Association of Brain Metastases With Immune Checkpoint Inhibitors Efficacy in Advanced Lung Cancer: A Systematic Review and Meta-Analysis

From pre-clinical to translational brain metastasis research: current challenges and emerging opportunities

Brain metastasis, characterized by poor clinical outcomes, is a devastating disease. Despite significant mechanistic and therapeutic advances in recent years, pivotal improvements in clinical interventions have remained elusive. The heterogeneous nature of the primary tumor of origin, complications in drug delivery across the blood-brain barrier, and the distinct microenvironment collectively pose formidable clinical challenges in developing new treatments for patients with brain metastasis. Although current preclinical models have deepened our basic understanding of the disease, much of the existing research on brain metastasis has employed a reductionist approach. This approach, which often relies on either in vitro systems or in vivo injection models in young and treatment-naive mouse models, does not give sufficient consideration to the clinical context. Given the translational importance of brain metastasis research, we advocate for the design of preclinical experimental models that take into account these unique clinical challenges and align more closely with current clinical practices. We anticipate that aligning and simulating real-world patient conditions will facilitate the development of more translatable treatment regimens. This brief review outlines the most pressing clinical challenges, the current state of research in addressing them, and offers perspectives on innovative metastasis models and tools aimed at identifying novel strategies for more effective management of clinical brain metastasis.

PD-1/PD-L1 Inhibitors as Monotherapy in the First-Line Treatment of Advanced Non-Small Cell Lung Cancer Patients with High PD-L1 Expression: An Expert Position Statement

INTRODUCTION

There are currently three first-line immunotherapy options used as monotherapy in advanced non-small cell lung cancer (NSCLC) patients with high programmed death ligand 1 (PD-L1) expression (≥50%). This manuscript aims to evaluate the available data on atezolizumab (AT), cemiplimab (CEMI), and pembrolizumab (PEMBRO) and to study the results obtained during pivotal trials, especially regarding patient subgroups.

METHODS

Nominal group and Delphi techniques were used. Eight Spanish experts in lung cancer (the scientific committee of the project) analyzed the use of immunotherapy monotherapy as first-line treatment in patients with NSCLC and high PD-L1 expression. The expert scientific committee formulated several statements based on a scientific review and their own clinical experience. Subsequently, 17 additional Spanish lung cancer experts were selected to appraise the committee's statements through two Delphi rounds. They completed a Delphi round via an online platform and voted according to a scale from 1 (strongly disagree) to 10 (strongly agree). The statements were approved if ≥70% of experts voted 7 or more.

RESULTS

A total of 20 statements were proposed covering the following areas: (1) general characteristics of pivotal clinical trials; (2) overall main outcomes of pivotal clinical trials; and (3) subgroup analysis. All statements reached consensus in the first round.

CONCLUSIONS

AT, CEMI, and PEMBRO as monotherapy can be considered the standard of care in patients with advanced NSCLC and high PD-L1 expression (≥50%). Moreover, some differences noted among the drugs analyzed in this document might facilitate treatment decision-making, especially in clinically relevant patient subgroups, when using PD-1/PD-L1 inhibitors. The high level of agreement reached among experts supports the proposed statements.

The influence of baseline characteristics on the efficacy of immune checkpoint inhibitors for advanced lung cancer: A systematic review and meta-analysis

Purpose: To investigate the impact of different baseline characteristics on the efficacy of immune checkpoint inhibitors (ICIs) for advanced lung cancer.

Methods: In order to identify eligible randomized controlled trials (RCTs), a systematic search was conducted in PubMed, Embase, Web of Science, and Scopus Cochrane Library databases. The primary outcomes were hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival (OS). To explore the potential interaction during the administration of ICI, patients were stratified by baseline characteristics.

Results: The meta-analysis included 24 RCTs. ① Compared with non-ICI therapy, patients with lung cancer benefitted more from immunotherapy (HR, 0.78; p < 0.0001). ② Patients without liver metastases could get more survival benefits than those with liver metastases (HR, 1.20; p = 0.0139). Similar outcomes were also observed in the following subgroups: small-cell lung cancer (HR, 1.20; p = 0.0433), subsequent line (HR, 1.40; p = 0.0147), and ICI monotherapy (HR, 1.40; p = 0.0147). ③ Subgroup analysis showed that tumor type affected the efficacy of immunotherapy in patients with brain metastases (HR, 0.72 vs. 1.41; interaction, p < 0.01). Among patients with smoking history (HR, 0.87 vs. 1.23; interaction, p = 0.05) and brain metastases (HR, 0.69 vs. 1.21; interaction, p = 0.05), the type of therapy (i.e., monotherapy or combination therapy) had potential influences on the efficacy of immunotherapy.

Conclusion: Some critical baseline characteristics could indicate the efficacy of ICI therapy. Liver metastasis status could predict the efficacy of ICI therapy for lung cancer. Compared with small-cell lung cancer, patients with brain metastases might have durable OS in non-small-cell lung cancer. The smoking history or brain metastasis status of patients could indicate the potential clinical benefits of monotherapy or combination therapy.

Adverse events of immunotherapy in non-small cell lung cancer: A systematic review and network meta-analysis

BACKGROUND

Immune checkpoint inhibitors have yielded significant treatment progress in non-small cell lung cancer (NSCLC), while some special adverse events (AEs) named immune-related adverse events (irAEs) were observed in clinical trials. We aimed to systematically assess the incidences of AEs in immunotherapy of NSCLC.

METHODS

We searched randomized controlled trials (RCTs) in PubMed/MEDLINE, Embase, Cochrane, and ClinicalTrail.gov before May 2021, and grouped arms into 10 treatment categories. We extracted AEs as serious (grade 3-5) or others (grade1-2) from all systems, and we pooled their incidences by random effects model. For arm-based pair-wise comparisons, we employed Bayesian network meta-analysis. Meta-regression was used to assess the contribution of coefficients.

RESULTS

Totally 23,322 patients from 52 RCTs were included. The overall incidences of serious AEs were 37.0% in chemotherapy arm, 33.0% in PD1 arm, and 37.0% in PDL1 arm, while in combined groups it was 47.0% in PDL1_Chemo arm, 43.0% in PD1_CTLA4 arm, and 48.0% in ICI_Target arm. The incidence of each serious AE was less than 4% in monotherapy, and slightly higher in combined groups. In network meta-analysis, the immunotherapeutic groups presented a significant higher incidence rank in colitis, hepatobiliary disorders, pneumonitis, and rash compared with chemotherapy. There was a significantly positive correlation between the occurrence of serious hepatitis (p < 0.0001) and PFS in PDL1 arm, likewise serious pneumonitis (p = 0.0049) and rash (p < 0.0001) in PD1 arm.

CONCLUSIONS

The overall incidences of AEs were similar in immune monotherapy compared with chemotherapy in NSCLC. Some irAEs were more common in immune therapy and their frequencies were positively associated with clinical efficacy.