NGS-based Tissue-Blood TMB Comparison and Blood-TMB Monitoring in Stage-III Non-Small Cell Lung Cancer Treated with Concurrent Chemoradiotherapy

In this study, we analyzed the blood-based TMB (b-TMB) and its dynamic changes in patients with locally advanced non-small cell lung cancer (LA-NSCLC) who received concurrent chemoradiotherapy. Baseline tissue and blood TMB from 15 patients showed a strong positive correlation (Pearson correlation = 0.937), and nearly all mutations were markedly reduced in the later course of treatment, indicating a treatment-related response. This study suggests that in patients with LA-NSCLC, b-TMB is a reliable biomarker, and its dynamic monitoring can help distinguish patients who might benefit most from the consolidated immunotherapy.

Biomarkers for Immunotherapy in Driver-Gene-Negative Advanced NSCLC

Outcome improvement in patients with driver-gene-negative advanced non-small cell lung cancer (NSCLC) has been significantly enhanced through targeting the immune system, specifically the PD-L1/PD-1 axis. Nevertheless, only a subset of patients with advanced NSCLC may derive benefits from immuno-monotherapy or immunotherapy combined with chemotherapy. Hence, in order to identify patients who will gain the maximum advantage from immunotherapy, it is crucial to investigate predictive biomarkers. This review provides a summary of the currently identified biomarkers associated with the extent of benefit from immuno-monotherapy or immunotherapy combined with chemotherapy in patients with advanced NSCLC. These biomarkers can be categorized into three groups: tumor-related, tumor-microenvironment-related, and host-factor-related.Tumor-related factors include PD-L1 expression, tumor mutational burden and specific genetic mutations, while tumor-microenvironment-related factors include extracellular vesicles and T-cell receptors, and host-related factors include systemic inflammation, circulating fatty acid profile, and the microbiome.

The prognostic biological markers of immunotherapy for non-small cell lung cancer: current landscape and future perspective

The emergence of immunotherapy, particularly programmed cell death 1 (PD-1) and programmed cell death ligand-1 (PD-L1) produced profound transformations for treating non-small cell lung cancer (NSCLC). Nevertheless, not all NSCLC patients can benefit from immunotherapy in clinical practice. In addition to limited response rates, exorbitant treatment costs, and the substantial threats involved with immune-related adverse events, the intricate interplay between long-term survival outcomes and early disease progression, including early immune hyperprogression, remains unclear. Consequently, there is an urgent imperative to identify robust predictive and prognostic biological markers, which not only possess the potential to accurately forecast the therapeutic efficacy of immunotherapy in NSCLC but also facilitate the identification of patient subgroups amenable to personalized treatment approaches. Furthermore, this advancement in patient stratification based on certain biological markers can also provide invaluable support for the management of immunotherapy in NSCLC patients. Hence, in this review, we comprehensively examine the current landscape of individual biological markers, including PD-L1 expression, tumor mutational burden, hematological biological markers, and gene mutations, while also exploring the potential of combined biological markers encompassing radiological and radiomic markers, as well as prediction models that have the potential to better predict responders to immunotherapy in NSCLC with an emphasis on some directions that warrant further investigation which can also deepen the understanding of clinicians and provide a reference for clinical practice.

Development and validation of blood tumor mutational burden reference standards

Tumor mutational burden (TMB), measured by exome or panel sequencing of tumor tissue or blood (bTMB), is a potential predictive biomarker for treatment benefit in patients with various cancer types receiving immunotherapy targeting checkpoint pathways. However, significant variability in TMB measurement has been observed. We developed contrived bTMB reference materials using DNA from tumor cell lines and donor-matched lymphoblastoid cell lines to support calibration and alignment across laboratories and platforms. Contrived bTMB reference materials were developed using genomic DNA from lung tumor cell lines blended into donor-matched lymphoblastoid cell lines at 0.5% and 2% tumor content, fragmented and size-selected to mirror the size profile of circulating cell-free tumor DNA with TMB scores of 7, 9, 20, and 26 mut/Mb. Variant allele frequency (VAF) and bTMB scores were assessed using PredicineATLAS and GuardantOMNI next-generation sequencing assays. DNA fragment sizes in the contrived reference samples were similar to those found within patient plasma-derived cell-free DNA, and mutational patterns aligned with those in the parental tumor lines. For the 7, 20, and 26 mut/Mb contrived reference samples with 2% tumor content, bTMB scores estimated using either assay aligned with expected scores from the parental tumor cell lines and showed good reproducibility. A bioinformatic filtration step was required to account for low-VAF artifact variants. We demonstrate the feasibility and challenges of producing and using bTMB reference standards across a range of bTMB levels, and how such standards could support the calibration and validation of bTMB platforms and help harmonization between panels and laboratories.

The diagnosis and treatment for a patient with cancer of unknown primary: A case report

Background: Cancer of unknown primary (CUP) is a class of metastatic malignant tumors whose primary location cannot be determined. The diagnosis and treatment of CUP are a considerable challenge for clinicians. Herein, we report a CUP case whose corresponding primary tumor sites were successfully identified, and the patient received proper treatment. Case report: In February 2022, a 74-year-old woman was admitted to the Medical Oncology Department at Sir Run Run Shaw Hospital for new lung and intestinal tumors after more than 9 years of breast cancer surgery. After laparoscopically assisted right hemicolectomy, pathology revealed mucinous adenocarcinoma; the pathological stage was pT2N0M0. Results from needle biopsies of lung masses suggested poorly differentiated cancer, ER (-), PR (-), and HER2 (-), which combined with the clinical history, did not rule out metastatic breast cancer. A surgical pathology sample was needed to determine the origin of the tumor tissue, but the patient's chest structure showed no indications for surgery. Analysis of the tumor's traceable gene expression profile prompted breast cancer, and analysis of next-generation amplification sequencing (NGS) did not obtain a potential drug target. We developed a treatment plan based on comprehensive immunohistochemistry, a gene expression profile, and NGS analysis. The treatment plan was formulated using paclitaxel albumin and capecitabine in combination with radiotherapy. The efficacy evaluation was the partial response (PR) after four cycles of chemotherapy and two cycles combined with radiotherapy. Conclusion: This case highlighted the importance of identifying accurate primary tumor location for patients to benefit from treatment, which will provide a reference for the treatment decisions of CUP tumors in the future.

Emerging Biomarkers in Immune Oncology to Guide Lung Cancer Management

Over the last decade, the use of targeted therapies and immune therapies led to drastic changes in the management lung cancer and translated to improved survival outcomes. This growing arsenal of therapies available for the management of non-small cell lung cancer added more complexity to treatment decisions. The genomic profiling of tumors and the molecular characterization of the tumor microenvironment gradually became essential steps in exploring and identifying markers that can enhance patient selection to facilitate treatment personalization and narrow down therapy options. The advent of innovative diagnostic platforms, such as next-generation sequencing and plasma genotyping (also known as liquid biopsies), has aided in this quest. Currently, programmed cell death ligand 1 expression remains the most recognized and fully validated predictive biomarker of response to immune checkpoint inhibitors. Other markers such as tumor mutational burden, tumor infiltrating lymphocytes, driver mutations, and other molecular elements of the tumor microenvironment bear the potential to be predictive tools; however, the majority are still investigational. In this review, we describe the advances noted thus far on currently validated as well as novel emerging biomarkers that have the potential to guide the use of immunotherapy agents in the management of non-small cell lung cancer.

Blood-based tumor mutational burden as a biomarker for atezolizumab in non-small cell lung cancer: the phase 2 B-F1RST trial

Tumor mutational burden (TMB) in circulating tumor DNA (ctDNA) has shown promise in predicting benefit from PD-L1/PD-1 inhibitors in retrospective studies. Aiming to assess blood TMB (bTMB) prospectively, we conducted B-F1RST (NCT02848651), an open-label, phase 2 trial that evaluated bTMB as a predictive biomarker for first-line atezolizumab monotherapy in locally advanced or metastatic stage IIIB–IVB non-small cell lung cancer (n = 152). The co-primary endpoints were investigator-assessed objective response rate (ORR) per RECIST version 1.1 and investigator-assessed progression-free survival (PFS) between high and low bTMB subgroups at the pre-defined bTMB ≥ 16 (14.5 mutations per megabase) cutoff. Secondary endpoints included investigator-assessed PFS, overall survival (OS) and duration of response at various bTMB cutoffs, as well as safety. Investigator-assessed PFS in the bTMB ≥ 16 versus bTMB < 16 groups was not statistically significant. However, bTMB ≥ 16 was associated with higher ORR, and ORR improved as bTMB cutoffs increased. No new safety signals were seen. In exploratory analyses, patients with maximum somatic allele frequency (MSAF) < 1% had higher ORR than patients with MSAF ≥ 1%. However, further analysis showed that this effect was driven by better baseline prognostics rather than by MSAF itself. At 36.5-month follow-up, an exploratory analysis of OS found that bTMB ≥ 16 was associated with longer OS than bTMB < 16. Further study and assay optimization will be required to develop bTMB as a predictive, standalone biomarker of immunotherapy or for use in conjunction with other biomarkers.

The randomized B-F1RST trial evaluating the clinical utility of blood tumor mutational burden as a predictor of benefit from atezolizumab in patients with advanced lung cancer did not meet its pre-specified primary objective, underscoring the need to further investigate the significance of bTMB as a relevant biomarker for patient selection.

Liquid Biopsy for Advanced NSCLC: A Consensus Statement From the International Association for the Study of Lung Cancer

Although precision medicine has had a mixed impact on the clinical management of patients with advanced-stage cancer overall, for NSCLC, and more specifically for lung adenocarcinoma, the advances have been dramatic, largely owing to the genomic complexity and growing number of druggable oncogene drivers. Furthermore, although tumor tissue is historically the "accepted standard" biospecimen for these molecular analyses, there are considerable innate limitations. Thus, liquid biopsy represents a practical alternative source for investigating tumor-derived somatic alterations. Although data are most robust in NSCLC, patients with other cancer types may also benefit from this minimally invasive approach to facilitate selection of targeted therapies. The liquid biopsy approach includes a variety of methodologies for circulating analytes. From a clinical point of view, plasma circulating tumor DNA is the most extensively studied and widely adopted alternative to tissue tumor genotyping in solid tumors, including NSCLC, first entering clinical practice for detection of EGFR mutations in NSCLC. Since the publication of the first International Association for the Study of Lung Cancer (IASLC) liquid biopsy statement in 2018, several additional advances have been made in this field, leading to changes in the therapeutic decision-making algorithm for advanced NSCLC and prompting this 2021 update. In view of the novel and impressive technological advances made in the past few years, the growing clinical application of plasma-based, next-generation sequencing, and the recent Food and Drug and Administration approval in the United States of two different assays for circulating tumor DNA analysis, IASLC revisited the role of liquid biopsy in therapeutic decision-making in a recent workshop in October 2020 and the question of "plasma first" versus "tissue first" approach toward molecular testing for advanced NSCLC. Moreover, evidence-based recommendations from IASLC provide an international perspective on when to order which test and how to interpret the results. Here, we present updates and additional considerations to the previous statement article as a consensus from a multidisciplinary and international team of experts selected by IASLC.

A clinical variable-based nomogram could predict the survival for advanced NSCLC patients receiving second-line atezolizumab

Objective

A nomogram model based on clinical variables was conducted to predict the survival in patients with non‐small cell lung cancer (NSCLC) receiving second‐line atezolizumab.

Methods

Four hundred and twenty‐four patients with NSCLC receiving atezolizumab from OAK study were regarded as the training cohort. Next, a nomogram model based on clinical variables in the training cohort was established to predict the survival of patients receiving atezolizumab. The concordance index, area under curve (AUC), and calibration plots were used to assess the performance of the nomogram model. In addition, 144 patients with NSCLC receiving atezolizumab from POPLAR study were regarded as the test cohort to validate the nomogram model. Using Kaplan–Meier and log‐rank test, we compared the survival difference between the high‐ and low‐risk groups, atezolizumab and docetaxel treatment groups, respectively.

Results

We successfully constructed a nomogram model based on different variable scores for predicting the survival in NSCLC patients receiving atezolizumab using the training cohort. According to risk score, patients receiving atezolizumab were divided into the high‐ and low‐risk groups. Importantly, in the training cohort, patients had worse overall survival (OS) in high‐risk group compared with the low‐risk group (median survival: 252.3 vs. 556.9 days; p < 0.0001). As expected, in the test cohort, the high‐risk patients also showed a worse OS (median survival: 288.8 vs. 529.3 days, p = 0.0003). In addition, all the patients from the training and test cohorts could be found the OS benefit from atezolizumab compared with docetaxel (all, p < 0.05).

Conclusions

The clinical variable‐based nomogram model could predict the survival benefit for NSCLC patients receiving second‐line atezolizumab.

Prognostic Role of Tumor Mutational Burden in Cancer Patients Treated With Immune Checkpoint Inhibitors: A Systematic Review and Meta-Analysis

Purpose

Immunotherapy is regarded as the most promising treatment for cancer. However, immune checkpoint inhibitors (ICIs) are not effective for all patients. Herein, we conducted a systematic review and meta-analysis to explore whether tumor mutational burden (TMB) can be used as a potential prognostic biomarker for cancer patients treated with ICIs.

Methods

We systematically retrieved relevant literature published in the PubMed, Embase, Web of Science, and Cochrane databases up to December 28, 2020. All cohort studies and clinical trials that reported hazard ratios (HRs) for overall (OS) and progression-free survival (PFS), as well as the corresponding 95% confidence intervals (CIs) of high and low TMB patients, were included. All statistical analyses were performed using the R software.

Results

Pooled results from a total of 32 studies with 6,131 participants showed significantly increased OS (HR: 0.61, 95% CI: 0.53–0.71; P <0.01) and PFS (HR: 0.51, 95% CI: 0.44–0.60; P <0.01) for the high TMB group receiving ICIs as compared to the low TMB group. Particularly, results were found to be more significant in studies with larger sample sizes (≥30), Western patients, higher TMB cutoff values (≥20 mut/Mb), anti–PD-1 therapy, and when the sample source was tissue and tumor type was either melanoma, small cell lung cancer, or gastric cancer.

Conclusion

TMB is a promising independent prognostic biomarker for cancer patients receiving ICIs, which could provide a new potential therapeutic strategy for high TMB patients who have failed traditional therapy. Furthermore, consistency in the key aspects of TMB assessment is expected in the future.

Systematic Review Registration

[https://www.crd.york.ac.uk/PROSPERO], Prospective Register of Systematic Reviews (PROSPERO), identifier: CRD42021229016.

[Current landscape of biomarker development for immune checkpoint inhibitors targeting PD-1/PD-L1 pathway in oncology]

The immune checkpoints inhibitors targeting PD-1 or PD-L1 represent a new paradigm in the cancer treatment strategy. However, some populations of patients do not benefit from these agents. The identification of predictive biomarkers appears as an essential step for the treatment pathway, to guarantee the access to an evidence-based medicine accounting for the potential toxicity profile, the cost for the healthcare system and the clinical benefit eventually provided by these new drugs. In this review, we propose, based on scientific literature and industrial communications, an overview of the current landscape of predictive biomarkers related to PD-1 or PD-L1 inhibitors efficacy, validated or under development, their evidence level, and limits accounting for identified or potential confounding factors. Our paper shows that, despite the important amount of work performed in this field, there is not yet a validated and efficient solution for the prediction of the activity and/or the toxicity of anti-PD-1 and anti-PD-L1 antibodies.

Blood Tumor Mutational Burden as a Predictive Biomarker in Patients With Advanced Non-Small Cell Lung Cancer (NSCLC)

This study was designed to investigate the impact of blood tumor mutational burden (bTMB) on advanced NSCLC in Southwest China. The relationship between the tTMB estimated by next-generation sequencing (NGS) and clinical outcome was retrospectively analyzed in tissue specimens from 21 patients with advanced NSCLC. Furthermore, the relationship between the bTMB estimated by NGS and clinical outcome was retrospectively assessed in blood specimens from 70 patients with advanced NSCLC. Finally, 13 advanced NSCLC patients were used to evaluate the utility of bTMB assessed by NGS in differentiating patients who would benefit from immunotherapy. In the tTMB group, tTMB ≥ 10 mutations/Mb was related to inferior progression-free survival (PFS) (hazard ratio [HR], 0.30; 95% CI, 0.08-1.17; log-rank P = 0.03) and overall survival (OS) (HR, 0.30; 95% CI, 0.08-1.16; log-rank P = 0.03). In the bTMB group, bTMB ≥ 6 mutations/Mb was associated with inferior PFS (HR, 0.32; 95% CI, 0.14-1.35; log-rank P < 0.01) and OS (HR, 0.31; 95% CI, 0.14-0.7; log-rank P < 0.01). In the immunotherapy section, bTMB ≥ 6 mutations/Mb was related to superior PFS (HR, 0.32; 95% CI, 0.14-1.35; log-rank P < 0.01) and objective response rates (ORRs) (bTMB < 6: 14.2%; 95% CI, 0.03-1.19; bTMB ≥ 6: 83.3%; 95% CI, 0.91-37.08; P = 0.02). These findings suggest that bTMB is a validated predictive biomarker for determining the clinical outcome of advanced NSCLC patients and may serve as a feasible predictor of the clinical benefit of immunotherapies (anti-PD-1 antibody) in the advanced NSCLC population in Yunnan Province.

PD-(L)1 Inhibitors as Monotherapy for the First-Line Treatment of Non-Small-Cell Lung Cancer Patients with High PD-L1 Expression: A Network Meta-Analysis

Programmed cell death-ligand 1 (PD-L1) has emerged as a potential biomarker for selection of patients more likely to respond to immunotherapy and as a prognostic factor in non-small cell lung cancer (NSCLC). In this network meta-analysis, we aimed to evaluate the efficacy of first-line anti-PD-(L)1 monotherapy in advanced NSCLC patients with high PD-L1 expression (≥50%) compared to platinum-based chemotherapy. We also evaluated efficacy outcomes according to tumor mutational burden (TMB). To that end, we conducted a systematic review. Six clinical trials with 2111 patients were included. In head-to-head comparisons, immunotherapy showed a significant improvement in progression-free survival (PFS: HRpooled = 0.69, 95% CI: 0.52-0.90, p = 0.007), overall survival (OS: HRpooled = 0.69, 95% CI: 0.61-0.78; p < 0.001) and overall response rate (ORR) (Risk ratio (RR)pooled = 1.354, 95% CI: 1.04-1.762, p = 0.024). In the assessment of relative efficacy for PFS through indirect comparisons, pembrolizumab (results from KEYNOTE-024) ranked highest followed by cemiplimab and atezolizumab, with statistical significance determined for some of the drugs. In terms of OS, cemiplimab ranked highest followed by atezolizumab and pembrolizumab, although non-significant OS was determined for these drugs. In conclusion, PD-(L)1 inhibitor monotherapy improves efficacy outcomes in the first line setting of advanced NSCLC patients with high PD-L1 expression. Evaluations with longer follow up are still needed to determine the superiority of any specific drug.

Biomarkers of Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer: Beyond PD-L1

Immunotherapy has markedly improved the survival rate of patients with non-small cell lung cancer (NSCLC) and has introduced a new era in lung cancer treatment. Although some patients achieve durable responses to checkpoint blockade, not all experience such benefits, and some suffer from significant immunotoxicities. Thus, it is crucial to identify potential biomarkers suitable for screening the population that may benefit from immunotherapy. Based on the current clinical trials, the aim of the present study was to review the biomarkers for immune checkpoint inhibition that may have the potential to predict the response to immunotherapy in patients with lung cancer. A non-systematic literature review was done. We searched for eligible randomized controlled trials (RCTs) from PubMed, Embase, and the Cochrane Central Register of Controlled Trials from January 2015 to January 2021. The keywords included biomarkers, immunotherapy, immune checkpoint inhibition, programmed death ligand 1 (PD-L1), and non-small cell lung cancer. Additional biomarkers beyond PD-L1 that have been shown to have predictive capacity include tumor mutational burden, microsatellite instability, lung immune prognostic index, gut microbiome, and certain alterations in genes (eg, STK11 deletion, LKB1 kinase mutation, MDM2/4 amplification) that confer immunoresistance. The biomarkers reviewed in this article could help us better select the appropriate immunotherapy treatment for patients with NSCLC.

The Predictive Efficacy of Tumor Mutation Burden (TMB) on Nonsmall Cell Lung Cancer Treated by Immune Checkpoint Inhibitors: A Systematic Review and Meta-Analysis

BACKGROUND

Nonsmall cell lung cancer (NSCLC) is the most common type of lung cancer, and the majority of NSCLC patients are diagnosed at the advanced stage. Chemotherapy is still the main treatment at present, and the overall prognosis is poor. In recent years, immunotherapy has developed rapidly. Immune checkpoint inhibitors (ICIs) as the representative have been extensively applied for treating various types of cancers. Tumor mutation burden (TMB) as a potential biomarker is used to screen appropriate patients for treatment of ICIs. To verify the predictive efficacy of TMB, a systematic review and meta-analysis were conducted to explore the association between TMB and ICIs.

METHOD

PubMed, EMBASE, Cochrane Library, and son on were systematically searched from inception to April 2020. Objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) were estimated.

RESULTS

A total of 11 studies consisting of 1525 nonsmall cell lung cancer (NSCLC) patients were included. Comparison of high and low TMB: pooled HRs for OS, 0.57 (95% CI 0.32 to 0.99; P = 0.046); PFS, 0.48 (95% CI 0.33 to 0.69; P < 0.001); ORR, 3.15 (95% CI 2.29 to 4.33; P < 0.001). Subgroup analysis values: pooled HRs for OS, 0.75 (95% CI 0.29 to 1.92, P = 0.548) for blood TMB (bTMB), 0.44 (95% CI 0.26 to 0.75, P = 0.003) for tissue TMB (tTMB); for PFS, 0.54 (95% CI 0.29 to 0.98, P = 0.044) and 0.43 (95% CI 0.26 to 0.71, P = 0.001), respectively.

CONCLUSIONS

These findings imply that NSCLC patients with high TMB possess significant clinical benefits from ICIs compared to those with low TMB. As opposed to bTMB, tTMB was thought more appropriate for stratifying NSCLC patients for ICI treatment.

The Challenges of Tumor Mutational Burden as an Immunotherapy Biomarker

Tumor mutational burden (TMB) reflects cancer mutation quantity. Mutations are processed to neo-antigens and presented by major histocompatibility complex (MHC) proteins to T cells. To evade immune eradication, cancers exploit checkpoints that dampen T cell reactivity. Immune checkpoint inhibitors (ICIs) have transformed cancer treatment by enabling T cell reactivation; however, response biomarkers are required, as most patients do not benefit. Higher TMB results in more neo-antigens, increasing chances for T cell recognition, and clinically correlates with better ICI outcomes. Nevertheless, TMB is an imperfect response biomarker. A composite predictor that also includes critical variables, such as MHC and T cell receptor repertoire, is needed.

Durvalumab With or Without Tremelimumab vs Standard Chemotherapy in First-line Treatment of Metastatic Non-Small Cell Lung Cancer: The MYSTIC Phase 3 Randomized Clinical Trial

Question

Does first-line durvalumab treatment with or without tremelimumab improve survival outcomes vs chemotherapy in patients with metastatic non–small cell lung cancer?

Findings

In this phase 3 randomized clinical trial including 1118 patients with non–small cell lung cancer, although the trial did not meet its primary end points, treatment with durvalumab resulted in a numerically reduced risk of death vs chemotherapy in patients with programmed cell death ligand 1 expression on at least 25% of tumor cells. In exploratory analyses, a blood tumor mutational burden threshold of at least 20 mutations per megabase was identified for optimal clinical benefit with durvalumab plus tremelimumab vs chemotherapy.

Meaning

These findings highlight the need for further investigation and prospective validation of blood tumor mutational burden as a predictive biomarker for immunotherapy.

Importance

Checkpoint inhibitors targeting programmed cell death 1 or its ligand (PD-L1) as monotherapies or in combination with anti–cytotoxic T-lymphocyte–associated antigen 4 have shown clinical activity in patients with metastatic non–small cell lung cancer.

Objective

To compare durvalumab, with or without tremelimumab, with chemotherapy as a first-line treatment for patients with metastatic non–small cell lung cancer.

Design, Setting, and Participants

This open-label, phase 3 randomized clinical trial (MYSTIC) was conducted at 203 cancer treatment centers in 17 countries. Patients with treatment-naive, metastatic non–small cell lung cancer who had no sensitizing EGFR or ALK genetic alterations were randomized to receive treatment with durvalumab, durvalumab plus tremelimumab, or chemotherapy. Data were collected from July 21, 2015, to October 30, 2018.

Interventions

Patients were randomized (1:1:1) to receive treatment with durvalumab (20 mg/kg every 4 weeks), durvalumab (20 mg/kg every 4 weeks) plus tremelimumab (1 mg/kg every 4 weeks, up to 4 doses), or platinum-based doublet chemotherapy.

Main Outcomes and Measures

The primary end points, assessed in patients with ≥25% of tumor cells expressing PD-L1, were overall survival (OS) for durvalumab vs chemotherapy, and OS and progression-free survival (PFS) for durvalumab plus tremelimumab vs chemotherapy. Analysis of blood tumor mutational burden (bTMB) was exploratory.

Results

Between July 21, 2015, and June 8, 2016, 1118 patients were randomized. Baseline demographic and disease characteristics were balanced between treatment groups. Among 488 patients with ≥25% of tumor cells expressing PD-L1, median OS was 16.3 months (95% CI, 12.2-20.8) with durvalumab vs 12.9 months (95% CI, 10.5-15.0) with chemotherapy (hazard ratio [HR], 0.76; 97.54% CI, 0.56-1.02; P = .04 [nonsignificant]). Median OS was 11.9 months (95% CI, 9.0-17.7) with durvalumab plus tremelimumab (HR vs chemotherapy, 0.85; 98.77% CI, 0.61-1.17; P = .20). Median PFS was 3.9 months (95% CI, 2.8-5.0) with durvalumab plus tremelimumab vs 5.4 months (95% CI, 4.6-5.8) with chemotherapy (HR, 1.05; 99.5% CI, 0.72-1.53; P = .71). Among 809 patients with evaluable bTMB, those with a bTMB ≥20 mutations per megabase showed improved OS for durvalumab plus tremelimumab vs chemotherapy (median OS, 21.9 months [95% CI, 11.4-32.8] vs 10.0 months [95% CI, 8.1-11.7]; HR, 0.49; 95% CI, 0.32-0.74). Treatment-related adverse events of grade 3 or higher occurred in 55 (14.9%) of 369 patients who received treatment with durvalumab, 85 (22.9%) of 371 patients who received treatment with durvalumab plus tremelimumab, and 119 (33.8%) of 352 patients who received treatment with chemotherapy. These adverse events led to death in 2 (0.5%), 6 (1.6%), and 3 (0.9%) patients, respectively.

Conclusions and Relevance

The phase 3 MYSTIC study did not meet its primary end points of improved OS with durvalumab vs chemotherapy or improved OS or PFS with durvalumab plus tremelimumab vs chemotherapy in patients with ≥25% of tumor cells expressing PD-L1. Exploratory analyses identified a bTMB threshold of ≥20 mutations per megabase for optimal OS benefit with durvalumab plus tremelimumab.

Trial Registration

ClinicalT rials.gov Identifier: NCT02453282

STK11 (LKB1) mutations in metastatic NSCLC: Prognostic value in the real world

BACKGROUND

Mutations in STK11 (STK11m) and frequently co-occurring KRAS mutations (KRASm/STK11m) are associated with poor survival in metastatic NSCLC (mNSCLC) immuno-oncology trials. There are limited data regarding the prognostic significance of these mutations in a real-world setting.

METHODS

This retrospective cohort study analyzed de-identified electronic medical records from the Flatiron Clinico-Genomic database to identify patients with mNSCLC who had initiated first-line immunotherapy (IO; alone or in combination) or chemotherapy under routine care between January 1, 2013 and June 30, 2017. The primary objectives were to assess the prevalence of STK11m and KRASm/STK11m and to determine associations of these mutations with overall and progression-free survival (OS, PFS).

RESULTS

Of 2407 patients with mNSCLC, STK11m and KRASm/STK11m were present in 13.6% and 6.5% of patients, respectively. Worse OS outcomes were observed in patients with STK11m versus STK11wt mNSCLC receiving IO (first-line, HR [95% CI], 1.4 [0.9-2.3; p = 0.1]; second-line [subset of first-line cohort], HR, 1.6 [1.3-2.0; p = 0.0002]) or chemotherapy (first-line, HR, 1.4 [1.2-1.6; p < 0.0001]); PFS outcomes showed similar trends. KRASm/STK11m double mutations were associated with worse OS and PFS outcomes versus KRASwt/STK11wt with IO and chemotherapy, similar to the single mutation (STK11m vs STK11wt) findings.

CONCLUSIONS

This large observational genomic study among patients receiving routine care highlights the negative prognostic impact of STK11m in patients with mNSCLC treated with IO or chemotherapy. These results complement previous clinical trial data and provide further evidence in the real world of a patient population that would benefit from new treatment options.

Choosing tumor mutational burden wisely for immunotherapy: A hard road to explore

Immunotherapy has revolutionized the treatment of cancer due to its remarkable efficacy and extensive survival benefit in multiple tumor types. However, predictive biomarkers are required to identify patients who are likely to respond to immunotherapy. Recently, tumor mutational burden (TMB) has been shown to be associated with clinical outcomes in diverse cancers, such as melanoma, non-small-cell lung cancer and colorectal cancer. Several studies have demonstrated that high TMB can effectively predict the objective response rate and progression-free survival, but the ability of TMB to predict overall survival is limited. Thus, the clinical utility of TMB as a predictive and prognostic biomarker in immunotherapy is currently controversial. Importantly, multiple factors can affect the accurate assessment of TMB and further interfere with its prediction of clinical outcomes. These factors include preanalytical factors such as sample status, analytical factors such as differences in platforms and methods for determining TMB and variability of cutoff values, and postanalytical factors such as inconsistent interpretation and reporting of results. In addition, the optimal definition and quantification of TMB are unclear and require harmonization and standardization for reliable clinical application. This review elaborates on the factors affecting TMB status in primary tumors, summarizes the clinical utility of TMB as a biomarker in immunotherapy, and evaluates the impact of each analysis stage on the accurate estimation of TMB, especially its quantification, aiming to facilitate TMB assessment in routine clinical settings.

Relationship Between Progression-Free Survival, Objective Response Rate, and Overall Survival in Clinical Trials of PD-1/PD-L1 Immune Checkpoint Blockade: A Meta-Analysis

PD-1/PD-L1 immune checkpoint blockade (ICB) has improved overall survival (OS) in solid tumor trials; however, parallel improvements in Response Evaluation Criteria in Solid Tumors (RECIST)-based surrogate end points, progression-free survival (PFS), and objective response rate (ORR), are not always observed. Here, we assess the surrogacy of PFS/ORR for OS with ICB therapy across advanced/metastatic tumors. In a trial-level analysis (N = 40 randomized trials), PFS, ORR, and OS treatment effects were correlated (Spearman's rho). In a patient-level analysis, data were extracted from available trials of durvalumab; the correlation of PFS and OS was evaluated (Bayesian normal-induced-copula-estimation model) and the ordinal association between objective response and OS hazard ratio (HR) were assessed with concordance index measures. High correlation was observed between PFS HR and OS HR in intention-to-treat (ITT; rho = 0.76) and PD-L1-enriched populations (0.74); modest (or limited) benefit in PFS was associated with meaningful improvement in OS. Moderate correlations were observed between ΔORR and OS HR: ITT, -0.63; PD-L1-enriched, -0.53. At the patient level, a positive association was observed between PFS and OS in non-small cell lung cancer (Kendall's Tau = 0.793; 95% confidence interval, 0.789-0.797), head and neck squamous cell carcinoma (0.794; 0.789-0.798), and bladder cancer (0.872; 0.869-0.875). Objective responders had significantly better OS (concordance index > 0.9) than nonresponders across these tumor types. Modest (or limited) improvement in RECIST-based end points did not rule out meaningful OS benefit, indicating they are imperfect surrogates and do not fully capture ICB clinical benefit. Therefore, caution is advised when basing early discontinuation of novel ICB agents on these end points.

Resistance to immune checkpoint inhibitors in non-small cell lung cancer: biomarkers and therapeutic strategies

The treatment landscape for patients with advanced non-small cell lung cancer has evolved greatly with the advent of immune checkpoint inhibitors. However, many patients do not derive benefit from checkpoint blockade, developing either primary or secondary resistance, highlighting a need for alternative approaches to modulate immune function. In this review, we highlight the absence of a common definition of primary and secondary resistance and summarize their frequency and clinical characteristics. Furthermore, we provide an overview of the biomarkers and mechanisms of resistance involving the tumor, the tumor microenvironment and the host, and suggest treatment strategies to overcome these mechanisms and improve clinical outcomes.

Double immune checkpoint blockade in advanced NSCLC

Immunotherapy-based options for patients with advanced non-small cell lung cancer (NSCLC) are increasing at an unprecedented pace, carrying the promise to prolong survival of this deadly disease. To maximize responses and extend benefit to a larger portion of patients, immunotherapy combination strategies are currently under investigation, with chemo-immunotherapy already in use. Combinations of programmed death-1/ligand-1 (PD-1/L1) and cytotoxic T lymphocytes antigen-4 (CTLA-4) were developed with the rationale of targeting complementary pathways involved in T cell activation, and already showed to be highly active in other malignancies. Recently, the phase III Checkmate 227 trial showed that combination of nivolumab and ipilimumab provided survival benefit in untreated advanced NSCLC patients. However, accurate patients' selection and appropriate sequencing of different immunotherapy-based approaches remain unsolved. In this review, we provide an overview of the currently available evidence on double immune checkpoint inhibition (ICI) for NSCLC treatment and discuss current issues and future perspectives.

Precision Medicine for NSCLC in the Era of Immunotherapy: New Biomarkers to Select the Most Suitable Treatment or the Most Suitable Patient

In recent years, the evolution of treatments has made it possible to significantly improve the outcomes of patients with non-small cell lung cancer (NSCLC). In particular, while molecular targeted therapies are effective in specific patient sub-groups, immune checkpoint inhibitors (ICIs) have greatly influenced the outcomes of a large proportion of NSCLC patients. While nivolumab activity was initially assessed irrespective of predictive biomarkers, subsequent pivotal studies involving other PD-1/PD-L1 inhibitors in pre-treated advanced NSCLC (atezolizumab within the OAK study and pembrolizumab in the Keynote 010 study) reported the first correlations between clinical outcomes and PD-L1 expression. However, PD-L1 could not be sufficient on its own to select patients who may benefit from immunotherapy. Many studies have tried to discover more precise markers that are derived from tumor tissue or from peripheral blood. This review aims to analyze any characteristics of the immunogram that could be used as a predictive biomarker for response to ICIs. Furthermore, we describe the most important genetic alteration that might predict the activity of immunotherapy.

Baseline Plasma Tumor Mutation Burden Predicts Response to Pembrolizumab-based Therapy in Patients with Metastatic Non-Small Cell Lung Cancer

PURPOSE

The role of plasma-based tumor mutation burden (pTMB) in predicting response to pembrolizumab-based first-line standard-of-care therapy for metastatic non-small cell lung cancer (mNSCLC) has not been explored.

EXPERIMENTAL DESIGN

A 500-gene next-generation sequencing panel was used to assess pTMB. Sixty-six patients with newly diagnosed mNSCLC starting first-line pembrolizumab-based therapy, either alone or in combination with chemotherapy, were enrolled (Clinicaltrial.gov identifier: NCT03047616). Response was assessed using RECIST 1.1. Associations were made for patient characteristics, 6-month durable clinical benefit (DCB), progression-free survival (PFS), and overall survival (OS).

RESULTS

Of 66 patients, 52 (78.8%) were pTMB-evaluable. Median pTMB was 16.8 mutations per megabase (mut/Mb; range, 1.9-52.5) and was significantly higher for patients achieving DCB compared with no durable benefit (21.3 mut/Mb vs. 12.4 mut/Mb, P = 0.003). For patients with pTMB ≥ 16 mut/Mb, median PFS was 14.1 versus 4.7 months for patients with pTMB < 16 mut/Mb [HR, 0.30 (0.16-0.60); P < 0.001]. Median OS for patients with pTMB ≥ 16 was not reached versus 8.8 months for patients with pTMB < 16 mut/Mb [HR, 0.48 (0.22-1.03); P = 0.061]. Mutations in ERBB2 exon 20, STK11, KEAP1, or PTEN were more common in patients with no DCB. A combination of pTMB ≥ 16 and absence of negative predictor mutations was associated with PFS [HR, 0.24 (0.11-0.49); P < 0.001] and OS [HR, 0.31 (0.13-0.74); P = 0.009].

CONCLUSIONS

pTMB ≥ 16 mut/Mb is associated with improved PFS after first-line standard-of-care pembrolizumab-based therapy in mNSCLC. STK11/KEAP1/PTEN and ERBB2 mutations may help identify pTMB-high patients unlikely to respond. These results should be validated in larger prospective studies.

Assessment of Blood Tumor Mutational Burden as a Potential Biomarker for Immunotherapy in Patients With Non-Small Cell Lung Cancer With Use of a Next-Generation Sequencing Cancer Gene Panel

Question

Is blood tumor mutational burden estimated by a next-generation gene sequencing panel with an optimized panel size and algorithm associated with clinical outcomes in patients with non–small cell lung cancer treated with anti–programmed cell death 1 (anti–PD-1) and anti–programmed cell death ligand 1 (anti–PD-L1) agents?

Findings

This study of 2 independent cohorts of patients (48 in cohort 1 and 50 in cohort 2) found that NCC-GP150 was a cost-effective panel for tumor mutational burden estimation with satisfactory performance. Blood tumor mutational burden estimated by NCC-GP150 correlated well with tissue tumor mutational burden calculated by whole-exome sequencing, and a blood tumor mutational burden of 6 or higher was positively associated with clinical benefits of anti–PD-1 and anti–PD-L1 therapy in patients with advanced non–small cell lung cancer.

Meaning

The findings suggest that blood tumor mutational burden measured by NCC-GP150 is a potential biomarker to identify patients with non–small cell lung cancer who could benefit from anti–PD-1 and anti–PD-L1 therapy.

Importance

Tumor mutational burden (TMB), as measured by whole-exome sequencing (WES) or a cancer gene panel (CGP), is associated with immunotherapy responses. However, whether TMB estimated by circulating tumor DNA in blood (bTMB) is associated with clinical outcomes of immunotherapy remains to be explored.

Objectives

To explore the optimal gene panel size and algorithm to design a CGP for TMB estimation, evaluate the panel reliability, and further validate the feasibility of bTMB as a clinical actionable biomarker for immunotherapy.

Design, Setting, and Participants

In this cohort study, a CGP named NCC-GP150 was designed and virtually validated using The Cancer Genome Atlas database. The correlation between bTMB estimated by NCC-GP150 and tissue TMB (tTMB) measured by WES was evaluated in matched blood and tissue samples from 48 patients with advanced NSCLC. An independent cohort of 50 patients with advanced NSCLC was used to identify the utility of bTMB estimated by NCC-GP150 in distinguishing patients who would benefit from anti–programmed cell death 1 (anti–PD-1) and anti–programmed cell death ligand 1 (anti–PD-L1) therapy. The study was performed from July 19, 2016, to April 20, 2018.

Main Outcomes and Measures

Assessment of the Spearman correlation coefficient between bTMB estimated by NCC-GP150 and tTMB calculated by WES. Evaluation of the association of bTMB level with progression-free survival and response to anti–PD-1 and anti–PD-L1 therapy.

Results

This study used 2 independent cohorts of patients with NSCLC (cohort 1: 48 patients; mean [SD] age, 60 [13] years; 15 [31.2%] female; cohort 2: 50 patients; mean [SD] age, 58 [8] years; 15 [30.0%] female). A CGP, including 150 genes, demonstrated stable correlations with WES for TMB estimation (median r² = 0.91; interquartile range, 0.89-0.92), especially when synonymous mutations were included (median r² = 0.92; interquartile range, 0.91-0.93), whereas TMB estimated by the NCC-GP150 panel found higher correlations with TMB estimated by WES than most of the randomly sampled 150-gene panels. Blood TMB estimated by NCC-GP150 correlated well with the matched tTMB calculated by WES (Spearman correlation = 0.62). In the anti–PD-1 and anti–PD-L1 treatment cohort, a bTMB of 6 or higher was associated with superior progression-free survival (hazard ratio, 0.39; 95% CI, 0.18-0.84; log-rank P = .01) and objective response rates (bTMB ≥6: 39.3%; 95% CI, 23.9%-56.5%; bTMB <6: 9.1%; 95% CI, 1.6%-25.9%; P = .02).

Conclusions and Relevance

The findings suggest that established NCC-GP150 with an optimized gene panel size and algorithm is feasible for bTMB estimation, which may serve as a potential biomarker of clinical benefit in patients with NSCLC treated with anti–PD-1 and anti–PD-L1 agents.

Role of liquid biopsy for thoracic cancers immunotherapy

Immunotherapy has shifted the therapeutic landscape in thoracic cancers. However, assessment of biomarkers for patient selection and disease monitoring remain challenging, especially considering the lack of tissue sample availability for clinical and research purposes. In this scenario, liquid biopsy (LB), defined as the study and characterization of biomarkers in body fluids, represents a useful alternative strategy. In other malignancies such as colorectal cancer, breast cancer or melanoma, the potential of LB has been more extensively explored for monitoring minimal residual disease or response to treatment, and to investigate mechanisms of resistance to targeted agents. Even if various experiences have already been published about the applications of LB in immunotherapy in thoracic cancers, the standardization of methodology and assessment of its clinical utility is still pending. In this review, the authors will focus on the applications of LB in immunotherapy in non-small cell lung cancer, small cell lung cancer, and malignant pleural mesothelioma, describing available data and future perspectives.

Allele Frequency-Adjusted Blood-Based Tumor Mutational Burden as a Predictor of Overall Survival for Patients With NSCLC Treated With PD-(L)1 Inhibitors

INTRODUCTION

Blood-based tumor mutational burden (bTMB) has been studied to identify patients with NSCLC who would benefit from anti-programmed cell death protein 1 (anti-PD-1) or anti-programmed death ligand 1 (anti-PD-L1) therapies. However, it failed to predict overall survival (OS) benefits, which warrants further exploration.

METHODS

Three independent cohorts of patients with NSCLC treated with immunotherapy were used in this study. A new bTMB algorithm was first developed in the two independent cohorts (POPLAR, N = 211, and OAK, N = 462) and further validated in the third National Cancer Center (NCC) cohort (N = 64).

RESULTS

bTMB-H (bTMB ≥ cutoff point) was not associated with favorable OS after immunotherapy regardless of the cutoff points in either the POPLAR and OAK or the NCC cohorts (p > 0.05) owing to its correlation with the amount of circulating tumor DNA, which was associated with poor OS. In the POPLAR and OAK cohorts, with allele frequency (AF) adjustment, a high AF bTMB (HAF-bTMB, mutation counts with an AF > 5%) was strongly correlated with the amount of circulating tumor DNA (Pearson r = 0.65), whereas a low AF bTMB (LAF-bTMB, mutation counts with an AF ≤ 5%) was not (Pearson r = 0.09). LAF-bTMB-H was associated with favorable OS (hazard ratio [HR] = 0.70, 95% confidence interval [CI]: 0.52-0.95, p = 0.02), progression-free survival (PFS; HR = 0.62, 95% CI: 0.47-0.80, p < 0.001), and objective response rate (ORR) (p < 0.001) after immunotherapy but not chemotherapy, with a cutoff point of 12 trained in the POPLAR cohort and validated in the OAK cohort. The LAF-bTMB algorithm was further validated in the NCC cohort in which LAF-bTMB-H was associated with OS (HR = 0.20, 95% CI: 0.05-0.84, p = 0.02), PFS (HR = 0.30, 95% CI: 0.13-0.70, p = 0.003), and ORR (p = 0.001).

CONCLUSIONS

We developed and validated a new LAF-bTMB algorithm as a feasible predictor of OS, PFS, and ORR after anti-PD-(L)1 therapies in patients with NSCLC, which needs to be prospectively validated.

The evolving use of pembrolizumab in combination treatment approaches for non-small cell lung cancer

Introduction: The immune checkpoint inhibitor, pembrolizumab, has revolutionized the treatment of non-small cell lung cancer (NSCLC). It is currently approved and widely used in patients with advanced NSCLC whose tumors have no EGFR or ALK genomic aberrations that express PD-L1 as single-agent treatment and irrespective of PD-L1 expression in combination with platinum-based doublet chemotherapy in the first-line setting.Areas covered: The authors have reviewed articles discussing pembrolizumab and NSCLC in MEDLINE between July 2013 to August 2019 and focus on recent advances in combining pembrolizumab with chemotherapy, radiotherapy and other novel agents in various stages of NSCLC.Expert opinion: Although pembrolizumab has revolutionized the treatment of advanced NSCLC, only a subset of patients benefit from single-agent therapy. Numerous trials combining pembrolizumab with chemotherapy and radiation have shown benefit and a large spectrum of novel combination strategies are being explored for improved synergies. In addition to PD-L1 tumor proportion score, validation of other biomarkers would be beneficial in stratifying patients and improving the predictive value of combining immune check point inhibitors and chemotherapy.

Liquid biopsy tracking of lung tumor evolutions over time

Introduction: The rise of the personalized era in lung cancer prompted the evaluation of novel diagnostic tools to overcome some of the limits of traditional tumor genotyping. Liquid biopsy refers to a multitude of minimally invasive techniques that can allow a real-time biomolecular characterization of the tumor through the analysis of human body fluids.Areas covered: Herein we provide a comprehensive overview of the role of liquid biopsy in lung cancer, mainly focusing on the most studied members of the liquid biopsy family, cell-free DNA (cfDNA) and circulating tumor cells (CTCs).Expert opinion: Among the different components of the large liquid biopsy family, cfDNA is the most studied and widely adopted source for tumor genotyping in lung cancer, already entered clinical practice for detection of both sensitizing and resistance EGFR mutations. However, the impressive technological advances made in the last few years are expanding its potential applications, allowing a more comprehensive plasma genotyping through next-generation sequencing and moving from advanced/metastatic disease to novel frontiers, such as early detection and minimal residual disease evaluation.

The evolving immuno-oncology landscape in advanced lung cancer: first-line treatment of non-small cell lung cancer

Lung cancer is the most common cancer and leading cause of cancer death. While targeted therapies have redefined treatment options for non-small cell lung carcinoma (NSCLC) with genetic aberrations such as epidermal growth factor and anaplastic lymphoma kinase, many patients do not harbour these oncogenic drivers. Cancer immunology has enabled the development of immune modulators that has dramatically altered the therapeutic landscape of advanced NSCLC. The success of immune-checkpoint inhibitors in pretreated NSCLC has led to the conduct of multiple studies exploring their role in the first-line setting. This article provides an overview of the evolving landscape of immune-checkpoint inhibitors with a focus on the programmed cell-death 1 (PD-1; pembrolizumab, nivolumab) and programmed cell-death ligand 1 (PD-L1; atezolizumab, durvalumab, avelumab) immune-checkpoint inhibitors as single agent or in combination with either chemotherapy or with another immune-checkpoint inhibitor in the treatment of NSCLC, the challenges faced, as well as future perspectives.

First-line immune checkpoint blockade for advanced non-small-cell lung cancer: Travelling at the speed of light

The development of PD-1, PD-L1 and CTLA-4 immune checkpoint inhibitors (CPI) has revolutionised the treatment of advanced non-small cell lung cancer (NSCLC). The potential of immunotherapy (IO) to induce durable responses for a subset of patients represents a therapeutic milestone. After the approval of front-line single agent pembrolizumab, IO-based combinations are rapidly entering clinical practice resulting in a fast change of treatment algorithms for advanced NSCLC. We hereby summarize the recent first-line phase 3 trials evaluating PD-(L)1 blockade plus chemotherapy (ChT) and PD-1 plus CTLA-4 CPI for advanced NSCLC and provide potential treatment recommendations.

Choosing wisely first line immunotherapy in non-small cell lung cancer (NSCLC): what to add and what to leave out

Immunotherapy has dramatically changed the therapeutic scenario in treatment naïve advanced non-small cell lung cancer (NSCLC). While single agent pembrolizumab has become the standard therapy in patients with PD-L1 expression on tumor cells ≥ 50%, the combination of pembrolizumab or atezolizumab and platinum-based chemotherapy has emerged as an effective first line treatment regardless of PD-L1 expression both in squamous and non-squamous NSCLC without oncogenic drivers. Furthermore, double immune checkpoint inhibition has shown promising results in treatment naïve patients with high tumor mutational burden (TMB). Of note, the presence of both negative PD-L1 expression and low TMB may identify a subgroup of patients who has little benefit from immunotherapy combinations and for whom the best treatment option may still be platinum-based chemotherapy. To date, first-line single agent immune checkpoint blockade has demonstrated limited activity in EGFR mutated NSCLC and the combination of immunotherapy and targeted agents has raised safety concerns in both EGFR and ALK positive NSCLC patients. Finally, in EGFR mutated or ALK rearranged NSCLC, atezolizumab in combination with platinum-based chemotherapy and bevacizumab is emerging as a potential treatment option upon progression to first line tyrosine kinase inhibitors.