22C3 pharmDx Research Articles

The Ring Study: an international comparison of PD-L1 diagnostic assays and their interpretation in non-small cell lung cancer, head and neck squamous cell cancer and urothelial cancer

PD-L1 immunohistochemistry has been approved as a diagnostic assay for immunotherapy. However, an international comparison across multiple cancers is lacking. This study aimed to assess the performance of PD-L1 diagnostic assays in non-small cell lung cancer (NSCLC), head and neck squamous cell cancer (HNSCC) and urothelial cancer (UC). The excisional specimens of NSCLC, HNSCC and UC were assayed by Ventana SP263 and scored at three sites in each country, including Australia, Brazil, Korea, Mexico, Russia and Taiwan. All slides were rotated to two other sites for interobserver scoring. The same cohort of NSCLC was assessed with Dako 22C3 pharmDx PD-L1 for comparison. The PD-L1 immunopositivity was scored according to the approved PD-L1 scoring algorithms which were the percentage of PD-L1-expressing tumour cell (TC) and tumour proportion score (TPS) by Ventana SP263 and Dako 22C3 staining, respectively. In NSCLC, the comparison demonstrated the comparability of the SP263 and 22C3 assays (cut-off of 1%, κ=0.71; 25%, κ=0.75; 50%, κ=0.81). The interobserver comparisons showed moderate to almost perfect agreement for SP263 in TC staining at 25% cut-off (NSCLC, κ=0.72 to 0.86; HNSCC, κ=0.60 to 0.82; UC, κ=0.68 to 0.91) and at 50% cut-off for NSCLC (κ=0.64 to 0.90). Regarding the immune cell (IC) scoring in UC, there was a lower correlation (concordance correlation coefficient=0.10 to 0.68) and poor to substantial agreements at the 1%, 5%, 10% and 25% cut-offs (κ= -0.04 to 0.76). The interchangeability of SP263 and 22C3 in NSCLC might be acceptable, especially at the 50% cut-off. In HNSCC, the performance of SP263 is comparable across five countries. In UC, there was low concordance of IC staining, which may affect treatment decisions. Overall, the study showed the reliability and reproducibility of SP263 in NSCLC, HNSCC and UC.

High interobserver and intraobserver reproducibility among pathologists assessing PD-L1 CPS across multiple indications.

A common concern among pathologists scoring PD-L1 immunohistochemical staining is interobserver and intraobserver variability. We assessed the interobserver and intraobserver reproducibility of PD-L1 scoring among trained pathologists using a combined positive score (CPS; tumour cell and tumour-associated immune cell staining). Data were collected for 2 years (2017-2019) from 456 pathologists worldwide. Digital training encompassed unique, tumour-specific training, and test sets. Samples were stained using PD-L1 IHC 22C3 pharmDx and evaluated at specific CPS cutoffs for gastric cancer (GC), cervical cancer (CC), urothelial cancer (UC), oesophageal cancer (OC), and head and neck squamous cell carcinoma (HNSCC). Pathologists underwent expert-to-peer training and scored 20 blinded samples on day 1 and 25 blinded samples on day 2 (including 15 of the day 1 samples). Interobserver and intraobserver reproducibility were assessed. For GC (120 observers) and CC (32 observers) samples assessed at CPS ≥1, average interobserver agreement was 91.5% and 91.0%, respectively, and average intraobserver agreement was 90.2% and 96.6%, respectively. For UC (139 observers) and OC (52 observers) samples measured at CPS ≥10, average interobserver agreement was 93.4% and 93.7%, respectively, and average intraobserver agreement was 92.0% and 92.5%, respectively. For HNSCC samples (113 observers), average interobserver agreement was 94.1% at CPS ≥1 and 86.5% at CPS ≥20; intraobserver agreement was 94.7% at CPS ≥1 and 90.5% at CPS ≥20. The consistently high interobserver and intraobserver concordance rates support the effectiveness of face-to-face training of many global pathologists for scoring PD-L1 CPS across multiple indications at several specific cutoffs.

Indirect Clinical Validation of a Programmed Death-Ligand 1 Laboratory-Developed Test for Gastric/Gastroesophageal Junction Adenocarcinoma with 22C3 Antibody Concentrate.

The PD-L1 IHC 22C3 pharmDx used on the Dako Autostainer Link 48 (ASL48) staining platform is an established method for assessing programmed death-ligand 1 (PD-L1) expression in tumor tissue and determining patient eligibility for pembrolizumab treatment; however, the availability of this platform is limited in Europe and Asia. The aims of this study were to develop and optimize protocols for the PD-L1 22C3 antibody concentrate with multiple immunohistochemistry staining platforms and to validate these protocols using PD-L1 combined positive score (CPS) with a cut-off of ≥1 in gastric or gastroesophageal junction adenocarcinoma. The 22C3 antibody concentrate was tested and optimized protocols were developed for use with three staining platforms: Dako ASL48, Ventana BenchMark ULTRA, and Leica BOND-MAX. Tumor specimens (N = 120) from patients with gastric or gastroesophageal junction adenocarcinoma were used for the validation study; these specimens were evaluated independently by three pathologists for PD-L1 CPS as a continuous variable and using a cut-off of ≥1. PD-L1 IHC 22C3 pharmDx used on the Dako ASL48 platform served as the reference or gold standard. The intraclass correlation coefficient of CPS as a continuous variable between the gold standard and each staining platform assessed was 0.910-0.989. When CPS was dichotomized based on a cut-off of ≥1, depending on the pathologist and the platform used, positive percentage agreement was 81-99% and negative percentage agreement was 90-100%. Interobserver agreement using the gold standard showed substantial agreement (κ=0.779). The PD-L1 22C3 antibody concentrate can potentially be used with the laboratory-developed test on three commercially available immunohistochemistry staining platforms to determine PD-L1 expression in tumor samples from patients with gastric or gastroesophageal junction adenocarcinoma.

EP16.01-029 Inter-tumor Heterogeneity of PD-L1 Expression in Non-small Cell Lung Cancer

The Dako PD-L1 immunohistochemistry (IHC) 22C3 pharmDx was approved by the US Food and Drug Administration, as a companion diagnostic test for pembrolizumab (Keytruda, Merk, Kenilworth, NJ, USA) in non-small cell lung cancer (NSCLC). Although increased PD-L1 expression levels can be associated with greater therapeutic efficacy of pembrolizumab, little is known about which tissue (primary or metastatic lesion) should be stained by 22C3 antibody. In this study, we investigated the concordant rate of PD-L1 expression between primary and metastatic lymph node.

T cell-inflamed gene expression profile and PD-L1 expression and pembrolizumab efficacy in advanced esophageal cancer.

Aim: Investigate the relationship between response to pembrolizumab and expression of the 18-gene T cell-inflamed gene expression profile (TcellinfGEP) or PD-L1 combined positive score (CPS) in esophageal cancer. Materials & methods: This analysis included heavily pretreated patients with advanced/metastatic esophageal/gastroesophageal junction adenocarcinoma or squamous cell carcinoma who received pembrolizumab in the single-arm, phase II study KEYNOTE-180. PD-L1 CPS was evaluated with PD-L1 IHC 22C3 pharmDx. Results: In patients with squamous cell carcinoma, trends toward enrichment for responders were observed for patients with PD-L1 CPS ≥10 tumors. In patients with adenocarcinoma, a trend was observed for TcellinfGEP but not for PD-L1. Conclusion: TcellinfGEP and PD-L1 CPS may enrich for responders to pembrolizumab in patients with esophageal cancer. Clinical trial registration: NCT02559687 (ClinicalTrials.gov).

Verification and validation of the anti-PD-L1 antibody, Clone 22C3 on a laboratory-developed test

AimsThe first aim of this study is to compare and validate the performance of the programmed death receptor ligand 1 (PD-L1) IHC 22C3 pharmDx assay kit processed via Dako Omnis...

Evaluation of pembrolizumab monotherapy in patients with previously treated advanced salivary gland carcinoma in the phase 2 KEYNOTE-158 study

AimWe evaluated pembrolizumab monotherapy in patients with advanced salivary gland carcinoma on the phase 2 KEYNOTE-158 study (NCT02628067). MethodsEligible patients had histologically/cytologically confirmed advanced salivary gland carcinoma with prior failure or intolerance to standard therapy, measurable disease per Response Evaluation Criteria in Solid Tumours (RECIST) v1.1., and ECOG performance status 0–1. Patients were enrolled irrespective of tumour PD-L1 expression. Patients received pembrolizumab 200 mg Q3W for up to 35 cycles (∼2 years). Radiographic imaging occurred every 9 weeks through month 12, then every 12 weeks. PD-L1 positivity was defined as combined positive score ≥1 (evaluated using PD-L1 IHC 22C3 pharmDx). The primary endpoint was objective response rate per RECIST v1.1. ResultsIn total, 109 patients were enrolled (PD-L1–positive, 25.7%). At the data cutoff (October 5, 2020), median follow-up was 53.3 (range, 50.8–56.3) months. Objective response rate was 4.6% (95% CI, 1.5–10.4%) among all patients (complete response, n = 1; partial response, n = 4) and was 10.7% (95% CI, 2.3–28.2%) in patients with PD-L1–positive disease and 2.6% (95% CI, 0.3–9.1%) in patients with PD-L1–negative disease. Duration of response was ≥24 months for all 5 responders; median duration of response was not reached (range, 25.1–49.8+ months). Median progression-free survival and overall survival were 4.0 (95% CI, 2.6–4.2) and 21.1 (95% CI, 15.9–25.5) months, respectively. Treatment-related adverse events occurred in 75.2% (grade 3–4, 15.6%; grade 5, 0%) of patients. Immune-mediated adverse events occurred in 22.0% of patients (grade 3, 5.5%; grade 4–5, 0). ConclusionsA small subset of patients with advanced salivary gland carcinoma treated with pembrolizumab had a response; all had response duration ≥2 years. The safety profile of pembrolizumab was manageable.

Genomic landscape of non-small-cell lung cancer with methylthioadenosine phosphorylase (MTAP) deficiency.

New treatment strategies for advanced non-small-cell lung carcinoma (NSCLC) include synthetic lethality targets focused on protein arginine methyl transferases such as PRMT5 that exploit the impact of genomic loss of methylthioadenosine phosphorylase (MTAP). Twenty nine thousand three hundred seventy nine advanced NSCLC cases underwent hybrid-capture based comprehensive genomic profiling between June 1, 2018 and May 31, 2020. PD-L1 expression was determined by immunohistochemistry (Dako 22C3 PharmDx assay). 13.4% (3928/29,379) NSCLC cases exhibited MTAP loss distributed in adenocarcinoma (59%), squamous cell carcinoma (22%), NSCLC not otherwise specified (16%), and 1% each for large-cell neuroendocrine, sarcomatoid, and adenosquamous carcinoma. Statistically significant differences in mitogenic driver alterations included more KRAS G12C mutations in MTAP-intact versus MTAP-lost (12% vs. 10%, p=0.0003) and fewer EGFR short variant mutations in MTAP-intact versus MTAP-lost NSCLC (10% vs. 13%, p < 0.0001). Statistically significant differences in currently untargetable genomic alterations included higher frequencies of TP53 (70% vs. 63%, p < 0.0001) and RB1 inactivation (10% vs. 2%, p < 0.0001) in MTAP-intact compared to MTAP-lost NSCLC. SMARCA4 inactivation (7% vs. 10%, p < 0.0001) was less frequent in MTAP-intact versus MTAP-lost NSCLC. Alterations in ERBB2, MET, ALK, ROS1, and NTRK1 did not significantly differ between the two groups. Predictors of immunotherapy efficacy were higher in MTAP-intact versus MTAP-lost NSCLC including tumor mutational burden (9.4 vs. 8.6 mut/Mb, p=0.001) and low (30% vs. 28%, p=0.01) and high PD-L1 (32% vs. 30%, p=0.01) expression. Alterations in biomarkers potentially predictive of immune checkpoint inhibitor resistance (STK11, KEAP1, and MDM2) were similar in the two groups. MTAP loss occurs in 13% of NSCLC, supporting the development of targeted therapies to exploit PRMT5 hyper-dependence. MTAP loss is accompanied by small differences in targeted and immunotherapy options which may impact future combination strategies.

Abstract 5737: Precision oncology driven real world clinical genomics data mining of MET alterations, TMB, and PDL-1 to empower indication agnostic patient enrollment and combination strategies

Abstract Background: Following MET inhibitor and checkpoint inhibitor approvals, it is essential to identify cancer indications that harbor molecular alterations of interest and a thorough real-world molecular genomics based characterization of those tumors would allow to expand cancer specific indications that might benefit from MET and checkpoint inhibitors and shed light on exploring clinically efficacious combo strategies. Importantly, such an approach provides the end-to-end solutions that shall significantly contribute to clinical translation and/or back translation strategies for innovative cancer therapies. Methods: We systemically interrogated FoundationInsights®, a dataset of real-world molecular genomic tumor profiling from North American patients, and investigated the prevalence of MET amplifications, METex14 skipping and MET fusions prevalence in 62110 unique patient samples across five indications (lung adenocarcinoma [LUAD], esophageal/gastroesophageal-junction/stomach adenocarcinoma [Eso/GEJ/Sto], papillary renal cell carcinoma, hepatocellular carcinoma [HCC] and glioblastoma). MET alteration prevalence was further categorized based on tumor cell PD-L1 IHC status (22C3 pharmDx) and TMB status. Additionally, comprehensive text mining from clinicaltrials.gov and landscape overview were conducted. Results: MET amplification was the most frequent MET alteration examined with a prevalence ranging from 1.4% in HCC to 4.8% in Eso/GEJ/Sto. In HCC and LUAD, MET amplification prevalence was higher in tumors with high TMB (≥10 mutations/megabase, P&amp;lt;0.05). In Eso/GEJ/Sto and LUAD, MET amplification occurrence was higher in PD-L1-high tumor vs. PD-L1-low or PD-L1-neg tumors (P&amp;lt;0.05). METex14 skipping mutations were observed in LUAD (2.3%), rarely in the other five tumor types analyzed (≤0.1%). Lastly in LUAD, METex14 skipping mutations were more frequent in PD-L1 high tumors but not those with high TMB (P&amp;lt;0.05). Text mining results indicate that- while most trials use MET amplification for patient stratification- there is a distinct tendency for MET inhibitor trials to increasingly include METex14 skipping as a major selection criterion as well. Conclusions: Real world genomics corroborated MET amplification as a predominant MET alteration across various indication. The potential clinical benefit to combine MET inhibitors with PD-1/PD-L1 blockades in specific indications and specific subsets of patients is further recognized. Collectively, the comprehensive molecular profiling &amp; text mining approaches will continue to guide application of precision medicine in clinical trial design based on appropriate biomarker selection. Citation Format: Zheng Feng, Jean-Christophe Pignon, Radwa Sharaf, Natalie Romanov, Julien Doudement, Lee A. Albacker, Noriaki Kurata, Neil R. Smith, Nobutoshi Matsushita, Juergen Scheuenpflug. Precision oncology driven real world clinical genomics data mining of MET alterations, TMB, and PDL-1 to empower indication agnostic patient enrollment and combination strategies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5737.

Abstract 5098: Genetic and immunologic characteristics of biliary tract cancer patients with LRP1B mutation

Abstract Background: Although the initial clinical results of immune checkpoint inhibitors (ICI) have been obtained in biliary tract cancer (BTC), and previous researches explored potential biomarkers for predicting response to ICI in BTC, and gene LRP1B was found as one of predictive biomarkers. Here we evaluated the mutation information of LRP1B in Chinese patients with BTC, and analyzed the potential explanation for more benefit from ICI treatment in patients with LRP1B mutation. Methods: The formalin-fixed paraffin-embedded specimens of 1324 cancer patients who have underwent next-generation sequencing (NGS) from 2016 to 2021, were included in this study. NGS was performed to detect gene mutation, and tumor mutational burden (TMB) measured by a 733 gene panel. PD-L1 expression detected by using Dako PD-L1 IHC 22C3 pharmDx. Result: The NGS results revealed that 12.76% (169/1324) patients with BTC have LRP1B mutation. Among these 1324 patients, 931 (patients with or without LRP1B mutations were 129 and 802, respectively) patients were available for analysis of TMB level, 820 ((patients with or without LRP1B mutations were 114 and 706, respectively)) patients for analysis of PD-L1 expression, and 1163 (patients with or without LRP1B mutations were 172 and 991, respectively) patients for analysis of MSI-H. TMB level and PD-L1 expression level were compared between groups with and without LRP1B mutation, and results showed that both these two biomarkers were higher in group with LRP1B mutation than without LRP1B mutation, especially TMB level was significantly higher (p&amp;lt;0.001).Further analysis revealed that the median TMB level, proportion of strong positive PD-L1 expression, and proportion of MSI-H were all higher in group of LRP1B mutation than wild type. Conclusion:These results suggest that LRP1B can be considered as one of effective biomarkers for ICI treatment in BTC, the underly mechanism may be related to the high TMB level. Citation Format: Weiwei Chen, Hushan Zhang, Hongmin Dong, Gang Wang, Xiaokai Li, Wanghua Chen, Guodong Li, Saixi Bai, Juan Chen, Wenling Wang. Genetic and immunologic characteristics of biliary tract cancer patients with LRP1B mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5098.

Abstract 5100: Analysis of genetic alterations related to hyper-progressive disease after immunotherapy in patients with non-small cell lung cancer

Abstract Background Hyper-progressive disease (HPD) is an unexpected response pattern observed in immune checkpoint therapy, such patients experience a very rapid disease progression (usually progressed seriously in three months). Predictors of HPD are one of the keys to the management of patients receiving immune checkpoint inhibitors. Some factors, such as MDM2/4 amplification, EGFR mutations and old age may be risk factors for HPD, but the results of different studies are inconsistent. Herein, we evaluated the characteristics of MDM2/4 alterations in Chinese patients with NSCLC. Methods The formalin-fixed paraffin-embedded specimens of cancer patients who have underwent next-generation sequencing (NGS) in 3D Medicines, a laboratory accredited by CAP and Clinical Laboratory Improvement Amendments (CLIA) from May 2017 to May 2020, were included in this study. NGS was performed to detect gene mutation, and tumor mutational burden (TMB) measured by a 733 gene panel. PD-L1 expression detected by using Dako PD-L1 IHC 22C3 pharmDx. Results The proportion of MDM2/4 amplification in Chinese NSCLC patients is 0.86%, the proportion of MDM2 and MDM4 amplification in Chinese NSCLC patients were 0.74% and 0.12%. respectively. Further analysis found lower TMB level in patients with MDM2/4 amplification than patients without MDM2/4 amplification (p&amp;lt;0.001). The median TMB level was also found lower in patients with MDM2/4 amplification than without, and higher ratio of patients with TMB-high (defined as TMB≥10mutant/Mb) was displayed in group with MDM2/4 amplification. Conversely, patients with TMB-high showed lower copy number gain in MDM2/4. However, no difference was found in level of PD-L1 expression between patients with and without MDM2/4 amplification. Conclusion HPD happened during ICI treatment in solid tumor with MDM2/4 amplification may associated with lower TMB level, and PD-L1 expression level has limit effect on MDM2/4 alteration related HPD. Citation Format: Xudong Xiang, Hushan Zhang, Deguang Wang, Heng Li, Qing Lei, Qianli Ma. Analysis of genetic alterations related to hyper-progressive disease after immunotherapy in patients with non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5100.

Abstract 5402: Urothelial carcinomas in different anatomical positions exhibit distinct genomic and immunological characteristics

Abstract Background Human bladder cancers were recently suggested to be grouped into different molecular subtypes. However, little is known about the difference in gene landscape between upper tract urothelial carcinoma (UTUC) and lower tract urothelial carcinoma (LTUC) of Chinese patients. Herein, we analyzed the genomic characteristics of primary UTUC and LTUC in China. Methods The formalin-fixed paraffin-embedded specimens of 250 LTUC and 121 UTUC patients have been consecutively collected and have underwent next-generation sequencing (NGS) from 2018 to 2021 in 3DMed Clinical Laboratory Inc. Gene mutation and TMB level were analyzed by NGS, detected PD-L1 expression by using Dako PD-L1 IHC 22C3 pharmDx, Tumor Proportion Score (TPS) was used to determine expression of PD-L1. Results NGS analysis showed that, in the samples of UTUC, the top ten gene mutations were CDKN2A/2B 6.6% (8/121), TP53 5.8% (7/121), FGF19 5.8% (7/121), TERT 3.3% (4/121), PREX2 3.3% (4/121), FRS2 3.3% (4/121), KDM6A 2.5% (3/121), PIK3CA 2.5% (3/121), EGFR 2.5% (3/121), MYCL 2.5% (3/121); while in the LTUC, the top gene mutations were TP53 44.4% (111/250), TERT 31.6% (79/250), CDKN2A/2B 25.7% (64/250), FGF3 18% (45/250), KDM6A 17.6% (44/250), PIK3CA 16.4% (41/250), RB1 14.0%(35/250), DGFR3 13.6% (34/250), ARID1A 12.4% (31/250). Furthermore, TMB level and PD-L1 expression in the UTUC and LTUC were also analyzed, and results showed that although the gene mutation was totally different, but no significant difference was found on TMB level (p&amp;gt;0.05). However, among these patients, higher PD-L1 expression level were found in UTUC than LTUC (p&amp;lt;0.05). Conclusion UTUC and LTUC in Chinese patients hold different gene landscape and PD-L1 expression, this suggested these patients may have different prognosis and response differently to targetable therapy and immunotherapy. Citation Format: Ruiqian Li, Hushan Zhang, Qilin Wang, Hong Yang, Yu Bai, Chen Hu, Hongyi Wu, Chongjian Zhang, Ziyong Wang, Qiwei Wang, Pengjie Xu, Jun Li. Urothelial carcinomas in different anatomical positions exhibit distinct genomic and immunological characteristics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5402.

Abstract 1259: PD-L1 expression by RNA-sequencing and survival from pembrolizumab in non-small cell lung cancer (NSCLC)

Abstract PURPOSE: The immunohistochemistry companion diagnostic test for pembrolizumab (IHC 22C3 pharmDx) lacks sensitivity, challenging immunotherapy selection for NSCLC patients with lower levels of expression. Unlike IHC 22C3, which restricts assessment of PD-L1 expression to viable tumor cells as a tumor proportion score (% TPS), mRNA next generation sequencing (RNA-seq) measures PD-L1 expression in the tumor microenvironment for both tumor and inflammatory background cells. RNA-seq previously demonstrated concordance with IHC and may be a robust alternative testing method for multiple tumor types. Here, we sought to optimize PD-L1 RNA-seq cutoff values in NSCLC to improve clinical sensitivity. PROCEDURE: NSCLC patients included in the study (n=3,465) were tested for PD-L1 expression by IHC 22C3 and clinically validated RNA-seq, measured as % rank (0-100) relative to a reference population based on normalized reads per million (nRPM). Patients were divided into an RNA-seq cut-off discovery cohort (n=3,168), and a test cohort pembrolizumab treated patients. Principal components analysis (PCA) was used to classify patients based on test results and explore cut-off values in the discovery cohort. Kaplan Meier curves and a Cox proportional hazards regression models assessed overall survival (OS) hazard ratios (HR) for RNA-seq versus standard of care IHC cut-offs in the test cohort. RESULTS: Unsupervised PCA clustering identified three distinct PD-L1 groups separated by combinations of significant over- and under-representation of RNA-seq and IHC result measures from prior testing. The groups were labeled as “low” (rank ≤40), “moderate” (rank 41-73), and “high” (rank ≥74), based on the median RNA-seq rank for each group (+/- 1SD for low and high). Both the low and moderate groups were overrepresented by patients in the PD-L1 IHC low and negative groups. The moderate group was overrepresented by patients with moderately high PD-L1 RNA-seq ranks (median=70), while the low group was overrepresented by patients that were not PD-L1 high by RNA-seq. The high group was overrepresented by patients high for PD-L1 by both IHC and RNA-seq. OS HRs were better for RNA-seq high versus moderate (HR=0.05, CI 0.00-0.63, p=.02), and RNA-seq high versus low (HR=0.16, CI 0.03-0.86, p=.03) groups compared to standard of care IHC 22C3 high versus low groups, (HR=0.21, CI 0.04-1.07, p=.06). Findings were non-significant for the RNA-seq moderate versus low groups, likely due to the limited and disproportionately high number of patients with poor performance status in these groups. CONCLUSIONS: PD-L1 expression by RNA-seq demonstrated improved clinical sensitivity in predicting OS versus standard of care PD-LI IHC in a pembrolizumab treated NSCLC patient cohort. Additional studies are needed to further define cut-offs in the context of performance status, and better understand immune escape mechanisms in the moderate group. Citation Format: Mary K. Nesline, Sarabjot Pabla, Yong Hee Lee, Paul DePietro, Amy Early, Roger Klein, Shengle Zhang, Jeffrey Conroy. PD-L1 expression by RNA-sequencing and survival from pembrolizumab in non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1259.

Abstract 3882: Translating genotype to immunophenotype in HRAS mutated head and neck squamous cell carcinoma (HNSCC) to identify effective Tipifarnib partners for optimal patient outcomes

Abstract Background: Tipifarnib is a highly selective farnesyltransferase inhibitor that has shown promising activity in HRAS mutant recurrent/metastatic HNSCC. The incidence of HRAS mutations in HNSCC is 4-10%. Since HRAS mutated HNSCC can be successfully targeted with Tipifarnib, we sought to analyze the immune and genomic landscape of these tumors to guide combinatorial strategies. Methods: We identified thirteen patients with HRAS mutant tumors. We included in the analysis 50 patients with HRAS wild-type tumors. Genomic DNA from baseline biopsies of tumors was purified and subjected to targeted sequencing (TruSightTM Oncology 500 panel). PD-L1 expression in formalin-fixed tumor samples was assessed using the PD-L1 IHC 22C3 pharmDx assay (Agilent Technologies, Carpinteria, CA, USA) and characterized by the combined positive score (CPS). Assessment of PD-L1+ cells inside and at the periphery of the tumor was performed. HRAS mutational status was correlated with PD-L1 status. The genomic data derived from the targeted gene panel of HRAS mutant tumors were compared to those with wild-type HRAS. Results: Thirty-seven patients had both genomic and PD-L1 expression data available. The presence of HRAS mutations was associated with higher TPS PD-L1 scores (26% vs 40% vs 100% in TPS &amp;lt;1%, 1-49% and &amp;gt;50% respectively, p=0.043). Similar results were obtained for CPS (28% vs 80% in CPS &amp;lt;10% and =&amp;gt;10%, p=0.047). HRAS mutations were more commonly found with TP53 mutations (16% in WT TP53 and 55.6% in mutated TP53, p=0.073). Higher PD-L1 TPS showed increased survival without reaching significance when measuring either in the margins (64.1 vs 35.8, p=0.066) or the center of the tumor (p=0.097) due to the small sample size. Conclusions: HRAS mutant HNSCC are associated with high PD-L1 expression and co-occurrence of p53 mutations. Combinations of tipifarnib with an anti-PD1 antibody, an anti-PDL1 antibody, or an anti-CTLA-4 antibody warrant clinical investigation in this rare subset of HNSCC. Citation Format: Amanda Psyrri, Miriam Anastasiou, Aris Spathis, Stergios Doumas, Panagiota Economopoulou, Ioannis Kotsantis, Anastasios Pantazopoulos, Anastasios Kyriazoglou, George Kavourakis, Theodoros Rampias, Periklis Foukas. Translating genotype to immunophenotype in HRAS mutated head and neck squamous cell carcinoma (HNSCC) to identify effective Tipifarnib partners for optimal patient outcomes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3882.

Programmed Death-Ligand 1 Expression in Lymphovascular Tumor Emboli in Lung Cancer

IntroductionProgrammed death-ligand 1 (PD-L1) expression determined by immunohistochemistry is the most widely used biomarker for predicting response to immune checkpoint inhibitors. The characteristics of PD-L1 expression in tumor cells inside lymphovascular spaces are largely unknown. Although PD-L1 expression in circulating tumor cells within vascular spaces had been studied, results were conflicting due to lack of standardized PD-L1 expression assessment. MethodsWe investigated PD-L1 expression in lung cancer primary tumor tissue, lymphovascular tumor emboli, and lymph node metastasis using the standard PD-L1 immunohistochemistry 22C3 pharmDx assay. PD-L1 expression was scored in the primary tumor, lymphovascular emboli, and lymph node metastasis by a pathologist using the tumor proportion score (TPS). ResultsWe collected and analyzed surgical specimens from 36 patients with lung cancer with lymph node metastasis. In the primary tumor, 64% of cases were PD-L1 negative (TPS < 1%), 25% were PD-L1 low (TPS 1%–49%), and 11% were PD-L1 high (TPS ≥ 50%). In contrast, in lymphovascular tumor emboli, 89% of cases were PD-L1 negative, 11% were PD-L1 low, and none were PD-L1 high. In lymph node metastases, 72% of cases were PD-L1 negative, 17% were PD-L1 low, and 11% were PD-L1 high. ConclusionsWe observed a significant decrease of PD-L1 expression in lymphovascular tumor emboli compared with that in primary tumors (p = 0.002). Whether such differences are related to intrinsic tumor cell heterogeneity or extrinsic factors such as the microenvironment warrants further investigation.

TRUCE-02: An open label, single-arm, phase II study of tislelizumab combined with nab-paclitaxel for high-risk non-muscle-invasive urothelial bladder carcinoma.

4507 Background: Pts with multiple or tumors with large invasion areas which are un-completely-resectable through TURBT would be recommended radical cystectomy in the clinical treatment. The KEYNOTE-057 study has illuminated the efficiency of immune checkpoint inhibitors monotherapy in HR-NMIBC pts, with acceptable adverse events (AEs). However, the role of PD-1/PD-L1 inhibitor in combination with chemotherapy in NMIBC pts remains unclear. We report preliminary treatment efficiency, safety data, and exploratory work of TRUCE-02 trial. Methods: TRUCE-02 is a phase II study for NMIBC pts with uncompletely resectable tumour by TURBT. The primary endpoint was complete response(absence of non-muscle-invasive bladder cancer or progressive disease). Pts that meet the criteria would receive tislelizumab 200mg on days 1 plus paclitaxel 200mg on days 2 every 3 weeks (Q3W) x 3 or 4 cycles followed by a comprehensive assessment including pathology, urine cytology, and imageology. Meanwhile, biomarker analyses included programmed death-ligand 1 (PD-L1) expression using the combined positive score (CPS; Dako 22C3 pharmDx assay) and whole transcriptome RNA sequencing of the tumor. Results: Between July 2020 and January 2022, 54 pts were enrolled. 42 pts have completed whole 3 or 4 treatment cycles and reached the primary endpoint. 23 pts achieved CR condition (56%, 95%CI, 43.6% and 74.4%). ORR of 60% (N=25/42, 95%CI, 45.2% and 74.8%). As a secondary endpoint, 33 pts remain cystectomy-free condition (78.6%, 95%CI, 66.2% and 91%). Grade 3-4 AEs were lower than 2%. Urine cytology showed its diagnostic efficiency of 68.42% (95%CI, 61.3% and 75.6%), urine FISH showed a diagnostic efficiency of 45.71% (95%CI, 37.7% and 53.4%) before pathological assessment. As for PD-L1 expression, 47.3% (N = 9/19) of response pts (CR+PR) showed positive, 50% (N = 5/10) of un-response pts (PD+SD) showed positive. We also found out through sequencing results that AR, TCF7L2 might be underlying markers that predict adverse outcomes for pts in this crew. HRR mutation may predict a positive prognosis and mutations in NMIBC which might predict the prognosis of this treatment plan. Conclusions: Tislelizumab with nab-paclitaxel represents a novel treatment option with a satisfactory benefit in treating NMIBC. PD-L1 expression has no obvious correlation with the efficiency of this treatment plan. WGS result also showed that there are mutation markers that may predict whether pts would benefit from this treatment plan. Clinical trial information: NCT04730232. [Table: see text]

Datopotamab deruxtecan (Dato-DXd) plus pembrolizumab in treatment-naive advanced/metastatic (adv/met) non–small cell lung cancer (NSCLC) with PD-L1 ≥ 50% and without actionable genomic alterations.

TPS3162 Background: First-line treatment with immunotherapy has significantly improved survival in patients with adv/met NSCLC. Pembrolizumab (pembro) as monotherapy has shown superior efficacy compared with chemotherapy in treatment-naive patients with advanced NSCLC and PD-L1 expression ≥50%, but most patients will ultimately experience progression. Dato-DXd is an antibody-drug conjugate (ADC) consisting of a humanized anti-TROP2 IgG1 monoclonal antibody attached to a topoisomerase I inhibitor payload via a stable tetrapeptide-based cleavable linker. In the ongoing phase 1 TROPION-PanTumor01 study (NCT03401385; DS1062-A-J101), Dato-DXd 6 mg/kg monotherapy demonstrated an objective response rate (ORR) of 28% and a manageable safety profile in pretreated patients with NSCLC. In addition, preclinical studies showed that DXd ADCs combined with an anti–PD-1 antibody was more effective than monotherapy with either agent alone. The tolerability of Dato-DXd 6 mg/kg in combination with pembrolizumab was confirmed in the phase 1b TROPION-Lung02 trial (NCT04526691; DS1062-A-U102). Here we describe the phase 3 TROPION-Lung08 trial evaluating Dato-DXd combined with pembro in treatment-naive patients with adv/met NSCLC. Methods: TROPION-Lung08 (NCT05215340; DS1062-A-U304) is a global, randomized, open-label, phase 3 trial of Dato-DXd plus pembro vs pembro alone in treatment-naive patients with adv/met non-actionable oncogenic driven NSCLC with PD-L1 ≥50% (as determined by PD-L1 IHC 22C3 pharmDx assay). Approximately 740 patients will be randomized to receive pembro 200 mg plus Dato-DXd 6 mg/kg or pembro 200 mg alone every 21 days until discontinuation or 35 cycles of pembro. Randomization will be stratified by Eastern Cooperative Oncology Group performance status (0 vs 1), histology (squamous vs nonsquamous), geographic region (East Asia vs rest of world), and smoking status (former/current vs never). Patients must have stage IIIB/IIIC NSCLC ineligible for curative treatment or stage IV disease. Patients must not have received prior systemic therapy; if patients received neoadjuvant/adjuvant systemic therapy without immune checkpoint inhibitors, it must have been given ≥6 months before the diagnosis of adv/met disease. The primary endpoints are progression-free survival (assessed by blinded independent central review per Response Evaluation Criteria in Solid Tumors [RECIST] version 1.1) and overall survival, with target hazard ratios of 0.65 and 0.75, respectively. Secondary endpoints include ORR, duration of response, time to response, disease control rate, safety, and antidrug antibody prevalence. Pharmacokinetic parameters, biomarkers, and patient-reported outcomes will also be explored. Clinical trial information: NCT05215340.

ENGOT-ov65/KEYNOTE-B96: Phase 3, randomized, double-blind study of pembrolizumab versus placebo plus paclitaxel with optional bevacizumab for platinum-resistant recurrent ovarian cancer.

TPS5617 Background: Despite therapeutic advances in ovarian cancer, platinum-resistant recurrent ovarian cancer (PROC) remains an area of high unmet clinical need and there is an urgent need for new treatments to further improve clinical outcomes. Addition of bevacizumab to non-platinum-based chemotherapy significantly improved PFS in patients with PROC but did not show a clear OS benefit. Thus far, the combination of paclitaxel and bevacizumab has shown the most promise in treatment of PROC, although the proportion of patients eligible for bevacizumab is limited by treatment-associated toxicities. Combination of the anti-PD-1 antibody pembrolizumab with weekly paclitaxel showed antitumor activity and manageable toxicity in patients with PROC in a single-arm, phase 2 study (Wenham Int J Gynecol Cancer 2018). The current study ENGOT-ov65/KEYNOTE-B96 (NCT05116189) compares the efficacy and safety of the addition of pembrolizumab to standard of care chemotherapy (weekly paclitaxel) with/without bevacizumab vs placebo plus weekly paclitaxel with/without bevacizumab in patients with PROC. Methods: In this randomized, placebo-controlled, double-blind, phase 3 study, eligible patients are aged ≥18 y with histologically confirmed epithelial ovarian, fallopian tube, or primary peritoneal carcinoma with 1-2 prior lines of systemic therapy, including at least 1 prior platinum-based therapy with ≥4 cycles in first line. Patients must have platinum-resistant disease (radiographic evidence of PD ≤6 mo after last platinum-based therapy dose), be eligible for paclitaxel (with/without bevacizumab per investigator discretion), have ECOG PS ≤1, radiographically evaluable disease per RECIST v1.1, and have a tumor sample for central evaluation of PD-L1 status. Approximately 616 patients will be randomized 1:1 to receive pembrolizumab 400 mg IV or placebo Q6W for up to 18 cycles (̃2 y) plus paclitaxel 80 mg/m2 on days 1, 8, and 15 of each Q3W cycle (with/without bevacizumab 10 mg/kg Q2W per investigator discretion) until PD or unacceptable toxicity. Randomization is stratified by planned bevacizumab use (yes vs no), region (US vs Europe vs rest of world), and PD-L1 status (combined positive score [CPS] &lt; 1 vs CPS 1- &lt; 10 vs CPS ≥10). Tumor PD-L1 status is determined using the PD-L1 IHC 22C3 pharmDx (Investigational Use Only) diagnostic kit. Tumor imaging is performed Q9W from randomization to week 54 and Q12W thereafter. The primary endpoint is PFS per RECIST version 1.1 by investigator review in patients with tumor PD-L1 CPS ≥1 and in all patients. Secondary endpoints are OS in patients with tumor PD-L1 CPS ≥1 and in all patients, PFS per RECIST version 1.1 by blinded independent central review in patients with tumor PD-L1 CPS ≥1 and in all patients, safety, and patient-reported outcomes. Enrollment is ongoing. Clinical trial information: NCT05116189.

KEYNOTE-B49: A phase 3, randomized, double-blind, placebo-controlled study of pembrolizumab plus chemotherapy in patients with HR+/HER2- locally recurrent inoperable or metastatic breast cancer.

TPS1118 Background: HR+/HER2− advanced breast cancer that progresses on endocrine therapy is treated with chemotherapy (chemo). The phase 1b KEYNOTE-028 trial showed durable activity with pembrolizumab (pembro) monotherapy in previously treated HR+/HER2−, PD-L1–positive (combined positive score [CPS] ≥1) advanced breast cancer. KEYNOTE-B49 (NCT04895358) is a phase 3, randomized, double-blind study of pembro + chemo vs placebo (pbo) + chemo in centrally assessed PD-L1–positive, HR+/HER2− locally recurrent inoperable or metastatic breast cancer (mBC) after progression on prior endocrine therapy. Methods: ∼800 patients (pts) with HR+/HER2− locally recurrent inoperable or mBC who are candidates for chemo (no prior chemo for metastatic disease) with PD-L1 CPS ≥1 and documented progression on prior endocrine therapy will be enrolled. Prior endocrine therapy comprises ≥2 lines (≥1 in combination with a CDK4/6 inhibitor) in the metastatic setting or 1 line with CDK4/6 inhibitor treatment for mBC in pts who had a relapse within 24 mo of primary surgery. Pts without prior CDK4/6 inhibitor treatment may enroll if they had progressed within 6 mo of starting endocrine therapy for metastatic disease and had previously relapsed within 24 mo of primary tumor surgery while on adjuvant endocrine therapy. Pts are randomized 1:1 to receive pembro 200 mg IV or pbo Q3W, each in combination with investigator’s choice of chemo: paclitaxel 90 mg/m2 IV on days 1, 8, and 15 Q4W; nab-paclitaxel 100 mg/m2 IV on days 1, 8, and 15 Q4W; liposomal doxorubicin 50 mg/m2 IV on day 1 Q4W; or capecitabine 1000 mg/m2 PO BID on days 1–14 Q3W. Randomization is stratified by tumor PD-L1 (CPS 1–9 vs ≥10), presence of visceral metastases (yes vs no), and chemo on-study (taxanes vs liposomal doxorubicin vs capecitabine). Treatment is continued until disease progression, unacceptable toxicity, withdrawal, or, for pembro/pbo, completion of 35 cycles (̃2 years); chemo can be continued per investigator discretion. Tumor PD-L1 status is determined centrally using the PD-L1 IHC 22C3 pharmDx assay (Agilent Technologies; Carpinteria, CA, USA). Radiologic assessments are performed Q9W for 54 wk and then Q12W thereafter. AEs occurring from randomization until 30 d after treatment discontinuation (90 d for serious AEs) are graded per NCI-CTCAE v 5.0. Primary endpoints are PFS per RECIST v1.1 by BICR and OS in pts with PD-L1 CPS ≥10 and ≥1 tumors, separately. Enrollment is ongoing at 204 international sites. Clinical trial information: NCT04895358.

Observer performance study to examine the feasibility of the AI-powered PD-L1 analyzer to assist pathologists’ assessment of PD-L1 expression using tumor proportion score in non–small cell lung cancer.

8529 Background: Programmed death ligand 1 (PD-L1) expression is the standard biomarker for PD-L1 inhibitors in advanced non-small cell lung cancer (NSCLC). However, evaluation of PD-L1 tumor proportion score (TPS) by pathologists causes inter-observer variation and demands time to interpret. This study aimed to evaluate the benefit of the artificial intelligence (AI) algorithm in assisting pathologists to determine TPS on PD-L1 immunohistochemistry (IHC) whole-slide images (WSIs) in NSCLC. Methods: Lunit SCOPE PD-L1, an AI-powered PD-L1 TPS analyzer, was developed from 393,565 tumor cells annotated by board-certified pathologists for PD-L1 expression in 802 WSIs stained by 22C3 pharmDx IHC. The AI model was developed based on a region-based convolutional neural network, and the model can detect and count PD-L1 positive or negative tumor cells from WSIs to calculate TPS. Seven independent board-certified pathologists scored ground truth (GT) of PD-L1 TPS from 199 WSI of NSCLC stained by 22C3 pharmDx IHC. TPS from each GT reader was grouped as negative (&lt; 1%), low (1% to 49%), or high (≥ 50%). The GT of each slide was determined by the consensus of GT readers. Another twelve independent board-certified pathologists scored PD-L1 TPS from the same WSIs as observer performance testers (OPT). They scored TPS twice with a washout interval of 4 weeks, with or without AI assistance. TPS accuracy change and reading time of OPT reader according to the presence or absence of AI assistance were analyzed. Results: The standalone accuracy of the AI model was 0.809 (95% CI: 0.690–0.941). With AI assistance, the overall accuracy of TPS had been changed from 0.799 (95% confidence interval [CI]: 0.764–0.836) to 0.832 (95% CI: 0.796–0.869) (P = 0.004). AI assistance increased the accuracy rate in 11 out of 12 OPT readers. The result of the generalized linear mixed model revealed that AI assistance and specimen type affected the probability of correct answer, while the order of reading did not (Table). The mean time to read with AI was 195.4±506.5 (mean±standard deviation) seconds, which was significantly shorter than the mean time to read without AI (285.1±1578.4, P &lt;0.001). Conclusions: This study demonstrates that an AI-powered PD-L1 TPS analyzer can assist board-certified pathologists in evaluating TPS of NSCLC by improving the accuracy of TPS group evaluation and reducing the time to read slides.[Table: see text]