Rationale for targeting the immune system through checkpoint molecule blockade in the treatment of non-small-cell lung cancer

BackgroundTreatments of non-small-cell lung cancer (NSCLC)—particularly of the squamous subtype—are limited. In this article, we describe the immunomodulatory environment in NSCLC and the potential for therapeutic targeting of the immune system through cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death-1 (PD-1) immune-checkpoint pathway blockade.Materials and methodsWe searched PubMed and presented abstracts for publications describing the clinical benefit of checkpoint blockade in NSCLC.ResultsAntibody-mediated checkpoint molecule blockade is being investigated in NSCLC, and of these approaches, the anti-CTLA-4 antibody ipilimumab has undergone the most extensive clinical study. By targeting the immune system rather than specific antigens, checkpoint blockade agents differ from vaccine therapy. In a phase II study in advanced NSCLC, phased ipilimumab with chemotherapy demonstrated the greatest efficacy in squamous NSCLC. A phase I study of nivolumab, an anti-PD-1 antibody, has suggested that this agent is also active against squamous and non-squamous NSCLC. Ongoing phase III studies are evaluating the therapeutic potential of these agents.ConclusionsAlthough treatment options for NSCLC are limited, a better understanding of the immune profile of this disease has facilitated the development of immunotherapeutics that target checkpoint blockade molecules, and clinical evaluation to date supports combining checkpoint blockade with chemotherapy for squamous NSCLC.     

EGFR tyrosine kinase mutation testing in the treatment of non-small-cell lung cancer

Background

Non-small-cell lung cancer (nsclc) tumours with activating mutations of the epidermal growth factor receptor (efgr) tyrosine kinase are highly sensitized to the effects of oral tyrosine kinase inhibitors such as gefitinib and erlotinib, suggesting the possibility of targeted treatment of nsclc based on EFGR mutation status. However, no standardized method exists for assessing the EGFR mutation status of tumours. Also, it is not known if available methods are feasible for routine screening. To address that question, we conducted a validation study of methods used for detecting EGFR mutations in exons 19 and 21 at molecular laboratories located in five specialized Canadian cancer centres.

Methods

The screening methods were first optimized using cell lines harbouring the mutations in question. A validation phase using anonymized patient samples followed.

Results

The methods used at the sites were highly specific and sensitive in detecting both mutations in cell-line dna (specificity of 100% and sensitivity of at least 1% across all centres). In the validation phase, we observed excellent concordance between the laboratories for detecting mutations in the patient samples. Concordant results were obtained in 26 of 30 samples (approximately 87%). In general, the samples for which results were discordant were also less optimal, containing small amounts of tumour.

Conclusions

Our results suggest that currently available methods are capable of reliably detecting exon 19 and exon 21 mutations of EFGR in tumour samples (provided that sufficient tumour material is available) and that routine screening for those mutations is feasible in clinical practice.     

Commensal microbiota contributes to predicting the response to immune checkpoint inhibitors in non-small-cell lung cancer patients

Immunotherapy against cancer, through immune checkpoint inhibitors targeting the programmed cell death-1/programmed cell death-ligand 1 axis, is particularly successful in tumors by relieving the immune escape. However, interindividual responses to immunotherapy are often heterogeneous. Therefore, it is essential to screen out predictive tumor biomarkers. In this study, we analyzed the commensal microbiota in stool samples and paired sputum samples from 75 metastatic non-small-cell lung cancer (NSCLC) patients at baseline and during treatment with immune checkpoint inhibitors. Results showed distinct microbes’ signatures between the gut microbiota and paired respiratory microbiota. The alpha diversity between the gut and respiratory microbiota was uncorrelated, and only the gut microbiota alpha diversity was associated with anti-programmed cell death-1 response. Higher gut microbiota alpha diversity indicated better response and more prolonged progression-free survival. Comparison of bacterial communities between responders and nonresponders showed some favorable/unfavorable microbes enriched in responders/nonresponders, indicating that commensal microbiota had potential predictive value for the response to immune checkpoint inhibitors. Generally, some rare low abundance gut microbes and high abundance respiratory microbes lead to discrepancies in microbial composition between responders and nonresponders. A significant positive correlation was observed between the abundance of Streptococcus and CD8⁺ T cells. These results highlighted the intimate relationship between commensal microbiota and the response to immunotherapy in NSCLC patients. Gut microbiota and respiratory microbiota are promising biomarkers to screen suitable candidates who are likely to benefit from immune checkpoint inhibitor-based immunotherapy.     

免疫检查点抑制剂在EGFR突变非小细胞肺癌治疗应用的研究进展

目前,表皮生长因子受体酪氨酸激酶抑制剂(epidermal growth factor receptor-tyrosine kinase inhibitor,EGFR-TKI)是表皮生长因子受体(epidermal growth factor receptor,EGFR)基因敏感突变晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)的一线治疗标准,但大多数患者最终出现获得性耐药。而针对免疫检查点程序性死亡受体(programmed death-1,PD-1)及其配体(PD-1 ligand,PD-L1)的抑制剂取得突破性进展,改变了NSCLC的治疗模式。多项研究显示,EGFR敏感突变NSCLC患者免疫检查点抑制剂疗效不佳,其可能机制主要包括EGFR敏感突变患者PD-L1的低表达、抑制性免疫微环境、低肿瘤突变负荷等等。通过对EGFR突变NSCLC患者特殊人群的选择,免疫检查点抑制剂与其他药物的联合应用,可能为EGFR敏感突变NSCLC患者的治疗带来希望。本文将对此进行综述,以期为表皮生长因子受体突变的非小细胞肺癌患者的治疗带来新的希望。     

Antibody-mediated thyroid dysfunction during T-cell checkpoint blockade in patients with non-small-cell lung cancer

BackgroundProgrammed cell death protein-1 (PD-1) blockade therapies have demonstrated durable responses and prolonged survival in a variety of malignancies. Treatment is generally well tolerated although immune-related adverse events (irAEs) can occur. Autoimmune thyroid dysfunction is among the most common irAE, but an assessment of the clinical, mechanistic, and immunologic features has not been previously described.Patient and methodsPatients with advanced non-small-cell lung cancer (NSCLC) treated with pembrolizumab at Memorial Sloan Kettering Cancer Center (n=51) as part of KEYNOTE-001 (NCT01295827) were included. Thyroid function test and anti-thyroid antibodies were assessed prospectively at each study visit, beginning before the first treatment. Frequency of development of thyroid dysfunction, association with anti-thyroid antibodies, clinical course, and relationship with progression-free survival and overall survival to treatment with pembrolizumab was evaluated.ResultsOf 51 patients treated, 3 were hypothyroid and 48 were not at baseline. Ten of 48 [21%, 95% confidence interval (CI) 10% to 35%] patients developed thyroid dysfunction requiring thyroid replacement. Anti-thyroid antibodies were present in 8 of 10 patients who developed thyroid dysfunction, compared with 3 of 38 who did not (80% versus 8%,P<0.0001). Thyroid dysfunction occurred early (median, 42 days) in the pembrolizumab course, and a majority (6 of 10 patients) experienced brief, transient hyperthyroidism preceding the onset of hypothyroidism; no persistent hyperthyroidism occurred. Both hyperthyroidism and hypothyroidism were largely asymptomatic. Overall survival with pembrolizumab was significantly longer in subjects who developed thyroid dysfunction (hazard ratio, 0.29; 95% CI 0.09–0.94;P = 0.04).ConclusionsThyroid dysfunction during pembrolizumab treatment of NSCLC is common and is characterized by early-onset, frequently preceded by transient hyperthyroidism, closely associated with anti-thyroid antibodies, and may be associated with improved outcomes. The presence of antibody-mediated toxicity in T-cell-directed therapy suggests an under-recognized impact of PD-1 biology in modulating humoral immunity.     

Double mutation and gene copy number of EGFR in gefitinib refractory non-small-cell lung cancer

Mutations of the epidermal growth factor receptor (EGFR) gene have been reported in non-small-cell lung cancer (NSCLC), especially in patients with adenocarcinoma and never smokers. Some common somatic mutations in EGFR, including deletion mutations in exon 19 and leucine-to-arginine substitution at amino acid position 858 (L858R) in exon 21, have been examined for their ability to predict sensitivity to gefitinib or erlotinib, which are selective EGFR tyrosine kinase inhibitors (EGFR-TKIs). On the other hand, reports have shown that the threonine-to-methionine substitution at amino acid position 790 (T790M) in exon 20 is related to gefitinib resistance. Some studies have indicated that high copy numbers of the EGFR gene may be a more effective molecular predictor to responsiveness and prolonged survival in patients treated with EGFR-TKIs. Here, we describe two NSCLC patients with the L858R mutation who did not respond to gefitinib. Case 1 harbored both the T790M and L858R mutations, and fluorescence in situ hybridization showed EGFR gene amplification. Case 2 harbored both the L858R and aspartic acid-to-tyrosine substitution at amino acid position 761 in exon 19 of EGFR mutations and had a high polysomy status for EGFR. In these two cases, tumors showed resistance to gefitinib treatment despite the presence of EGFR L858R mutation and increased copy number. Our findings encourage further molecular analysis to elucidate the relationship between the EGFR status, including mutations and amplifications, and the responsiveness of NSCLC to gefitinib.     

Analytical performance of the cobas EGFR mutation assay for Japanese non-small-cell lung cancer

Introduction

Clinical outcomes in non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations have been reported to be correlated with the use of EGFR-tyrosine kinase inhibitors (EGFR-TKIs). Therefore, it is essential to confirm the presence of EGFR mutations using highly sensitive testing methods. In this study, we compared the performance of the cobas^® EGFR Mutation Test (cobas EGFR assay) and the therascreen^® EGFR RGQ PCR Kit (therascreen EGFR assay) for use as an in vitro diagnostic (IVD) product.

Methods

We extracted DNA from 150 formalin-fixed, paraffin-embedded tissue samples from 150 patients diagnosed with NSCLC, and performed a comparative study of the cobas EGFR and therascreen EGFR assay methods. All discordant results were re-analyzed by direct sequencing.

Results

The concordance rate between the cobas EGFR assay and the therascreen EGFR assay was 98.0% (145/148). EGFR mutations were detected at a frequency of 40.9% (61/149) in NSCLC specimens using the cobas EGFR assay and 40.2% (60/149) using the therascreen EGFR assay. Three discrepant results were found in this study. Two double mutations were detected by the cobas EGFR assay but only one in the therascreen EGFR assay. No invalid results resulted from sample analysis by the cobas EGFR assay.

Conclusions

Our results show a high concordance rate (98.0%) of cobas EGFR assay with an existing IVD product, the therascreen EGFR assay. Since they are IVD diagnostic products, both assays proved to be simple, validated methods in detecting the most common, clinically significant EGFR mutations and proved to be helpful for appropriate treatment guidance for NSCLC patients.     

EGFR exon mutation distribution and outcome in non-small-cell lung cancer: a Portuguese retrospective study

Epidermal growth factor receptor (EGFR) mutations play a predictive role in advanced stages of non-small-cell lung cancer (NSCLC) patients. We conducted this study in order to assess EGFR status in a Portuguese population and its role in NSCLC patients' outcomes. Patients were submitted to EGFR assessment by high-resolution melting and/or direct sequencing. Kaplan?CMeier curve was used to assess overall survival and progression-free survival (PFS). Two hundred forty eight out of 322 participants were assessed for EGFR status. Forty-two patients (16.9?%) presented EGFR-mutated status: one patient (2.4?%) presented exon 18; 21 patients (50?%), exon 19; one patient (2.4?%), exon 20; and 18 patients (45.2?%), exon 21 mutations, p?<?0.001. PFS was not assessed (n.a.) for patient with exon 18 mutation, and for the other patients with mutations, it was 7?months (3.96?C10.03) (exon 19), <1?month (exon 20), and 7?months (0?C14.2) (exon 21) (p?=?0.027). Overall survival (OS) was 11?months (exon 18), 11?months (1?C18) (exon 19), 1?month (exon 20), and 7.5?months (2?C70) (exon 21) (p?=?n.a). This study suggests that the EGFR mutation is herein observed in a higher proportion than expected for a Caucasian population, and OS is a little less than that published in the literature.     

放疗协同免疫检查点阻滞剂治疗肿瘤的机制

随着对肿瘤免疫机制的深入研究,学者们注意到了放疗激活机体产生全身免疫效应的现象,改变了放疗是“免疫抑制性”的片面认识.然而,放疗虽能增强机体的抗肿瘤免疫,在临床上,接受放疗的患者仍避免不了复发、转移.研究表明,这与肿瘤微环境诱导的免疫检查点通路异常激活密切相关.因此,将放疗与免疫检查点阻滞剂联合应用,改善肿瘤微环境,能提高肿瘤治疗效果.     

In vitro modeling to determine mutation specificity of EGFR tyrosine kinase inhibitors against clinically relevant EGFR mutants in non-small-cell lung cancer

EGFR mutated lung cancer accounts for a significant subgroup of non-small-cell lung cancer (NSCLC). Over the last decade, multiple EGFR tyrosine kinase inhibitors (EGFR-TKIs) have been developed to target mutated EGFR. However, there is little information regarding mutation specific potency of EGFR-TKIs against various types of EGFR mutations. The purpose of this study is to establish an in vitro model to determine the “therapeutic window” of EGFR-TKIs against various types of EGFR mutations, including EGFR exon 20 insertion mutations. The potency of 1^st (erlotinib), 2^nd (afatinib) and 3^rd (osimertinib and rociletinib) generation EGFR-TKIs was compared in vitro for human lung cancer cell lines and Ba/F3 cells, which exogenously express mutated or wild type EGFR. An in vitro model of mutation specificity was created by calculating the ratio of IC50 values between mutated and wild type EGFR. The in vitro model identified a wide therapeutic window of afatinib for exon 19 deletions and L858R and of osimertinib and rociletinib for T790M positive mutations. The results obtained with our models matched well with previously reported preclinical and clinical data. Interestingly, for EGFR exon 20 insertion mutations, most of which are known to be resistant to 1^st and 2^nd generation EGFR-TKIS, osimertinib was potent and presented a wide therapeutic window. To our knowledge, this is the first report that has identified the therapeutic window of osimertinib for EGFR exon 20 insertion mutations. In conclusion, this model will provide a preclinical rationale for proper selection of EGFR-TKIs against clinically-relevant EGFR mutations.