Addition of Immune Checkpoint Inhibitors to Chemotherapy vs Chemotherapy Alone as First-Line Treatment in Extensive-Stage Small-Cell Lung Carcinoma: A Systematic Review and Meta-Analysis

Introduction

The addition of immune checkpoint inhibitors (ICIs) to conventional chemotherapy (CT) as first-line treatment improves survival in extensive-stage small-cell lung cancer (ES-SCLC). The aim of this meta-analysis was to determine the relative efficacy of first-line ICIs compared with CT in patients with ES-SCLC.

Methods

Two independent reviewers extracted relevant data according to PRISMA guidelines and assessed the risk of bias using the Cochrane Collaboration's risk-of-bias tool. Meta-analysis was conducted using random-effects models to calculate an average effect size for overall survival (OS), progression-free survival (PFS), and safety outcomes in the overall populations and clinically relevant subgroups.

Results

A literature search of PubMed and Embase was performed. Six randomized controlled clinical trials (IMpower133, CHECKMATE-451, CASPIAN, KEYNOTE-604, and phase II and III ipilimumab plus CT trials) with a total of 3757 patients were included. Compared with CT alone, ICIs plus CT showed a favourable effect on OS (hazard ratio [HR] 0.85; 95% confidence intervals [CI] 0.79–0.96) and PFS (HR 0.78; 95% CI 0.72–0.83) but a non-significant increase in the risk of experiencing any adverse event (relative risk, 1.05; 95% CI 0.99–1.11). The estimated HR for OS favoured ICI combinations in all planned subgroups according to age (< 65 years/≥ 65 years), sex (men/women), and ECOG performance status (0/1). Analysis by specific ICI revealed significant improvements in OS only for atezolizumab + CT (HR 1.36; 95% CI 1.09–1.69) and durvalumab + CT (HR 1.35; 95% CI 1.12–1.62) compared with CT alone.

Conclusion

Combining anti-programmed cell death ligand 1 antibodies with platinum/etoposide is a superior therapeutic approach compared to CT alone for the first-line treatment of patients with ES-SCLC.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40487-021-00182-0.

Emerging principles of brain immunology and immune checkpoint blockade in brain metastases

Brain metastases are the most common type of brain tumours, harbouring an immune microenvironment that can in principle be targeted via immunotherapy. Elucidating some of the immunological intricacies of brain metastases has opened a therapeutic window to explore the potential of immune checkpoint inhibitors in this globally lethal disease. Multiple lines of evidence suggest that tumour cells hijack the immune regulatory mechanisms in the brain for the benefit of their own survival and progression. Nonetheless, the role of the immune checkpoint in the complex interplays between cancers cells and T cells and in conferring resistance to therapy remains under investigation. Meanwhile, early phase trials with immune checkpoint inhibitors have reported clinical benefit in patients with brain metastases from melanoma and non-small cell lung cancer. In this review, we explore the workings of the immune system in the brain, the immunology of brain metastases, and the current status of immune checkpoint inhibitors in the treatment of brain metastases.

Application of immune checkpoint inhibitors in EGFR-mutant non-small-cell lung cancer: from bed to bench

Targeted therapies are efficient in the context of oncogenic driver mutations. Epidermal growth factor receptor (EGFR)-mutant lung cancers represent a distinct subset of non-small-cell lung cancer (NSCLC) with marked sensitivity to EGFR tyrosine kinase inhibitors (TKIs). Despite the high response rate to EGFR TKIs in EGFR-mutant lung cancer, resistance and tumor recurrence are unavoidable. Therapeutic options are restricted in patients after exhaustion of targeted therapies. Immune checkpoint inhibitors (ICIs) represent a novel therapeutic option for advanced NSCLC with significant overall survival benefit in registration trials. No superiority in terms of long-term survival was observed in the EGFR mutation subgroup when ICIs were given as monotherapy in second-line treatment in earlier studies. Thus, the appropriate application of ICIs to patients harboring EGFR mutations remains an important field of ongoing research. Here, we discuss different immune checkpoint blockade strategies, including ICIs alone and in combination with TKIs, chemotherapy, radiation, and antiangiogenic agents in EGFR-mutant NSCLC as first-line and subsequent treatments. We also summarize the evidence concerning the heterogeneous molecular features and immune signatures of EGFR mutations and their associations with ICI therapy outcomes. This study was performed to improve our understanding of the optimal mode of immune-based treatment approaches in EGFR-mutant NSCLC.

Combination treatments with immunotherapy in brain metastases patients

Immune checkpoint inhibitors (ICI) have revolutionized the treatment of many advanced cancers. However, in most pivotal trials, patients with brain metastases (BM) were either excluded, or only selected patients were allowed. Therefore, there are still some concerns about the safety/efficacy ratio of ICI in patients with BM. In this special report we will provide an overview on the biological rationale for using ICI in the treatment of BM, the reported BM-related outcomes of clinical trials with a focus on ICI plus chemotherapy and ICI plus ICI combinations. Last, we will provide future challenges with this strategy, as well as directions for future research.

Radiation Therapy for Small Cell Lung Cancer: An ASTRO Clinical Practice Guideline

PURPOSE

Several sentinel phase III randomized trials have recently been published challenging traditional radiation therapy (RT) practices for small cell lung cancer (SCLC). This American Society for Radiation Oncology guideline reviews the evidence for thoracic RT and prophylactic cranial irradiation (PCI) for both limited-stage (LS) and extensive-stage (ES) SCLC.

METHODS

The American Society for Radiation Oncology convened a task force to address 4 key questions focused on indications, dose fractionation, techniques and timing of thoracic RT for LS-SCLC, the role of stereotactic body radiation therapy (SBRT) compared with conventional RT in stage I or II node negative SCLC, PCI for LS-SCLC and ES-SCLC, and thoracic consolidation for ES-SCLC. Recommendations were based on a systematic literature review and created using a consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

The task force strongly recommends definitive thoracic RT administered once or twice daily early in the course of treatment for LS-SCLC. Adjuvant RT is conditionally recommended in surgically resected patients with positive margins or nodal metastases. Involved field RT delivered using conformal advanced treatment modalities to postchemotherapy volumes is also strongly recommended. For patients with stage I or II node negative disease, SBRT or conventional fractionation is strongly recommended, and chemotherapy should be delivered before or after SBRT. In LS-SCLC, PCI is strongly recommended for stage II or III patients who responded to chemoradiation, conditionally not recommended for stage I patients, and should be a shared decision for patients at higher risk of neurocognitive toxicities. In ES-SCLC, radiation oncologist consultation for consideration of PCI versus magnetic resonance surveillance is strongly recommended. Lastly, the use of thoracic RT is strongly recommended in select patients with ES-SCLC after chemotherapy treatment, including a conditional recommendation in those responding to chemotherapy and immunotherapy.

CONCLUSIONS

RT plays a vital role in both LS-SCLC and ES-SCLC. These guidelines inform best clinical practices for local therapy in SCLC.