Automated tumor immunophenotyping predicts clinical benefit from anti-PD-L1 immunotherapy.

Cancer immunotherapy has transformed the clinical approach to patients with malignancies, as profound benefits can be seen in a subset of patients. To identify this subset, biomarker analyses increasingly focus on phenotypic and functional evaluation of the tumor microenvironment to determine if density, spatial distribution, and cellular composition of immune cell infiltrates can provide prognostic and/or predictive information. Attempts have been made to develop standardized methods to evaluate immune infiltrates in the routine assessment of certain tumor types; however, broad adoption of this approach in clinical decision-making is still missing. We developed approaches to categorize solid tumors into 'desert', 'excluded', and 'inflamed' types according to the spatial distribution of CD8+ immune effector cells to determine the prognostic and/or predictive implications of such labels. To overcome the limitations of this subjective approach, we incrementally developed four automated analysis pipelines of increasing granularity and complexity for density and pattern assessment of immune effector cells. We show that categorization based on 'manual' observation is predictive for clinical benefit from anti-programmed death ligand 1 therapy in two large cohorts of patients with non-small cell lung cancer or triple-negative breast cancer. For the automated analysis we demonstrate that a combined approach outperforms individual pipelines and successfully relates spatial features to pathologist-based readouts and the patient's response to therapy. Our findings suggest that tumor immunophenotype generated by automated analysis pipelines should be evaluated further as potential predictive biomarkers for cancer immunotherapy. © 2024 The Pathological Society of Great Britain and Ireland.

The association of histopathologic features after neoadjuvant chemo-immunotherapy with clinical outcome: Sub-analyses from the randomized double-blinded, placebo-controlled, Phase III IMagyn050/GOG3015/ENGOT-ov39 study.

OBJECTIVE: Histopathologic characteristics after neoadjuvant chemotherapy (NACT) may correlate with outcome. This study evaluates histopathologic features after immunotherapy and NACT/bevacizumab, and associated clinical outcomes. METHODS: Evaluable tissue from IMagyn050/GOG3015/ENGOT-ov39 patients from prespecified anatomic sites from interval cytoreductive surgery (ICS) after NACT/bevacizumab plus atezolizumab/placebo underwent central histopathologic scoring and analyzed with clinical outcomes. RESULTS: The predefined population had 243 evaluable NACT patients, with 48.1% tumors being PD-L1-positive. No statistically significant differences in PFS (16.9 months vs. 19.2 months, p = 0.21) or OS (41.5 months vs. 45.1 months, p = 0.67) between treatment arms were seen. Substantial residual tumor (RT) (3+) was identified in 26% atezolizumab vs. 24% placebo arms (p = 0.94). Most showed no (1+) necrosis (82% vs. 96%, respectively, p = 0.69), moderate (2+) to severe (3+) fibrosis (71% vs. 75%, respectively, p = 0.82), and extensive (2+) inflammation (53% vs. 47% respectively, p = 0.48). No significant histopathologic differences were identified by tissue site or by arm. Multivariate analyses showed increased risk for progression with moderate and substantial RT (13.6 mon vs. 21.1 mon, hazard ratio 2.0, p < 0.01; 13.6 mon vs. 21.1 mon, HR 1.9, p < 0.01, respectively); but decreased risk for death with extensive inflammation (46.9 mon vs. 36.3 mon, HR 0.65, p = 0.02). Inflammation also correlated with greater likelihood of response to NACT/bevacizumab plus immunotherapy (odds ratio 2.9, p < 0.01). Modeling showed inflammation as a consistent but modest predictor for OS. CONCLUSIONS: Detailed histologic assessment of ICS specimens appear to identify characteristics, such as inflammation and residual tumor, that may provide insight to certain clinical outcomes. Future work potentially leveraging emerging tools may provide further insight into outcomes.

Overall survival and patient-reported outcome results from the placebo-controlled randomized phase III IMagyn050/GOG 3015/ENGOT-OV39 trial of atezolizumab for newly diagnosed stage III/IV ovarian cancer.

OBJECTIVE: To determine the impact on overall survival (OS) and patient-reported outcomes (PROs) of combining atezolizumab with standard therapy for newly diagnosed stage III/IV ovarian cancer. METHODS: The placebo-controlled double-blind randomized phase III IMagyn050/GOG 3015/ENGOT-OV39 trial (NCT03038100) assigned eligible patients to 3-weekly atezolizumab 1200 mg or placebo for 22 cycles with platinum-based chemotherapy and bevacizumab. Coprimary endpoints were progression-free survival (already reported) and OS in the PD-L1-positive and intent-to-treat (ITT) populations, tested hierarchically. Prespecified PRO analyses focused on disease-related abdominal pain and bloating symptoms (European Organisation for Research and Treatment of Cancer QLQ-OV28), functioning, and health-related quality of life (HRQoL) (QLQ-C30). RESULTS: After 38 months' median follow-up, the OS hazard ratio in the PD-L1-positive population was 0.83 (95% CI, 0.66-1.06; p = 0.13); median OS was not estimable with atezolizumab versus 49.2 months with placebo. The hazard ratio for OS in the ITT population was 0.92 (95% CI, 0.78-1.09; median 50.5 versus 46.6 months, respectively). At week 9, similar proportions of patients in both arms of the neoadjuvant cohort showed ≥10-point improvement from baseline in abdominal pain and bloating, functioning, and HRQoL. In the primary surgery cohort, similar proportions of patients in each arm had improved, stable, or worsened physical and role function and HRQoL from baseline over time. Neither cohort showed differences between arms in treatment-related symptoms or overall side-effect bother. CONCLUSIONS: Incorporation of atezolizumab into standard therapy for newly diagnosed ovarian cancer does not significantly improve efficacy or impose additional treatment burden for patients. CLINICALTRIALS: gov registration: NCT03038100.

Influence of Genomic Landscape on Cancer Immunotherapy for Newly Diagnosed Ovarian Cancer: Biomarker Analyses from the IMagyn050 Randomized Clinical Trial.

PURPOSE: To explore whether patients with BRCA1/2-mutated or homologous recombination deficient (HRD) ovarian cancers benefitted from atezolizumab in the phase III IMagyn050 (NCT03038100) trial. PATIENTS AND METHODS: Patients with newly diagnosed ovarian cancer were randomized to either atezolizumab or placebo with standard chemotherapy and bevacizumab. Programmed death-ligand 1 (PD-L1) status of tumor-infiltrating immune cells (IC) was determined centrally (VENTANA SP142 assay). Genomic alterations, including deleterious BRCA1/2 alterations, genomic loss of heterozygosity (gLOH), tumor mutation burden (TMB), and microsatellite instability (MSI), were evaluated using the FoundationOne assay. HRD was defined as gLOH ≥ 16%, regardless of BRCA1/2 mutation status. Potential associations between progression-free survival (PFS) and genomic biomarkers were evaluated using standard correlation analyses and log-rank of Kaplan-Meier estimates. RESULTS: Among biomarker-evaluable samples, 22% (234/1,050) harbored BRCA1/2 mutations and 46% (446/980) were HRD. Median TMB was low irrespective of BRCA1/2 or HRD. Only 3% (29/1,024) had TMB ≥10 mut/Mb, and 0.3% (3/1,022) were MSI-high. PFS was better in BRCA2-mutated versus BRCA2-non-mutated tumors and in HRD versus proficient tumors. PD-L1 positivity (≥1% expression on ICs) was associated with HRD but not BRCA1/2 mutations. PFS was not improved by adding atezolizumab in BRCA2-mutated or HRD tumors; there was a trend toward enhanced PFS with atezolizumab in BRCA1-mutated tumors. CONCLUSIONS: Most ovarian tumors have low TMB despite BRCA1/2 mutations or HRD. Neither BRCA1/2 mutation nor HRD predicted enhanced benefit from atezolizumab. This is the first randomized double-blind trial in ovarian cancer demonstrating that genomic instability triggered by BRCA1/2 mutation or HRD is not associated with improved sensitivity to immune checkpoint inhibitors. See related commentary by Al-Rawi et al., p. 1645.

CD8+ T cell-intrinsic IL-6 signaling promotes resistance to anti-PD-L1 immunotherapy.

Although immune checkpoint inhibitors (ICIs) are established as effective cancer therapies, overcoming therapeutic resistance remains a critical challenge. Here we identify interleukin 6 (IL-6) as a correlate of poor response to atezolizumab (anti-PD-L1) in large clinical trials of advanced kidney, breast, and bladder cancers. In pre-clinical models, combined blockade of PD-L1 and the IL-6 receptor (IL6R) causes synergistic regression of large established tumors and substantially improves anti-tumor CD8+ cytotoxic T lymphocyte (CTL) responses compared with anti-PD-L1 alone. Circulating CTLs from cancer patients with high plasma IL-6 display a repressed functional profile based on single-cell RNA sequencing, and IL-6-STAT3 signaling inhibits classical cytotoxic differentiation of CTLs in vitro. In tumor-bearing mice, CTL-specific IL6R deficiency is sufficient to improve anti-PD-L1 activity. Thus, based on both clinical and experimental evidence, agents targeting IL-6 signaling are plausible partners for combination with ICIs in cancer patients.

Tissue and liquid biopsy profiling reveal convergent tumor evolution and therapy evasion in breast cancer.

Pathological and genomic profiling have transformed breast cancer care by matching patients to targeted treatments. However, tumors evolve and evade therapeutic interventions often through the acquisition of genomic mutations. Here we examine patients profiled with tissue (TBx) and liquid biopsy (LBx) as part of routine clinical care, to characterize the tumor evolutionary landscape and identify potential vulnerabilities in the relapsed setting. Real-world evidence demonstrates that LBx is utilized later in care and identifies associations with intervening therapy. While driver events are frequently shared, acquired LBx alterations are detected in a majority of patients, with the highest frequency in ER+ disease and in patients with longer biopsy intervals. Acquired mutations are often polyclonal and present at lower allelic fractions, suggesting multi-clonal convergent evolution. In addition to well-characterized resistance mutations (e.g., ESR1, NF1, RB1, ERBB2), we observe a diversity of rarer but potentially targetable mutations (e.g., PIK3CA, HRAS/NRAS/KRAS, FGFR1/2/3, BRAF) and fusions (e.g., FGFR1/2, ERBB2, RET), as well as BRCA1/2 reversions through a variety of mechanisms, including splice alterations and structural deletions. This study provides insights on treatment and selection-driven tumor evolution and identifies potential combinatorial treatment options in advanced breast cancer.

PARP Inhibitor Insensitivity to BRCA1/2 Monoallelic Mutations in Microsatellite Instability-High Cancers.

PURPOSE: To examine the overlap of homologous recombination deficiency (HRD) and microsatellite instability high (MSI-H) status, and to dissect driver versus bystander status of BRCA1/2 mutations (BRCAm) in this context. METHODS: A pan-cancer comprehensive genomic profiling cohort (n = 213,199) was examined for overlap between BRCAm and MSI-H status. BRCA1/2 variant zygosity was examined and correlated with MSI-H status, tumor mutational burden, and genome-wide loss of heterozygosity (gLOH). Clinical histories of two patients with prostate cancer with co-occurring BRCAm and MSI-H are described. RESULTS: HRD and MSI-H phenotypes were generally mutually exclusive events (P < .001). BRCAm that co-occurred together with high tumor mutational burden or MSI-H were predominantly monoallelic bystander alterations. In breast, ovarian, and pancreatic cancers, very few BRCAm occurred in the context of MSI-H; however, in prostate cancer, 12.8% of BRCA1 and 3.4% of BRCA2 alterations co-occurred with MSI-H. In these BRCA-associated cancers, co-occurring BRCAm were generally monoallelic and were not associated with elevated gLOH. Two patients with prostate cancer with co-occurring BRCAm and MSI-H showed resistance to poly (ADP-ribose) polymerase inhibition but sensitivity to subsequent anti-programmed cell death protein 1 therapy. CONCLUSION: MSI-H status and HRD are generally mutually exclusive phenomena across cancer types, but may rarely co-occur, especially in prostate cancer. Although MSI-H samples had a higher BRCAm prevalence relative to microsatellite-stable tumors, these BRCA1/2 mutations were generally monoallelic and were not associated with elevated gLOH. Our findings suggest that most BRCAm coexisting with microsatellite instability are likely bystander events that may not result in sensitivity to poly (ADP-ribose) polymerase inhibitors.

Epigenetic promoter alterations in GI tumour immune-editing and resistance to immune checkpoint inhibition.

OBJECTIVES: Epigenomic alterations in cancer interact with the immune microenvironment to dictate tumour evolution and therapeutic response. We aimed to study the regulation of the tumour immune microenvironment through epigenetic alternate promoter use in gastric cancer and to expand our findings to other gastrointestinal tumours. DESIGN: Alternate promoter burden (APB) was quantified using a novel bioinformatic algorithm (proActiv) to infer promoter activity from short-read RNA sequencing and samples categorised into APBhigh, APBint and APBlow. Single-cell RNA sequencing was performed to analyse the intratumour immune microenvironment. A humanised mouse cancer in vivo model was used to explore dynamic temporal interactions between tumour kinetics, alternate promoter usage and the human immune system. Multiple cohorts of gastrointestinal tumours treated with immunotherapy were assessed for correlation between APB and treatment outcomes. RESULTS: APBhigh gastric cancer tumours expressed decreased levels of T-cell cytolytic activity and exhibited signatures of immune depletion. Single-cell RNAsequencing analysis confirmed distinct immunological populations and lower T-cell proportions in APBhigh tumours. Functional in vivo studies using 'humanised mice' harbouring an active human immune system revealed distinct temporal relationships between APB and tumour growth, with APBhigh tumours having almost no human T-cell infiltration. Analysis of immunotherapy-treated patients with GI cancer confirmed resistance of APBhigh tumours to immune checkpoint inhibition. APBhigh gastric cancer exhibited significantly poorer progression-free survival compared with APBlow (median 55 days vs 121 days, HR 0.40, 95% CI 0.18 to 0.93, p=0.032). CONCLUSION: These findings demonstrate an association between alternate promoter use and the tumour microenvironment, leading to immune evasion and immunotherapy resistance.

Impact of Anti-HER2 Treatments Combined With Atezolizumab on the Tumor Immune Microenvironment in Early or Metastatic Breast Cancer: Results From a Phase Ib Study.

BACKGROUND: Despite advances, there continues to be unmet need in breast cancer. Combining anti-programmed death-ligand 1 (PD-L1) cancer immunotherapy atezolizumab with other targeted therapies may enhance T-cell-dependent cytolytic antitumor activity. METHODS: This open-label, phase Ib study evaluated the safety of atezolizumab-based combinations with antibody-dependent cellular cytotoxicity or antibody-drug conjugate (ADC) agents. Patients with unresectable human epidermal growth factor receptor 2-positive (HER2+) locally advanced or metastatic breast cancer (mBC) received atezolizumab with trastuzumab/pertuzumab, atezolizumab with the ADC ado-trastuzumab emtansine (T-DM1), or atezolizumab with trastuzumab/pertuzumab and docetaxel. In an early-breast cancer (eBC) "window of opportunity" study, patients with operable HER2+ locally advanced or inflammatory eBC received neoadjuvant atezolizumab with trastuzumab/pertuzumab or atezolizumab/T-DM1, followed by docetaxel, carboplatin, and trastuzumab/pertuzumab. Exploratory outcomes included tumor response and biomarkers. RESULTS: By March 15, 2019, 73 patients were enrolled. Safety findings were consistent with the treatment components' individual profiles. Objective responses were observed in 2 of 6 and 5 of 14 patients in 2 mBC cohorts receiving atezolizumab/T-DM1 and in 6 of 6 patients with mBC receiving atezolizumab, trastuzumab/pertuzumab, and docetaxel. PD-L1 in immune cells was the only biomarker that increased with atezolizumab/T-DM1. In the window of opportunity cohorts, PD-L1 levels and CD8+ T-cell infiltration increased from baseline in HER2+ eBC tumors receiving atezolizumab with trastuzumab/pertuzumab or T-DM1, irrespective of response. Despite increases in T-cell and B-cell gene signatures with trastuzumab/pertuzumab, but not T-DM1, neither combination promoted T-cell receptor clonal expansion. CONCLUSION: Atezolizumab with antibody-dependent cellular cytotoxicity or ADC agents appears safe and may activate the adaptive immune system of patients with HER2+ eBC tumors more than those with mBC tumors.

Molecular determinants of response to PD-L1 blockade across tumor types.

Immune checkpoint inhibitors targeting the PD-1/PD-L1 axis lead to durable clinical responses in subsets of cancer patients across multiple indications, including non-small cell lung cancer (NSCLC), urothelial carcinoma (UC) and renal cell carcinoma (RCC). Herein, we complement PD-L1 immunohistochemistry (IHC) and tumor mutation burden (TMB) with RNA-seq in 366 patients to identify unifying and indication-specific molecular profiles that can predict response to checkpoint blockade across these tumor types. Multiple machine learning approaches failed to identify a baseline transcriptional signature highly predictive of response across these indications. Signatures described previously for immune checkpoint inhibitors also failed to validate. At the pathway level, significant heterogeneity is observed between indications, in particular within the PD-L1+ tumors. mUC and NSCLC are molecularly aligned, with cell cycle and DNA damage repair genes associated with response in PD-L1- tumors. At the gene level, the CDK4/6 inhibitor CDKN2A is identified as a significant transcriptional correlate of response, highlighting the association of non-immune pathways to the outcome of checkpoint blockade. This cross-indication analysis reveals molecular heterogeneity between mUC, NSCLC and RCC tumors, suggesting that indication-specific molecular approaches should be prioritized to formulate treatment strategies.

PD-L1 Immunohistochemistry Assay Comparison in Atezolizumab Plus nab-Paclitaxel-Treated Advanced Triple-Negative Breast Cancer.

BACKGROUND: In the phase III IMpassion130 study, atezolizumab plus nab-paclitaxel (A+nP) showed clinical benefit in advanced or metastatic triple-negative breast cancer patients who were programmed death-ligand 1 (PD-L1)+ (tumor-infiltrating immune cells [IC] ≥1%) using the SP142 immunohistochemistry assay. Here we evaluate 2 other PD-L1 assays for analytical concordance with SP142 and patient-associated clinical outcomes. METHODS: Samples from 614 patients (68.1% of intention-to-treat population) were centrally evaluated by immunohistochemistry for PD-L1 status on IC (VENTANA SP142, SP263, Dako 22C3) or as a combined positive score (CPS; 22C3). RESULTS: Using SP142, SP263, and 22C3 assays, PD-L1 IC ≥1% prevalence was 46.4% (95% confidence interval [CI] = 42.5% to 50.4%), 74.9% (95% CI = 71.5% to 78.3%), and 73.1% (95% CI = 69.6% to 76.6%), respectively; 80.9% were 22C3 CPS ≥1. At IC ≥1% (+), the analytical concordance between SP142 and SP263 and 22C3 was 69.2% and 68.7%, respectively. Almost all SP142+ cases were captured by other assays (double positive), but several SP263+ (29.6%) or 22C3+ (29.0%) cases were SP142- (single positive). A+nP clinical activity vs placebo+nP in SP263+ and 22C3+ patients (progression-free survival [PFS] hazard ratios [HRs] = 0.64 to 0.68; overall survival [OS] HRs = 0.75 to 0.79) was driven by double-positive cases (PFS HRs = 0.60 to 0.61; OS HRs = 0.71 to 0.75) rather than single-positive cases (PFS HRs = 0.68 to 0.81; OS HRs = 0.87 to 0.95). Concordance for harmonized cutoffs for SP263 (IC ≥4%) and 22C3 (CPS ≥10) to SP142 (IC ≥1%) was subpar (approximately 75%). CONCLUSIONS: 22C3 and SP263 assays identified more patients as PD-L1+ (IC ≥1%) than SP142. No inter-assay analytical equivalency was observed. Consistent improved A+nP efficacy was captured by the SP142 PD-L1 IC ≥1% subgroup nested within 22C3 and SP263 PD-L1+ (IC ≥1%) populations.

Atezolizumab, Bevacizumab, and Chemotherapy for Newly Diagnosed Stage III or IV Ovarian Cancer: Placebo-Controlled Randomized Phase III Trial (IMagyn050/GOG 3015/ENGOT-OV39).

PURPOSE: To evaluate the addition of the humanized monoclonal antiprogrammed death ligand-1 (PD-L1) antibody, atezolizumab, to platinum-based chemotherapy and bevacizumab in newly diagnosed stage III or IV ovarian cancer (OC). METHODS: This multicenter placebo-controlled double-blind randomized phase III trial (ClinicalTrials.gov identifier: NCT03038100) enrolled patients with newly diagnosed untreated International Federation of Gynecology and Obstetrics (FIGO) stage III or IV OC who either had undergone primary cytoreductive surgery with macroscopic residual disease or were planned to receive neoadjuvant chemotherapy and interval surgery. Patients were stratified by FIGO stage, Eastern Cooperative Oncology Group performance status, tumor immune cell PD-L1 staining, and treatment strategy and randomly assigned 1:1 to receive 3-weekly cycles of atezolizumab 1,200 mg or placebo (day 1, cycles 1-22), with paclitaxel plus carboplatin (day 1, cycles 1-6) plus bevacizumab 15 mg/kg (day 1, cycles 2-22), omitting perioperative bevacizumab in neoadjuvant patients. The co-primary end points were investigator-assessed progression-free survival and overall survival in the intention-to-treat and PD-L1-positive populations. RESULTS: Between March 8, 2017, and March 26, 2019, 1,301 patients were enrolled. The median progression-free survival was 19.5 versus 18.4 months with atezolizumab versus placebo, respectively (hazard ratio, 0.92; 95% CI, 0.79 to 1.07; stratified log-rank P = .28), in the intention-to-treat population and 20.8 versus 18.5 months, respectively (hazard ratio, 0.80; 95% CI, 0.65 to 0.99; P = .038), in the PD-L1-positive population. The interim (immature) overall survival results showed no significant benefit from atezolizumab. The most common grade 3 or 4 adverse events were neutropenia (21% with atezolizumab v 21% with placebo), hypertension (18% v 20%, respectively), and anemia (12% v 12%). CONCLUSION: Current evidence does not support the use of immune checkpoint inhibitors in newly diagnosed OC. Insight from this trial should inform further evaluation of immunotherapy in OC.

Atezolizumab and nab-Paclitaxel in Advanced Triple-Negative Breast Cancer: Biomarker Evaluation of the IMpassion130 Study.

BACKGROUND: Understanding the impact of the tumor immune microenvironment and BRCA1/2-related DNA repair deficiencies on the clinical activity of immune checkpoint inhibitors may help optimize both patient and treatment selection in metastatic triple-negative breast cancer. In this substudy from the phase 3 IMpassion130 trial, immune biomarkers and BRCA1/2 alterations were evaluated for association with clinical benefit with atezolizumab and nab-paclitaxel (A+nP) vs placebo and nP in unresectable (P+nP) locally advanced or metastatic triple-negative breast cancer. METHODS: Patients were randomly assigned 1:1 to nab-paclitaxel 100 mg/m2 (days 1, 8, and 15 of a 28-day cycle) and atezolizumab 840 mg every 2 weeks or placebo until progression or toxicity. Progression-free survival and overall survival were evaluated based on programmed death-ligand 1 (PD-L1) expression on immune cells (IC) and tumor cells, intratumoral CD8, stromal tumor-infiltrating lymphocytes, and BRCA1/2 mutations. RESULTS: PD-L1 IC+ in either primary or metastatic tumor tissue was linked to progression-free survival and overall survival benefit with A+nP. PD-L1 IC+ low (26.9%; 243 of 902 patients) and high (13.9%; 125 of 902 patients) populations had improved outcomes that were comparable. Intratumoral CD8 and stromal tumor-infiltrating lymphocytes positivity (sTIL+) were associated with PD-L1 IC+ status; improved outcomes were observed with A+nP vs P+nP only in CD8+ and sTIL+ patients who were also PD-L1 IC+. BRCA1/2 mutations (occurring in 14.5% [89 of 612 patients]) were not associated with PD-L1 IC status, and PD-L1 IC+ patients benefited from A+nP regardless of BRCA1/2 mutation status. CONCLUSIONS: Although A+nP was more efficacious in patients with richer tumor immune microenvironment, clinical benefit was only observed in patients whose tumors were PD-L1 IC+.

Prevalence Study of PD-L1 SP142 Assay in Metastatic Triple-negative Breast Cancer.

Metastatic triple-negative breast cancer (mTNBC) is the most aggressive breast cancer subtype. Programmed death ligand 1 (PD-L1) on immune cells (IC) using the VENTANA SP142 assay is linked to improved clinical outcome in atezolizumab plus nab-paclitaxel-treated patients with mTNBC in the IMpassion130 study. The goal of the current study was to evaluate prevalence of VENTANA SP142 PD-L1 assay by anatomic location in 670 histologically confirmed TNBC cases from subjects with metastatic disease screened for the phase 1 study PCD4989g (NCT01375842). PD-L1 immunohistochemistry was centrally tested on tumor cells (TC) and on tumor infiltrating IC, following manufacturer's instructions. At a 1% cutoff, tumor PD-L1 was more prevalent in IC than TC: 46% were PD-L1 IC+/TC-, 3% were PD-L1 IC-/TC+, and 10% were PD-L1 IC+/TC+. PD-L1 IC and TC immunostaining correlated with CD274 RNA expression, as assessed by fluidigm. Analyses of anatomic locations suggest that prevalence of PD-L1 IC+ was highest in lymph nodes (65.0%), lowest in liver metastases (26.9%), while breast tissue was intermediate (57.1%). Matched paired samples from the same subject collected synchronously or asynchronously showed a PD-L1 IC status agreement of 80% (8/10) and 75% (15/20), respectively. Our results suggest that the anatomic location of metastases and time of collection may influence the detection of PD-L1.

Enrichment of circulating tumor-derived extracellular vesicles from human plasma.

Extracellular vesicles (EVs) are gaining considerable traction within the liquid biopsy arena, as carriers of information from cells in distant sites that may not be accessible for biopsy. Therefore, there is a need to develop methods to enrich for specific EV subtypes, based on their cells of origin. Here we describe the development of an automated method to enrich tumor-derived EVs from plasma using the CellSearch technology compared to Total EVs isolated using differential ultracentrifugation (DUC). We use a modified CellSearch protocol to enrich EpCAM+ EVs from the plasma of patients with non-small cell lung carcinoma (NSCLC) and triple negative breast cancer (TNBC). As a test case, we examined PD-L1, an immune checkpoint ligand known to be expressed in some tumor tissues, to demonstrate enrichment for EpCAM+ EVs. For this purpose, we developed two custom immunoassays utilizing the Simoa HD-1 analyzer (Quanterix) to detect PD-L1 in EVs and interrogate specific EV populations from human plasma. PD-L1 was present in Total EVs from the plasma of healthy individuals and cancer patients, since it is also expressed on several immune cells. However, EpCAM+ EVs were only detectable from the plasma of cancer patients, suggesting these are tumor-derived EVs. As low as 250 µL of plasma could be used to reliably detect PD-L1 from patient-derived EpCAM+ EVs. In summary, this report demonstrates the development of a robust tumor-derived EV enrichment method from human blood. Furthermore, this proof-of-concept study is extendable to other known cancer-specific proteins expressed on EVs exuded from tumors.

Neoadjuvant atezolizumab in combination with sequential nab-paclitaxel and anthracycline-based chemotherapy versus placebo and chemotherapy in patients with early-stage triple-negative breast cancer (IMpassion031): a randomised, double-blind, phase 3 trial.

BACKGROUND: Preferred neoadjuvant regimens for early-stage triple-negative breast cancer (TNBC) include anthracycline-cyclophosphamide and taxane-based chemotherapy. IMpassion031 compared efficacy and safety of atezolizumab versus placebo combined with nab-paclitaxel followed by doxorubicin plus cyclophosphamide as neoadjuvant treatment for early-stage TNBC. METHODS: This double-blind, randomised, phase 3 study enrolled patients in 75 academic and community sites in 13 countries. Patients aged 18 years or older with previously untreated stage II-III histologically documented TNBC were randomly assigned (1:1) to receive chemotherapy plus intravenous atezolizumab at 840 mg or placebo every 2 weeks. Chemotherapy comprised of nab-paclitaxel at 125 mg/m2 every week for 12 weeks followed by doxorubicin at 60 mg/m2 and cyclophosphamide at 600 mg/m2 every 2 weeks for 8 weeks, which was then followed by surgery. Stratification was by clinical breast cancer stage and programmed cell death ligand 1 (PD-L1) status. Co-primary endpoints were pathological complete response in all-randomised (ie, all randomly assigned patients in the intention-to-treat population) and PD-L1-positive (ie, patients with PD-L1-expressing tumour infiltrating immune cells covering ≥1% of tumour area) populations. This study is registered with ClinicalTrials.gov (NCT03197935), Eudra (CT2016-004734-22), and the Japan Pharmaceutical Information Center (JapicCTI-173630), and is ongoing. FINDINGS: Between July 7, 2017, and Sept 24, 2019, 455 patients were recruited and assessed for eligibility. Of the 333 eligible patients, 165 were randomly assigned to receive atezolizumab plus chemotherapy and 168 to placebo plus chemotherapy. At data cutoff (April 3, 2020), median follow-up was 20·6 months (IQR 8·7-24·9) in the atezolizumab plus chemotherapy group and 19·8 months (8·1-24·5) in the placebo plus chemotherapy group. Pathological complete response was documented in 95 (58%, 95% CI 50-65) patients in the atezolizumab plus chemotherapy group and 69 (41%, 34-49) patients in the placebo plus chemotherapy group (rate difference 17%, 95% CI 6-27; one-sided p=0·0044 [significance boundary 0·0184]). In the PD-L1-positive population, pathological complete response was documented in 53 (69%, 95% CI 57-79) of 77 patients in the atezolizumab plus chemotherapy group versus 37 (49%, 38-61) of 75 patients in the placebo plus chemotherapy group (rate difference 20%, 95% CI 4-35; one-sided p=0·021 [significance boundary 0·0184]). In the neoadjuvant phase, grade 3-4 adverse events were balanced and treatment-related serious adverse events occurred in 37 (23%) and 26 (16%) patients, with one patient per group experiencing an unrelated grade 5 adverse event (traffic accident in the atezolizumab plus chemotherapy group and pneumonia in the placebo plus chemotherapy group). INTERPRETATION: In patients with early-stage TNBC, neoadjuvant treatment with atezolizumab in combination with nab-paclitaxel and anthracycline-based chemotherapy significantly improved pathological complete response rates with an acceptable safety profile. FUNDING: F Hoffmann-La Roche/Genentech.

Safety and Clinical Activity of Atezolizumab Plus Bevacizumab in Patients with Ovarian Cancer: A Phase Ib Study.

PURPOSE: Atezolizumab has shown antitumor activity in patients with ovarian cancer. Dual blockade of programmed death-ligand 1 (PD-L1) and VEGF enhances anticancer immunity and augments antitumor activity in several cancers. The safety and efficacy of atezolizumab plus bevacizumab were evaluated in patients with ovarian cancer. PATIENTS AND METHODS: In this open-label, multicenter phase Ib study, patients with platinum-resistant ovarian cancer received intravenous atezolizumab (1,200 mg) and bevacizumab (15 mg/kg) once every 3 weeks. The primary endpoint was safety; secondary endpoints included overall response rate (ORR), duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Exploratory biomarkers were also evaluated. RESULTS: Twenty patients received treatment. Treatment-related adverse events occurred in 19 patients (95%); seven (35%) had grade 3/4 events. No grade 5 events occurred. The safety profile of atezolizumab plus bevacizumab was consistent with those of the individual agents. Two patients (10%) discontinued treatment because of pneumonitis and small bowel obstruction. Three patients had partial responses of 11.3-18.9 months' duration; the ORR was 15%. Eight patients (40%) had stable disease, hence the disease control rate was 55%. The median DOR was not reached (95% confidence interval, 11.3-not reached). Median PFS was 4.9 months (range, 1.2-20.2); median OS was 10.2 months (range, 1.2-26.6). No association was seen between treatment response and PD-L1 expression, tumor histology, or number of prior therapies. CONCLUSIONS: Atezolizumab plus bevacizumab led to durable responses and/or disease stabilization in some patients with platinum-resistant ovarian cancer; the safety profiles were consistent with those of each agent.

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.

Atezolizumab plus nab-paclitaxel as first-line treatment for unresectable, locally advanced or metastatic triple-negative breast cancer (IMpassion130): updated efficacy results from a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Immunotherapy in combination with chemotherapy has shown promising efficacy across many different tumour types. We report the prespecified second interim overall survival analysis of the phase 3 IMpassion130 study assessing the efficacy and safety of atezolizumab plus nab-paclitaxel in patients with unresectable, locally advanced or metastatic triple-negative breast cancer. METHODS: In this randomised, placebo-controlled, double-blind, phase 3 trial, done in 246 academic centres and community oncology practices in 41 countries, patients aged 18 years or older, with previously untreated, histologically documented, locally advanced or metastatic triple-negative breast cancer, and Eastern Cooperative Oncology Group performance status of 0 or 1 were eligible. Patients were randomly assigned (1:1) using a permuted block method (block size of four) and an interactive voice-web response system. Randomisation was stratified by previous taxane use, liver metastases, and PD-L1 expression on tumour-infiltrating immune cells. Patients received atezolizumab 840 mg or matching placebo intravenously on day 1 and day 15 of every 28-day cycle and nab-paclitaxel 100 mg/m2 of body surface area intravenously on days 1, 8, and 15 until progression or unacceptable toxicity. Investigators, patients, and the funder were masked to treatment assignment. Coprimary endpoints were investigator-assessed progression-free survival per Response Evaluation Criteria in Solid Tumors version 1.1 and overall survival, assessed in the intention-to-treat population and in patients with PD-L1 immune cell-positive tumours (tumours with ≥1% PD-L1 expression). The final progression-free survival results were previously reported at the first interim overall survival analysis. The prespecified statistical testing hierarchy meant that overall survival in the subgroup of PD-L1 immune cell-positive patients could only be formally tested if overall survival was significantly different between the treatment groups in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02425891. FINDINGS: Between June 23, 2015, and May 24, 2017, 902 patients were enrolled, of whom 451 were randomly assigned to receive atezolizumab plus nab-paclitaxel and 451 were assigned to receive placebo plus nab-paclitaxel (the intention-to-treat population). Six patients from each group did not receive treatment. At the second interim analysis (data cutoff Jan 2, 2019), median follow-up was 18·5 months (IQR 9·6-22·8) in the atezolizumab group and 17·5 months (8·4-22·4) in the placebo group. Median overall survival in the intention-to-treat patients was 21·0 months (95% CI 19·0-22·6) with atezolizumab and 18·7 months (16·9-20·3) with placebo (stratified hazard ratio [HR] 0·86, 95% CI 0·72-1·02, p=0·078). In the exploratory overall survival analysis in patients with PD-L1 immune cell-positive tumours, median overall survival was 25·0 months (95% CI 19·6-30·7) with atezolizumab versus 18·0 months (13·6-20·1) with placebo (stratified HR 0·71, 0·54-0·94]). As of Sept 3, 2018 (the date up to which updated safety data were available), the most common grade 3-4 adverse events were neutropenia (38 [8%] of 453 patients in the atezolizumab group vs 36 [8%] of 437 patients in the placebo group), peripheral neuropathy (25 [6%] vs 12 [3%]), decreased neutrophil count (22 [5%] vs 16 [4%]), and fatigue (17 [4%] vs 15 [3%]). Treatment-related deaths occurred in two (<1%) patients in the atezolizumab group (autoimmune hepatitis related to atezolizumab [n=1] and septic shock related to nab-paclitaxel [n=1]) and one (<1%) patient in the placebo group (hepatic failure). No new treatment-related deaths have been reported since the primary clinical data cutoff date (April 17, 2018). INTERPRETATION: Consistent with the first interim analysis, this second interim overall survival analysis of IMpassion130 indicates no significant difference in overall survival between the treatment groups in the intention-to-treat population but suggests a clinically meaningful overall survival benefit with atezolizumab plus nab-paclitaxel in patients with PD-L1 immune cell-positive disease. However, this positive result could not be formally tested due to the prespecified statistical testing hierarchy. For patients with PD-L1 immune cell-positive metastatic triple-negative breast cancer, atezolizumab plus nab-paclitaxel is an important therapeutic option in a disease with high unmet need. FUNDING: F Hoffmann-La Roche and Genentech.

Tumor immune microenvironment and genomic evolution in a patient with metastatic triple negative breast cancer and a complete response to atezolizumab.

BACKGROUND: Metastatic TNBC (mTNBC) has a poor prognosis and few treatment options. The anti-PD-L1 antibody atezolizumab demonstrated clinical activity in mTNBC patients with PD-L1-positive tumor-infiltrating immune cells. The current study describes the tumor immune microenvironment (TiME) and genomic evolution across sequential therapies in a patient with a 31-year history of TNBC and a complete response (CR) to atezolizumab monotherapy. MATERIALS AND METHODS: In 1986, the patient had surgery and radiotherapy (XRT) for newly diagnosed TNBC, followed by surgery and adjuvant chemotherapy for two locoregional recurrences. She developed mTNBC in 2009 and was sequentially treated with capecitabine, gemcitabine-carboplatin-iniparib (GCI), XRT and an experimental vaccine. She experienced disease progression (PD) to all these therapies. In 2013, she had a PD-L1 positive tumor and enrolled in a phase 1 atezolizumab monotherapy study (PCD4989g; NCT01375842). She received atezolizumab for 1 year with initial pseudo-progression followed by a partial response. After 1 year without treatment she experienced PD, reinitiated atezolizumab and subsequently achieved CR. Tumor specimens were collected at numerous times between 2008 and 2015 and assessed by immunohistochemistry, RNA-seq and DNA-seq. RESULTS: TiME biomarkers, including CD8, ICs and PD-L1 on IC, increased after capecitabine and remained high after GCI, XRT and through pseudo-progression on atezolizumab. At PD post-atezolizumab exposure, TiME biomarkers decreased but PD-L1 status remained positive. Immune-related RNA signatures confirmed these findings. TNBC subtyping revealed evolution from luminal androgen receptor (LAR) to basal-like immune activated (BLIA). Genomic profiling showed truncal alterations in RB1 and TP53, while the presence of other genomic alterations varied over time. Tumor mutational burden peaked after XRT and declined after atezolizumab exposure. CONCLUSIONS: This case report describes the evolution of TiME and TNBC molecular subtypes/genomics over time with sequential therapies in a TNBC patient with a CR to atezolizumab monotherapy. These data suggest the TiME is pliable and may be manipulated to maximize response to immunotherapy (NCT01375842, https://clinicaltrials.gov/ct2/show/NCT01375842?term=NCT01375842&rank=1 ).