Comparison of SP142 and 22C3 Immunohistochemistry PD-L1 Assays for Clinical Efficacy of Atezolizumab in Non–Small Cell Lung Cancer: Results From the Randomized OAK Trial

BackgroundThis phase III OAK trial (NCT02008227) subgroup analysis (data cutoff, January 9, 2019) evaluated the predictive value of 2 PD-L1 IHC tests (VENTANA SP142 and Dako 22C3) for benefit from atezolizumab versus docetaxel by programmed death ligand 1 (PD-L1) status in patients with previously treated metastatic non–small cell lung cancer.MethodsPD-L1 expression was assessed prospectively with SP142 on tumor cells (TC) and tumor-infiltrating immune cells (IC) and retrospectively with 22C3 using a tumor proportion score (TPS) based on TC membrane staining. Efficacy was assessed in the 22C3 biomarker-evaluable population (22C3-BEP) (n = 577; 47.1% of SP142-intention-to-treat population) and non–22C3-BEP (n = 648) in PD-L1 subgroups (high, low, and negative) and according to selection by 1 or both assays.ResultsIn the 22C3-BEP, overall survival benefits with atezolizumab versus docetaxel were observed across PD-L1 subgroups; benefits were greatest in SP142-defined PD-L1–high (TC3 or IC3: hazard ratio [HR], 0.39 [95% confidence interval (CI), 0.25-0.63]) and 22C3-defined PD-L1–high (TPS ≥ 50%: HR, 0.56 [95% CI, 0.38-0.82]) and low (TPS, 1% to < 50%: HR, 0.55 [95% CI, 0.37-0.82]) groups. Progression-free survival improved with increasing PD-L1 expression for both assays. SP142 and 22C3 assays identified overlapping and unique patient populations in PD-L1–high, positive, and negative subgroups. Overall survival and progression-free survival benefits favored atezolizumab over docetaxel in double PD-L1–positive and negative groups; patients with both SP142- and 22C3-positive tumors derived the greatest benefit.ConclusionsDespite different scoring algorithms and differing sensitivity levels, the SP142 and 22C3 assays similarly predicted atezolizumab benefit at validated PD-L1 thresholds in patients with non–small cell lung cancer.     

Programmed Death Ligand 1 Immunohistochemistry in Triple-Negative Breast Cancer: Evaluation of Inter-Pathologist Concordance and Inter-Assay Variability

PurposeThe programmed death ligand 1 (PD-L1) SP142 assay with a 1% immune cell (IC) cutoff is approved for the selection of advanced triple-negative breast cancer (TNBC) patients for atezolizumab treatment. We aimed to evaluate the interobserver concordance of PD-L1 scoring and inter-assay variability of various PD-L1 assays in TNBC.MethodsThirty patients with primary TNBC were selected, and SP142, SP263, 22C3, and E1L3N assays were performed. PD-L1 staining in ICs and tumor cells (TCs) was scored by 10 pathologists who were blinded to the assay. The interobserver concordance among pathologists and the inter-assay variability of the four PD-L1 assays were analyzed. For SP142, the intraobserver concordance among the six pathologists was analyzed after training.ResultsThe adjusted means of PD-L1 IC scoring ranged from 6.2% to 12.9% for the four assays; the intraclass correlations showed moderate (0.584–0.649) reader concordance. The PD-L1 IC scoring with a 1% cutoff resulted in identical scoring in 40.0%–66.7% of cases and a poor to moderate agreement (Fleiss κ statistic [FKS] = 0.345–0.534) for the four assays. The SP142 assay had the widest range of positive rate (56.5%–100.0%), lowest number of cases with identical scoring, and lowest FKS at 1% cutoff. Pairwise comparison of adjusted means showed significantly decreased PD-L1 staining in SP142 compared with the other assays in both ICs and TCs. As for the intraobserver concordance in the SP142 assay, the overall percent agreement was 87.8% with a 1% IC cutoff. After training, the proportion of cases with identical scoring at a 1% IC cutoff increased to 70.0%; the FKS also increased to 0.610.ConclusionThe concordance of PD-L1 IC scoring among pathologists was low, at the 1% cutoff for the SP142 assay without training. SP142 showed the lowest PD-L1 expression in both IC and TC.     

Updated Overall Survival Analysis From IMpower110: Atezolizumab Versus Platinum-Based Chemotherapy in Treatment-Naive Programmed Death-Ligand 1–Selected NSCLC

IntroductionIMpower110 previously revealed significant overall survival (OS) benefit with atezolizumab versus chemotherapy in patients with treatment-naive EGFR- and ALK-negative (wild type [WT]) metastatic NSCLC with high programmed death-ligand 1 (PD-L1) expression (≥50% on tumor cells [TCs] or ≥10% on tumor-infiltrating immune cells [ICs], per SP142 immunohistochemistry assay; p = 0.0106). We present primary OS analyses in lower PD-L1 expression groups and an updated, exploratory analysis in the high PD-L1 expression group.MethodsThis open-label, phase 3 trial randomized patients with PD-L1 expression on greater than or equal to 1% of TC or IC to receive atezolizumab or platinum-based chemotherapy. The primary end point was OS, hierarchically tested in PD-L1 expression WT subgroups: first the high PD-L1 expression subgroup, then the high-or-intermediate PD-L1 expression subgroup (≥5% on TC or IC), and then the any PD-L1 expression subgroup (≥1% on TC or IC).ResultsThe any PD-L1 expression WT population included 554 patients (excluded 18 EGFR- or ALK-positive patients). With 17 months’ additional follow-up, OS improvement in the atezolizumab versus chemotherapy arm was not statistically significant in high-or-intermediate PD-L1 expression WT patients (n = 328; hazard ratio = 0.87, 95% confidence interval: 0.66–1.14, p = 0.3091; median = 19.9 versus 16.1 mo), precluding formal OS testing in any PD-L1 expression WT patients. Exploratory analysis in high PD-L1 expression WT patients (n = 205) revealed maintained OS benefit in the atezolizumab arm (hazard ratio = 0.76, 95% confidence interval: 0.54–1.09; median = 20.2 versus 14.7 mo). Updated safety data continued to favor atezolizumab.ConclusionsStatistical significance for OS was not revealed in the high-or-intermediate expression WT group, and, as a result, OS in the any PD-L1 expression WT group was not formally tested. No new safety signals were found. This updated analysis of IMpower110 supports using atezolizumab in treatment-naive, metastatic WT NSCLC with high PD-L1 expression.     

PD-L1 Immunohistochemistry Assays for Lung Cancer: Results from Phase 1 of the Blueprint PD-L1 IHC Assay Comparison Project

IntroductionThe Blueprint Programmed Death Ligand 1 (PD-L1) Immunohistochemistry (IHC) Assay Comparison Project is an industrial-academic collaborative partnership to provide information on the analytical and clinical comparability of four PD-L1 IHC assays used in clinical trials.MethodsA total of 39 NSCLC tumors were stained with four PD-L1 IHC assays (22C3, 28-8, SP142, and SP263), as used in the clinical trials. Three experts in interpreting their respective assays independently evaluated the percentages of tumor and immune cells staining positive at any intensity. Clinical diagnostic performance was assessed through comparisons of patient classification above and below a selected expression cutoff and by agreement using various combinations of assays and cutoffs.ResultsAnalytical comparison demonstrated that the percentage of PD-L1–stained tumor cells was comparable when the 22C3, 28-8, and SP263 assays were used, whereas the SP142 assay exhibited fewer stained tumor cells overall. The variability of immune cell staining across the four assays appears to be higher than for tumor cell staining. Of the 38 cases, 19 (50.0%) were classified above and five (13%) were classified below the selected cutoffs of all assays. For 14 of the 38 cases (37%), a different PD-L1 classification would be made depending on which assay/scoring system was used.ConclusionsThe Blueprint PD-L1 IHC Assay Comparison Project revealed that three of the four assays were closely aligned on tumor cell staining whereas the fourth showed consistently fewer tumor cells stained. All of the assays demonstrated immune cell staining, but with greater variability than with tumor cell staining. By comparing assays and cutoffs, the study indicated that despite similar analytical performance of PD-L1 expression for three assays, interchanging assays and cutoffs would lead to “misclassification” of PD-L1 status for some patients. More data are required to inform on the use of alternative staining assays upon which to read different specific therapy-related PD-L1 cutoffs.     

PD-L1 Expression by Two Complementary Diagnostic Assays and mRNA In Situ Hybridization in Small Cell Lung Cancer

IntroductionTherapeutic antibodies to immune checkpoints show promising results. Programmed death-ligand 1 (PD-L1), an immune checkpoint ligand, blocks the cancer immunity cycle by binding the PD-L1 receptor (programmed death 1). We investigated PD-L1 protein expression and messenger RNA (mRNA) levels in SCLC.MethodsPD-L1 protein expression and mRNA levels were determined by immunohistochemistry (IHC) with SP142 and Dako 28-8 PD-L1 antibodies and in situ hybridization in primary tumor tissue microarrays in both tumor cells and tumor-infiltrating immune cells (TIICs) obtained from a limited-disease SCLC cohort of 98 patients. An additional cohort of 96 tumor specimens from patients with extensive-disease SCLC was assessed for PD-L1 protein expression in tumor cells with Dako 28-8 antibody only.ResultsThe overall prevalence of PD-L1 protein expression in tumor cells was 16.5%. In the limited-disease cohort, the prevalences of PD-L1 protein expression in tumor cells with SP142 and Dako 28-8 were 14.7% and 19.4% (tumor proportion score cutoff ≥1%) and PD-L1 mRNA ISH expression was positive in 15.5% of tumor samples. Increased PD-L1 protein/mRNA expression was associated with the presence of more TIICs (p < 0.05). The extensive-disease cohort demonstrated a 14.9% positivity of PD-L1 protein expression in tumor cells with Dako 28-8 antibody.ConclusionsA subset of SCLCs is characterized by positive PD-L1 and/or mRNA expression in tumor cells. Higher PD-L1 and mRNA expression correlate with more infiltration of TIICs. The prevalence of PD-L1 in SCLC is lower than that published for NSCLC. The predictive role of PD-L1 expression in SCLC treatment remains to be established.     

IMpower150 Final Overall Survival Analyses for Atezolizumab Plus Bevacizumab and Chemotherapy in First-Line Metastatic Nonsquamous NSCLC

IntroductionWe report the final overall survival (OS) analyses of atezolizumab-carboplatin-paclitaxel (ACP [experimental arm]) and OS data with approximately 39.8 months of median follow-up with atezolizumab-bevacizumab-carboplatin-paclitaxel (ABCP) versus bevacizumab-carboplatin-paclitaxel (BCP) in chemotherapy-naive patients with metastatic nonsquamous NSCLC in the phase 3 IMpower150 study (NCT02366143).MethodsIn this randomized, open-label study (N = 1202), coprimary end points included investigator-assessed progression-free survival and OS in intention-to-treat (ITT) wild-type (WT; no EGFR or ALK alterations) patients. Secondary and exploratory end points included OS in ITT and programmed death-ligand 1 (PD-L1) subgroups defined by the VENTANA SP142 and SP263 immunohistochemistry assays.ResultsAt the final analysis with ACP versus BCP (data cutoff: September 13, 2019; minimum follow-up: 32.4 mo), ACP had numerical, but not statistically significant, improvements in OS (ITT-WT: median OS = 19.0 versus 14.7 mo; hazard ratio = 0.84; 95% confidence interval: 0.71–1.00). OS benefit was sustained with ABCP versus BCP (ITT-WT: 19.5 versus 14.7 mo; hazard ratio = 0.80; 95% confidence interval: 0.67–0.95). Exploratory analyses in the SP142-defined PD-L1 subgroups revealed longer median OS with ABCP and ACP versus BCP in PD-L1–high and PD-L1–positive subgroups; in the PD-L1–negative subgroups, median OS was similar with ACP and ABCP versus BCP. Safety was consistent with that in earlier analyses (data cutoff: January 22, 2018).ConclusionsAt the final IMpower150 OS analysis, ACP had numerical, but not statistically significant, OS improvement versus BCP. Updated data with an additional 20 months of follow-up revealed continued OS improvement with ABCP versus BCP in all patients.     

The Immune Microenvironment,Genome-wide Copy Number Aberrations,and Survival in Mesothelioma

IntroductionResults of recent clinical studies of immune checkpoint inhibitors in malignant pleural mesothelioma (MPM) have dampened initial enthusiasm. However, the immune environment and targets of these treatments such as programmed cell death protein 1 and its ligand programmed death ligand 1 (PD-L1) have not been well characterized in MPM. Using a large cohort of patients, we investigated PD-L1 expression, immune infiltrates, and genome-wide copy number status and correlated them to clinicopathological features.MethodsTissue microarrays were constructed and stained with PD-L1(clone E1L3N [Cell Signaling Technology, Danvers, MA]), cluster of differentiation 4, cluster of differentiation 8, and forkhead box P3 antibodies. PD-L1 positivity was defined as at least 5% membranous staining regardless of intensity, and high PD-L1 positivity was defined as at least 50%. Genomic DNA from a representative subset of 113 patients was used for genome-wide copy number analysis. The percent genome alteration was computed as a proxy for genomic instability, and statistical analyses were used to relate copy number aberrations to other variables.ResultsAmong 329 patients evaluated, PD-L1 positivity was detected in 130 of 311 (41.7%), but high PD-L1 positivity was seen in only 30 of 311 (9.6%). PD-L1 positivity correlated with nonepithelioid histological subtype and increased infiltration with cluster of differentiation 4–positive, cluster of differentiation 8–positive, and forkhead box P3–positive lymphocytes. High PD-L1–positive expression correlated with worse prognosis (hazard ratio = 2.37, 95% confidence interval: 1.57–3.56, p < 0.001) in univariate analysis but not in multivariate analysis. Higher percent genome alteration was associated with epithelioid histological subtype and poorer survival (hazard ratio = 1.59, 95% confidence interval: 1.01–2.5, p = 0.04) but not PD-L1 expression.ConclusionsPD-L1 expression was associated with nonepithelioid MPM, poor clinical outcome, and increased immunological infiltrates. Increased genomic instability did not correlate with PD-L1 expression but was associated with poorer survival.     

Correlation between Classic Driver Oncogene Mutations in EGFR,ALK, or ROS1 and 22C3–PD-L1 ≥50% Expression in Lung Adenocarcinoma

IntroductionTargeted somatic genomic analysis (EGFR, anaplastic lymphoma receptor tyrosine kinase gene [ALK], and ROS1) and programmed death ligand 1 (PD-L1) tumor proportion score (TPS) determined by immunohistochemistry (IHC) are used for selection of first-line therapies in advanced lung cancer; however, the frequency of overlap of these biomarkers in routine clinical practice is poorly reported.MethodsWe retrospectively probed the first 71 pairs of patients with lung adenocarcinoma from our institution. They were analyzed for PD-L1 by IHC using the clone 22C3 pharmDx kit (Agilent Technologies, Santa Clara, CA) and evaluated for co-occurrence of genomic aberrations and clinicopathologic characteristics.ResultsSurgical resection specimens, small biopsy (transbronchial or core needle) samples, and cytologic cell blocks (needle aspirates or pleural fluid) were tested. A PD-L1 TPS of at least ≥50% was seen in 29.6% of tumors. Of 19 tumors with EGFR mutations, ALK fluorescence in situ hybridization positivity, or ROS1 fluorescence in situ hybridization positivity, 18 had a PD-L1 TPS less than 50% versus only one tumor with a PD-L1 TPS of at least 50% (p = 0.0073). Tumors with a PD-L1 TPS of at least 50% were significantly associated with smoking status compared with tumors with a PD-L1 TPS less than 50% but were not associated with patient sex, ethnicity, tumor stage, biopsy site, or biopsy type/preparation.ConclusionsPD-L1 IHC can be performed on routine clinical lung cancer specimens. A TPS of at least 50% seldom overlaps with presence of driver oncogenes with approved targeted therapies. Three biomarker-specified groups of advanced lung adenocarcinomas can now be defined, each paired with a specific palliative first-line systemic therapy of proven clinical benefit: (1) EGFR/ALK/ROS1-affected adenocarcinoma paired with a matched tyrosine kinase inhibitor (∼20% of cases), (2) PD-L1–enriched adenocarcinoma (TPS ≥50%) paired with anti–PD-1 pembrolizumab (∼30% of cases), and (3) biomarker-negative (i.e., EGFR/ALK/ROS1/PD-L1–negative) adenocarcinoma paired with platinum doublet chemotherapy with or without bevacizumab (∼50% of cases).     

LAG-3 Protein Expression in Non–Small Cell Lung Cancer and Its Relationship with PD-1/PD-L1 and Tumor-Infiltrating Lymphocytes

IntroductionImmunotherapy targeting the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) checkpoint has shown promising efficacy in patients with NSCLC. Lymphocyte activating 3 gene (LAG-3) is another important checkpoint, and its role in NSCLC is still not clear. In this study we investigated lymphocyte activing 3 (LAG-3) protein expression; its correlation with PD-1, PD-L1, and tumor-infiltrating lymphocytes (TILs); and its association with survival in NSCLC.MethodsThe expression of LAG-3 (EPR4392 [Abcam, Cambridge, MA]) protein was assessed in 55 NSCLC cell lines by immunohistochemistry. LAG-3, PD-1 (NAT 105 [Cell Marque, Rocklin, CA]), and PD-L1 (22C3 [Dako, Carpenteria, CA]) protein expression was evaluated by immunohistochemistry, and TIL abundance was scored in 139 surgically resected specimens from patients with NSCLC. We also verified results in samples from 62 patients with untreated NSCLC and detected a correlation between LAG-3 expression and EGFR and KRAS mutation and echinoderm microtubule associated protein like 4 gene (EML4)–anaplastic lymphoma receptor tyrosine kinase gene (ALK) rearrangement.ResultsLAG-3 was not expressed on any of the 55 NSCLC cell lines. However, LAG-3 was expressed on the TILs in 36 patients with NSCLC (25.9%). Sixty patient samples (43.2%) were positive for PD-1 on the TILs, and 25 (18.0%) were positive for PD-L1 on tumor cells. Neither LAG-3 nor PD-1 was expressed on the tumor cells. LAG-3 was overexpressed on the TILs in nonadenocarcinoma compared with in adenocarcinoma (p = 0.031). LAG-3 expression on TILs was significantly correlated with that of PD-1 on TILs (p < 0.001) and PD-L1 on tumor cells (p = 0.041) but not with TIL percentage (p = 0.244). With the logistic regression model, the ORs for LAG-3 were 0.320 (95% confidence interval [CI]: 0.110–0.929) and 4.364 (95% CI: 1.898–10.031) when nonadenocarcinoma was compared with adenocarcinoma and TILs that were negative for PD-1 were compared with those positive for PD-1. Recurrence-free survival was significantly different in patients whose TILs were LAG-3–negative as opposed to LAG-3–positive (1.91 years [95% CI: 0.76–3.06] versus 0.87 years [95% CI: 0.27–1.47] [p = 0.025]). Likewise, LAG-3 status of TILs (negative versus positive) did significantly affect overall survival (OS) (3.04 years [95% CI: 2.76–3.32] versus 1.08 years [95% CI: 0.42–1.74] [p = 0.039]). Using Kaplan-Meier analysis, we found that patients with both PD-L1–negative tumor cells and LAG-3–negative TILs have longer recurrence-free survival than patients who are either PD-L1– or LAG-3–positive or both PD-L1– and LAG-3–positive (2.09 years [95% CI: 0.90–3.28] versus 1.42 years [95% CI: 0.46–2.34] versus 0.67 years [95% CI: 0.00–1.45] [p = 0.007]). In the verification stage, high expression of LAG-3 was also significantly correlated with higher expression of PD-1 on TILs (p = 0.016) and PD-L1 on tumor cells (p = 0.014). There was no correlation between LAG-3 expression and EGFR (p = 0.325) and KRAS mutation (p = 1.000) and ALK fusion (p = 0.562).ConclusionsLAG-3 is expressed on TILs in tumor tissues of some patients with NSCLC. Its expression was higher in nonadenocarcinoma and correlated with PD-1/PD-L1 expression. LAG-3 positivity or both LAG-3 and PD-L1 positivity was correlated with early postoperative recurrence. LAG-3 was related to poor prognosis.     

Multicenter Comparison of 22C3 PharmDx (Agilent) and SP263 (Ventana) Assays to Test PD-L1 Expression for NSCLC Patients to Be Treated with Immune Checkpoint Inhibitors

IntroductionAmong the several agents targeting the programmed cell death 1 (PD-1) pathway, pembrolizumab is currently the only one approved for the treatment of patients with NSCLC in association with a companion diagnostic assay, the anti–PD-L1 immunohistochemical (IHC) 22C3 PharmDx (Agilent Technologies, Santa Clara, CA) using the Dako Autostainer (Dako, Carpinteria, CA). However, the Dako platform is not present in each pathology department, and this technical limitation is a major problem for the diffusion of the PD-L1 IHC predictive test for pembrolizumab.MethodsThe Italian Society of Anatomic Pathology and Cytopathology and the Italian Association of Medical Oncology in an independent, multicenter study compared the in vitro diagnostics PD-L1 IHC 22C3 pharmDx test (Agilent) on the Dako Autostainer and the in vitro diagnostics Ventana PD-L1 (SP263) test on the Ventana BenchMark platform (Ventana Medical Systems, Tucson, AZ). Using serial sections from tissue microarrays, 100 lung adenocarcinomas were locally stained and scored in four centers with the same antibody batches.ResultsA high analytical correlation (more than 90% at the lower 95% confidence interval [CI] value) between PD-L1 expression levels obtained with the 22C3 and SP263 assays was observed. At the proposed clinically relevant cutoffs (≥50% and ≥1%), the overall concordances between 22C3 and SP263 data were 0.99 (95% CI: 0.96–1) and 0.80 (95% CI: 0.68–0.91), respectively. The lower agreement between data obtained with the 22C3 and SP263 clones at the cutoff of 1% or higher was mainly related to the lower (about 80%) interrater agreement at this cutoff with each clone.ConclusionsThese results indicate a high correlation between PD-L1 IHC expression data obtained with the Agilent PD-L1 IHC 22C3 pharmDx and the Ventana PD-L1 (SP263) tests in NSCLC and suggest that the two assays could be utilized interchangeably as an aid to select patients for first-line and second-line treatment with pembrolizumab and potentially with other anti–PD-1/PD-L1 checkpoint inhibitors.     

Interobserver Reliability of Programmed Cell Death Ligand-1 Scoring Using the VENTANA PD-L1 (SP263) Assay in NSCLC

IntroductionThe VENTANA PD-L1 (SP263) Assay is approved for use with anti–programmed cell death-1/programmed cell death ligand-1 (PD-1/PD-L1) therapies in NSCLC and urothelial carcinoma. Here, we investigate interobserver reliability of the SP263 assay, applied to PD-L1 scoring of tumor cells (TCs) in NSCLC.MethodsSix practicing European pulmonary pathologists independently scored the proportion of TCs expressing PD-L1 (TC score) from 200 archival, commercially sourced, formalin-fixed paraffin-embedded NSCLC resections stained using the SP263 assay. Agreement in scores was analyzed using the intraclass correlation coefficient and concordance in patient’s classification using Fleiss’ kappa.ResultsResults from 172 samples showed strong pair-wise correlations between pathologists (R² >0.89) for TC scoring with an intraclass correlation coefficient of 0.96. Overall agreement was greater than 90% for TC of 1% and above, and greater than 94% for TCs of at least 25% and at least 50%. Fleiss’ kappa showed substantial agreement for TC of 1% and above, and almost perfect agreement for TCs of at least 25% and at least 50%.ConclusionsAssessment of TC score in NSCLC was highly reproducible using the SP263 assay, building confidence in the accuracy of this assay in selection of patients for anti–PD-1/PD-L1 therapy.     

Impact of Patient Characteristics,Prior Therapy,and Sample Type on Tumor Cell Programmed Cell Death Ligand 1 Expression in Patients with Advanced NSCLC Screened for the ATLANTIC Study

IntroductionWe evaluated the impact of patient characteristics, sample types, and prior non-immunotherapy treatment on tumor cell (TC) programmed cell death ligand 1 (PD-L1) expression using samples from patients with advanced NSCLC.MethodsPatients (N = 1590) screened for the ATLANTIC study submitted a recently acquired (≤3 months) or archival (>3 months to >3 years old) tumor sample for PD-L1 assessment using the VENTANA PD-L1 (SP263) Assay with a cutoff of ≥25% of TCs expressing PD-L1 (TC ≥25%). Samples were acquired either before or after the two or more treatment regimens required for study entry and sample age varied among patients. A subset of patients (n = 123) provided both recent and archival samples.ResultsA total of 517 of 1590 (32.5%) patients had TC greater than or equal to 25%: prevalence was greater in smokers versus nonsmokers (p = 0.0005) and those with EGFR− versus EGFR+ tumors (p = 0.0002); these effects were independent. Prevalence of TC greater than or equal to 25% was increased in recent metastatic versus primary (p = 0.005) and recent versus archival (p = 0.039) samples. Chemotherapy or radiotherapy, but not tyrosine kinase inhibition, before sampling was associated with significantly increased PD-L1 prevalence. PD-L1 status (TC ≥25% cutoff) remained unchanged in 74.0% of patients with recent and archival samples; where PD-L1 status changed, it was more likely to increase than decrease over time or with intervening treatment.ConclusionsSeveral factors potentially impact PD-L1 TC greater than or equal to 25% prevalence in advanced NSCLC; however, no characteristic can be considered a surrogate for PD-L1 expression. Fresh biopsy may provide more accurate assessment of current tumoral PD-L1 expression where a low/negative result is seen in an archival sample, especially if the patient has received intervening therapy.     

Prognostic Impact of Programmed Death-ligand 1 and Surrounding Immune Status on Stage I Lung Cancer

BackgroundThe programmed death 1/programmed death-ligand 1 (PD-L1) pathway reportedly is as an important factor determining effects of immunotherapy; however, its prognostic impact is controversial, and its association with the surrounding immune microenvironment has not yet been elucidated.Patients and MethodsWe retrospectively analyzed 126 patients with pathologic stage I non–small-cell lung cancer. Patients with lepidic-dominant adenocarcinoma were excluded. PD-L1 expression was evaluated with immunohistochemistry correlated with clinicopathologic features and surrounding immune microenvironment status, including CD4, CD8, regulatory T cells, and human leukocyte antigen class I. Factors affecting prognosis were assessed by Kaplan-Meier and Cox regression analyses.ResultsTwenty-three (18.3%) patients were positive for PD-L1 expression. No significant correlation was observed between PD-L1 expression and the surrounding immune microenvironment status. The PD-L1–positive group had a worse prognosis than the PD-L1–negative group (5-year recurrence-free survival rates, 63.4% vs. 81.0%; P = .061). Among surrounding immune cells, intratumoral CD8 status had the strongest impact on prognosis (P = .12). In the intratumoral CD8–high group, PD-L1 expression demonstrated no significant prognostic impact, whereas in the intratumoral CD8–low group, patients positive for PD-L1 demonstrated a significantly worse prognosis than those negative for PD-L1 (5-year recurrence-free survival rates, 41.7% vs. 78.6%; P = .034). Multivariable Cox regression analysis revealed that ‘PD-L1–positive and intratumoral CD8–low’ status was an independent prognostic factor (hazard ratio, 3.80; 95% confidence interval, 1.22-10.5; P = .023).ConclusionsThe prognostic impact of the PD-1/PD-L1 pathway may be distinct according to concurrent intratumoral CD8 status.     

Programmed Cell Death Ligand 1 Expression in Resected Non–Small Cell Lung Cancer

BackgroundRecently, anti–programmed cell death 1 (PD-1) and anti–programmed cell death ligand 1 (PD-L1) immunotherapies have yielded promising outcomes for patients with advanced non–small cell lung cancer (NSCLC) and led to great interest in applying these agents to treat resectable early-stage NSCLC. The objective of our study was to evaluate PD-L1 protein expression in resectable early-stage NSCLC specimens from a large Northern European cohort, examine the relationship to clinical characteristics, and demonstrate the prognostic role in resected NSCLC.Materials and MethodsA large cohort of 875 NSCLC tumors consisted of 337 patients from Sweden and 538 patients from Norway was studied. All the patients had undergone pulmonary resection, and most patients had had early-stage NSCLC. PD-L1 protein expression was assessed by immunohistochemistry using the Dako PD-L1 22C3 pharmDx kit. The tumor proportion score for PD-L1 protein expression was compared with comprehensive demographic and clinicopathologic data.ResultsThe overall prevalence of PD-L1 protein expression in the resectable NSCLC cohort was 9.5% at a tumor proportion score cutoff of ≥ 50%. Stage I NSCLC had lower PD-L1 expression compared with that of the other stages (P = .0012). PD-L1 expression correlated with wild-type EGFR gene expression (P = .0156) and mutated KRAS gene expression (P = .0004). No significant association was found between PD-L1 expression and mortality after multivariable adjustment for clinical characteristics, although the survival curves showed PD-L1 expression significantly correlated with a poor prognosis in the total NSCLC cohort and in the adenocarcinoma subgroup.ConclusionPD-L1 expression in the present large cohort of resectable NSCLC was relatively low compared with data from clinical trials of advanced NSCLC. PD-L1 expression correlated positively with tumor stage, wild-type EGFR, and KRAS mutation. PD-L1 expression was not found as an independent prognostic factor in the present study. These findings could be important in the future when evaluating the role of anti–PD-1/PD-L1 immunotherapy in the setting of neoadjuvant or adjuvant trials for early-stage resectable NSCLC.     

Predictive Performance of Four Programmed Cell Death Ligand 1 Assay Systems on Nivolumab Response in Previously Treated Patients with Non–Small Cell Lung Cancer

Introduction

Nivolumab has demonstrated efficacy against metastatic NSCLC. Four programmed cell death ligand 1 (PD-L1) immunohistochemistry (IHC) assay systems are available for identification of responders among patients with NSCLC, and these assays show some differing characteristics. Accordingly, in this study, we evaluated the ability of these assays to identify responders to nivolumab therapy.

PD-L1 Assay Concordance in Metastatic Renal Cell Carcinoma and Metastatic Urothelial Carcinoma

BackgroundImmune checkpoint inhibitors are now standard of care for many patients with metastatic renal cell carcinoma (mRCC) and metastatic urothelial carcinoma (mUC). Given real-world limitations in programmed death-ligand 1 (PD-L1) testing, concordance studies between PD-L1 assays are needed. We undertook comparisons of Dako 28-8 and Ventana SP142 assays in mRCC and Dako 22C3 and Ventana SP263 assays in mUC.Patients and MethodsThirty-two patients with mRCC and 18 patients with mUC who had received immune checkpoint inhibitor therapy were identified. Formalin-fixed paraffin-embedded tumor samples for patients with mRCC were evaluated with Dako 28-8 and Ventana SP142 PD-L1 immunohistochemistry assays. For patients with mUC, formalin-fixed paraffin-embedded tumor samples were evaluated with Dako 22C3 and Ventana SP263 PD-L1 immunohistochemistry assays.ResultsThe majority (29/32; 91%) of mRCC cases were concordant between assays. The majority (17/18; 94%) of mUC cases were also concordant between assays.ConclusionsThere was strong concordance between PD-L1 assays chosen for comparison in both mRCC and mUC, with similar performance characteristics. One limitation is the small number of cases in this study; larger comparison studies are needed for this biomarker in mRCC and mUC.     

Programmed Death-Ligand 1 Tumor Proportion Score and Overall Survival From First-Line Pembrolizumab in Patients With Nonsquamous Versus Squamous NSCLC

IntroductionFor patients with NSCLC receiving immune checkpoint inhibitors, programmed death-ligand 1 (PD-L1) tumor proportion score (TPS) has been validated as a predictive biomarker for improved overall survival (OS). Nevertheless, its histology-specific predictive value in patients with advanced squamous versus nonsquamous cancers remains unclear. To evaluate the differential value of PD-L1 TPS as a predictive biomarker for OS after first-line pembrolizumab in patients with squamous versus nonsquamous NSCLC.MethodsRetrospective, observational study of patients diagnosed with having advanced NSCLC who were treated between October 2015 and April 2019 at community oncology clinics and academic medical centers in a deidentified electronic health record–derived database. Included patients were diagnosed with having advanced or metastatic NSCLC, received treatment with first-line, single-agent pembrolizumab, and had documentation of PD-L1 testing with a numeric result. Exclusion criteria included alterations in EGFR, ALK, and ROS1. The primary end point was OS from start of first-line pembrolizumab therapy by squamous or nonsquamous histology and PD-1 expression level measured by TPS (low, <50% or high, ≥50%).ResultsThe cohort of 1460 patients with NSCLC who received pembrolizumab as a first-line therapy had a mean age of 72 years. Histology was 28% squamous and 72% nonsquamous. PD-L1 expression was low in 13% and high in 87%. No meaningful differences in age, sex, or smoking history were observed by PD-L1 TPS or histology type. A generalized gamma model adjusting for sex and stage at diagnosis found that for patients with nonsquamous histology, high PD-L1 TPS was significantly associated with improved OS by a median OS difference of 8.4 months (p < 0.001). In contrast, for patients with squamous histology, there was no evidence of association between PD-L1 expression level and OS (p = 0.283). PD-L1–related incremental differences in median OS between the patients with squamous and nonsquamous tumors were significantly different (p = 0.034).ConclusionsAmong patients with NSCLC treated with first-line pembrolizumab, high PD-L1 TPS is associated with OS among patients with nonsquamous NSCLC, but not among patients with squamous NSCLC.     

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.

Efficacy of Immune Checkpoint Inhibitors in Lung Sarcomatoid Carcinoma

IntroductionImmune checkpoint inhibitors (ICIs) have improved cancer prognosis but have not been evaluated specifically in sarcomatoid carcinoma (SC), a rare lung cancer subtype with poor prognosis. As such, our study sought to retrospectively assess the efficacy of ICI in SC.MethodsAll consecutive patients with centrally confirmed SC treated using ICI as a second-line treatment or beyond between 2011 and 2017 were enrolled. Programmed death-ligand 1 (PD-L1) tumor expression was assessed using immunohistochemistry (SP263 clone) and the tumor mutational burden (TMB) with the Foundation One panel. TMB was considered high if it was greater than or equal to 10 mutations per megabase.ResultsOverall, 37 patients with SC were evaluated, predominantly men (73%) with a median age of 63.2 years (36.8–79.7) and who were current or former smokers (94.6%). Immunotherapy (nivolumab, 86.5% of cases) was given as a second-line treatment in 54% of the patients and as third-line treatment or beyond in 46% of the patients. The objective response rate was 40.5% and disease control rate was 64.8%, regardless of PD-L1 status. Median overall survival was 12.7 months (range: 0.3–45.7). One-third of patients exhibited early progression. The median PD-L1 expression was 70% (0–100). There was a trend toward higher PD-L1 expression in responsive diseases, with an objective response rate of 58.8% in patients with PD-L1+ and 0% in the one patient with PD-L1- (p = 0.44). The median TMB was 18 (4–39) mutations per megabase, with 87.5% of the cases displaying a high TMB. There was a trend toward higher TMB in responders versus stable or progressive diseases (p = 0.2).ConclusionsPatients with SC exhibited high response rates and prolonged overall survival under ICI treatment. These data support the prospective investigation of ICI in patients with SC who are under first-line treatment.