22C3 Assay Research Articles

A comparative study of PD-L1 IHC assays using immune cell scoring and CPS in breast cancer.

e15262 Background: The clinical benefit of immune checkpoint inhibitors (ICIs) targeting the programmed death-1/programmed death ligand 1 (PD-L1) pathway has previously been demonstrated across a range of tumor types, including in PD-L1+ patients with metastatic triple-negative breast cancer (TNBC). Various PD-L1 immunohistochemistry (IHC) assays and scoring algorithms are being investigated to select patients with breast cancer (BC) most likely to respond to ICIs. Scoring algorithms include PD-L1 expression on tumor cells, immune cells (ICs), or both. We compared the analytical concordance of 3 PD-L1 IHC assays and evaluated PD-L1+ prevalence, using combined positive score (CPS) and % IC scoring algorithms in commercially procured TNBC and hormone receptor–positive, HER2-negative (HR+/HER2−) BC samples. Methods: PD-L1 expression was assessed by HistoGeneX (Naperville, IL) in 163 commercially procured, surgically resected, formalin-fixed, paraffin-embedded BC samples (mostly stage I–III) using the Ventana PD-L1 (SP142) and Dako PD-L1 IHC 28-8 and 22C3 pharmDx assays in conjunction with the CPS (28-8 and 22C3 assays) and % IC algorithms (SP142 and 28-8 assays). PD-L1+ prevalence with each assay and concordance between assays were calculated using CPS ≥ 1 and IC ≥ 1% cutoffs, with a single pathologist assigned to each scoring algorithm. Results: 93 HR+/HER2− BC and 70 TNBC samples were evaluable for PD-L1 expression across all assays and algorithms. Overall concordance was higher between the 28-8 and 22C3 assays (CPS cutoff of 1) than between the 28-8 and SP142 assays (IC cutoff of 1%). PD-L1+ prevalence was similar with the 28-8 and 22C3 assays (CPS ≥ 1) and higher with the 28-8 assay (IC ≥ 1%) than with the SP142 assay (IC ≥ 1%). PD-L1+ samples identified by the SP142 assay (IC ≥ 1%) were mostly included within PD-L1+ sample sets defined by the 28-8 assay (IC ≥ 1% and CPS ≥ 1). PD-L1+ prevalence was higher in TNBC vs HR+/HER2− BC for all assays (Table). No clear trend in PD-L1+ prevalence was observed across tumor grade and stage. Conclusions: High analytical concordance was observed between the 28-8 and 22C3 assays (CPS cutoff of 1) in both HR+/HER2− BC and TNBC samples. PD-L1+ prevalence varied according to IHC assay, scoring algorithm, and cutoff used. Further studies are needed to select the most appropriate PD-L1 assay and scoring algorithm for BC clinical trials. [Table: see text]

Economic evaluation of SP142 IHC assay versus 22C3 IHC assay in patients with unresectable locally advanced or metastatic triple-negative breast cancer in the Brazilian private healthcare system.

e13097 Background: The IMpassion130 trial has demonstrated that atezolizumab plus nab-paclitaxel results in significant clinical benefits for patients with unresectable locally advanced or metastatic (aTNBC). The SP142 IHC assay is a clinically validated and FDA-approved PD-L1 test to identify patients with aTNBC for treatment with atezolizumab plus nab-paclitaxel. A post hoc analysis of IMpassion130 evaluated two other PD-L1 IHC assays, 22C3 and SP263, for analytical and clinical concordance with SP142 and the PD-L1 prevalence by each assay. The prevalence of PD-L1+ per SP142 (tumor-infiltrating immune cells 1%), 22C3 (combined positive score1) and SP263 (tumor-infiltrating immune cells 1%), were 46%, 81% and 75%, respectively. The study compared only SP142 assay with 22C3 assay because patients with SP142 negative and 22C3 positive did not demonstrate a significant clinical benefit for progression-free survival (PFS) and overall survival (OS). Therefore the study aimed to demonstrate the economic impact of these assays in the treatment with atezolizumab plus nab-paclitaxel. Methods: Data of PFS and OS from the post hoc analysis of Impassion130 were extracted to develop a Markov model to simulate the clinical and economic impact of the patient with atezolizumab plus nab-paclitaxel guided by SP142 and 22C3 assays. The analysis considered the cost of atezolizumab+nab-paclitaxel, the cost associated with the management of the adverse events and the cost of the assay. The costs were based on CBHPM (Classificação Brasileira Hierarquizada de Procedimentos Médicos), CMED PF18% (Câmara de Regulação do Mercado de Medicamentos) and local publications. An univariate sensitivity analysis was performed. Results: The study demonstrated that SP142 assay has the potential to save 175,917 BRL (45,595 USD) with atezolizumab plus nab-paclitaxel per patients with aTNBC in three years. Conclusions: The SP142 assay can optimize the use of atezolizumab plus nab-paclitaxel avoiding its use in patient who will not have a significant clinical improvement.

Programmed Death-Ligand 1 Immunohistochemistry Assay Comparison Studies in NSCLC: Characterization of the 73-10 Assay.

Several programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) assays have been developed independently within clinical programs for therapeutic anti-programmed cell death protein 1 (anti-PD-1) or PD-L1 antibodies, necessitating assessment of assay comparability. We characterized the Dako PD-L1 IHC 73-10 assay used in clinical trials of avelumab (anti-PD-L1) or bintrafusp alfa (M7824; bifunctional immunotherapy) and compared it with the Dako PD-L1 IHC 22C3 pharmDx assay, an approved companion diagnostic for pembrolizumab monotherapy in patients with advanced NSCLC. Formalin-fixed, paraffin-embedded NSCLC tumor samples from a commercial source and from the JAVELIN Solid Tumor phase 1 trial of avelumab (NCT01772004) were stained using the 73-10 and 22C3 IHC assays with a standard protocol. Both assays displayed expected PD-L1 staining patterns. In 148 commercial NSCLC samples, the 73-10 assay stained greater than or equal to 1%, greater than or equal to 50%, and greater than or equal to 80% of tumor cells as PD-L1+ in 64.2%, 36.5%, and 23.6% of the samples, respectively, whereas the 22C3 assay stained 20.3% of the samples as greater than or equal to 50% PD-L1+. In 83 NSCLC clinical trial samples, the 73-10 assay stained 79.5% and 31.3% of the samples as greater than or equal to 1% and greater than or equal to 80% PD-L1+, respectively, whereas the 22C3 assay stained 59.0% and 21.7% as greater than or equal to 1% and greater than or equal to 50% PD-L1+, respectively. Efficacy of avelumab was similar in the subgroups classified with the 73-10 and 22C3 assays using greater than or equal to 80% and greater than or equal to 50% PD-L1+ cutoffs, with objective response rates of 26.9% and 33.3%, respectively. The 73-10 assay demonstrated high sensitivity for PD-L1 staining, and staining was comparable between the greater than or equal to 80% cutoff of the 73-10 assay and greater than or equal to 50% cutoff of the 22C3 assay.

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

Immune 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. Thirty-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. The majority (29/32; 91%) of mRCC cases were concordant between assays. The majority (17/18; 94%) of mUC cases were also concordant between assays. There 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.

Abstract A07: Assessment of concordance among 22C3, SP263, and SP142 immunohistochemistry assay for PD-L1 expression in non-small cell lung cancer

Abstract Background: PD-L1 expression, as determined by immunohistochemistry (IHC), is the most commonly use predictive biomarker for anti-PD-1 and anti-PD-L1 agents in currently available in clinical practice. However, multiple antibodies have been utilized in IHC assays and interpretation of their results has not been standardized. Recently, several studies have compared different antibodies and IHC systems for PD-L1 tests. We aimed to evaluate the similarity and concordance between three validated, commercially available PD-L1 IHC assays for non-small cell lung cancer (Dako 22C3, Ventana SP263, and Ventana SP142). Methods: We evaluated 219 samples from patients with non-small cell lung cancer at the Daegu Catholic University Medical Center between June 2017 and July 2018. Each tumor sample was stained with PD-L1 IHC 22C3, SP263, and SP142. PD-L1 expression was scored at different cut-off levels for each IHC antibodies (22C3 assay: <1%, 1-49%, and ≥50%, SP263: <10%, ≥10 and <25%, and ≥25%, SP142: <1%, 1-4%, 5-49%, and ≥50%). Results: Among the 219 samples, three different antibodies showed well correlation for PD-L1 expression (22C3 vs. SP263; r=0.896, p<0.001, 22C3 vs. SP142; r=0.750, p<0.001, SP263 vs. SP142; r=0.728, p<0.001). 22C3 IHC assay produced the similar results with SP263 IHC assay (Kappa value=0.510, p<0.001). However, 22C3 vs. SP263 and SP263 vs. SP142 showed poor concordance (Kappa value=0.171, p=0.004, and Kappa value=0.240, p<0.001, respectively). Conclusions: 22C3, SP263, and SP142 IHC assays showed good correlation for PD-L1 expression. 22C3 IHC assay showed good concordance with SP263, but SP142. Citation Format: Chi Young Jung, Eun Jin Kim, Woo Jung Sung. Assessment of concordance among 22C3, SP263, and SP142 immunohistochemistry assay for PD-L1 expression in non-small cell lung cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A07.

Association of positive Ki-67 and PD-L1 expressions in post neoadjvuant chemotherapy (NAC) radical cystectomy samples with lack of tumor downstaging (TD) and shorter overall survival (OS) in patients with muscle-invasive bladder cancer (MIBC).

554 Background: Previous chart review studies have reported that adjuvant chemotherapy after NAC did not clearly increase OS in MIBC cases characterized by a lack of TD. There is an unmet need to develop biomarkers to guide adjuvant therapy for this patient population. High levels of expression of cell proliferation marker Ki-67 are associated with poor outcome in chemotherapy naïve bladder cancer. Expression of PD-L1 has been studied as a potential predictive biomarker for anti-PD1 or PD-L1 therapies in metastatic MIBC. We therefore studied Ki-67 and PD-L1 expression in post NAC radical cystectomy samples at Moffitt Cancer Center and correlate them with TD and OS. Methods: Tissue microarrays (TMAs) were constructed from 116 post NAC cystectomy samples. The expressions of Ki-67 were evaluated with immunohistochemistry (IHC) and considered positive if any of the cores per sample were stained positive for Ki-67. The Dako 22C3 assay was used for PD-L1 IHC and the combined positive score of 10 or above was considered positive for PD-L1. Results: The median survival of this cohort of 116 patients was 33.4 months (range: 1.13 -127 months). 40 patients (35%) had TD and 21 patients (18%) achieved pathological complete response. Using Cox regression for OS, positive Ki-67 expression in post NAC radical cystectomy sample was associated with poorer OS (hazard ratio=2.412, 95% CI:1.076-5.408, p=0.033), independent of the pathological N stage. Patients with Ki67/PD-L1 double-negative tumors had a significantly longer median OS of 98.2 months versus 29.9 and 26.9 months in PD-L1-/Ki67+ and PD-L1+/Ki67+ tumors respectively (Log-rank test, p=0.0361). Lack of TD was significantly associated with positive Ki-67 (P<0.001) and positive PD-L1 (p=0.003) in the post NAC samples with a multi-variable logistic regression model. Conclusions: Positive Ki-67 and PD-L1 expressions in post NAC radical cystectomy samples were associated with inferior OS and absence of TD. Adjuvant anti-PD1 therapy either alone or in combination with chemotherapy would be indicated for this subset of patients.

Abstract PD1-07: Exploratory analytical harmonization of PD-L1 immunohistochemistry assays in advanced triple-negative breast cancer: A retrospective substudy of IMpassion130

Abstract Background: In the Phase 3 IMpassion130 (NCT02425891) trial in metastatic triple-negative breast cancer (mTNBC), first-line atezolizumab + nab-paclitaxel (A+nP) significantly improved PFS vs placebo + nab-paclitaxel (P+nP) in the intent-to-treat (ITT) and PD-L1+ (PD-L1-stained immune cells [IC] ≥ 1% of the tumor area by VENTANA PD-L1 SP142 assay) populations. SP142 is currently the only validated assay for selecting patients who may derive benefit with A+nP. In post-hoc analyses of IMpassion130 (Rugo, ESMO 2019, submitted), PD-L1 status was also evaluated by Dako 22C3 and VENTANA SP263 assays. The SP142+ population (IC ≥ 1%; 46% prevalence) was captured within the 22C3 (CPS ≥ 1, 81% prevalence) and SP263 (IC ≥ 1%, 75% prevalence) subgroups, which identified more patients (pts) with PD-L1+ tumors. A+nP clinical activity was highest in pts identified as PD-L1+ by both SP142 and 22C3/SP263. HRs for clinical activity were lower in pts identified as PD-L1+ by 22C3/SP163, but PD-L1- by SP142. There was no suggestion of clinical benefit in pts identified as PD-L1- by both SP142 and 22C3/SP263. In the current retrospective exploratory analysis, we attempted to harmonize the PD-L1 assays by identifying cutoffs for 22C3 or SP263 that replicate the SP142 IC ≥ 1% population. Methods: Samples from IMpassion130 were assessed by a central laboratory for PD-L1 expression using VENTANA SP142 or SP263 IHC assays or Dako 22C3 IHC assay. Optimal cutoffs for 22C3 and SP263 were identified as those that maximize the analytical concordance (defined as overall percentage agreement; OPA) with the clinically validated SP142 IC 1% cutoff as the reference standard. Association with clinical activity was analyzed in the biomarker-evaluable population (BEP) in tumor samples from pts evaluated by the three PD-L1 assays. Results: In the BEP (n = 614; 68% of ITT), the intraclass correlation index (Spearman r) between SP142 IC and 22C3 CPS or SP263 IC was 0.57 and 0.69, respectively. The model-derived cutoffs with highest OPA (75%) for SP142 IC ≥ 1% were CPS 10 for 22C3 and IC 4% for SP263. Compared with our previous analyses at standard cutoffs (22C3 CPS 1; SP263 IC 1%), model-derived cutoffs resulted in negative percentage agreement increases from 45% to 74% (22C3) and from 34% to 77% (SP263), accompanied by positive percentage agreement reductions from 98% to 74% (22C3) and to 73% (SP263). These data suggest that the SP142 assay may identify a different population from the 22C3 or SP263 assays. For 22C3 at CPS 10, 36% of pts were SP142+/22C3+, but 10% were SP142+/22C3-, and 17% SP142-/22C3+. For SP263 at IC 4%, 34% of pts were SP142+/SP263+, but 12% were SP142+/SP263-, and 12% SP142-/SP263+. See table for prevalences, medians and HR point estimates for PFS and OS with the model-derived cutoffs. Conclusions: The suboptimal OPAs achieved with the model-derived cutoffs indicate that the assays could not be harmonized. Differences in SP142+ vs 22C3+ or SP263+ populations at model-derived cutoffs suggest that SP142, 22C3 and SP263 may not identify the same tumor biology. Additional data are required to understand these differences. Findings from these hypothesis-generating, post-hoc exploratory analyses based on mathematical modeling should be interpreted with caution. Currently, the VENTANA PD-L1 SP142 IHC assay (IC ≥ 1%) is the only clinically validated companion assay to select pts with mTNBC for A+nP treatment. Populationn (%)Median PFS, moPFS HRMedian OS, moOS HRA+nPP+nP(95% CI)A+nPP+nP(95% CI)BEP614 (100)7.45.40.7221.119.20.84(0.61, 0.86)(0.68, 1.03)SP142IC ≥ 1%285 (46)8.34.10.627.317.90.74(0.47, 0.78)(0.54, 1.01)IC < 1%329 (54)5.75.60.8620.820.70.95(0.68, 1.09)(0.72, 1.27)22C3CPS ≥ 10325 (53)7.55.50.712218.70.77(0.56, 0.91)(0.57, 1.03)CPS < 10289 (47)5.85.40.7320.219.40.94(0.57, 0.93)(0.69, 1.26)SP263IC ≥ 4%286 (47)8.75.50.6428.919.60.71(0.49, 0.83)(0.51, 0.98) Citation Format: Hope Rugo, Sherene Loi, Sylvia Adams, Peter Schmid, Andreas Schneeweiss, Carlos H Barrios, Hiroji Iwata, Véronique Diéras, Eric P Winer, Mark M Kockx, Dieter Peeters, Stephen Y Chui, Jennifer C Lin, Anh Nguyen Duc, Guiseppe Viale, Luciana Molinero, Leisha A Emens. Exploratory analytical harmonization of PD-L1 immunohistochemistry assays in advanced triple-negative breast cancer: A retrospective substudy of IMpassion130 [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD1-07.

PD-L1 Testing in Gastric Cancer by the Combined Positive Score of the 22C3 PharmDx and SP263 Assay with Clinically Relevant Cut-offs.

PurposeWe provide a comparison between 22C3 pharmDx and SP263 assay, for evaluating programmed death ligand 1 (PD-L1) expression in advanced gastric cancer (GC) patients.Materials and MethodsThe PD-L1 immunohistochemistry by 22C3 pharmDx and SP263 assays was performed in the center of the tumor (CT) and invasive margin (IM) in 379 GC tissues using tissue microarrays and interpreted as combined positive score (CPS) and tumor proportion score (TPS). Of the total samples, 55 samples were independently reviewed by five pathologists.ResultsThe two assays showed a high correlation in both the CPS and TPS. At a CPS ≥ 1 cut-off, 219 (57.8%) and 231 (60.9%) GCs were positive for PD-L1 with the 22C3 and SP263 assays, and at ≥ 10 cut-off, 37 (9.8%) and 36 (9.5%) GCs were positive, respectively. The overall percent agreement (OPA) was greater than 90% with CPS ≥ 1 and ≥ 10 cut-offs, and TPS ≥ 1% and ≥ 10% cut-offs. There was higher OPA between the two assays with a CPS cut-off ≥ 10 (99.2%) than ≥ 1 (94.7%). The percent agreement between the CT and IM was higher with a CPS cut-off ≥ 10 (92.9%) than ≥ 1 (77.6%). Patient with positive expression at CPS ≥ 5 cut-off had a significantly better outcomes in both assays. Interobserver variability among five pathologists was higher than the assay variability.ConclusionTwo assays for PD-L1 expression in GC showed high agreement. These results provide guidance for selecting eligible patients with GC for pembrolizumab treatment.

Concordance of Programmed Death-Ligand 1 Expression between SP142 and 22C3/SP263 Assays in Triple-Negative Breast Cancer.

PurposeTriple-negative breast cancer (TNBC) represents a major clinical challenge due to its aggressive and metastatic behavior and the lack of available targeted therapies. Therefore, therapeutic strategies are needed to improve TNBC patient management. Recently, atezolizumab and nab-paclitaxel chemotherapy has been approved by the Food and Drug Administration for the first-line treatment of patients with locally advanced and metastatic TNBC. The programmed death-ligand 1 (PD-L1) immunohistochemical SP142 assay was also approved as a companion diagnostic device for selecting TNBC patients for atezolizumab treatment. This study aimed to evaluate and compare the analytical performance of the PD-L1 22C3/SP263 assays in comparison with the SP142 assay for ≥ 1% immune cells (ICs).MethodsImmunohistochemical expression for the PD-L1 22C3/SP263 assays, in comparison with the SP142 assay, was analyzed for the ≥ 1% ICs in 95 TNBCs.ResultsAt the 1% cut-off value, the proportions of positive cases were 52.6% for the SP142 assay in infiltrating ICs and 50.5% and 52.6% for the 22C3 and SP263 assays in tumor cells, respectively. The PD-L1 SP263 assay had the highest while the PD-L1 22C3 assay had the lowest total positive expression rate at all cut-off values. The concordance rate between the assays was highest at a 1% cut-off value and decreased when the cut-off value increased. The concordance rate between the SP142 and SP263 assays at 1% cut-off was high, while in comparison, the concordance rate between the SP142 and 22C3 assays at 1% cut-off was relatively lower.ConclusionThis study demonstrates that although the 22C3 assay at a 1% cut-off value compared with the PD-L1 SP142 assay at the clinically relevant cut-off shows comparable but not interchangeable analytical performance, the analytical performance of the SP263 assay at a 1% cut-off value shows interchangeable performance with the PD-L1 SP142 assay at the clinically relevant cut-off.

External quality assessment demonstrates that PD-L1 22C3 and SP263 assays are systematically different.

PD‐L1 inhibitors are part of first line treatment options for patients with advanced non‐small cell lung cancer. PD‐L1 immunohistochemistry (IHC) assays act as either a companion or a complementary diagnostic. The purpose of this study is to describe the experience of external quality assurance (EQA) provider UK NEQAS ICC and ISH with the comparison of different PD‐L1 assays used in daily practice. Three EQA rounds (pilot, run A and run B) were carried out using formalin fixed paraffin embedded samples with sample sets covering a range of epitope concentrations, including ‘critical samples’ near to clinical threshold cut‐offs. An expert panel (n = 4) evaluated all returned slides simultaneously and independently on a multi‐header microscope together with the participants own in‐house control material. The tonsil sample was evaluated as ‘acceptable’ or ‘unacceptable’, and for the other samples the percentage of PD‐L1 stained tumour cells were estimated in predetermined categories (<1%, 1 to <5%, 5 to <10%, 10 to <25%, 25 to <50%, 50 to <80%, 80 to 100%). In the pilot and the two subsequent runs the number of participating laboratories was 43, 69 and 76, respectively. The pass rate for the pilot run was 67%; this increased to 81% at run A and 82% at run B. For two ‘critical samples’, in runs A and B, 22C3 IHC had significantly higher PD‐L1 expression than SP263 IHC (p < 0.001), whilst the PD‐L1 scores for the other six samples were similar for all assays. In run A the laboratory developed tests (LDTs) using 22C3 scored lower than the commercial 22C3 tests (p = 0.01). After the initial testing, improvement in performance of PD‐L1 IHC is shown for approved and LDT PD‐L1 assays. Equivalency of approved PD‐L1 22C3 and SP263 assays cannot be assumed as the scores cross the clinically relevant thresholds of 1% and 50% PD‐L1 expression.

Inter-tumor heterogeneity of PD-L1 expression in non-small cell lung cancer.

The Dako PD-L1 immunohistochemistry (IHC) 22C3 pharmDx and the Dako 28-8 IHC pharmDx assays were approved by the US Food and Drug Administration, as a companion diagnostic test for pembrolizumab (Keytruda, Merk, Kenilworth, NJ, USA) and a complementary diagnostic test for nivolumab (Opdivo, Bristol Meyer Squibb, New York, NY, USA) in non-small cell lung cancer (NSCLC), respectively. Increased PD-L1 expression levels can be associated with greater therapeutic efficacy of pembrolizumab relative to other anti-PD-1 agents. However, in treatment decision making, little is known about which tissue (primary or metastatic lesion) should be stained by 22C3 antibody. We investigated the relationship between PD-L1 expression in primary tumors and paired metastatic lymph nodes using the 22C3 assay, and evaluated the concordance between the 22C3 and 28-8 assays. PD-L1 expression was evaluated in cells from primary tumors and paired metastatic lymph nodes using the 22C3 and 28-8 IHC assays. Total 35 patients with primary tumor and paired metastatic lymph node were enrolled into this study, and all samples were surgically resected, formalin-fixed, and paraffin-embedded NSCLC tissues. Tumor cells exhibiting complete or partial membrane staining, were considered as PD-L1 positive. On the basis of tumor proportion score (TPS), all samples were classified as no expression (TPS: <1%), low expression (TPS: 1-49%), or high expression (TPS: ≥50%). TPS distribution was markedly different between primary tumors and paired metastatic lymph nodes. In 22C3 IHC assay, TPS similar to that of metastatic lymph nodes was demonstrated in 10 primary tumors, and concordance rate between them was 28.6%. Concurrently, in 28-8 IHC assay, 11 primary tumors had TPS similar to that of metastatic lymph nodes, with a concordance rate of 31.4%. TPS concordance rates (for both 22C3 and 28-8 antibodies) between primary tumors and paired lymph nodes were low. Inter-tumor heterogeneity of PD-L1 expression is an important issue for clinical oncologists during treatment planning.

A comparability study of immunohistochemical assays for PD-L1 expression in hepatocellular carcinoma

Programmed death ligand 1 (PD-L1) protein expression by immunohistochemistry is a promising biomarker for PD-1/PD-L1 blockade in hepatocellular carcinoma. There are a number of commercially available PD-L1 assays. Our study aimed to compare the analytical performance of different PD-L1 assays and evaluate the reliability of pathologists in PD-L1 scoring. Consecutive sections from tumor samples from 55 patients with surgically resected primary hepatocellular carcinoma were stained with four standardized PD-L1 assays (22C3, 28–8, SP142, and SP263). We also correlated the PD-L1 protein level by immunohistochemistry with the mRNA level of those genes associated with tumor immune microenvironment by the NanoString platform. Five pathologists independently assessed PD-L1 expression on tumor cells [tumor proportion score] together with tumor-infiltrating immune cells (combined positive score). The 22C3, 28–8, and SP263 assays had comparable sensitivity in detecting PD-L1 expression, whereas the SP142 assay was the least sensitive assay. The inter-assay agreement measured by intraclass correlation coefficients for the tumor proportion score and combined positive score were 0.646 and 0.780, respectively. The inter-rater agreement was good to excellent (the overall intraclass correlation coefficient for the tumor proportion score and combined positive score was 0.946 and 0.809, respectively). Pathologists were less reliable in scoring combined positive score than tumor proportion score, particularly when using the SP142 assay. Up to 18% of samples were misclassified by individual pathologists in comparison to the consensus score at the cutoff of combined positive score ≥ 1. The combined positive score by the 22C3 assay demonstrated the strongest correlation with immune-related gene mRNA signatures, closely followed by combined positive scores by the 28–8 and SP263 assays. In conclusion, the 22C3, 28–8, and SP263 assays are highly concordant in PD-L1 scoring and suggest the interchangeability of these three assays. Further improvement of the accuracy in assessing PD-L1 expression at a low cutoff is still necessary.

A multicenter analysis of genomic profiles and PD-L1 expression of primary lymphoepithelioma-like carcinoma of the lung

To understand the molecular mechanism of tumorigenesis of pulmonary lymphoepithelioma-like carcinoma and explore potential therapeutic strategies, we investigated the genomic profiles and PD-L1 expression of 29 Chinese pulmonary lymphoepithelioma-like carcinoma patients at various stages. We performed capture-based targeted sequencing on tissue samples collected from 27 patients with sufficient samples using a panel consisting of 520 cancer-related genes, spanning 1.64 Mb of the human genome. We identified 184 somatic mutations in 109 genes from 26 patients. One patient had no mutations detected by this panel. Copy number variations were detected in 52% (14/27) of the patients, with a majority having advanced-stage disease (10/14). Except for the detection of ERBB2 amplification and KRAS mutation in two patients, no other classic lung cancer driver mutations were detected. Interestingly, 78% (21/27) of the patients had mutations in epigenetic regulators. Of the 184 mutations identified, 51 occurred in 29 epigenetics-related genes. Furthermore, we performed PD-L1 immunohistochemistry staining using the Dako 22C3 assay and demonstrated that 69% (20/29) of the cohort had positive PD-L1 expression, of which three patients received and benefited from a PD-1 inhibitor. In conclusion, we elucidated a distinct genomic landscape associated with pulmonary lymphoepithelioma-like carcinoma with no classic lung cancer driver mutation but an enrichment of mutations in epigenetic regulators. The detection of high PD-L1 expression and lack of any canonical druggable driver mutations raises the potential of checkpoint immunotherapy for pulmonary lymphoepithelioma-like carcinoma.

LBA20 - Performance of PD-L1 immunohistochemistry (IHC) assays in unresectable locally advanced or metastatic triple-negative breast cancer (mTNBC): Post-hoc analysis of IMpassion130

LBA20 - Performance of PD-L1 immunohistochemistry (IHC) assays in unresectable locally advanced or metastatic triple-negative breast cancer (mTNBC): Post-hoc analysis of IMpassion130

MA15.02 Deep Learning Approach for Automated Tumor Cells Detection and Estimation of PD-L1 22C3 Assay Expression in Lung Adenocarcinoma

MA15.02 Deep Learning Approach for Automated Tumor Cells Detection and Estimation of PD-L1 22C3 Assay Expression in Lung Adenocarcinoma

2023P - Evaluating the prevalence of the expression of PD-L1 in NSCLC specimens with short-duration formalin fixation using IHC 22C3 pharmDx

BackgroundImmune checkpoint inhibitors mediated by PD-1 and PD-L1 are promising treatments for various tumors. The PD-L1 expression in tumor cells was found to be correlated with the likelihood of a response to PD-1- or PD-L1-targeted therapy in non-small cell lung cancer (NSCLC). For PD-L1 immunohistochemistry (IHC), 22C3 pharmDx is the only companion diagnostic assay that can identify NSCLC patients suitable for pembrolizumab treatment. Specimens are scored and divided into 3 categories (<1%, 1-49%, ≥50%) based on the tumor proportion score (TPS). The PD-L1 prevalence in NSCLC patients screened for the KEYNOTE-024 trial was 31% with TPS <1%, 39% with TPS 1-49%, and 30% with TPS ≥50%. While specimens used for the IHC 22C3 assay are recommended to be formalin-fixed for 12-72h, the specimens were fixed in 10% neutral-buffered formalin for less than 6h in our institution. Thus, we retrospectively assessed the PD-L1 prevalence in NSCLC patients to determine whether the PD-L1 TPS differs according to the duration of formalin fixation. MethodsWe screened consecutive NSCLC patients who underwent tumor biopsy by bronchoscopy between January 2017 and June 2018 at National Hospital Organization Fukuokahigashi Medical Center. In the present study, we only included 70 patients whose tumors were formalin-fixed for less than 6h and whose PD-L1 expression had been evaluated by IHC with antibodies to human PD-L1 (22C3 pharmDx). ResultsThe PD-L1 prevalence in patients with NSCLC in our hospital was 26 (37%) with TPS<1%, 23 (33%) with TPS 1-49%, and 21 (30%) with TPS ≥50%, suggesting that small biopsy samples obtained by bronchoscopy that were formalin-fixed for <6h are suitable for PD-L1 IHC. We also performed analyzed in 35 surgically-resected NSCLC specimens that had been formalin-fixed for 1-7 days by PD-L1 IHC. The PD-L1 prevalence was 20 (57%) for TPS < 1%, 9 (26%) for TPS 1-49%, and 6 (17%) for TPS ≥50%. ConclusionsThe PD-L1 prevalence in specimens with short-duration formalin fixation was consistent with the results of the KEYNOTE-024 trial. We will present our conclusion regarding these results, including the characteristics of patients and the PD-L1 prevalence in specimens fixed for 12-72h in our institution, from July 2018 onward. Legal entity responsible for the studyNational Hospital Organization Fukuokahigashi Medical Center. FundingJSPS KAKENHI JP18K15927. DisclosureAll authors have declared no conflicts of interest.

Comparison of continuous measures across diagnostic PD-L1 assays in non-small cell lung cancer using automated image analysis

Tumor programmed cell death ligand-1 (PD-L1) expression is a key biomarker to identify patients with non-small cell lung cancer who may have an enhanced response to anti-programmed cell death-1 (PD-1)/PD-L1 treatment. Such treatments are used in conjunction with PD-L1 diagnostic immunohistochemistry assays. We developed a computer-aided automated image analysis with customized PD-L1 scoring algorithm that was evaluated via correlation with manual pathologist scores and used to determine comparability across PD-L1 immunohistochemistry assays. The image analysis scoring algorithm was developed to quantify the percentage of PD-L1 positive tumor cells on scans of whole-slide images of archival tumor samples from commercially available non-small cell lung cancer cases, stained with four immunohistochemistry PD-L1 assays (Ventana SP263 and SP142 and Dako 22C3 and 28-8). The scans were co-registered and tumor and exclusion annotations aligned to ensure that analysis of each case was restricted to comparable tissue areas. Reference pathologist scores were available from previous studies. F1, a statistical measure of precision and recall, and overall percentage agreement scores were used to assess concordance between pathologist and image analysis scores and between immunohistochemistry assays. In total, 471 PD-L1-evalulable samples were amenable to image analysis scoring. Image analysis and pathologist scores were highly concordant, with F1 scores ranging from 0.8 to 0.9 across varying matched PD-L1 cutoffs. Based on F1 and overall percentage agreement scores (both manual and image analysis scoring), the Ventana SP263 and Dako 28-8 and 22C3 assays were concordant across a broad range of cutoffs; however, the Ventana SP142 assay showed very different characteristics. In summary, a novel automated image analysis scoring algorithm was developed that was highly correlated with pathologist scores. The algorithm permitted quantitative comparison of existing PD-L1 diagnostic assays, confirming previous findings that indicate a high concordance between the Ventana SP263 and Dako 22C3 and 28-8 PD-L1 immunohistochemistry assays.

Abstract 3130: Using digital pathology based “IO Scorecards” to describe relationships between PD-L1 expression and CD8 positive immune cell infiltration

Abstract Several studies have shown that the location and expression of infiltrating immune cells in patient tumors can better identify which patients are more likely to respond to anti- PD-1/PD-L1 therapy. In particular, immunohistochemistry-based studies have shown that the spatial location of PD-L1 expression has particular biological relevance, as PD-L1 expression in the tumor cells or immune cells in the tumor syncytium, tumor microenvionment (TME), or tumor-stroma boundary all describe differential PD-L1 biology. Here, we use Flagship’s digital pathology platform (cTA®) to investigate IHC based PD-L1 and CD8 staining patterns in Non-Small Cell Lung (NSCLC) and Urothelial Carcinoma (UC) tissue biopsies. The cTA platform creates thousands of per-cell Biofeatures™ derived from the digital pathology images of the IHC stained tissue, and applies Artificial Intelligence (AI) to the data to summary score endpoints for patient and cohort classification. In this approach, each tissue’s IO landscape is represented using an “IO Scorecard“, which summarizes the IHC biomarker data in a summary score which captures a comprehensive analysis of the tissue sample. The AI-determined scorecard models can be used to monitor changes before and after drug treatment and/or create predictive models for patient response outcomes. In this study, NSCLC and Urothelial Carcinoma samples were sectioned and stained using either the FDA-approved Dako 22C3 or SP263 PD-L1 IHC assays. Serial sections of each tissue specimen were also stained for CD8 expression. The cTA process detected all cells, assigned them to the tumor or TME compartments, and recorded the Biofeatures™ data which characterized PD-L1 or CD8 staining in the Tumor, Tumor/TME margin, or TME compartments. The method was validated by its ability to reproduce pathologist scoring for PD-L1 and CD8. Using the accepted data, we used the AI system to create novel Scorecard based patient classifications which describe differential PD-L1 status, CD8 status, and PD-L1/CD8 status combined. The AI Scorecard approach demonstrated that certain PD-L1 staining Biofeatures™ may also predict the CD8 status of a tumor, suggesting that additional CD8 staining may not be necessary to understand important expression patterns pertaining to cytotoxic T-cells. In summary, we demonstrated how the “IO Scorecards” are able to classify patients into differential immune status cohorts using a novel AI based scoring system, which relies only on PD-L1 IHC staining, by creating a comprehensive, contextual profile of PD-L1 staining that does not require additional CD8 IHC staining to characterize the impact of cytotoxic T-cells in a tissue sample. Citation Format: Charles Caldwell, Will Paces, Jeni Caldara, Bharathi Vennapusa, Joseph S. Krueger. Using digital pathology based “IO Scorecards” to describe relationships between PD-L1 expression and CD8 positive immune cell infiltration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3130.

PD-L1 expression in non–small cell lung cancer: evaluation of the diagnostic accuracy of a laboratory-developed test using clone E1L3N in comparison with 22C3 and SP263 assays

Different studies have evaluated the comparability of various immunohistochemical assays for PD-L1 expression evaluation, with contrasting results. Besides the important issues related to analytic performance and comparability of validated assays, not all platforms are available in all laboratories; moreover, standardized assays are very expensive, and funding for PD-L1 testing is hard to obtain, especially in the research setting. One of the most widely used and inexpensive PD-L1 clones is E1L3N (Cell Signaling Technology, Danvers, MA), which is labeled for research use only. In this work, we wanted to further study and validate in a larger cohort the analytical performance of E1L3N clone on Ventana platform (Ventana Medical Systems, Tucson, AZ) and its comparability with assays SP263 and 22C3 run onto their dedicated platforms. Serial sections of tissue microarrays built from 165 cases of resected lung cancer were stained for E1L3N onto Ventana platform following a previously reported protocol and for 22C3 and SP263 assays onto their respective platforms following manufacturer's instructions. Overall, we found very high concordance when comparing E1L3N with SP263 at both 1% and 50% cutoffs. Lower concordance was found between E1L3N and 22C3 at both cutoffs; however, 100% sensitivity was found for E1L3N compared with both SP263 and 22C3 at 50% cutoff. Given the 100% sensitivity at 50% cutoff demonstrated by E1L3N in comparison with both SP263 and 22C3 and therefore the lack of false-negative cases, we propose an algorithm for PD-L1 testing in NSCLC when considering pembrolizumab as first-line therapy.

Concordance between PD-L1 assays for metastatic renal cell carcinoma (mRCC) and metastatic urothelial carcinoma (mUC).

e14259 Background: Immune checkpoint inhibitors (ICIs) are standard of care for mRCC and mUC patients (pts). PD-L1 status is gaining importance as a predictive biomarker, particularly for cisplatin-ineligible mUC. PD-L1 positivity is defined differently by PD-L1 assay and tumor type, with limited concordance studies. Given real-world limitations in PD-L1 testing, assay concordance studies are needed to distinguish positive (pos)/negative (neg) results and treatment selection. We compared Dako 28–8 and Ventana SP142 assays in mRCC and Dako 22C3 and Ventana SP263 assays in mUC. Methods: 32 pts with mRCC and 18 pts with mUC who had received ICI therapy at Duke Cancer Institute were identified. FFPE archival tumor samples for pts with mRCC were evaluated with Dako 28–8 and Ventana SP142 PD-L1 immunohistochemistry (IHC) assays. For pts with mUC, FFPE archival tumor samples were evaluated with Dako 22C3 and Ventana SP263 PD-L1 IHC assays. Scoring was validated by two pathologists using the scoring system for each assay. PD-L1 status was subsequently correlated to best RECIST response (objective response rate (ORR) defined as stable disease or better). Results: Tissue was obtained from primary tissue in 72% of mRCC cases and in 61% of mUC cases, with remainder from metastatic biopsies. The majority of mRCC cases (29/32, 91%) were concordant between Dako 28-8 and Ventana SP142 assays (8 cases pos and 21 cases neg), with 3 discordant cases (1 case pos for Dako 28-8 but neg for Ventana SP142 and 2 cases neg for Dako 28-8 but pos for Ventana SP142), all from primary tissue. The majority of mUC cases (17/18, 94%) were also concordant between Dako 22C3 and Ventana SP263 assays (2 pos cases and 15 neg cases), with 1 indeterminate Dako 22C3 test on a metastatic biopsy due to background lymph node. In mRCC, the ORR for PD-L1 pos cases was 45% (5/11) versus 33% (8/24) for PD-L1 neg cases. In mUC, the ORR for PD-L1 positive cases was 50% (1/2) versus 31% (5/16) for PD-L1 neg cases. Conclusions: There was strong concordance between the clinically meaningful PD-L1 assays chosen for comparison in both mRCC and mUC. mUC results were limited by low PD-L1 expression in this cohort. Although PD-L1 status does not fully predict for response to ICIs, this suggests that PD-L1 testing could be used interchangeably for the majority of cases when selecting ICI treatment in mRCC and mUC.