Case report: A persistently expanded T cell response in an exceptional responder to radiation and atezolizumab for metastatic non-small cell lung cancer.

Most patients with advanced non-small cell lung cancer (NSCLC) do not achieve a durable remission after treatment with immune checkpoint inhibitors. Here we report the clinical history of an exceptional responder to radiation and anti-program death-ligand 1 (PD-L1) monoclonal antibody, atezolizumab, for metastatic NSCLC who remains in a complete remission more than 8 years after treatment. Sequencing of the patient's T cell repertoire from a metastatic lesion and the blood before and after anti-PD-L1 treatment revealed oligoclonal T cell expansion. Characterization of the dominant T cell clone, which comprised 10% of all clones and increased 10-fold in the blood post-treatment, revealed an activated CD8+ phenotype and reactivity against 4 HLA-A2 restricted neopeptides but not viral or wild-type human peptides, suggesting tumor reactivity. We hypothesize that the patient's exceptional response to anti-PD-L1 therapy may have been achieved by increased tumor immunogenicity promoted by pre-treatment radiation therapy as well as long-term persistence of oligoclonal expanded circulating T cells.

Intratumoral CD103+ CD8+ T cells predict response to PD-L1 blockade.

BACKGROUND: CD8+ tissue-resident memory T (TRM) cells, marked by CD103 (ITGAE) expression, are thought to actively suppress cancer progression, leading to the hypothesis that their presence in tumors may predict response to immunotherapy. METHODS: Here, we test this by combining high-dimensional single-cell modalities with bulk tumor transcriptomics from 1868 patients enrolled in lung and bladder cancer clinical trials of atezolizumab (anti-programmed cell death ligand 1 (PD-L1)). RESULTS: ITGAE was identified as the most significantly upregulated gene in inflamed tumors. Tumor CD103+ CD8+ TRM cells exhibited a complex phenotype defined by the expression of checkpoint regulators, cytotoxic proteins, and increased clonal expansion. CONCLUSIONS: Our analyses indeed demonstrate that the presence of CD103+ CD8+ TRM cells, quantified by tracking intratumoral CD103 expression, can predict treatment outcome, suggesting that patients who respond to PD-1/PD-L1 blockade are those who exhibit an ongoing antitumor T-cell response.

C-reactive protein reduction post treatment is associated with improved survival in atezolizumab (anti-PD-L1) treated non-small cell lung cancer patients.

PURPOSE: Overall survival (OS) is the most significant endpoint for evaluation of treatment benefit with checkpoint inhibitors (CPI) in cancer. We evaluated serum C-reactive protein (CRP) in non-small cell lung cancer (NSCLC) trials with atezolizumab (anti-PD-L1) as an early OS surrogate. METHODS: Serum from patients enrolled in randomized Phase II (n = 240) and Phase III (n = 701) trials of NSCLC patients (POPLAR, OAK) who progressed on prior-platinum chemotherapy, were analyzed for CRP levels over time. Patients were grouped by changes in CRP levels post-treatment as either increased (≥ 1.5 fold), decreased (≤ 1.5 fold) or unchanged (within +1.5 fold) relative to pre-treatment levels to assess association with progression free survival (PFS) and OS. RESULTS: Decrease in serum CRP levels at 6 weeks relative to pre-treatment were observed in patients with RECIST1.1 based complete or partial responses (CR/PR) to atezolizumab whereas patients with disease progression (PD) demonstrated an increase in CRP levels in the Phase II POPLAR study, and confirmed in the Phase III OAK study. Decrease in serum CRP as early as six weeks post treatment predicted improved PFS and OS, even in patients who were determined as stable disease (SD) in their first scan. This effect was not observed in the chemotherapy arms. CONCLUSION: Modulation of serum CRP correlates with clinical outcome post-atezolizumab treatment. This routine lab test may provide utility in informing OS signals as early as 6 weeks post-initiation of therapy with CPIs in NSCLC.

Immune-stimulating antibody conjugates elicit robust myeloid activation and durable antitumor immunity.

Innate pattern recognition receptor agonists, including Toll-like receptors (TLRs), alter the tumor microenvironment and prime adaptive antitumor immunity. However, TLR agonists present toxicities associated with widespread immune activation after systemic administration. To design a TLR-based therapeutic suitable for systemic delivery and capable of safely eliciting tumor-targeted responses, we developed immune-stimulating antibody conjugates (ISACs) comprising a TLR7/8 dual agonist conjugated to tumor-targeting antibodies. Systemically administered human epidermal growth factor receptor 2 (HER2)-targeted ISACs were well tolerated and triggered a localized immune response in the tumor microenvironment that resulted in tumor clearance and immunological memory. Mechanistically, ISACs required tumor antigen recognition, Fcγ-receptor-dependent phagocytosis and TLR-mediated activation to drive tumor killing by myeloid cells and subsequent T-cell-mediated antitumor immunity. ISAC-mediated immunological memory was not limited to the HER2 ISAC target antigen since ISAC-treated mice were protected from rechallenge with the HER2- parental tumor. These results provide a strong rationale for the clinical development of ISACs.

Clinical Activity and Safety of Atezolizumab in a Phase 1 Study of Patients With Relapsed/Refractory Small-Cell Lung Cancer.

BACKGROUND: Programmed death-ligand 1 (PD-L1) protein is expressed in various cancers, including small-cell lung cancer (SCLC). Atezolizumab inhibits PD-L1 signaling, thus restoring tumor-specific T-cell immunity. Here, we report results from the first-in-human phase 1 PCD4989g study (NCT01375842) of atezolizumab, in a cohort of patients with relapsed/refractory SCLC. PATIENTS AND METHODS: Eligible patients with incurable or metastatic SCLC, which was advanced or recurrent since the last antitumor therapy, received atezolizumab 15 mg/kg or 1200 mg intravenously every 3 weeks for 16 cycles or until loss of clinical benefit. The primary endpoint was safety. Efficacy and biomarkers of antitumor activity were also assessed. RESULTS: Seventeen patients were enrolled. Any-grade and grade ≥3 treatment-related adverse events (TRAEs) occurred in 11 (64.7%) and 5 (29.4%) patients, respectively. The most common any-grade TRAE was fatigue (4 patients [23.5%]). Partial response to atezolizumab was achieved in 1 patient (5.9%) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1), and 3 (17.6%) per immune-related response criteria (irRC). Durations of response were 2.8 to > 45.7 months. Median investigator-assessed progression-free survival (PFS) per RECIST v1.1 and irRC was 1.5 (95% confidence interval [CI], 1.2-2.7) and 2.9 (95% CI, 1.2-6.1) months, respectively. Median overall survival (OS) was 5.9 months (95% CI, 4.3-12.6). Patients with high (≥ median expression) T-effector gene signature and PD-L1 mRNA expression appeared to show a trend toward improved PFS (per irRC) and OS. CONCLUSION: Atezolizumab was generally well tolerated and exhibited antitumor activity in a small cohort of patients with relapsed/refractory SCLC.

Dendritic cells dictate responses to PD-L1 blockade cancer immunotherapy.

PD-L1/PD-1 blocking antibodies have demonstrated therapeutic efficacy across a range of human cancers. Extending this benefit to a greater number of patients, however, will require a better understanding of how these therapies instigate anticancer immunity. Although the PD-L1/PD-1 axis is typically associated with T cell function, we demonstrate here that dendritic cells (DCs) are an important target of PD-L1 blocking antibody. PD-L1 binds two receptors, PD-1 and B7.1 (CD80). PD-L1 is expressed much more abundantly than B7.1 on peripheral and tumor-associated DCs in patients with cancer. Blocking PD-L1 on DCs relieves B7.1 sequestration in cis by PD-L1, which allows the B7.1/CD28 interaction to enhance T cell priming. In line with this, in patients with renal cell carcinoma or non-small cell lung cancer treated with atezolizumab (PD-L1 blockade), a DC gene signature is strongly associated with improved overall survival. These data suggest that PD-L1 blockade reinvigorates DC function to generate potent anticancer T cell immunity.

Late-differentiated effector neoantigen-specific CD8+ T cells are enriched in peripheral blood of non-small cell lung carcinoma patients responding to atezolizumab treatment.

BACKGROUND: There is strong evidence that immunotherapy-mediated tumor rejection can be driven by tumor-specific CD8+ T cells reinvigorated to recognize neoantigens derived from tumor somatic mutations. Thus, the frequencies or characteristics of tumor-reactive, mutation-specific CD8+ T cells could be used as biomarkers of an anti-tumor response. However, such neoantigen-specific T cells are difficult to reliably identify due to their low frequency in peripheral blood and wide range of potential epitope specificities. METHODS: Peripheral blood mononuclear cells (PBMC) from 14 non-small cell lung cancer (NSCLC) patients were collected pre- and post-treatment with the anti-PD-L1 antibody atezolizumab. Using whole exome sequencing and RNA sequencing we identified tumor neoantigens that are predicted to bind to major histocompatibility complex class I (MHC-I) and utilized mass cytometry, together with cellular 'barcoding', to profile immune cells from patients with objective response to therapy (n = 8) and those with progressive disease (n = 6). In parallel, a highly-multiplexed combinatorial tetramer staining was used to screen antigen-specific CD8+ T cells in peripheral blood for 782 candidate tumor neoantigens and 71 known viral-derived control peptide epitopes across all patient samples. RESULTS: No significant treatment- or response associated phenotypic difference were measured in bulk CD8+ T cells. Multiplexed peptide-MHC multimer staining detected 20 different neoantigen-specific T cell populations, as well as T cells specific for viral control antigens. Not only were neoantigen-specific T cells more frequently detected in responding patients, their phenotypes were also almost entirely distinct. Neoantigen-specific T cells from responder patients typically showed a differentiated effector phenotype, most like Cytomegalovirus (CMV) and some types of Epstein-Barr virus (EBV)-specific CD8+ T cells. In contrast, more memory-like phenotypic profiles were observed for neoantigen-specific CD8+ T cells from patients with progressive disease. CONCLUSION: This study demonstrates that neoantigen-specific T cells can be detected in peripheral blood in non-small cell lung cancer (NSCLC) patients during anti-PD-L1 therapy. Patients with an objective response had an enrichment of neoantigen-reactive T cells and these cells showed a phenotype that differed from patients without a response. These findings suggest the ex vivo identification, characterization, and longitudinal follow-up of rare tumor-specific differentiated effector neoantigen-specific T cells may be useful in predicting response to checkpoint blockade. TRIAL REGISTRATION: POPLAR trial NCT01903993 .

Immune profiles in primary squamous cell carcinoma of the head and neck.

OBJECTIVES: In this study we describe the tumor microenvironment, the signaling pathways and genetic alterations associated with the presence or absence of CD8+ T-cell infiltration in primary squamous cell carcinoma of the head and neck (SCCHN) tumors. MATERIALS AND METHODS: Two SCCHN multi-analyte cohorts were utilized, the Cancer Genome Atlas (TCGA) and the Chicago Head and Neck Genomics (CHGC) cohort. A well-established chemokine signature classified SCCHN tumors into high and low CD8+ T-cell inflamed phenotypes (TCIP-H, TCIP-L respectively). Gene set enrichment and iPANDA analyses were conducted to dissect differences in signaling pathways, somatic mutations and copy number aberrations for TCIP-H versus TCIP-L tumors, stratified by HPV status. RESULTS: TCIP-H SCCHN tumors were enriched in multiple immune checkpoints irrespective of HPV-status. HPV-positive tumors were enriched in markers of T-regulatory cells (Tregs) and HPV-negative tumors in protumorigenic M2 macrophages. TCIP-L SCCHN tumors were enriched for the ß-catenin/WNT and Hedgehog signaling pathways, had frequent mutations in NSD1, amplifications in EGFR and YAP1, as well as CDKN2A deletions. TCIP-H SCCHN tumors were associated with the MAPK/ERK, JAK/STAT and mTOR/AKT signaling pathways, and were enriched in CASP8, EP300, EPHA2, HRAS mutations, CD274, PDCD1LG2, JAK2 amplifications. CONCLUSIONS: Our findings support that combinatorial immune checkpoint blockade and depletion strategies targeting Tregs in HPV-positive and M2 macrophages in HPV-negative tumors may lead to improved antitumor immune responses in patients with TCIP-H SCCHN. We highlight novel pathways and genetic events that may serve as candidate biomarkers and novel targeted therapies to enhance the efficacy of immunotherapy in SCCHN patients.

Atezolizumab in combination with carboplatin plus nab-paclitaxel chemotherapy compared with chemotherapy alone as first-line treatment for metastatic non-squamous non-small-cell lung cancer (IMpower130): a multicentre, randomised, open-label, phase 3 trial.

BACKGROUND: Atezolizumab (a monoclonal antibody against PD-L1), which restores anticancer immunity, improved overall survival in patients with previously treated non-small-cell lung cancer and also showed clinical benefit when combined with chemotherapy as first-line treatment of non-small-cell lung cancer. IMpower130 aimed to assess the efficacy and safety of atezolizumab plus chemotherapy versus chemotherapy alone as first-line therapy for non-squamous non-small-cell lung cancer. METHODS: IMpower130 was a multicentre, randomised, open-label, phase 3 study done in 131 centres across eight countries (the USA, Canada, Belgium, France, Germany, Italy, Spain, and Israel). Eligible patients were aged 18 years or older, and had histologically or cytologically confirmed stage IV non-squamous non-small-cell lung cancer, an Eastern Cooperative Oncology Group performance status of 0 or 1, and received no previous chemotherapy for stage IV disease. Patients were randomly assigned (2:1; permuted block [block size of six] with an interactive voice or web response system) to receive atezolizumab (1200 mg intravenously every 3 weeks) plus chemotherapy (carboplatin [area under the curve 6 mg/mL per min every 3 weeks] plus nab-paclitaxel [100 mg/m2 intravenously every week]) or chemotherapy alone for four or six 21-day cycles followed by maintenance therapy. Stratification factors were sex, baseline liver metastases, and PD-L1 tumour expression. Co-primary endpoints were investigator-assessed progression-free survival and overall survival in the intention-to-treat wild-type (ie, EGFRwt and ALKwt) population. The safety population included patients who received at least one dose of the study drug. This study is registered with ClinicalTrials.gov, number NCT02367781. FINDINGS: Between April 16, 2015, and Feb 13, 2017, 724 patients were randomly assigned and 723 were included in the intention-to-treat population (one patient died before randomisation, but was assigned to a treatment group; this patient was excluded from the intention-to-treat population) of the atezolizumab plus chemotherapy group (483 patients in the intention-to-treat population and 451 patients in the intention-to-treat wild-type population) or the chemotherapy group (240 patients in the intention-to-treat population and 228 patients in the intention-to-treat wild-type population). Median follow-up in the intention-to-treat wild-type population was similar between groups (18·5 months [IQR 15·2-23·6] in the atezolizumab plus chemotherapy group and 19·2 months [15·4-23·0] in the chemotherapy group). In the intention-to-treat wild-type population, there were significant improvements in median overall survival (18·6 months [95% CI 16·0-21·2] in the atezolizumab plus chemotherapy group and 13·9 months [12·0-18·7] in the chemotherapy group; stratified hazard ratio [HR] 0·79 [95% CI 0·64-0·98]; p=0·033) and median progression-free survival (7·0 months [95% CI 6·2-7·3] in the atezolizumab plus chemotherapy group and 5·5 months [4·4-5·9] in the chemotherapy group; stratified HR 0·64 [95% CI 0·54-0·77]; p<0·0001]). The most common grade 3 or worse treatment-related adverse events were neutropenia (152 [32%] of 473 in the atezolizumab plus chemotherapy group vs 65 [28%] of 232 in the chemotherapy group), anaemia (138 [29%] vs 47 [20%]), and decreased neutrophil count (57 [12%] vs 19 [8%]). Treatment-related serious adverse events were reported in 112 (24%) of 473 patients in the atezolizumab plus chemotherapy group and 30 (13%) of 232 patients in the chemotherapy group. Treatment-related (any treatment) deaths occurred in eight (2%) of 473 patients in the atezolizumab plus chemotherapy group and one (<1%) of 232 patients in the chemotherapy group. INTERPRETATION: IMpower130 showed a significant and clinically meaningful improvement in overall survival and a significant improvement in progression-free survival with atezolizumab plus chemotherapy versus chemotherapy as first-line treatment of patients with stage IV non-squamous non-small-cell lung cancer and no ALK or EGFR mutations. No new safety signals were identified. This study supports the benefit of atezolizumab, in combination with platinum-based chemotherapy, as first-line treatment of metastatic non-small-cell lung cancer. FUNDING: F. Hoffmann-La Roche.

Absence of PD-L1 expression on tumor cells in the context of an activated immune infiltrate may indicate impaired IFNγ signaling in non-small cell lung cancer.

BACKGROUND: In non-small cell lung cancer (NSCLC), PD-L1 expression on either tumor cells (TC) or both TC and tumor-infiltrating immune cells (IC) is currently the most used biomarker in cancer immunotherapy. However, the mechanisms involved in PD-L1 regulation are not fully understood. To provide better insight in these mechanisms, a multiangular analysis approach was used to combine protein and mRNA expression with several clinicopathological characteristics. PATIENTS AND METHODS: Archival tissues from 640 early stage, resected NSCLC patients were analyzed with immunohistochemistry for expression of PD-L1 and CD8 infiltration. In addition, mutational status and expression of a selection of immune genes involved in the PD-L1/PD-1 axis and T-cell response was determined. RESULTS: Tumors with high PD-L1 expression on TC or on IC represent two subsets of NSCLC with minimal overlap. We observed that PD-L1 expression on IC irrespective of expression on TC is a good marker for inflammation within tumors. In the tumors with the highest IC expression and absent TC expression an association with reduced IFNγ downstream signaling in tumor cells was observed. CONCLUSIONS: These results show that PD-L1 expression on TC and IC are both independent hallmarks of the inflamed phenotype in NSCLC, and TC-negative/IC-high tumors can also be categorized as inflamed. The lack of correlation between PD-L1 TC and IC expression in this subgroup may be caused by impaired IFNγ signaling in tumor cells. These findings may bring a better understanding of the tumor-immune system interaction and the clinical relevance of PD-L1 expression on IC irrespective of PD-L1 expression on TC.

Atezolizumab plus bevacizumab and chemotherapy in non-small-cell lung cancer (IMpower150): key subgroup analyses of patients with EGFR mutations or baseline liver metastases in a randomised, open-label phase 3 trial.

BACKGROUND: The IMpower150 trial showed significant improvements in progression-free and overall survival with atezolizumab plus bevacizumab plus carboplatin plus paclitaxel (ABCP) versus the standard-of-care bevacizumab plus carboplatin plus paclitaxel (BCP) in chemotherapy-naive patients with non-squamous non-small-cell lung cancer. Here, we report the efficacy of ABCP or atezolizumab plus carboplatin plus paclitaxel (ACP) versus BCP in key patient subgroups. METHODS: IMpower150 was a randomised, open-label, phase 3 study done at 240 academic medical centres and community oncology practices across 26 countries worldwide. Patients with chemotherapy-naive metastatic non-small-cell lung cancer were randomly assigned (1:1:1) to receive ABCP, ACP, or BCP every three weeks. The co-primary endpoints were overall survival and investigator-assessed progression-free survival in intention-to-treat wild-type patients (patients with epidermal growth factor receptor [EGFR] or anaplastic lymphoma kinase [ALK] genetic alterations were excluded). Efficacy was assessed in key subgroups within the intention-to-treat population, including patients with EGFR mutations (both sensitising and non-sensitising; EGFR-positive) previously treated with one or more tyrosine kinase inhibitors and patients with baseline liver metastases. Overall survival in the intention-to-treat population was included among secondary efficacy endpoints. Exploratory endpoints included the proportion of patients achieving an objective response in the intention-to-treat population, including EGFR-positive patients and patients with baseline liver metastases. Data are reported as per the Jan 22, 2018, data cutoff date, at which the number of coprimary prespecified overall survival events was met in the ABCP versus BCP groups. This trial is registered with ClinicalTrials.gov, number NCT02366143, and is ongoing. FINDINGS: Between March 31, 2015, and Dec 30, 2016, 1202 patients were enrolled. 400 patients were randomly assigned to ABCP, 402 to ACP, and 400 to BCP. In EGFR-positive patients (124 of 1202), median overall survival was not estimable (NE; 95% CI 17·0-NE) with ABCP (34 of 400) and 18·7 months (95% CI 13·4-NE) with BCP (45 of 400; hazard ratio [HR] 0·61 [95% CI 0·29-1·28]). Improved overall survival with ABCP versus BCP was observed in patients with sensitising EGFR mutations (median overall survival NE [95% CI NE-NE] with ABCP [26 of 400] vs 17·5 months [95% CI 11·7-NE] with BCP [32 of 400]; HR 0·31 [95% CI 0·11-0·83]) and in the intention-to-treat population (19·8 months [17·4-24·2] vs 14·9 months [13·4-17·1]; HR 0·76 [0·63-0·93]). Improved median overall survival with ABCP versus BCP was seen in patients with baseline liver metastases (13·3 months [11·6-NE] with ABCP [52 of 400] vs 9·4 months [7·9-11·7] with BCP [57 of 400]; HR 0·52 [0·33-0·82]). Median overall survival was 21·4 months (95% CI 13·8-NE) with ACP versus 18·7 months (95% CI 13·4-NE) with BCP in EGFR-positive patients (HR 0·93 [95% CI 0·51-1·68]). No overall survival benefit was seen with ACP versus BCP in patients with sensitising EGFR mutations (HR 0·90 [95% CI 0·47-1·74]), in the intention-to-treat population (HR 0·85 [0·71-1·03]), or in patients with baseline liver metastases (HR 0·87 [0·57-1·32]). In the intention-to-treat safety-evaluable population, grade 3-4 treatment-related events occurred in 223 (57%) patients in the ABCP group, in 172 (43%) in the ACP group, and in 191 (49%) in the BCP group; 11 (3%) grade 5 adverse events occurred in the ABCP group, as did four (1%) in the ACP group, and nine (2%) in the BCP group. INTERPRETATION: Improved survival was noted for patients treated with ABCP compared with those given BCP in the intention-to-treat population, and in patients with baseline liver metastases. The overall survival signal in the subgroup of patients with EGFR sensitising mutations warrants further study. FUNDING: F. Hoffmann-La Roche, Genentech.

Development of a PD-L1 Complementary Diagnostic Immunohistochemistry Assay (SP142) for Atezolizumab.

Cancer immunotherapies, such as atezolizumab, are proving to be a valuable therapeutic strategy across indications, including non-small cell lung cancer (NSCLC) and urothelial cancer (UC). Here, we describe a diagnostic assay that measures programmed-death ligand 1 (PD-L1) expression, via immunohistochemistry, to identify patients who will derive the most benefit from treatment with atezolizumab, a humanized monoclonal anti-PD-L1 antibody. We describe the performance of the VENTANA PD-L1 (SP142) Assay in terms of specificity, sensitivity, and the ability to stain both tumor cells (TC) and tumor-infiltrating immune cells (IC), in NSCLC and UC tissues. The reader precision, repeatability and intermediate precision, interlaboratory reproducibility, and the effectiveness of pathologist training on the assessment of PD-L1 staining on both TC and IC were evaluated. We detail the analytical validation of the VENTANA PD-L1 (SP142) Assay for PD-L1 expression in NSCLC and UC tissues and show that the assay reliably evaluated staining on both TC and IC across multiple expression levels/clinical cut-offs. The reader precision showed high overall agreement when compared with consensus scores. In addition, pathologists met the predefined training criteria (≥85.0% overall percent agreement) for the assessment of PD-L1 expression in NSCLC and UC tissues with an average overall percent agreement ≥95.0%. The assay evaluates PD-L1 staining on both cell types and is robust and precise. In addition, it can help to identify those patients who may benefit the most from treatment with atezolizumab, although treatment benefit has been demonstrated in an all-comer NSCLC and UC patient population.

Differential regulation of PD-L1 expression by immune and tumor cells in NSCLC and the response to treatment with atezolizumab (anti-PD-L1).

Programmed death-ligand 1 (PD-L1) expression on tumor cells (TCs) by immunohistochemistry is rapidly gaining importance as a diagnostic for the selection or stratification of patients with non-small cell lung cancer (NSCLC) most likely to respond to single-agent checkpoint inhibitors. However, at least two distinct patterns of PD-L1 expression have been observed with potential biological and clinical relevance in NSCLC: expression on TC or on tumor-infiltrating immune cells (ICs). We investigated the molecular and cellular characteristics associated with PD-L1 expression in these distinct cell compartments in 4,549 cases of NSCLC. PD-L1 expression on IC was more prevalent and likely reflected IFN-γ-induced adaptive regulation accompanied by increased tumor-infiltrating lymphocytes and effector T cells. High PD-L1 expression on TC, however, reflected an epigenetic dysregulation of the PD-L1 gene and was associated with a distinct histology described by poor immune infiltration, sclerotic/desmoplastic stroma, and mesenchymal molecular features. Importantly, durable clinical responses to atezolizumab (anti-PD-L1) were observed in patients with tumors expressing high PD-L1 levels on either TC alone [40% objective response rate (ORR)] or IC alone (22% ORR). Thus, PD-L1 expression on TC or IC can independently attenuate anticancer immunity and emphasizes the functional importance of IC in regulating the antitumor T cell response.

Blood-based tumor mutational burden as a predictor of clinical benefit in non-small-cell lung cancer patients treated with atezolizumab.

Although programmed death-ligand 1-programmed death 1 (PD-L1-PD-1) inhibitors are broadly efficacious, improved outcomes have been observed in patients with high PD-L1 expression or high tumor mutational burden (TMB). PD-L1 testing is required for checkpoint inhibitor monotherapy in front-line non-small-cell lung cancer (NSCLC). However, obtaining adequate tumor tissue for molecular testing in patients with advanced disease can be challenging. Thus, an unmet medical need exists for diagnostic approaches that do not require tissue to identify patients who may benefit from immunotherapy. Here, we describe a novel, technically robust, blood-based assay to measure TMB in plasma (bTMB) that is distinct from tissue-based approaches. Using a retrospective analysis of two large randomized trials as test and validation studies, we show that bTMB reproducibly identifies patients who derive clinically significant improvements in progression-free survival from atezolizumab (an anti-PD-L1) in second-line and higher NSCLC. Collectively, our data show that high bTMB is a clinically actionable biomarker for atezolizumab in NSCLC.

Safety and clinical activity of atezolizumab monotherapy in metastatic non-small-cell lung cancer: final results from a phase I study.

INTRODUCTION: Atezolizumab, an anti-programmed death-ligand 1 (PD-L1) antibody, inhibits PD-L1:PD-1 and PD-L1:B7.1 interactions, restoring anticancer immunity. Here, we report final analyses from the non-small-cell lung cancer (NSCLC) cohort of the first atezolizumab phase I study. METHODS: Patients with NSCLC received atezolizumab 1-20 mg/kg or 1200 mg intravenously every 3 weeks. Baseline PD-L1 expression on tumour cells (TCs) and tumour-infiltrating immune cells (ICs) was assessed (VENTANA SP142 immunohistochemistry assay). Exploratory subgroup analyses investigated responses by baseline PD-L1 expression and oncogenic mutational status. RESULTS: Eighty-nine patients, 98% of whom had received previous systemic therapy, were evaluable for safety and antitumour activity. Atezolizumab was well tolerated, with grade III/IV treatment-related adverse events (TRAEs) observed in 10 patients (11%). All-grade TRAEs occurring in >10% of patients were fatigue, nausea and decreased appetite; grade III/IV TRAEs occurring in >2% of patients were fatigue, dyspnoea, hyponatremia and hypoxia. One patient died from treatment-unrelated pneumonia. Objective response rate (ORR) was 50% (95% confidence interval [CI], 28%-72%), 33% (20%-48%), 29% (18%-41%) and 11% (1%-35%) for the TC3 or IC3, TC2/3 or IC2/3, TC1/2/3 or IC1/2/3 and TC0 and IC0 subgroups, respectively. All-patient ORR was 23% (95% CI, 14%-33%). Median duration of response was 16.4 months (range, 7.2-53.4+). One-, 2-, and 3-year survival rates were 63% (95% CI, 53%-73%), 37% (26%-47%) and 28% (18%-38%), respectively. CONCLUSIONS: Single-agent atezolizumab was well tolerated with long-term clinical benefits, including durable responses and survival, in pretreated NSCLC. Improved responses and survival rates were seen with increasing baseline PD-L1 expression. CLINICALTRIALS. GOV IDENTIFIER: NCT01375842.

Atezolizumab for First-Line Treatment of Metastatic Nonsquamous NSCLC.

BACKGROUND: The cancer-cell-killing property of atezolizumab may be enhanced by the blockade of vascular endothelial growth factor-mediated immunosuppression with bevacizumab. This open-label, phase 3 study evaluated atezolizumab plus bevacizumab plus chemotherapy in patients with metastatic nonsquamous non-small-cell lung cancer (NSCLC) who had not previously received chemotherapy. METHODS: We randomly assigned patients to receive atezolizumab plus carboplatin plus paclitaxel (ACP), bevacizumab plus carboplatin plus paclitaxel (BCP), or atezolizumab plus BCP (ABCP) every 3 weeks for four or six cycles, followed by maintenance therapy with atezolizumab, bevacizumab, or both. The two primary end points were investigator-assessed progression-free survival both among patients in the intention-to-treat population who had a wild-type genotype (WT population; patients with EGFR or ALK genetic alterations were excluded) and among patients in the WT population who had high expression of an effector T-cell (Teff) gene signature in the tumor (Teff-high WT population) and overall survival in the WT population. The ABCP group was compared with the BCP group before the ACP group was compared with the BCP group. RESULTS: In the WT population, 356 patients were assigned to the ABCP group, and 336 to the BCP group. The median progression-free survival was longer in the ABCP group than in the BCP group (8.3 months vs. 6.8 months; hazard ratio for disease progression or death, 0.62; 95% confidence interval [CI], 0.52 to 0.74; P<0.001); the corresponding values in the Teff-high WT population were 11.3 months and 6.8 months (hazard ratio, 0.51 [95% CI, 0.38 to 0.68]; P<0.001). Progression-free survival was also longer in the ABCP group than in the BCP group in the entire intention-to-treat population (including those with EGFR or ALK genetic alterations) and among patients with low or negative programmed death ligand 1 (PD-L1) expression, those with low Teff gene-signature expression, and those with liver metastases. Median overall survival among the patients in the WT population was longer in the ABCP group than in the BCP group (19.2 months vs. 14.7 months; hazard ratio for death, 0.78; 95% CI, 0.64 to 0.96; P=0.02). The safety profile of ABCP was consistent with previously reported safety risks of the individual medicines. CONCLUSIONS: The addition of atezolizumab to bevacizumab plus chemotherapy significantly improved progression-free survival and overall survival among patients with metastatic nonsquamous NSCLC, regardless of PD-L1 expression and EGFR or ALK genetic alteration status. (Funded by F. Hoffmann-La Roche/Genentech; IMpower150 ClinicalTrials.gov number, NCT02366143 .).

Updated Efficacy Analysis Including Secondary Population Results for OAK: A Randomized Phase III Study of Atezolizumab versus Docetaxel in Patients with Previously Treated Advanced Non-Small Cell Lung Cancer.

INTRODUCTION: The efficacy and safety of atezolizumab versus the efficacy and safety of docetaxel as second- or third-line treatment in patients with advanced NSCLC in the primary (n = 850) and secondary (n = 1225) efficacy populations of the randomized phase III OAK study (respectively referred to as the intention-to-treat [ITT] 850 [ITT850] and ITT1225) at an updated data cutoff were assessed. METHODS: Patients received atezolizumab, 1200 mg, or docetaxel, 75 mg/m2, intravenously every 3 weeks until loss of clinical benefit or disease progression, respectively. The primary end point was overall survival (OS) in the ITT population and programmed death-ligand 1-expressing subgroup. A sensitivity analysis was conducted to evaluate the impact of subsequent immunotherapy use in the docetaxel arm on the observed survival benefit with atezolizumab. RESULTS: Atezolizumab demonstrated an OS benefit versus docetaxel in the updated ITT850 (hazard ratio [HR] = 0.75, 95% confidence interval: 0.64-0.89, p = 0.0006) and the ITT1225 (HR = 0.80, 95% confidence interval: 0.70-0.92, p = 0.0012) after minimum follow-up times of 26 and 21 months, respectively. Improved survival with atezolizumab was observed across programmed death-ligand 1 and histological subgroups. In the immunotherapy sensitivity analysis, the relative OS benefit with atezolizumab was slightly greater in the ITT850 (HR = 0.69) and ITT1225 (HR = 0.74) than the conventional OS estimate. Fewer patients receiving atezolizumab experienced grade 3 or 4 treatment-related adverse events (14.9%) than did patients receiving docetaxel (42.4%); no grade 5 adverse events related to atezolizumab were observed. CONCLUSIONS: The results of the updated ITT850 and initial ITT1225 analyses were consistent with those of the primary efficacy analysis demonstrating survival benefit with atezolizumab versus with docetaxel. Atezolizumab continued to demonstrate a favorable safety profile after longer treatment exposure and follow-up.

FIR: Efficacy, Safety, and Biomarker Analysis of a Phase II Open-Label Study of Atezolizumab in PD-L1-Selected Patients With NSCLC.

INTRODUCTION: The FIR phase II study (NCT01846416) evaluated the efficacy and safety of anti-programmed death-ligand 1 (PD-L1) atezolizumab in advanced NSCLC selected by tumor cell (TC) or tumor-infiltrating immune cell (IC) PD-L1 expression. METHODS: Patients with PD-L1 TC2/3 (PD-L1 staining on ≥5% of TC) or IC2/3 tumors (PD-L1 staining on ≥5% of IC; determined by SP142 PD-L1 immunohistochemistry assay) with paired fresh and archival histology samples were recruited into cohort 1 (chemotherapy-naive/>6 months between adjuvant chemotherapy and recurrence), cohort 2 (≥ second-line without brain metastases), or cohort 3 (≥ second-line with treated brain metastases). Patients received 1200 mg atezolizumab on day 1 (21-day cycles). Primary endpoint was investigator-assessed modified Response Evaluation Criteria in Solid Tumors, objective response rate (Response Evaluation Criteria in Solid Tumors v1.1). Secondary endpoints were overall survival, progression-free survival, duration of response, and safety. RESULTS: Patients (N = 138) were enrolled (137 evaluable for response: cohort 1, n = 31; cohort 2, n = 93; and cohort 3, n = 13). Investigator-assessed objective response rate was 32%, 21%, and 23% for cohorts 1, 2, and 3, respectively. Treatment-related adverse events were reported in 81%, 67%, and 69% of patients, respectively, including grade 3-4 treatment-related adverse events in 16%, 19%, and 15%, respectively. Moreover, 88.6% (86 of 97) paired baseline tumor samples had <5% change in TC/IC PD-L1 expression over time. CONCLUSIONS: Atezolizumab monotherapy showed clinical activity in patients with NSCLC, including those with brain metastases; safety was consistent with previous trials. Atezolizumab has completed phase III monotherapy studies in second-line. Front-line trials are ongoing, confirming these favorable results.

Prognostic Significance of PD-L1+ and CD8+ Immune Cells in HPV+ Oropharyngeal Squamous Cell Carcinoma.

Human papilloma virus-positive oropharyngeal squamous cell carcinoma (HPV+ OPSCC) represents a distinct subgroup of head and neck cancers associated with clinical outcomes that are not accurately categorized by existing tumor-node-metastasis-based staging methods. Given the significant impact of immune parameters, such as tumor-infiltrating lymphocytes (TIL) in many cancers, we sought to determine if immunophenotyping tumors can improve categorization of HPV+ OPSCCs for prognostic purposes. In a cohort of 190 patients with HPV+ OPSCC, we quantified and determined the localization of CD8+ TILs, as well as PD-L1-expressing tumor cells (TC) and immune cells (IC). The prognostic significance of these parameters on overall survival (OS) was evaluated, and their contribution to existing prognostic models was determined. High CD8+ TIL abundance (≥30% on stromal or intratumoral ICs) was seen in 61.3% patients and was associated with improved OS [HR, 0.4; 95% confidence interval (CI), 0.2-0.9; P = 0.017]. Although the expression of PD-L1 on TC was not prognostic, high expression of PD-L1 on ≥5% of intratumoral ICs was found in 38.5% patients and was significantly associated with improved OS (HR, 0.37; 95% CI, 0.15-0.93; P = 0. 023). Both high intratumoral IC PD-L1 expression and abundant CD8+ TILs in HPV+ OPSCCs identify subgroups of patients with excellent outcomes and provide additional prognostic information beyond existing staging systems. Cancer Immunol Res; 6(3); 295-304. ©2018 AACR.

Molecular and Histopathological Characterization of the Tumor Immune Microenvironment in Advanced Stage of Malignant Pleural Mesothelioma.

INTRODUCTION: Malignant pleural mesothelioma (MPM) is a rare, highly aggressive, and relatively chemoresistant and radioresistant malignancy with limited therapeutic options. Our objective was to investigate the prevalence of programmed death ligand 1 (PD-L1) and the characteristics of the immune environment in this disease. METHODS: A total of 99 archival tumors from advanced-stage MPM were immunohistochemically tested in parallel for PD-L1 in two different laboratories, and 87 of them were profiled for immune gene expression by NanoString analysis for 800 genes. A prior study on the same samples indicated a low mutational load with a complex mutational landscape of genetic variations more frequently associated with the p53/DNA repair and phosphoinisitide-3-kinase pathways. RESULTS: PD-L1 expression was found in 16% of the MPM tumor samples, either in the tumor cells or the infiltrating immune cells. Gene expression analysis suggested that MPM is an inflamed tumor type and can be classified into three different subgroups on the basis of the different expression profiles of immune-related genes, of which two groups showed varying degrees of expression of immune-related genes. Overall, these molecular findings suggest that these subgroups of MPM associated with PD-L1 positivity and expression of immune-related genes accounting for 60% of MPMs represent a candidate subtype that may respond to cancer immunotherapy. CONCLUSIONS: These data suggest that 60% of patients with MPM characterized by either PD-L1 expression or an inflamed status are attractive candidates for cancer immunotherapeutic options.