with lung cancer experience long-term clinical benefit with immune checkpoint inhibitors (ICIs). However, most patients develop disease progression during treatment or after treatment discontinuation. Definitions of immune resistance are heterogeneous according to different clinical and biologic features. Primary resistance and acquired resistance, related to tumor-intrinsic and tumor-extrinsic mechanisms, are identified according to previous response patterns and timing of occurrence. The clinical resistance patterns determine differential clinical approaches. To date, several combination therapies are under development to delay or prevent the occurrence of resistance to ICIs, including the blockade of immune coinhibitory signals, the activation of those with costimulatory functions, the modulation of the tumor microenvironment, and the targeting T-cell priming. Tailoring the specific treatments with distinctive biologic resistance mechanisms would be ideal to improve the design and results of clinical trial. In this review, we reviewed the available evidence on immune resistance mechanisms, clinical definitions, and management of resistance to ICIs in lung cancer. We also reviewed data on novel strategies under investigation in this setting.

First-Line Treatment of Advanced Non-Small-Cell Lung Cancer with Immune-Checkpoint Inhibitors: New Combinations and Long-Term Data

Treatment of metastatic non-small-cell lung cancers (NSCLCs) has long been based on cytotoxic chemotherapy. Immune checkpoint inhibitors (ICIs), notably monoclonal antibodies directed against programmed cell death protein-1 (PD-1) or its ligand (PD-L1), have transformed therapeutic standards in thoracic oncology. These ICIs are now the reference first-line therapy, and numerous phase III trials have established their efficacy in treatment-naïve patients. First-line pembrolizumab monotherapy was validated for patients with ≥ 50% of tumor cells expressing PD-L1 and, in the USA, for patients with ≥ 1% PD-L1 positivity. More recently, cemiplimab as monotherapy was also validated for patients whose tumors expressed ≥ 50% PD-L1. Several ICIs (pembrolizumab, atezolizumab, nivolumab, and recently durvalumab) in combination with chemotherapy achieved overall survival gains among "all comers", compared with chemotherapy alone. The results were more contrasting for paired immunotherapies combining anti-PD-L1 and anti-cytotoxic T-lymphocyte antigen-4 agents, with the benefit/risk balance not yet fully established. Recently, nivolumab-ipilimumab and two chemotherapy cycles limited patient exposure to chemotherapy and obtained positive results compared with the latter alone. However, those phase III trials included selected patients in good general condition and without active brain metastases. Little is known about immunotherapy and combination immunotherapy-chemotherapy efficacies in never-smokers or patients with tumors harboring an epidermal growth factor receptor (EGFR) mutation or anaplastic lymphoma kinase (ALK) translocation. In this review, we report our analysis of the main results available on first-line ICI use, as monotherapy or combined or in combination with chemotherapy, to treat metastatic NSCLCs in general and also for specific populations: the elderly, never-smokers, patients with brain metastases, and those with an EGFR mutation or ALK translocation.