Evaluation of PD-L1 Expression in Colorectal Carcinomas by Comparing Scoring Methods and Their Significance in Relation to Clinicopathologic Parameters

BACKGROUND

This study aims to evaluate PD-L1 expression in colorectal carcinomas (CRCs) by using the tumor proportion score (TPS) and the combined positive score (CPS), and to investigate whether there is a correlation with clinicopathologic features.

METHODS

A cross-sectional study was conducted that included samples from patients with colorectal adenocarcinoma treated with colon resection and rectal resection after neoadjuvant radio- and chemotherapy at the Department of Abdominal Surgery at Požega Hospital in the period from 2017 to 2022. The study included 102 tumor tissue samples from patients after resection and the pathohistological diagnosis of adenocarcinoma.

RESULTS

In our study, the PD-L1 positivity rate after the TPS was 42 (41%) samples, and after the CPS, 97 (95%) of them (p < 0.001). The positive expression of PD-L1 in tumor cells using the TPS method showed a statistically significant association with adenocarcinoma (TPS ≥ 10-50% and ≥50%). There were significantly more that were moderately differentiated, with TPS ≥ 50%, and those poorly differentiated had values ≥ 10-50%. There were significantly more patients with a status of more than one positive lymph node with TPS values ≥ 10-50%. Patients without metastases in the lymph nodes are significantly more likely to have CPS values > 50%, compared with other lymph node statuses.

CONCLUSIONS

These results suggest that the total number of PD-L1-expressing cells, including tumor and immune cells, is a more sensitive biomarker than the number of PD-L1-expressing tumor cells alone in CRC.

An artificial intelligence-powered PD-L1 combined positive score (CPS) analyser in urothelial carcinoma alleviating interobserver and intersite variability

AIMS

Immune checkpoint inhibitors targeting programmed death-ligand 1 (PD-L1) have shown promising clinical outcomes in urothelial carcinoma (UC). The combined positive score (CPS) quantifies PD-L1 22C3 expression in UC, but it can vary between pathologists due to the consideration of both immune and tumour cell positivity.

METHODS AND RESULTS

An artificial intelligence (AI)-powered PD-L1 CPS analyser was developed using 1,275,907 cells and 6175.42 mm2 of tissue annotated by pathologists, extracted from 400 PD-L1 22C3-stained whole slide images of UC. We validated the AI model on 543 UC PD-L1 22C3 cases collected from three institutions. There were 446 cases (82.1%) where the CPS results (CPS ≥10 or <10) were in complete agreement between three pathologists, and 486 cases (89.5%) where the AI-powered CPS results matched the consensus of two or more pathologists. In the pathologist's assessment of the CPS, statistically significant differences were noted depending on the source hospital (P = 0.003). Three pathologists reevaluated discrepancy cases with AI-powered CPS results. After using the AI as a guide and revising, the complete agreement increased to 93.9%. The AI model contributed to improving the concordance between pathologists across various factors including hospital, specimen type, pathologic T stage, histologic subtypes, and dominant PD-L1-positive cell type. In the revised results, the evaluation discordance among slides from different hospitals was mitigated.

CONCLUSION

This study suggests that AI models can help pathologists to reduce discrepancies between pathologists in quantifying immunohistochemistry including PD-L1 22C3 CPS, especially when evaluating data from different institutions, such as in a telepathology setting.

PD-L1 expression in fine-needle aspiration cell blocks of head and neck squamous-cell carcinoma and its cytohistological concordance

BACKGROUND

PD-L1 immunoexpression in head and neck squamous-cell carcinoma (HNSCC) determines immunotherapy eligibility. Patients are often diagnosed using fine-needle aspiration (FNA) of metastatic lymph nodes, however, the cytohistologic correlation of the combined positive score (CPS) is largely unknown.

METHODS

This study retrospectively identified 96 paired histologic (HS) and cytologic specimens (CyS), between 2016 and 2020, diagnosed with HNSCC. Cases with <100 tumor cells (n = 54) or missing block(s) (n = 8) were excluded. All 34 case pairs were scored with CPS using the PD-L1 22C3 pharmDx assay at clinically relevant cut-offs of <1%, 1%-19%, and ≥20% independently by three observers blinded to the case pairs (CyS with corresponding HS).

RESULTS

The CPS (<1/1-19/≥20) for CyS and HS were as follows: 10(29.4%)/10(29.4%)/14(41.2%) and 2(5.9%)/13(38.2%)/19(55.9%), respectively. There was fair overall cytohistologic agreement (OA) of 76.5% (k = 0.261) at the CPS cut-off of 1. The OA did not differ significantly between site-matched (n = 13) and -unmatched (n = 21) case pairs (p = .4653). CyS has a specificity and positive predictive value (PPV) of 100% but a negative predictive value (NPV) of only 20% as compared to its paired HS.

CONCLUSIONS

Our study demonstrates fair CPS cytohistologic correlation in HNSCC specimens using the PD-L1 IHC 22C3 pharmDx assay with high PPV but low NPV. This suggest that determining PD-L1 status in FNA specimens can play an important role in the clinical management of HNSCC patients.

Digital Pathology Applications for PD-L1 Scoring in Head and Neck Squamous Cell Carcinoma: A Challenging Series

The assessment of programmed death-ligand 1 (PD-L1) combined positive scoring (CPS) in head and neck squamous cell carcinoma (HNSCC) is challenged by pre-analytical and inter-observer variabilities. An educational program to compare the diagnostic performances between local pathologists and a board of pathologists on 11 challenging cases from different Italian pathology centers stained with PD-L1 immunohistochemistry on a digital pathology platform is reported. A laboratory-developed test (LDT) using both 22C3 (Dako) and SP263 (Ventana) clones on Dako or Ventana platforms was compared with the companion diagnostic (CDx) Dako 22C3 pharm Dx assay. A computational approach was performed to assess possible correlations between stain features and pathologists' visual assessments. Technical discordances were noted in five cases (LDT vs. CDx, 45%), due to an abnormal nuclear/cytoplasmic diaminobenzidine (DAB) stain in LDT (n = 2, 18%) and due to variation in terms of intensity, dirty background, and DAB droplets (n = 3, 27%). Interpretative discordances were noted in six cases (LDT vs. CDx, 54%). CPS remained unchanged, increased, or decreased from LDT to CDx in three (27%) cases, two (18%) cases, and one (9%) case, respectively, around relevant cutoffs (1 and 20, k = 0.63). Differences noted in DAB intensity/distribution using computational pathology partly explained the LDT vs. CDx differences in two cases (18%). Digital pathology may help in PD-L1 scoring, serving as a second opinion consultation platform in challenging cases. Computational and artificial intelligence tools will improve clinical decision-making and patient outcomes.

Impact of programmed death-ligand 1 (PD-L1) positivity on clinical and molecular features of patients with metastatic gastric cancer

BACKGROUND

Programmed death-ligand 1 (PD-L1) is an important screening biomarker to select patients with gastric cancer (GC) for optimized treatment, including immune checkpoint inhibitors (ICI).

METHODS

In this single-institution retrospective cohort study, patients with metastatic GC with available PD-L1 results between October 2019 and September 2021 were identified by reviewing their electronic medical records. Genomic data were obtained from the Samsung Medical Center Clinical Sequencing Platform.

RESULTS

Among the 399 patients, 276 (69%) had a PD-L1 combined positive score (CPS) ≥1, 155 (39%) had a CPS between 1 and 5, and 121 (30%) had a CPS ≥5. Of the 121 patients with CPS ≥5, 28 (23%) had a known etiology for "inflamed tumor," with Epstein-Barr virus (EBV) positivity (N = 11) or high tumor mutational burden (TMB) (N = 17), which included microsatellite instability (MSI) (N = 9). PD-L1 CPS ≥5 was observed in 11/11 (100%) patients with EBV positivity, 9/12 (75%) patients with MSI, and 17/33 (52%) patients with high TMB. For the 108 patients who received ICI therapy, CPS ≥5 was the only predictor significantly associated with survival in multivariable analyses, including TMB, MSI, or EBV. Objective response rate (ORR) was 49% in patients with CPS ≥5, 30% in patients with 1 ≤ CPS <5, and 19% in patients with CPS <1. Among the 31 responders to ICI therapy, 27 (87%) had a CPS of ≥1. Mutations in TET2, IRS2, DOT1L, PTPRT, and LRP1B were associated with a higher ORR (63%-100%), whereas MDC1 mutations were associated with a low ORR (22%).

CONCLUSIONS

PD-L1 expression is an independent and sensitive biomarker for ICI therapy. Considering its significant association with several gene alterations, including PIK3CA mutations and MET amplification, combining ICI therapy with other targeted agents may be a promising therapeutic strategy for GC.

PD-L1 and HLA-class I expression status and their therapeutic implication in oesophageal small-cell carcinoma

AIMS

Oesophageal small-cell carcinoma is a rare and highly aggressive subtype of oesophageal cancer with a dismal prognosis. To explore the potential applicability of immunotherapy, we investigated the expression status of programmed death ligand 1 (PD-L1) and human leukocyte antigen (HLA)-class I and the degree of tumour-infiltrating lymphocytes (TILs) in oesophageal small-cell carcinoma.

METHODS AND RESULTS

PD-L1 and HLA-class I expression levels were evaluated in 10 pure small-cell carcinomas and five mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs). The combined positive score (CPS) and tumour proportion score (TPS) were used for PD-L1 assessment. Immunohistochemistry for mismatch repair (MMR) proteins was also performed. PD-L1 immunohistochemistry demonstrated CPS ≥1 in nine (60%), CPS ≥10 in five (33%), and TPS ≥1 in five (33%) cases. Overall survival was significantly longer in patients with CPS ≥1 than in those with CPS <1. HLA-class I deficiency (>50% tumour cells) was noted in five cases (33%), with no significant correlation with PD-L1 expression status. Among the five MiNENs, HLA-class I expression was decreased in the small-cell carcinoma component of three cases. HLA-class I deficiency was significantly associated with higher TNM stage and reduced TIL levels. MMR deficiency was not observed in any case.

CONCLUSION

Given that a significant subset (40%) exhibited PD-L1 CPS ≥1 with preserved HLA-class I expression and high levels of TIL, the PD-1/PD-L1 pathway is a potential therapeutic target for oesophageal small-cell carcinoma.

Correlation between fibroblast growth factor receptor mutation, programmed death ligand-1 expression and survival in urinary bladder cancer based on real-world data

Background: Programmed cell death (PD)-1/PD-ligand 1 (PD-L1) inhibitors have made a breakthrough in the therapy of advanced urothelial bladder cancer (UBC). The impact of Fibroblast Growth Factor Receptor 3 (FGFR3) mutation on the effectiveness of PD-L1 treatment remains still unclear. Objective: Our study aimed to investigate the frequency of FGFR mutations at different tumor stages, and their relation to PD-L1 status and survival. Methods: 310 patients with urothelial bladder cancer and subsequent radical cystectomy were included in a retrospective study over a 10-year study period at the University of Szeged, Hungary. FGFR3 mutations from the most infiltrative areas of the tumor were analyzed by targeted next-generation sequencing and PD-L1 (28-8 DAKO) tests (tumor positive score -TPS and combined positives score-CPS). In T0 cases FGFR3 mutations were analyzed from the earlier resection samples. Survival and oncological treatment data were collected from the National Health Insurance Fund (NHIF). Neoadjuvant, adjuvant and palliative conventional chemotherapies were allowed; immunotherapies were not. The relationship between the covariates was tested using chi-square tests, and survival analysis was performed using the Kaplan-Meier model and Cox proportional hazards regression. Results: PD-L1 and FGFR could be tested successfully in 215 of the 310 UBC samples [pT0_cyst 19 (8.8%); St.0-I 43 (20%); St.II 41 (19%); St.III-IV 112 (52%)]. Significant pairwise dependency was found between tumor stage, FGFR3 mutation status and PD-L1 expression (p < 0.01). Samples with FGFR mutation were more common in less advanced stages and were also less likely to demonstrate PD-L1 expression. The effect of all investigated factors on survival was found to correlate with tumor stage. Conclusion: FGFR alteration frequency varied between the different stages of cancer. Higher positivity rates were observed at early stages, but lower levels of PD-L1 expression were detected in patients with FGFR mutations across at all stages of the disease.

Correlation between imaging features on computed tomography and combined positive score of PD-L1 expression in patients with gastric cancer

OBJECTIVE

To explore the correlation between computed tomography (CT) features and combined positive score (CPS) of programmed cell death ligand 1 (PD-L1) expression in patients with gastric cancer (GC).

METHODS

This study reviewed an institutional database of patients who underwent GC operation without neoadjuvant chemotherapy between December 2019 and September 2020. The CPS results of PD-L1 expression of postoperative histological examination were recorded by pathology. Baseline CT features were measured, and their correlation with CPS 5 or 10 score groups of PD-L1 expression was analyzed.

RESULTS

Data for 153 patients with GC were collected. Among them, 124 were advanced GC patients, and 29 were early GC patients. None of the CT features significantly differed between CPS groups with a cutoff score of 5 and a score of 10 in patients with early GC. In advanced GC, the presence of lymph nodes with short diameters >10 mm was significantly different (P=0.024) between the CPS<5 and CPS≥5 groups. CT features such as tumor attenuation in the arterial phase, long and short diameter of the largest lymph node, the sum of long diameter of the two largest lymph nodes, the sum of short diameter of the two largest lymph nodes, and the presence of lymph nodes with short diameters >10 mm significantly differed between the CPS<10 and CPS≥10 groups in advanced GC. The sensitivity, specificity and area under receiver operating characteristic (ROC) curve of logistic regression model for predicting CPS≥10 was 71.7%, 50.0% and 0.671, respectively. Microsatellite instability (MSI) status was significantly different in CPS groups with cutoff score of 5 and 10 in advanced GC patients.

CONCLUSIONS

CT findings of advanced GC patients with CPS≥10 showed greater arterial phase enhancement and larger lymph nodes. CT has the potential to help screen patients suitable for immunotherapy.

Pembrolizumab for the treatment of advanced esophageal cancer

The prognosis of patients with advanced esophageal cancer (EC) remains poor and there are limited effective therapeutic agents for EC. Pembrolizumab monotherapy exerts clinically meaningful benefits for advanced esophageal squamous cell carcinoma patients with a combined positive score of ≥10. Additionally, pembrolizumab plus doublet chemotherapy results in a significant survival benefit for patients with advanced EC as first-line treatment compared with chemotherapy alone. We provide an overview of immune checkpoint inhibitors and present important clinical data related to treatment for EC patients. In our opinion, pembrolizumab plus chemotherapy should be the standard first-line treatment for patients with advanced EC, regardless of histology and combined positive score. Biomarker studies to identify patient populations in which immune checkpoint inhibitors are expected to show efficacy are needed.

The Evolution of Immune Checkpoint Inhibitors in Advanced Urothelial Carcinoma

Simple Summary

Urothelial carcinoma is an aggressive cancer with a high risk of metastatic progression. Chemotherapy plays a key role in the management of metastatic urothelial carcinoma, with, however, no possibility of cure. Immune checkpoint inhibitors have significantly improved the outcomes of patients, delaying progression of disease and improving quality of life. However, many questions remain concerning the optimal use of immunotherapy in urothelial carcinoma: When to start? Which biomarker of sensitivity/resistance to use? Which of the available options will increase the efficacy of immune checkpoint inhibitors? We review the mechanisms of immune checkpoint inhibitors as well as the current management of patients with metastatic urothelial carcinoma in the era of immunotherapy.

Abstract

Urothelial carcinoma is an aggressive cancer and development of metastases remains a challenge for clinicians. Immune checkpoint inhibitors (ICIs) are significantly improving the outcomes of patients with metastatic urothelial cancer (mUC). These agents were first used in monotherapy after failure of platinum-based chemotherapy, but different strategies explored the optimal use of ICIs in a first-line metastatic setting. The “maintenance” strategy consists of the introduction of ICIs in patients who experienced benefit from first-line chemotherapy in a metastatic setting. This allows an earlier use of ICIs, without waiting for disease progression. We review the optimal management of mUC in the era of ICIs, based on the key clinical messages arising from the pivotal trials.

Efficacy and activity of PD-1 blockade in patients with advanced esophageal squamous cell carcinoma: a systematic review and meta-analysis with focus on the value of PD-L1 combined positive score

BACKGROUND

Recently, several randomized controlled trials (RCTs) investigated immunotherapy-based regimens versus chemotherapy alone in patients with advanced esophageal squamous cell carcinoma (ESCC). Here we conducted a systematic review and meta-analysis on the efficacy and activity of programmed cell death protein 1 blockade in these patients, with focus on the value of programmed death-ligand 1 combined positive score (CPS) for selecting patients who may benefit the most.

METHODS

RCTs investigating treatment with or without immune checkpoint inhibitors for advanced ESCC were selected. The hazard ratio (HR) and the odds ratio were used to compare the treatment effect on survival outcomes and tumor response, respectively, for immunotherapy-based regimens compared with standard chemotherapy, overall and according to geographic region or treatment line. We carried out a subgroup analysis comparing patients with CPS ≥10 or <10 and the evidence for treatment effect was evaluated by interaction test.

RESULTS

A total of 5257 patients and 10 RCTs were included. Overall, the HR for overall survival benefit with immunotherapy-based regimens was 0.71 [95% confidence interval (CI) 0.66-0.76] compared with chemotherapy alone; such effect was independent from geographical region (Asia versus rest of the world) and treatment line (upfront versus second/further lines). The HR for progression-free survival benefit and the odds ratio for overall response rate increase were 0.78 (95% CI 0.66-0.93) and 1.50 (95% CI 1.22-1.83), respectively. The HR for overall survival benefit with immunotherapy-based treatment was 0.60 (95% CI 0.51-0.70) for CPS ≥10 subgroup versus 0.83 (95% CI 0.69-1.00) for CPS <10 (P for interaction 0.009).

CONCLUSIONS

Immune checkpoint inhibitors have a consistent benefit in reducing the risk of death for ESCC patients which is dependent on programmed death-ligand 1 CPS status. Further investigations of biomarkers for immunotherapy in the subgroup of patients with CPS <10 are needed.

PD-L1 testing and immunotherapy selection - early laboratory experience and its potential role in head and neck cancer management

Anti-programmed cell death protein-1 (PD-1) therapy has been relatively recently approved in a defined context by NICE in adults in the management of recurrent and metastatic head and neck squamous cell carcinomas (HNSCC). In this context, companion diagnostic programmed cell death ligand-1 (PD-L1) testing, previously established at our center for lung and bladder tumors, was undertaken in a few head and neck cancer cases. The scope of this study was to audit the relevant PD-L1 data and integrate the findings in our current clinical practice, with a view to promote improved routine laboratory biomarkers in HNSCC. Histopathology reports documenting tumor type, PD-L1 result and type of clone/assay were included in this study. Over a 5-year period, PD-L1 testing was undertaken in 199 cancer cases, including 3 with head and neck squamous carcinoma with low focal positive staining. Immunotherapy treatment in HNSCC demonstrates a discreet but still significant improvement in the overall survival of PD-L1 positive subjects.

Comparison of the Prognostic Value of Ki-67 and Programmed Cell Death Ligand-1 in Patients with Upper Tract Urothelial Carcinoma

We retrospectively enrolled 102 patients with upper tract urothelial carcinoma (UTUC) who underwent radical nephroureterectomy to examine the prognostic value of Ki-67 and programmed cell death ligand-1 (PD-L1). Then, we performed PD-L1 and Ki-67 immunohistochemical staining on whole tissue sections. The cut-off value of PD-L1 positivity was a combined positive score (CPS) ≥10 and the Ki-67 overexpression was 20%. Among the 102 patients, 16.7% and 48.0% showed positive PD-L1 expression and Ki-67 overexpression, respectively. A CPS ≥10 was significantly associated with a higher pathological T stage (p = 0.049). In addition, Ki-67 overexpression was significantly associated with a pathological T stage ≥ 2 (p = 0.027) and tumour necrosis (p = 0.016). In the multivariable analysis, a positive PD-L1 expression was significantly correlated with worse cancer-specific survival (HR = 3.66, 95% CI =1.37−9.77, p = 0.01). However, there was no predictive value using a combination of PD-L1 expression and Ki-67 overexpression as a prognostic predictor. Compared with Ki-67 overexpression, a positive PD-L1 expression with CPS ≥ 10 was a stronger independent prognostic factor for CSS in patients with UTUC.

Challenges facing pathologists evaluating PD-L1 in head & neck squamous cell carcinoma

BACKGROUND

Programmed death-ligand 1 (PD-L1) expression with combined positive score (CPS) ≥1 is required for administration of checkpoint inhibitor therapy in recurrent/metastatic head and neck squamous cell carcinoma (HNSCC). The 22C3 pharmDx Dako immunohistochemical assay is the one approved as companion diagnostic for pembrolizumab, but many laboratories work on other platforms and/or with other clones, and studies exploring the potential interchangeability of assays have appeared.

EVIDENCE FROM THE LITERATURE

After review of the literature, it emerges that the concordance among assays ranges from fair to moderate, with a tendence of assay SP263 to yield a higher quota of positivity and of assay SP142 to stain better immune cells. Moreover, pathologists achieve very good concordance in assessing PD-L1 CPS, particularly with SP263.

CONCLUSIONS

Differences in terms of platforms, procedures, and study design still preclude a quantitative synthesis of evidence and clearly further work is needed to draw stronger conclusions on the interchangeability of PD-L1 assays in HNSCC.

Prognostic and Predictive Factors in Advanced Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous disease arising from the mucosa of the upper aerodigestive tract. Despite multimodality treatments approximately half of all patients with locally advanced disease relapse and the prognosis of patients with recurrent or metastatic HNSCC is dismal. The introduction of checkpoint inhibitors improved the treatment options for these patients and pembrolizumab alone or in combination with a platinum and fluorouracil is now the standard of care for first-line therapy. However, approximately only one third of unselected patients respond to this combination and the response rate to checkpoint inhibitors alone is even lower. This shows that there is an urgent need to improve prognostication and prediction of treatment benefits in patients with HNSCC. In this review, we summarize the most relevant risk factors in the field and discuss their roles and limitations. The human papilloma virus (HPV) status for patients with oropharyngeal cancer and the combined positive score are the only biomarkers consistently used in clinical routine. Other factors, such as the tumor mutational burden and the immune microenvironment have been highly studied and are promising but need validation in prospective trials.

Distinct genomic landscapes of gastroesophageal adenocarcinoma depending on PD-L1 expression identify mutations in RAS-MAPK pathway and TP53 as potential predictors of immunotherapy efficacy

BACKGROUND

The impact of molecular alterations on programmed death-ligand 1 (PD-L1) combined positive score (CPS) is not well studied in gastroesophageal adenocarcinomas (GEAs). We aimed to characterize genomic features of tumors with different CPSs in GEAs.

PATIENTS AND METHODS

Genomic alterations of 2518 GEAs were compared in three groups (PD-L1 CPS ≥ 10, high; CPS = 1-9, intermediate; CPS < 1, low) using next-generation sequencing. We assessed the impact of gene mutations on the efficacy of immune checkpoint inhibitors (ICIs) and tumor immune environment based on the Memorial Sloan Kettering Cancer Center and The Cancer Genome Atlas databases.

RESULTS

High, intermediate, and low CPSs were seen in 18%, 54% and 28% of GEAs, respectively. PD-L1 positivity was less prevalent in women and in tissues derived from metastatic sites. PD-L1 CPS was positively associated with mismatch repair deficiency/microsatellite instability-high, but independent of tumor mutation burden distribution. Tumors with mutations in KRAS, TP53, and RAS-mitogen-activated protein kinase (MAPK) pathway were associated with higher PD-L1 CPSs in the mismatch repair proficiency and microsatellite stability (pMMR&MSS) subgroup. Patients with RAS-MAPK pathway alterations had longer overall survival (OS) from ICIs compared to wildtype (WT) patients [27 versus 13 months, hazard ratio (HR) = 0.36, 95% confidence interval (CI): 0.19-0.7, P = 0.016] and a similar trend was observed in the MSS subgroup (P = 0.11). In contrast, patients with TP53 mutations had worse OS from ICIs compared to TP53-WT patients in the MSS subgroup (5 versus 21 months, HR = 2.39, 95% CI: 1.24-4.61, P = 0.016).

CONCLUSIONS

This is the largest study to investigate the distinct genomic landscapes of GEAs with different PD-L1 CPSs. Our data may provide novel insights for patient selection using mutations in TP53 and RAS-MAPK pathway and for the development of rational combination immunotherapies in GEAs.

Programmed cell death protein 1/programmed death ligand 1 but not HER2 is a potential therapeutic target in gastric neuroendocrine carcinoma

AIMS

Gastric neuroendocrine carcinoma (NEC) is a rare and aggressive subtype with a poor prognosis. We aim to investigate expression profiles of HER2 and programmed death ligand 1 (PD-L1) in gastric NEC to test the potential applicability of drugs targeting these molecules.

METHODS AND RESULTS

Expression levels of HER2 and PD-L1 were evaluated in 25 gastric NECs, including 10 pure NECs and 15 mixed adenocarcinoma-NECs, and a combined positive score (CPS) was used to evaluate PD-L1 expression. The correlations of expression levels with both clinicopathological features and the expression of p53, retinoblastoma protein (Rb) and mismatch repair proteins were also analysed. Eighteen of the 25 (72%) cases showed a PD-L1 CPS of ≥ 1, which was previously shown to be associated with response to pembrolizumab. Positive nodal metastasis and low tumour-infiltrating lymphocyte (TIL) levels at the invasive margin were significantly associated with a PD-L1 CPS of < 1. The NEC component was HER2-negative in all cases, whereas HER2 positivity was observed in the adenocarcinoma component of six of 15 (40%) mixed adenocarcinoma-NECs. Mismatch repair deficiency, a mutant pattern of p53 expression and loss of Rb expression were observed in four (16%), 17 (68%) and nine (36%) cases, respectively, although these alterations were not associated with the PD-L1 CPS or other clinicopathological characteristics.

CONCLUSIONS

HER2 is unlikely to be an effective target in gastric NEC owing to the lack of HER2 expression, whereas the PD-1/PD-L1 pathway is a potential therapeutic target for gastric NEC because of the relatively high prevalence of a PD-L1 CPS of ≥ 1 in this subtype.

Pembrolizumab monotherapy in Japanese patients with advanced ovarian cancer: Subgroup analysis from the KEYNOTE-100

Interim results from the two-cohort, phase 2 KEYNOTE-100 study (NCT02674061) of 376 patients with previously treated advanced recurrent ovarian cancer (ROC) showed that pembrolizumab monotherapy was associated with an objective response rate (ORR) of 8.0% (95% CI, 5.4-11.2). We present outcomes for the Japanese patients (n = 21) enrolled in KEYNOTE-100. Patients with epithelial ROC had received either 1-3 prior chemotherapy lines and had platinum-free interval or treatment-free interval (PFI; TFI) of 3-12 months (cohort A) or 4-6 prior chemotherapy lines and had PFI/TFI of ≥3 months (cohort B). All patients received pembrolizumab 200 mg every 3 weeks as monotherapy for 2 years or until progression, death, unacceptable toxicity or consent withdrawal. Primary objectives were ORR per RECIST v1.1 for each cohort and higher programmed death ligand-1 (PD-L1) tumor expression. The relationship between PD-L1 expression (measured as combined positive score [CPS]) and ORR was assessed. Twenty-one Japanese patients (cohort A, n = 19; cohort B, n = 2) were treated. The median (range) age was 57 (37-78) years; 19 (90.5%) patients had ECOG status of 0 and 16 (76.2%) patients had stage III-IV disease. ORR was 19.0% (95% CI, 5.4-41.9) and seemed to increase with increasing PD-L1 expression. A total of 13 (61.9%) patients had treatment-related adverse events (TRAE), and 5 (23.8%) had grade 3-4 TRAE. There were no treatment-related deaths in this subpopulation. Pembrolizumab monotherapy was associated with antitumor activity in Japanese patients with ROC, with no new safety signals identified in this subpopulation. The data suggested a trend toward higher PD-L1 expression among some patients with higher ORR.

Antitumor activity and safety of pembrolizumab in patients with advanced recurrent ovarian cancer: results from the phase II KEYNOTE-100 study

BACKGROUND

Advanced recurrent ovarian cancer (ROC) is the leading cause of gynecologic cancer-related death in developed countries and new treatments are needed. Previous studies of immune checkpoint blockade showed low objective response rates (ORR) in ROC with no identified predictive biomarker.

PATIENTS AND METHODS

This phase II study of pembrolizumab (NCT02674061) examined two patient cohorts with ROC: cohort A received one to three prior lines of treatment with a platinum-free interval (PFI) or treatment-free interval (TFI) between 3 and 12 months and cohort B received four to six prior lines with a PFI/TFI of ≥3 months. Pembrolizumab 200 mg was administered intravenously every 3 weeks until cancer progression, toxicity, or completion of 2 years. Primary end points were ORR by Response Evaluation Criteria in Solid Tumors version 1.1 per blinded independent central review by cohort and by PD-L1 expression measured as combined positive score (CPS). Secondary end points included duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

Cohort A enrolled 285 patients; the first 100 served as the training set for PD-L1 biomarker analysis. Cohort B enrolled 91 patients. ORR was 7.4% for cohort A and 9.9% for cohort B. Median DOR was 8.2 months for cohort A and not reached for cohort B. DCR was 37.2% and 37.4%, respectively, in cohorts A and B. Based on the training set analysis, CPS 1 and 10 were selected for evaluation in the confirmation set. In the confirmation set, ORR was 4.1% for CPS <1, 5.7% CPS ≥1, and 10.0% for CPS ≥10. PFS was 2.1 months for both cohorts. Median OS was not reached for cohort A and was 17.6 months for cohort B. Toxicities were consistent with other single-agent pembrolizumab trials.

CONCLUSIONS

Single-agent pembrolizumab showed modest activity in patients with ROC. Higher PD-L1 expression was correlated with higher response.

CLINICAL TRIAL NUMBER

Clinicaltrials.gov, NCT02674061.