Immune suppressive microenvironment in brain metastatic non-small cell lung cancer: comprehensive immune microenvironment profiling of brain metastases versus paired primary lung tumors (GASTO 1060)

Immunotherapy for metastatic non-small cell lung cancer: Is it really a no-brainer?

There is still much progress to be made in understanding the underlying mechanisms of brain metastasis development and its optimal therapy in non–small cell lung cancer (NSCLC); it is very important to expand research in this area because brain metastasis strongly affects patients' quality of life and overall survival. This editorial reviews the available data in the context of a recent meta‐analysis of the pivotal IMpower130, IMpower131, and IMpower150 studies, which explores metastatic epidermal growth factor receptor and anaplastic lymphoma kinase wild‐type NSCLC to determine potential preventative factors and risk factors for the development of brain metastasis, specifically the question of whether immunotherapy (the anti–programmed death ligand 1 antibody, atezolizumab in particular) plays a role in preventing brain metastasis.

PD-(L)1 inhibitors plus bevacizumab and chemotherapy as first-line therapy in PD-L1-negative metastatic lung adenocarcinoma: a real-world data

BACKGROUND

Chemotherapy combined with immune checkpoint inhibitors (IC), bevacizumab (BC), or both (IBC) is the preferred first-line therapy for PD-L1-negative and oncogenic-driver wild-type metastatic lung adenocarcinoma. However, the optimal strategy is still undetermined.

METHODS

This retrospective study enrolled PD-L1-negative metastatic lung adenocarcinoma patients from four cancer centers between January 1, 2018 and June 30, 2022. All the patients received IC, BC, or IBC as the first-line therapies. The efficacy and safety were evaluated.

RESULTS

A total of 205 patients were included, with 60, 83, and 62 patients in IC, BC, and IBC groups, respectively. The baseline characteristics among three groups were well balanced. Patients treated with IBC had the highest objective response rate (ORR) (43.5%) and disease control rate (DCR) (100%) relative to those treated with IC (40.4%, 84.2%) or BC (40.5%, 96.2%) (ORR: P = 0.919, DCR: P < 0.01). Compared with the IC (6.74 m) or BC (8.28 m), IBC treatment significantly improved median progression-free survival (mPFS) (9.53 m, P = 0.005). However, no difference in overall survival (OS) was observed. When stratified by different clinical and molecular information, we found that male gender, ever smoking, wild-type genes mutations, and adrenal metastasis predict superior PFS benefit when treated with IBC. In patients with liver metastasis, IBC or BC treatment displayed better PFS compared with IC. No additional adverse reactions were observed in IBC group compared with other two groups.

CONCLUSION

Combined IBC treatment achieved superior DCR and PFS compared with IC or BC in patients with PD-L1-negative metastatic lung adenocarcinoma, while did not increase the adverse events.

Spatial and temporal heterogeneity of tumor immune microenvironment between primary tumor and brain metastases in NSCLC

BACKGROUND

Brain metastasis is a common outcome in non-small cell lung cancer, and despite aggressive treatment, its clinical outcome is still frustrating. In recent years, immunotherapy has been developing rapidly, however, its therapeutic outcomes for primary lung cancer and brain metastases are not the same, suggesting that there may be differences in the immune microenvironment of primary lung cancer and brain metastases, however, we currently know little about these differences.

METHODS

Seventeen paired samples of NSCLC and their brain metastases and 45 other unpaired brain metastases samples were collected for the current study. Immunohistochemical staining was performed on all samples for the following markers: immune checkpoints CTLA-4, PD-1, PD-L1, B7-H3, B7-H4, IDO1, and EphA2; tumor-infiltrating lymphocytes (TILs) CD3, CD4, CD8, and CD20; tumor-associated microglia/macrophages (TAMs) CD68 and CD163; and tumor proliferation index Ki-67. The differences in expression of these markers were compared in 17 paired samples, and the effect of the expression level of these markers on the prognosis of patients was analyzed in lung adenocarcinoma brain metastases samples. Subsequently, multiplex immunofluorescence staining was performed in a typical lung-brain paired sample based on the aforementioned results. The multiplex immunofluorescence staining results revealed the difference in tumor immune microenvironment between primary NSCLC and brain metastases.

RESULTS

In 17 paired lesions, the infiltration of CTLA-4+ (P = 0.461), PD-1+ (P = 0.106), CD3+ (P = 0.045), CD4+ (P = 0.037), CD8+ (P = 0.008), and CD20+ (P = 0.029) TILs in brain metastases were significantly decreased compared with primary tumors. No statistically significant difference was observed in the CD68 (P = 0.954) and CD163 (P = 0.654) TAM infiltration between primary NSCLC and paired brain metastases. In all the brain metastases lesions, the expression of PD-L1 is related to the time interval of brain metastases in NSCLC. In addition, the Cox proportional hazards regression models showed high expression of B7-H4 (hazard ratio [HR] = 3.276, 95% confidence interval [CI] 1.335-8.041, P = 0.010) and CD68 TAM infiltration (HR = 3.775, 95% CI 1.419-10.044, P = 0.008) were independent prognosis factors for lung adenocarcinoma brain metastases patients.

CONCLUSIONS

Both temporal and spatial heterogeneity is present between the primary tumor and brain metastases of NCSLC. Brain metastases lesions exhibit a more immunosuppressive tumor immune microenvironment. B7-H4 and CD68+ TAMs may have potential therapeutic value for lung adenocarcinoma brain metastases patients.

Harnessing immunotherapy for brain metastases: insights into tumor-brain microenvironment interactions and emerging treatment modalities

Brain metastases signify a deleterious milestone in the progression of several advanced cancers, predominantly originating from lung, breast and melanoma malignancies, with a median survival timeframe nearing six months. Existing therapeutic regimens yield suboptimal outcomes; however, burgeoning insights into the tumor microenvironment, particularly the immunosuppressive milieu engendered by tumor-brain interplay, posit immunotherapy as a promising avenue for ameliorating brain metastases. In this review, we meticulously delineate the research advancements concerning the microenvironment of brain metastases, striving to elucidate the panorama of their onset and evolution. We encapsulate three emergent immunotherapeutic strategies, namely immune checkpoint inhibition, chimeric antigen receptor (CAR) T cell transplantation and glial cell-targeted immunoenhancement. We underscore the imperative of aligning immunotherapy development with in-depth understanding of the tumor microenvironment and engendering innovative delivery platforms. Moreover, the integration with established or avant-garde physical methodologies and localized applications warrants consideration in the prevailing therapeutic schema.

Cerebrospinal fluid immunological cytokines predict intracranial tumor response to immunotherapy in non-small cell lung cancer patients with brain metastases

Background

Immunotherapy has shown intracranial efficacy in non-small cell lung cancer (NSCLC) patients with brain metastases. However, predictive biomarkers for intracranial response to immunotherapy are lacking. This post-hoc analysis aimed to explore the potential of immunological cytokines in cerebrospinal fluid (CSF) to predict intracranial tumor response to immunotherapy in patients with brain metastases.

Methods

Treatment-naive NSCLC patients with brain metastases who received camrelizumab plus chemotherapy were enrolled. Paired plasma and CSF samples were prospectively collected at baseline and the first treatment assessment. All samples were analyzed for 92 immuno-oncology cytokines using Olink's panels.

Results

A total of 28 patients were included in this analysis. At baseline, most immunological cytokines were significantly lower in CSF than in plasma, whereas a subset comprising CD83, PTN, TNFRSF21, TWEAK, ICOSLG, DCN, IL-8, and MCP-1, was increased in CSF. Baseline CSF levels of LAMP3 were significantly higher in patients with intracranial tumor response, while the levels of CXCL10, IL-12, CXCL11, IL-18, TIE2, HGF, and PDCD1 were significantly lower. Furthermore, the CXCL10, CXCL11, TIE2, PDCD1, IL-18, HGF, and LAMP3 in CSF were also significantly associated with intracranial progression-free survival for immunotherapy. The identified cytokines in CSF were decreased at the first treatment evaluation in patients with intracranial tumor response. The logistic CSF immuno-cytokine model yielded an AUC of 0.91, as compared to PD-L1 expression (AUC of 0.72).

Conclusions

Immunological cytokines in CSF could predict intracranial tumor response to immunotherapy in NSCLC patients with brain metastases, and the findings warrant validation in a larger prospective cohort study.

Trial registration

ClinicalTrials.gov identifier: NCT04211090.

Immunotherapy and brain metastasis in lung cancer: connecting bench side science to the clinic

Brain metastases (BMs) are the most common form of intracranial malignant neoplasms in adults, with a profound impact on quality of life and traditionally associated with a dismal prognosis. Lung cancer accounts for approximately 40%-50% of BM across different tumors. The process leading to BMs is complex and includes local invasion, intravasation, tumor cells circulation into the bloodstream, disruption of the blood-brain barrier, extravasation of tumor cells into the brain parenchyma, and interaction with cells of the brain microenvironment, among others. Once the tumor cells have seeded in the brain parenchyma, they encounter different glial cells of the brain, as well as immune cells. The interaction between these cells and tumor cells is complex and is associated with both antitumoral and protumoral effects. To overcome the lethal prognosis associated with BMs, different treatment strategies have been developed, such as immunotherapy with immune checkpoint inhibitors, particularly inhibitors of the PD-1/PD-L1 axis, which have demonstrated to be an effective treatment in both non-small cell lung cancer and small cell lung cancer. These antibodies have shown to be effective in the treatment of BM, alone or in combination with chemotherapy or radiotherapy. However, many unsolved questions remain to be answered, such as the sequencing of immunotherapy and radiotherapy, the optimal management in symptomatic BMs, the role of the addition of anti-CTLA-4 antibodies, and so forth. The complexity in the management of BMs in the era of immunotherapy requires a multidisciplinary approach to adequately treat this devastating event. The aim of this review is to summarize evidence regarding epidemiology of BM, its pathophysiology, current approach to treatment strategies, as well as future perspectives.

Immunotherapy: an emerging modality to checkmate brain metastasis

The diagnosis of brain metastasis (BrM) has historically been a dooming diagnosis that is nothing less than a death sentence, with few treatment options for palliation or prolonging life. Among the few treatment options available, brain radiotherapy (RT) and surgical resection have been the backbone of therapy. Within the past couple of years, immunotherapy (IT), alone and in combination with traditional treatments, has emerged as a reckoning force to combat the spread of BrM and shrink tumor burden. This review compiles recent reports describing the potential role of IT in the treatment of BrM in various cancers. It also examines the impact of the tumor microenvironment of BrM on regulating the spread of cancer and the role IT can play in mitigating that spread. Lastly, this review also focuses on the future of IT and new clinical trials pushing the boundaries of IT in BrM.

Radiomics for the non-invasive prediction of PD-L1 expression in patients with brain metastases secondary to non-small cell lung cancer

BACKGROUND

The expression level of the programmed cell death ligand 1 (PD-L1) appears to be a predictor for response to immunotherapy using checkpoint inhibitors in patients with non-small cell lung cancer (NSCLC). As differences in terms of PD-L1 expression levels in the extracranial primary tumor and the brain metastases may occur, a reliable method for the non-invasive assessment of the intracranial PD-L1 expression is, therefore of clinical value. Here, we evaluated the potential of radiomics for a non-invasive prediction of PD-L1 expression in patients with brain metastases secondary to NSCLC.

PATIENTS AND METHODS

Fifty-three NSCLC patients with brain metastases from two academic neuro-oncological centers (group 1, n = 36 patients; group 2, n = 17 patients) underwent tumor resection with a subsequent immunohistochemical evaluation of the PD-L1 expression. Brain metastases were manually segmented on preoperative T1-weighted contrast-enhanced MRI. Group 1 was used for model training and validation, group 2 for model testing. After image pre-processing and radiomics feature extraction, a test-retest analysis was performed to identify robust features prior to feature selection. The radiomics model was trained and validated using random stratified cross-validation. Finally, the best-performing radiomics model was applied to the test data. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analyses.

RESULTS

An intracranial PD-L1 expression (i.e., staining of at least 1% or more of tumor cells) was present in 18 of 36 patients (50%) in group 1, and 7 of 17 patients (41%) in group 2. Univariate analysis identified the contrast-enhancing tumor volume as a significant predictor for PD-L1 expression (area under the ROC curve (AUC), 0.77). A random forest classifier using a four-parameter radiomics signature, including tumor volume, yielded an AUC of 0.83 ± 0.18 in the training data (group 1), and an AUC of 0.84 in the external test data (group 2).

CONCLUSION

The developed radiomics classifiers allows for a non-invasive assessment of the intracranial PD-L1 expression in patients with brain metastases secondary to NSCLC with high accuracy.

Outcome differences between PD-1/PD-L1 inhibitors-based monotherapy and combination treatments in NSCLC with brain metastases

INTRODUCTION

Without the clear immunophenotyping of brain metastases (BrMs), the optimal treatment strategy based on PD-1/PD-L1 inhibitor for patients with non-small-cell lung cancer (NSCLC) and BrMs remains unknown.

METHODS

308 patients with NSCLC received PD-1/PD-L1 inhibitor-based monotherapy or combination therapy were retrospectively identified. Kaplan-Meier curves with log-rank tests were used to determine the treatment outcomes differences. Transcriptomic analysis of paired primary lung lesions and BrMs were performed to dissect the specific tumor immune microenvironment (TIME) of BrMs.

RESULTS

The presence of BrMs was associated with significantly inferior PFS (2.5 vs. 3.7 months; P = 0.0053) and OS (8.3 vs. 15.4 months; P = 0.0122) in monotherapy group, while it was only associated with poorer PFS (4.6 vs. 7.0 months; P = 0.0009) but similar OS (22.8 vs. 21.0 months; P = 0.9808) in combination treatment group. Of patients with BrMs, PD-1/PD-L1 inhibitor plus antiangiogenic therapy was associated with longest PFS (7.7 vs. 3.2 vs. 2.5 months; P = 0.0251) and OS (29.2 vs. 15.8 vs. 8.3 months; P = 0.0001) when compared with PD-1/PD-L1 inhibitor plus chemotherapy or anti-PD-1/PD-L1 monotherapy. Multivariate analyses suggested that combination treatment was independently correlated with significantly longer PFS (P = 0.028) and OS (P < 0.001) in patients with BrMs. Transcriptomic analysis showed a suppressive TIME in BrMs with decreased CD4⁺ T cells and M1 macrophages but increased M2 macrophages infiltration.

CONCLUSION

NSCLC with BrMs obtained barely satisfactory overall benefit from anti-PD-1/PD-L1 monotherapy, partly due to its immunosuppressive TIME. PD-1/PD-L1 inhibitor-based combination treatment, especially anti-PD-1/PD-L1 plus anti-angiogenic treatment, could significantly improve the clinical outcomes of patients with NSCLC and BrMs.

Mutational signatures of synchronous and metachronous brain metastases from lung adenocarcinoma

Brain metastasis (BM) is an important cause of mortality for cancer patients. Many patients were diagnosed with brain metastases at their first visit who have not received any treatment while a subset of patients did not have distant metastases at the first visit and brain metastases were detected during the course of systemic therapies. The difference in their genomic characterization is unclear. 96 lung adenocarcinoma patients were enrolled in our study. 53 patients (55%) had synchronous metastatic brain tumors. 43 (45%) patients had metachronous brain metastases. We performed 168 panel-targeted gene sequencing cerebrospinal fluid (CSF) and plasma samples from patients to identify genomic features of synchronous brain metastases (SBM) and metachronous brain metastases (MBM). In conclusion, CSF liquid biopsies have a priority in detecting gene alteration. A comprehensive comparison of molecular profiling between SBM and MBM revealed the most frequently altered genes in both groups were EGFR and TP53, but with different exon point mutations. RTK-RAS and TP53 pathways were the most affected pathways.

The role of immune checkpoint inhibitors in patients with intracranial metastatic disease

Intracranial metastatic disease (IMD) complicates the course of nearly 2-4% of patients with systemic cancer. The prevalence of IMD has been increasing over the past few decades. Historically, definitive treatment for brain metastases (BM) has been limited to radiation therapy or surgical resection. Chemotherapies have not typically proven valuable in the treatment of IMD, with the exception of highly chemotherapy-sensitive lesions. Recent data have supported a role for systemic targeted therapies and immune checkpoint inhibitors (ICIs) in the treatment of select patients with IMD. There remains, however, a clear clinical need for further investigation to delineate the role of ICIs in patients with BM. In this review, we outline and describe recent and current efforts to identify the efficacy of ICI therapy in patients with IMD.

PD-L1 testing by immunohistochemistry in immuno-oncology

Immunotherapy, based on immune checkpoint inhibitors targeting the Programmed cell death ligand 1 (PD-L1) and/or Programmed Death Receptor 1 (PD-1), has substantially improved the outcomes of patients with various cancers. However, only ~30% of patients benefit from immune checkpoint inhibitors. Tumor PD-L1 expression, assessed by immunohistochemistry, is the most widely validated and used predictive biomarker to guide the selection of patients for immune checkpoint inhibitors. PD-L1 assessment may be challenging due to the necessity for different companion diagnostic assays for required specific immune checkpoint inhibitors and a relatively high level of inter-assay variability in terms of performance and cutoff levels. In this review, we discuss the role of PD-L1 immunohistochemistry as a predictive test in immunotherapy (immuno-oncology), highlight the complexity of the PD-L1 testing landscape, discuss various preanalytical, analytical and clinical issues that are associated with PD-L1 assays, and provide some insights into optimization of PD-L1 as a predictive biomarker in immuno-oncology.