Safety and efficacy of immune checkpoint blockade in patients with advanced nonsmall cell lung cancer and brain metastasis

The presence of brain metastases (BM) is a negative prognostic factor for patients with advanced nonsmall cell lung cancer (NSCLC). Their incidence seems to be higher in patients with oncogene-driven tumours, especially those with EGFR-mutated or ALK-rearranged tumours. Although targeted treatments demonstrate significant efficacy regarding BM, they only apply to a minority of NSCLC patients. On the other hand, systemic therapies for nononcogenic-driven NSCLC with BM have shown limited clinical benefit. In recent years, immunotherapy alone or combined with chemotherapy has been adopted as a new standard of care in first-line therapy. This approach seems to be beneficial to patients with BM in terms of efficacy and toxicity. Combined immune checkpoint inhibition as well as the combination of immunotherapy and radiation therapy show promising results with significant, but overall acceptable toxicity. A pragmatic approach of allowing enrolment of patients with untreated or symptomatic BM in randomised trials evaluating immune checkpoint inhibitors strategies, possibly coupled with central nervous system-related endpoints may be needed to generate data to refine treatment for this patient population.

Immunotherapy in NSCLC Patients with Brain Metastases

Approximately 40% of unselected non-small cell lung cancer (NSCLC) patients develop brain metastases (BMs) during their disease, with considerable morbidity and mortality. The management of BMs in patients with NSCLC is a clinical challenge and requires a multidisciplinary approach to gain effective intracranial disease control. Over the last decade, immune checkpoint inhibitors (ICIs) have emerged as a game-changer in the treatment landscape of advanced NSCLC, with significant improvements in survival outcomes, although patients with BMs are mostly underrepresented in randomized clinical trials. Moreover, the safety and activity of ICIs and radiotherapy combinations compared with single-agent or sequential modalities is still under evaluation to establish the optimal management of these patients. The aim of this review is to summarize the state-of-the-art of clinical evidence of ICIs intracranial activity and the main challenges of incorporating these agents in the treatment armamentarium of NSCLC patients with BMs.

The Strategies and Mechanisms of Immune Checkpoint Inhibitors for Brain Metastases in NSCLC

Brain metastases are more and more common among patients with non-small cell lung cancer (NSCLC). TKI therapy could provide ideal outcomes for patients harboring epidermal growth factor receptor or ALK mutations. For wild-type patients, however, survival is poor because there are few effective treatments other than radiotherapy. Immune checkpoint inhibitors (ICIs) have changed the management of advanced NSCLC. However, the exclusion of patients with active brain metastasis (BM) from most ICI trials precludes the generalization of results. Accordingly, a variety of appropriate real-world studies and clinical trials are being developed to evaluate tumor response. Increasingly encouraging results have suggested that ICIs could be active in the central nervous system (CNS) in select patients with high PD-L1 expression and low CNS disease burden. With the extensive use of ICIs in NSCLC patients with BM, many important questions have emerged concerning issues such as the clinical response to a single ICI, use of ICIs combined with chemotherapy or radiation, the biological mechanism and appropriate sequencing of local and systemic therapy combinations, and safety and toxicity. The present review summarizes the advances in systemic ICIs for the treatment of NSCLC patients with BM, discusses factors associated with efficacy and toxicity, and explores future directions.

Real-world experience of nivolumab in the treatment of poor performance status patients with advanced non-small cell lung cancer

Background

Nivolumab improves disease control and survival in advanced NSCLC in patients with good performance status (PS), but there is limited data on its efficacy in patients with poor PS.

Aim

Primary objective of the study was to evaluate the efficacy and safety of nivolumab and examine the influence of PS on outcomes.

Methods and Results

Retrospective analysis of patients treated with single‐agent nivolumab for advanced NSCLC at a single institution was performed.

Sixty‐six patients treated with nivolumab were identified (33 male) with a median age of 68.5 years. Fifty‐six (85%) patients were current or former smokers and 17 (26%) had brain metastasis. All patients had received prior chemotherapy, 39 (59%) patients received one and 27 (41%) had ≥2 prior lines of therapy. Median overall survival (OS) was 7.1 months (95%CI 3.61–11.3) in the overall study population. OS of patients with PS ≥2 at the start of treatment was 3.04 months (95%CI 1.64–7.36) as compared to 10.23 months (95%CI 7.06–18.9) with PS ≤1. The overall response rate was 7% (four patients had a partial response), 23 (40%) patients had stable disease; the overall disease control rate (partial response and stable disease) was 47%. Twenty‐six (40%) patients had PS ≥2 at the start of treatment and 2 (8%) of these patients developed a partial response, 4 (15%) had stable disease; the overall disease control rate was 23%. Fourteen (58%) patients with PS ≥2 had disease progression at the time of first disease response evaluation. In the overall population, 20% of patients experienced grade ≥3 treatment‐related adverse events (TRAEs), most commonly pneumonitis, hepatitis, and colitis. Fourteen TRAEs led to treatment discontinuation, 9 (23%) adverse events (AEs) in patients with PS ≤1 and 5 (19%) with PS ≥2. Fourteen (21%) patients died within 30 days of the last nivolumab treatment.

Conclusion

There was no significant difference in toxicity leading to treatment discontinuation between the poor and good PS groups, but survival was shorter with poorer PS. PS appears to be an important prognostic factor and remains a relevant discriminator in the selection of treatment with immunotherapy for lung cancer.

PD-1/PD-L1 Inhibitor Combined with Chemotherapy Can Improve the Survival of Non-Small Cell Lung Cancer Patients with Brain Metastases

Introduction

Immune checkpoint inhibitor (ICI) monotherapy has limited efficacy in patients with non-small cell lung cancer (NSCLC) and brain metastases (BMs). With the wide use of ICI-based combinations, the efficacy of different ICI combination strategies in patients with NSCLC and BMs needs to be further elucidated.

Methods

We retrospectively reviewed 526 patients with non-small cell lung cancer (NSCLC) treated with ICIs from January 2016 to December 2019 in the Shanghai Pulmonary Hospital. Patients with BMs treated with ICIs were further divided into two groups: those with BM prior to the ICI treatment (pBM group), and those with BM after the treatment (aBM group). We assessed intracranial progression-free survival (IPFS), systemic progression-free survival (SPFS), overall survival (OS), intracranial objective response rate (IORR), and intracranial disease control rate (IDCR).

Results

We found 77 patients out of 526 with BMs; 69 presented the BMs prior to the ICI treatments and 8 showed BMs after the ICI treatments. In the pBM group, the median IPFS and SPFS were 7.39 months and 5.39 months, respectively. Combination therapy significantly improved both the IPFS (p=0.007) and the SPFS (p=0.007) when compared with monotherapy. Further analysis demonstrated that ICIs combined with chemotherapy significantly improved both the IPFS (p=0.009) and the SPFS (p=0.006) when compared with monotherapy. While ICIs combined with anti-angiogenic therapy improved the SPFS (p=0.005) but not the IPFS (p=0.139). The median OS was 27.43 months for patients in the pBM group. Further analyses suggested that combination treatment also improved the OS when compared with monotherapy (p=0.003). Subgroup analysis results showed that ICIs combined with chemotherapy led to better OS than ICIs monotherapy (p=0.006). Radiotherapy had no significant impact on survival (IPFS p=0.272, OS p=0.142) in the patients of the pBM group.

Conclusion

ICIs combined with chemotherapy demonstrated survival benefits over ICI monotherapy in patients with NSCLCs and BMs.

Immune Checkpoint Inhibitors for Non-Small-Cell Lung Cancer with Brain Metastasis : The Role of Gamma Knife Radiosurgery

Objective

Immune checkpoint inhibitors (ICIs) are approved for treating non-small-cell lung cancer (NSCLC); however, the safety and efficacy of combined ICI and Gamma Knife radiosurgery (GKS) treatment remain undefined. In this study, we retrospectively analyzed patients treated with ICIs with or without GKS at our institute to manage patients with brain metastases from NSCLC.

Methods

We retrospectively reviewed medical records of patients with brain metastases from NSCLC treated with ICIs between January 2015 and December 2017. Of 134 patients, 77 were assessable for brain responses and categorized into three groups as follows : group A, ICI alone (n=26); group B, ICI with concurrent GKS within 14 days (n=24); and group C, ICI with non-concurrent GKS (n=27).

Results

The median follow-up duration after brain metastasis diagnosis was 19.1 months (range, 1–77). At the last follow-up, 53 patients (68.8%) died, 20 were alive, and four were lost to follow-up. The estimated median overall survival (OS) of all patients from the date of brain metastasis diagnosis was 20.0 months (95% confidence interval, 12.5–27.7) (10.0, 22.5, and 42.1 months in groups A, B, and C, respectively). The OS was shorter in group A than in group C (p=0.001). The intracranial disease progression-free survival (p=0.569), local progression-free survival (p=0.457), and complication rates did not significantly differ among the groups. Twelve patients showed leptomeningeal seeding (LMS) during follow-up. The 1-year LMS-free rate in treated with ICI alone group (69.1%) was significantly lower than that in treated with GKS before ICI treatment or within 14 days group (93.2%) (p=0.004).

Conclusion

GKS with ICI showed no favorable OS outcome in treating brain metastasis from NSCLC. However, GKS with ICI did not increase the risk of complications. Furthermore, compared with ICI alone, GKS with ICI may be associated with a reduced incidence of LMS. Further understanding of the mechanism, which remains unknown, may help improve the quality of life of patients with brain metastasis.

Whole-brain Radiation and Pembrolizumab Treatment for a Non-small-cell Lung Cancer Patient with Meningeal Carcinomatosis Lacking Driver Oncogenes Led to a Long-term Survival

We herein report a 66-year-old woman with advanced lung adenocarcinoma [programmed cell death and its ligand 1 (PD-L1) tumor proportion score 60%] lacking driver oncogenes in whom meningeal carcinomatosis, along with sudden onset dizziness, deafness, and consciousness disturbance, appeared after second-line chemotherapy. Whole-brain radiation therapy (WBRT) and Pembrolizumab were subsequently administered, and third-line chemotherapy with Pembrolizumab is now ongoing. At the time of writing, the patient has achieved a 23-month survival without disease progression. Our findings suggest that the combination of WBRT and an immune checkpoint inhibitor is effective for non-small-cell lung cancer patients lacking driver oncogenes who develop meningeal carcinomatosis.

PD-1/PD-L1 Blockers in NSCLC Brain Metastases: Challenging Paradigms and Clinical Practice

Immune checkpoint inhibitors (ICI) have revolutionized the management of advanced non-small cell lung cancer (NSCLC). However, most pivotal phase III trials systematically excluded patients with active brain metastases, precluding the generalization of the results. Although theoretically restricted from crossing the blood-brain barrier, the novel pharmacokinetic/pharmacodynamic profiles of anti-PD-1/PD-L1 drugs have prompted studies to evaluate their activity in patients with NSCLC with active central nervous system (CNS) involvement. Encouraging results have suggested that ICI could be active in the CNS in selected patients with driver-negative advanced NSCLC with high PD-L1 expression and low CNS disease burden. Single-agent CNS response rates around 30% have been reported. Beyond this particular setting, anti-PD-1/PD-L1 antibodies have been evaluated in patients receiving local therapy for brain metastases (BM), addressing concerns about potential neurologic toxicity risks associated with radiotherapy, more specifically, radionecrosis (RN). Accordingly, a variety of clinical and imaging strategies are being appropriately developed to evaluate tumor response and to rule out pseudoprogression or radionecrosis. Our purpose is to critically summarize the advances regarding the role of systemic anti-PD-1/PD-L1 antibodies for the treatment of NSCLC BM. Data were collected from the PubMed database, reference lists, and abstracts from the latest scientific meetings. Recent reports suggest anti-PD-1/PD-L1 agents are active in a subset of patients with NSCLC with BM showing acceptable toxicity. These advances are expected to change soon the management of these patients but additional research is required to address concerns regarding radionecrosis and the appropriate sequencing of local and systemic therapy combinations.

Immune Checkpoint Blockade - How Does It Work in Brain Metastases?

Immune checkpoints restrain the immune system following its activation and their inhibition unleashes anti-tumor immune responses. Immune checkpoint inhibitors revolutionized the treatment of several cancer types, including melanoma, and immune checkpoint blockade with anti-PD-1 and anti-CTLA-4 antibodies is becoming a frontline therapy in metastatic melanoma. Notably, up to 60% of metastatic melanoma patients develop metastases in the brain. Brain metastases (BrM) are also very common in patients with lung and breast cancer, and occur in ∼20-40% of patients across different cancer types. Metastases in the brain are associated with poor prognosis due to the lack of efficient therapies. In the past, patients with BrM used to be excluded from immune-based clinical trials due to the assumption that such therapies may not work in the context of "immune-specialized" environment in the brain, or may cause harm. However, recent trials in patients with BrM demonstrated safety and intracranial activity of anti-PD-1 and anti-CTLA-4 therapy. We here discuss how immune checkpoint therapy works in BrM, with focus on T cells and the cross-talk between BrM, the immune system, and tumors growing outside the brain. We discuss major open questions in our understanding of what is required for an effective immune checkpoint inhibitor therapy in BrM.

Dramatic Response of Leptomeningeal Carcinomatosis to Nivolumab in PD-L1 Highly Expressive Non-small Cell Lung Cancer: A Case Report

In a patient who had been diagnosed of located squamous cell lung carcinoma, pneumonectomy, and adjuvant chemotherapy were performed. Brain recurrence and subsequent lung metastatic disease were uncontrolled by neurosurgery, holocranial radiotherapy, and first-line chemotherapy. In August 2015, appearance of leptomeningeal carcinomatosis triggered severe clinical deterioration and threatened the patient's life. Anti-PD1 immune checkpoint inhibitor Nivolumab was initiated in an attempt to stop tumor growth, achieving a spectacular brain and pulmonary complete response and clinical improvement, without serious adverse effects. High expression PD-L1 level (100%) was found in the pathological tissue sample. Nivolumab was maintained for more than 2 years and stopped in December 2017 after 28 months of treatment, with no disease evidence. More than 3 years after its onset, the patient maintains an outstanding PS with complete tumor response and no evidence of disease in last surveillance CT scan and brain MRI.

Pembrolizumab for non-small cell lung cancer with central nervous system metastases: A two-case report

Non-small cell lung cancer (NSCLC) accounts for up to 85% of all lung cancers. Central nervous system metastases are a common complication of NSCLC and confer a poor prognosis and a dismal survival rate. Treatment is limited, has poor outcomes, and affects patient quality of life. Pembrolizumab is an anti-PD-1 antibody that has shown good results for the management of NSCLC. However, its penetration of the central nervous system has not been well studied, and patients with untreated brain metastases are excluded from most clinical trials. Herein, we report two cases of NSCLC with brain metastases in patients successfully treated with pembrolizumab, and discuss the efficacy and safety of pembrolizumab in these patients. Pembrolizumab has shown good control and the patients have had long progression-free survival with a high quality of life. Neither patient has experienced serious or grade 3-4 treatment-related adverse events. Pembrolizumab demonstrates activity in brain metastases in NSCLC patients with an acceptable safety profile. Thus, there may be a role for systemic immunotherapy in patients with untreated or progressive brain metastases.

Immune Checkpoint Inhibitors for the Treatment of Central Nervous System (CNS) Metastatic Disease

While the CNS has long been viewed as an immune-privileged environment, a paradigm shift in neuro-immunology has elevated the role of systemic immunotherapy for the treatment of metastatic disease. Increasing knowledge regarding the presence of a CNS lymphatic system and the physical and biochemical alteration of the blood brain barrier (BBB) by the tumor microenvironment suggests immune cell trafficking in and out of the CNS is possible. Emerging clinical data suggest immune checkpoint inhibitors (ICIs) can stimulate T cells peripherally to in turn have anti-tumor effects in the CNS. For example, anti-programmed cell death-1 (PD-1) monotherapy with pembrolizumab has shown intracranial response rates of 20-30% in patients with melanoma or non-small cell lung cancer (NSCLC) brain metastases. The combination of nivolumab and ipilimumab [anti-PD-1 and anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4)] showed an intracranial response rate of 55% in patients with melanoma brain metastases. More data are needed to confirm these response rates and to determine mechanisms of efficacy and resistance. While local therapies such as stereotactic radiosurgery (SRS), whole-brain radiation therapy (WBRT), and surgery remain current mainstays, ICIS offer potential decreased neurotoxicity. This review summarizes the biological rationale for systemic immunotherapy to treat CNS metastatic disease, existing clinical data on ICIs in this setting and ongoing clinical trials exploring areas of unmet need.

The benefit and risk of nivolumab in non-small-cell lung cancer: a single-arm meta-analysis of noncomparative clinical studies and randomized controlled trials

Nivolumab is a programmed cell death 1 (PD-1) receptor inhibitor antibody that enhances immune system antitumor activity. Although it is used for treating advanced non-small-cell lung cancer (NSCLC), its actual efficacy has not been determined. We searched PubMed, the Cochrane Library, Embase, MEDLINE, and Web of Science for related noncomparative clinical studies and randomized controlled trials (RCTs) to assess nivolumab benefit and risk in NSCLC. The main outcomes were objective response rate (ORR), 1-year overall survival rate (1-yOS rate), and progression-free survival rate at 24 weeks (PFS at 24 weeks rate), any-grade adverse effects rate (any-grade AEs%), and grade 3-4 AE rate (grade 3-4 AEs%). Relative risk (RR) was used to compare ORR in patients with positive and negative programmed cell death ligand 1 (PD-L1) expression. Random-effects models were used to determine pooled effect size and two-sided 95% confidence intervals (95% CI). We included 20 studies (17 noncomparative open-label cohort studies, three RCTs) involving 3404 patients in our meta-analysis. The modified nivolumab ORR was 18% (95% CI: 15-20%), the 1-yOS rate was 45% (95% CI: 40-50%), PFS at 24 weeks rate was 42% (95% CI: 37-48%), any-grade AEs% was 61% (95% CI: 50-73%), and grade 3-4 AEs% was 12% (95% CI: 9-16%). PD-L1 expression was related with the nivolumab ORR. Nivolumab potentially causes ongoing response, long-term PFS, and reduced treatment-related AEs. PD-L1 expression predicts the outcome of nivolumab immunotherapy. More high-quality and well-designed RCTs with large sample sizes are warranted to prove our findings.

Immunotherapy targeting immune check-point(s) in brain metastases

Immunotherapy with monoclonal antibodies (mAb) directed to different immune check-point(s) is showing a significant clinical impact in a growing number of human tumors of different histotype, both in terms of disease response and long-term survival patients. In this rapidly changing scenario, treatment of brain metastases remains an high unmeet medical need, and the efficacy of immunotherapy in these highly dismal clinical setting remains to be largely demonstrated. Nevertheless, up-coming observations are beginning to suggest a clinical potential of cancer immunotherapy also in brain metastases, regardless the underlying tumor histotype. These observations remain to be validated in larger clinical trials eventually designed also to address the efficacy of therapeutic mAb to immune check-point(s) within multimodality therapies for brain metastases. Noteworthy, the initial proofs of efficacy on immunotherapy in central nervous system metastases are already fostering clinical trials investigating its therapeutic potential also in primary brain tumors. We here review ongoing immunotherapeutic approaches to brain metastases and primary brain tumors, and the foreseeable strategies to overcome their main biologic hurdles and clinical challenges.