22C3 Dako Research Articles

Abstract 6404: Clinical scenario of immune checkpoint inhibitor treatment in metastatic nasopharyngeal carcinoma

Abstract Advanced in local treatment technology and early detection methodology, distant metastasis became a critical issue in Nasopharyngeal carcinoma (NPC). Recently, cancer immunotherapy especially immune checkpoint inhibitors (ICIs) including anti-programmed death-1 (PD-1) and PD-1 ligand (PD-L1) monoclonal antibodies (Mabs) had a rapid progress in cancer patient management. We try to clarify the clinical scenario of immune-related parameters in metastatic NPC. We had check 81 metastatic tissue PD-L1 expression without ICI treatment from the tissue bank of CGMH, Linkou, during 2005~2019. Using anti-PD-L1 antibody, 22C3 Dako, tumor proportional score (TPS) was positive in 43.2% (35/81) checked tissue and combine positive score (CPS) was positive in 58.0% (47/81) tissue respectively. For overall survival (OS) combined with PD-L1 expression in metastatic tissue analysis, positive CPS but not TPS correlated with longer survival with statistical significance (TPS: >0% vs =0%, median survival, 24m vs 22.5m, p=0.615186; CPS: >0% vs =0%, median survival, 28m vs 16m, p=0.003709). Retrospectively analysis of metastatic NPC treatment of combination of chemotherapy, ICIs, and local treatment in our institute in the past 6 years, total 40 patients was enrolled with median overall survival of 34.1 months. Objective response rate by RECIST criteria for immunotherapy-based regimen was 75% (CR:40%; PR:35%) and disease control rate was 85%. According to response by RECIST criteria, median overall survival were 34.1 months vs. 16.7 months respectively for responders and non-responders. With pre-treated NLR as cutoff value of 1.6, difference of median overall survival between two groups (responder vs nonresponder) was statistically significant (p=0.021). We also found that lower median post-treatment NLR in responders than in non-responders (1.4 vs. 3.2, p=0.013). Using rapid lymphocyte amplification protocol via IL-2 stimulation, the PBMC from most of the patient received ICIs treatment can be amplified 1~10 folds and positively correlated with total lymphocyte count. Through flowcytometry analysis, we found these amplified PBMC was lymphocyte dominant and rich in CD8+. We also found these amplified PBMC can kill the NPC EBV-positive cell line and xenograft in vitro and in vivo. These results demonstrated that combination of chemotherapy, ICIs, and local treatment will benefit metastatic NPC patients. Citation Format: Cheng-Lung Hsu, Yung-Chia Kuo. Clinical scenario of immune checkpoint inhibitor treatment in metastatic nasopharyngeal carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6404.

Comparability of laboratory-developed and commercial PD-L1 assays in non-small cell lung carcinoma

PD-L1 expression in non-small cell lung cancer (NSCLC) is predictive of response to treatment with PD-1 and PD-L1 inhibitors. Different inhibitors have been developed with different PD-L1 assays, which use different PD-1 antibody clones on different immunohistochemistry platforms. Depending on instrument and reagent availability, laboratory-developed tests with cross-platform use of PD-L1 antibodies may have practical benefits over commercial assays. The 22C3 pharmDx Assay (referred to as 22C3 DAKO), the VENTANA PD-L1 SP263 Assay (referred to as SP263 VENTANA) and a lab-developed test using the 22C3 antibody on the VENTANA BenchMark ULTRA IHC/ISH system (referred to as 22C3 VENTANA) were performed on whole sections of 85 NSCLC surgical resections. All sections were independently scored by three pathologists using tumor proportion scores. Correlation coefficients for continuous scores in pairwise comparisons between assays ranged from 0.976 to 0.978. When using a 1% positivity threshold (dichotomous scores), the 22C3 DAKO assay and 22C3 VENTANA assays showed the greatest agreement (93% agreement, κ = 0.86, 95% CI 0.75–0.97), and the 22C3 DAKO and SP263 VENTANA assays tended to show slightly less agreement (84% agreement, κ = 0.66, 95% CI 0.50–0.82). When using a 50% positivity threshold (dichotomous scores), all pairwise comparisons showed similar agreement (96–99% agreement, κ = 0.89–0.97). Overall, there was no significant difference between assays at 1% or 50% thresholds (P = .77). These data are consistent with potential interchangeability of these assays, which may widen the scope of PD-L1 assays available to laboratories and reduce logistical barriers to testing.

Tumor mutational burden (TMB) profile of K-RAS/TP-53 co-mutation in metastatic non-small cell lung cancer (m-NSCLC).

2626 Background: Early data suggests that co-occurring genetic events define biological heterogeneity in K-RAS mutant NSCLC, with K-RAS/ TP-53 (KP) co-mutated subset having potential therapeutic vulnerabilities to immune checkpoint blockade (ICB). To explore the immunological basis for these findings, we evaluated the immune biomarker profile (TMB/PD-L1) in KP mutant m-NSCLC using a large next-generation sequencing (NGS) dataset. Methods: Caris life sciences NGS dataset consisting of 1317 m-NSCLC tissue samples from 2016-18 was queried. PD-L1pos was defined as ≥ 1% staining using 22c3 Dako assay. TMB was measured by counting all somatic non-synonymous missense mutations using targeted NGS (592 genes). TMB-high (H) was defined as ≥ 10 mutations/Megabase (mut/Mb). P-values were calculated using Chi-square and Mann-Whitney test. Results: K-RAS mutations were identified in 28.7% (378/1317). Within this K-RAS mutant group, KP subset constituted 49.4% (187/378), remaining were K-RAS mutated/ TP-53 wild type (K-Pwt). 72.2 % (135/187) of KP had PD-L1pos with 51.9% (97/187) having PD-L1 ≥ 50%. KP had higher median TMB vs. K-Pwt (14.5 vs. 9.0 mut/Mb, p<0.001) and higher % of TMB-H vs. K-Pwt (79.9 vs. 45.1%, p<0.001; Table). Even in the PD-L1neg group, KP had higher % of TMB-H vs. K-Pwt (86.5 vs. 41.5%, p<0.001). K-RAS or TP-53 exon-subtypes had no difference in median TMB or % of TMB-H. Across metastatic sites, brain tissue had the highest % of KP subset (38.3%, 68/187) followed by bone (28.9%, 54/187). Within KP subset, brain tissue had higher median TMB vs. bone (16 vs. 11 mut/Mb, p<0.01) as well as greater % of TMB-H vs. bone (86.5 vs. 68.5%, p=0.01). Conclusions: This is the largest dataset to date highlighting the unique immune profile of KP mutant m-NSCLC. Our results show that KP subset has a significantly higher TMB than K-Pwt, especially in the PD-L1neg subgroup. Metastatic site-specific variations in TMB were also observed for the KP subset. These findings could have therapeutic implications in guiding patient selection for ICB and merit prospective investigation.[Table: see text]