Prevalence and Heterogeneity of PD-L1 Expression by 22C3 Assay in Routine Population-Based and Reflexive Clinical Testing in Lung Cancer

PD-L1 expression in resected lung adenocarcinoma: prevalence and prognostic significance in relation to the IASLC grading system

AIMS

Programmed death-ligand 1 (PD-L1) expression is a predictive biomarker for adjuvant immunotherapy and has been linked to poor differentiation in lung adenocarcinoma. However, its prevalence and prognostic role in the context of the novel histologic grade has not been evaluated.

METHODS

We analysed a cohort of 1233 patients with resected lung adenocarcinoma where PD-L1 immunohistochemistry (22C3 assay) was reflexively tested. Tumour PD-L1 expression was correlated with the new standardized International Association for the Study of Lung Cancer (IASLC) histologic grading system (G1, G2, and G3). Clinicopathologic features including patient outcome were analysed.

RESULTS

PD-L1 was positive (≥1%) in 7.0%, 23.5%, and 63.0% of G1, G2, and G3 tumours, respectively. PD-L1 positivity was significantly associated with male sex, smoking, and less sublobar resection among patients with G2 tumours, but this association was less pronounced in those with G3 tumours. PD-L1 was an independent risk factor for recurrence (adjusted hazard ratio [HR] = 3.25, 95% confidence intervals [CI] = 1.93-5.48, P < 0.001) and death (adjusted HR = 2.69, 95% CI = 1.13-6.40, P = 0.026) in the G2 group, but not in the G3 group (adjusted HR for recurrence = 0.94, 95% CI = 0.64-1.40, P = 0.778).

CONCLUSION

PD-L1 expression differs substantially across IASLC grades and identifies aggressive tumours within the G2 subgroup. This knowledge may be used for both prognostication and designing future studies on adjuvant immunotherapy.

First-line Treatment Patterns and Outcomes in Advanced Non-Small Cell Lung Cancer in Sweden: A Population-based Real-world Study with Focus on Immunotherapy

BACKGROUND AND PURPOSE

The treatment landscape for patients with advanced non-small cell lung cancer (NSCLC) has evolved significantly since the introduction of immunotherapies. We here describe PD-L1 testing rates, treatment patterns, and real-world outcomes for PD-(L)1 inhibitors in Sweden.

MATERIALS AND METHODS

Data were obtained from the Swedish National Lung Cancer Registry for patients with advanced NSCLC and Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-2 who initiated first-line -systemic treatment from 01 April 2017 to 30 June 2020. PD-L1 testing was available in the registry from 01 January 2018. Kaplan-Meier was used for overall survival (OS) by type treatment and histology.

RESULTS

A total of 2,204 patients with pathologically confirmed unresectable stage IIIB/C or IV NSCLC initiated first-line treatment, 1,807 (82%) with nonsquamous (NSQ) and 397 (18%) with SQ. Eighty-six per cent (NSQ) or 85% (SQ) had been tested for PD-L1 expression, a proportion that increased over time. The use of platinum-based therapy as first-line treatment decreased substantially over time while there was an upward trend for PD-(L)1-based therapy. Among patients with PS 0-1 initiating a first-line PD-(L)1 inhibitor monotherapy, the median OS was 18.6 and 13.3 months for NSQ and SQ NSCLC patients, respectively, while for the PD-(L)1 inhibitor and chemotherapy combination regimen, the median OS was 24.0 months for NSQ and not evaluable for SQ patients.

INTERPRETATION

The majority of advanced NSCLCs in Sweden were tested for PD-L1 expression. Real-world OS in patients with PS 0-1 receiving first-line PD-(L)1 inhibitor-based regimens was similar to what has been reported in pivotal clinical trials on PD-(L)1 inhibitors.

Survival outcomes of targeted and immune consolidation therapies in locally advanced unresectable lung adenocarcinoma

BACKGROUND

Locally advanced non-small cell lung cancer (LA-NSCLC) presents unique challenges due to its progression and tumor heterogeneity. The effectiveness of consolidation therapies, particularly in patients with gene mutations, remains an area of active investigation.

METHODS

In this retrospective cohort study, we examined data from 3,454 patients with unresectable lung adenocarcinoma (LUAD), narrowing our focus to 242 individuals with stage II/III. We gathered patient data, such as demographics, ECOG status, histology, treatment specifics, and gene expression, from patients in China. The study's primary outcome was overall survival (OS), while progression-free survival (PFS) served as the secondary outcome.

RESULTS

In this study, 50 % of the 242 patients underwent only radical chemoradiotherapy, with 45.87 % (111/242) exhibiting driver gene mutations, predominantly EGFR (58.57 %), followed by KRAS and ALK. Patients with mutations who received either targeted or immune consolidation therapy demonstrated a significantly longer median PFS (42.97 months vs. 24.87 months, p = 0.014) and improved OS (not reached vs. 24.37 months, p = 0.006), compared to those without consolidation therapy. Targeted therapy in mutant patients resulted in an extended median PFS (42.87 months) compared to immune therapy (27.03 months, p = 0.029), with no significant difference in OS. Median PFS and OS were similar between mutant and wild-type patients receiving immune therapy (p = 0.380 and p = 0.928, respectively).

CONCLUSION

This study underscores the efficacy of targeted consolidation therapy in enhancing PFS in LUAD patients with genetic mutations. It also shows that immune consolidation therapy provides similar survival benefits to mutant and wild-type patients. Future research should focus on optimizing these therapies for improved patient outcomes.

Characterization of 164 patients with NRAS mutated non-small cell lung cancer (NSCLC)

BACKGROUND

NRAS mutations are observed in less than 1% of non-small cell lung cancer (NSCLC). Clinical data regarding this rare subset of lung cancer are scarce and response to systemic treatment such as chemotherapy or immune checkpoint inhibitors (ICI) has never been reported.

METHODS

All consecutive patients with an NRAS mutated NSCLC, diagnosed between August 2014 and November 2020 in 14 French centers, were included. Clinical and molecular data were collected and reviewed from medical records.

RESULTS

Out of the 164 included patients, 106 (64.6%) were men, 150 (91.5%) were current or former smokers, and 104 (63.4%) had stage IV NSCLC at diagnosis. The median age was 62 years, and the most frequent histology was adenocarcinoma (81.7%). NRAS activating mutations were mostly found in codon 61 (70%), while codon 12 and 13 alterations were observed in 16.5% and 4.9% of patients, respectively. Programmed death ligand-1 expression level <1%/1-49%/≥50% were respectively found in 30.8%/27.1%/42.1% of tumors. With a median follow-up of 12.5 months, median overall survival (OS) of stage IV patients was 15.3 months (95% CI 9.9-27.6). No significant difference in OS was found according to the type of mutation (codon 61 vs. other), HR = 1.12 (95% CI 0.65-1.95). Among stage IV patients treated with platinum-based doublet (n = 66), ICI (n = 48), or combination of both (n = 10), objective response rate, and median progression free survival were respectively 45% and 5.8 months, 35% and 6.9 months, 70% and 8.6 months.

CONCLUSION

NRAS mutated NSCLC are characterized by a high frequency of smoking history and codon 61 mutations. Further studies are needed to confirm the encouraging outcome of immunotherapy in combination with chemotherapy.

Real-world prevalence of PD-L1 expression in non-small cell lung cancer: an Australia-wide multi-centre retrospective observational study

An investigator-initiated, Australia-wide multi-centre retrospective observational study was undertaken to investigate the real-world prevalence of programmed death ligand-1 (PD-L1) expression in non-small cell lung carcinoma (NSCLC). Multiple centres around Australia performing PD-L1 immunohistochemistry (IHC) were invited to participate. Histologically confirmed NSCLC of any stage with a PD-L1 IHC test performed for persons aged ≥18 years between 1 January 2018 and 1 January 2020, and eligible for review, were identified at each centre, followed by data extraction and de-identification, after which data were submitted to a central site for collation and analysis. In total data from 6690 eligible PD-L1 IHC tests from histologically (75%) or cytologically (24%) confirmed NSCLC of any stage were reviewed from persons with a median age of 70 years, 43% of which were female. The majority (81%) of tests were performed using the PD-L1 IHC SP263 antibody with the Ventana BenchMark Ultra platform and 19% were performed using Dako PD-L1 IHC 22C3 pharmDx assay. Reported PD-L1 tumour proportion score (TPS) was ≥50% for 30% of all tests, with 62% and 38% scoring PD-L1 ≥1% and <1%, respectively. Relative prevalence of clinicopathological features with PD-L1 scores dichotomised to <50% and ≥50%, or to <1% and ≥1%, were examined. Females scored ≥1% slightly more often than males (64% vs 61%, respectively, p=0.013). However, there was no difference between sexes or age groups (<70 or ≥70 years) where PD-L1 scored ≥50%. Specimens from patients with higher stage (III/IV) scored ≥1% or ≥50% marginally more often compared to specimens from patients with lower stage (I/II) (p≤0.002). Proportions of primary and metastatic specimens did not differ where PD-L1 TPS was ≥1%, however more metastatic samples scored TPS ≥50% than primary samples (metastatic vs primary; 34% vs 27%, p<0.001). Cytology and biopsy specimens were equally reported, at 63% of specimens, to score TPS ≥1%, whereas cytology samples scored TPS ≥50% slightly more often than biopsy samples (34% vs 30%, respectively, p=0.004). Resection specimens (16% of samples tested) were reported to score TPS ≥50% or ≥1% less often than either biopsy or cytology samples (p<0.001). There was no difference in the proportion of tests with TPS ≥1% between PD-L1 IHC assays used, however the proportion of tests scored at TPS ≥50% was marginally higher for 22C3 compared to SP263 (34% vs 29%, respectively, p<0.001). These real-world Australian data are comparable to some previously published global real-world data, with some differences noted.

KRAS4A and KRAS4B in liquid biopsy of metastatic lung adenocarcinoma patients treated with Pembrolizumab or chemotherapy plus Pembrolizumab

KRAS is involved in the stability and expression of PD-L1. We investigated the expression of circulating mRNA (cmRNA) of KRAS4A and KRAS4B and the possible impact on progression-free survival (PFS) of patients with metastatic lung adenocarcinoma treated with immunotherapy. Patients without driver mutations undergoing Pembrolizumab (P) or P plus chemotherapy (PC) were prospectively accrued for liquid biopsy analysis of KRAS4A, KRAS4B, and PD-L1 cmRNA. Both KRAS isoforms were also studied for association with PD-L1 cmRNA. Of 56 patients, 28 received P and 28 PC. Patients with high levels of both KRAS isoforms showed significantly better PFS. The median PFS for KRAS4A was 29 months (95% CI 22-29 months) and KRAS4B 24 months (95% CI 13-29 months), respectively. The median PFS of patients with low levels of both isoforms was 12 months (95% CI 6-15 months for KRAS4A and 95% CI 5-20 months for KRAS4B). High KRAS4A retained a significant positive association with PFS in the multivariate model. An exploratory analysis in treatment subgroups found a positive association between high KRAS4A and KRAS4B with PFS in patients treated with P. PD-L1 cmRNA was significantly higher in patients with high KRAS isoforms levels and this effect was pronounced for high KRAS4A carriers. KRAS4A deserves further investigation as a potential marker for defining patients who may benefit the most from immune checkpoint inhibitors therapy and improving personalized cancer immunotherapeutic strategies.

Multi-omics analyses reveal spatial heterogeneity in primary and metastatic oesophageal squamous cell carcinoma

BACKGROUND

Biopsies obtained from primary oesophageal squamous cell carcinoma (ESCC) guide diagnosis and treatment. However, spatial intra-tumoral heterogeneity (ITH) influences biopsy-derived information and patient responsiveness to therapy. Here, we aimed to elucidate the spatial ITH of ESCC and matched lymph node metastasis (LNmet ).

METHODS

Primary tumour superficial (PTsup ), deep (PTdeep ) and LNmet subregions of patients with locally advanced resectable ESCC were evaluated using whole-exome sequencing (WES), whole-transcriptome sequencing and spatially resolved digital spatial profiling (DSP). To validate the findings, immunohistochemistry was conducted and a single-cell transcriptomic dataset was analysed.

RESULTS

WES revealed 15.72%, 5.02% and 32.00% unique mutations in PTsup , PTdeep and LNmet , respectively. Copy number alterations and phylogenetic trees showed spatial ITH among subregions both within and among patients. Driver mutations had a mixed intra-tumoral clonal status among subregions. Transcriptome data showed distinct differentially expressed genes among subregions. LNmet exhibited elevated expression of immunomodulatory genes and enriched immune cells, particularly when compared with PTsup (all P < .05). DSP revealed orthogonal support of bulk transcriptome results, with differences in protein and immune cell abundance between subregions in a spatial context. The integrative analysis of multi-omics data revealed complex heterogeneity in mRNA/protein levels and immune cell abundance within each subregion.

CONCLUSIONS

This study comprehensively characterised spatial ITH in ESCC, and the findings highlight the clinical significance of unbiased molecular classification based on multi-omics data and their potential to improve the understanding and management of ESCC. The current practices for tissue sampling are insufficient for guiding precision medicine for ESCC, and routine profiling of PTdeep and/or LNmet should be systematically performed to obtain a more comprehensive understanding of ESCC and better inform treatment decisions.

PD-L1 Expression by RNA-Sequencing in Non-Small Cell Lung Cancer: Concordance with Immunohistochemistry and Associations with Pembrolizumab Treatment Outcomes

Programmed cell death ligand (PD-L1) expression by immunohistochemistry (IHC) lacks sensitivity for pembrolizumab immunotherapy selection in non-small cell lung cancer (NSCLC), particularly for tumors with low expression. We retrospectively evaluated transcriptomic PD-L1 by mRNA next-generation sequencing (RNA-seq). In an unselected NSCLC patient cohort (n = 3168) tested during standard care (2017-2021), PD-L1 IHC and RNA-seq demonstrated moderate concordance, with 80% agreement overall. Most discordant cases were either low or negative for PD-L1 expression by IHC but high by RNA-seq. RNA-seq accurately discriminated PD-L1 IHC high from low tumors by receiver operator curve (ROC) analysis but could not distinguish PD-L1 IHC low from negative tumors. In a separate pembrolizumab monotherapy cohort (n = 102), NSCLC tumors classified as PD-L1 high versus not high by RNA-seq had significantly improved response, progression-free survival, and overall survival as an individual measure and in combination with IHC high or low status. PD-L1 IHC status (high or low) trended toward but had no significant associations with improved outcomes. Conventional PD-L1 IHC testing has inherent limitations, making it an imperfect reference standard for evaluating novel testing technologies. RNA-seq offers an objective PD-L1 measure that could represent a complementary method to IHC to improve NSCLC patient selection for immunotherapy.

Correlation of Programmed Death-Ligand 1 Expression With Lung Adenocarcinoma Histologic and Molecular Subgroups in Primary and Metastatic Sites

Programmed death-ligand 1 (PD-L1) expression in terms of the tumor proportion score (TPS) is the main predictive biomarker approved for immunotherapy against lung nonsmall cell carcinoma. Although some studies have explored the associations between histology and PD-L1 expression in pulmonary adenocarcinoma, they have been limited in sample size and/or extent of examined histologic variables, which may have resulted in conflicting information. In this observational retrospective study, we identified primary and metastatic lung adenocarcinoma cases in the span of 5 years and tabulated the detailed histopathologic features, including pathological stage, tumor growth pattern, tumor grade, lymphovascular and pleural invasion, molecular alterations, and the associated PD-L1 expression for each case. Statistical analyses were performed to detect associations between PD-L1 and these features. Among 1658 cases, 643 were primary tumor resections, 751 were primary tumor biopsies, and 264 were metastatic site biopsies or resections. Higher TPS significantly correlated with high-grade growth patterns, grade 3 tumors, higher T and N stage, presence of lymphovascular invasion, and presence of MET and TP53 alterations, whereas lower TPS correlated with lower-grade tumors and presence of EGFR alterations. There was no difference in PD-L1 expression in matched primary and metastases, although higher TPS was observed in metastatic tumors due to the presence of high-grade patterns in these specimens. TPS showed a strong association with a histologic pattern. Higher-grade tumors had higher TPS, which is also associated with more aggressive histologic features. Tumor grade should be kept in mind when selecting cases and blocks for PD-L1 testing.

In vivo detection of circulating tumor cells predicts high-risk features in patients with bladder cancer

Previous studies have suggested the potential diagnostic value of circulating tumor cells (CTCs). This study aims to validate the efficacy of in vivo detection of CTCs in bladder cancer (BC) patients. A total of 216 BC patients were enrolled in this study. All patients had one in vivo detection of CTCs before initial treatment as a baseline parameter. The results of CTCs were associated with different clinicopathological features including molecular subtypes. PD-L1 expression on CTCs was also assessed and compared with its expression on tumors. CTC positive was defined as > 2 CTCs detected. Among all 216 patients, 49 (23%) were detected as CTC positive (> 2 CTCs) at baseline. Positive detection of CTCs was associated with multiple high-risk clinicopathological features including the multiplicity of the tumor (P = 0.02), tumor size (P < 0.01), tumor stage (P < 0.01), tumor grade (P < 0.01) and tumor PD-L1 expression (P = 0.01). The expression of PD-L1 on tumor and CTCs were not coordinated. Only 55% (74/134) matched the same status of PD-L1 expression on tumor and CTCs, along with 56 CTC ⁽⁺⁾ Tissue ^(-) and 4 CTC ^(-) Tissue ⁽⁺⁾ (P < 0.01). Our study has demonstrated the efficacy of in vivo detection of CTCs. The positive detection of CTCs is associated with multiple clinicopathological features. PD-L1 expression on CTCs has the potential to be a supplementary biomarker for immunotherapy.

Spatial multi-omics revealed the impact of tumor ecosystem heterogeneity on immunotherapy efficacy in patients with advanced non-small cell lung cancer treated with bispecific antibody

BACKGROUND

Immunotherapy for malignant tumors has made great progress, but many patients do not benefit from it. The complex intratumoral heterogeneity (ITH) hindered the in-depth exploration of immunotherapy. Conventional bulk sequencing has masked intratumor complexity, preventing a more detailed discovery of the impact of ITH on treatment efficacy. Hence, we initiated this study to explore ITH at the multi-omics spatial level and to seek prognostic biomarkers of immunotherapy efficacy considering the presence of ITH.

METHODS

Using the segmentation strategy of digital spatial profiling (DSP), we obtained differential information on tumor and stromal regions at the proteomic and transcriptomic levels. Based on the consideration of ITH, signatures constructed by candidate proteins in different regions were used to predict the efficacy of immunotherapy.

RESULTS

Eighteen patients treated with a bispecific antibody (bsAb)-KN046 were enrolled in this study. The tumor and stromal areas of the same samples exhibited distinct features. Signatures consisting of 11 and 18 differentially expressed DSP markers from the tumor and stromal areas, respectively, were associated with treatment response. Furthermore, the spatially resolved signature identified from the stromal areas showed greater predictive power for bsAb immunotherapy response (area under the curve=0.838). Subsequently, our stromal signature was validated in an independent cohort of patients with non-small cell lung cancer undergoing immunotherapy.

CONCLUSION

We deciphered ITH at the spatial level and demonstrated for the first time that genetic information in the stromal region can better predict the efficacy of bsAb treatment.

TRIAL REGISTRATION NUMBER

NCT03838848.

Atypical Response in Metastatic Non-Small Cell Lung Cancer Treated with PD-1/PD-L1 Inhibitors: Radiographic Patterns and Clinical Value of Local Therapy

PURPOSE

To explore the clinical characteristics, management, and survival outcomes of advanced NSCLC patients treated with PD-1/PD-L1 inhibitors who presented with an atypical response (AR).

METHODS

A total of 926 PD-1/PD-L1-inhibitor-treated patients with metastatic NSCLC from three academic centers were retrospectively reviewed. All measurable lesions were evaluated by RECIST version 1.1.

RESULTS

Fifty-six (6.1%) patients developed AR. The median time to the occurrence of AR was 2.0 months. Patients with no fewer than 3 metastatic organs at baseline were more prone to develop AR in advanced NSCLC (p = 0.038). The common sites of progressive lesions were lymph nodes (33.8%) and lungs (29.7%). The majority (78.2%) of patients with AR had only 1-2 progressive tumor lesions, and most (89.1%) of the progressive lesions developed from originally existing tumor sites. There was no significance in terms of survival between patients with AR and those with typical response (TR). Local therapy was an independent predictor for PFS of patients with AR (p = 0.025).

CONCLUSIONS

AR was not an uncommon event in patients with metastatic NSCLC treated with PD-1/PD-L1 inhibitors, and it had a comparable prognosis to those with TR. Proper local therapy targeting progressive lesions without discontinuing original PD-1/PD-L1 inhibitors may improve patient survival.

Immune checkpoint therapy and response biomarkers in non-small-cell lung cancer: Serum NY-ESO-1 and XAGE1 antibody as predictive and monitoring markers

Immune checkpoint inhibitors (ICI) are key drugs in systemic therapy for advanced non-small-cell lung cancer (NSCLC) and have recently been incorporated into neoadjuvant and adjuvant settings for surgical resection. Currently, ICI combinations with cytotoxic agents are frequently used in clinical practice, although several ICI clinical trials have failed to produce long-term clinical benefits. Unfortunately, clinical benefit is moderate and limited considering physical and financial burden. Therefore, selecting appropriate patients and regimens for ICI therapy is important, and biomarkers are necessary for their selection. Tumor PD-L1 expression is universally used as a biomarker; however, PD-L1 assays show low analytical validity and reproducibility due to the visual-scoring system by pathologists. Recent tumor immunology studies explore that neoantigens derived from somatic mutations and the collaboration between T and B cells efficiently elicit antitumor responses. This suggests that high tumor mutational burden and T-cell infiltration are predictive biomarkers. However, B cells producing antibody (Ab) remain poorly understood and analyzed as biomarkers. We found that NY-ESO-1 and XAGE1 of cancer-testis antigen frequently elicit spontaneous humoral and cellular immune responses in NSCLC. Serum Ab against these antigens were detected in approximately 25% of NSCLC patients and predicted ICI monotherapy responses. In addition, the Ab levels were decreased with tumor shrinkage after ICI therapy. Thus, NY-ESO-1 and XAGE1 Ab are potentially biomarkers predicting and monitoring response to ICI therapy. For clinical applications, a fully-automated assay system measuring the Ab was developed. Here, we review current ICI therapy, tumor immunology, and biomarkers in NSCLC, and discuss the applicability of the serum biomarkers NY-ESO-1 and XAGE1 Ab.

Validation of E1L3N antibody for PD-L1 detection and prediction of pembrolizumab response in non-small-cell lung cancer

BACKGROUND

The programmed death-ligand 1 (PD-L1) 22C3 assay is one of the approved companion diagnostic assays for receiving anti-programmed cell death ligand 1 (PD-L1) therapy. Our study evaluated the performance of E1L3N and 22C3 antibodies in estimating PD-L1 expression in non-small cell lung cancer (NSCLC).

METHODS

Our retrospective study included 46 patients diagnosed with unresectable EGFR/ALK/ROS1-negative NSCLC who received first-line pembrolizumab therapy between 2018 and 2021. PD-L1 immunohistochemistry of baseline tissue biopsy samples was performed using PDL1-E1L3N and PDL1-22C3 antibodies. The concordance between the PD-L1 assays and the treatment outcomes was assessed.

RESULTS

Using a tumor proportion score (TPS) cutoff of ≥1%, 67.4% of patients are evaluated to be positive using PDL1-E1L3N and 73.9% using PDL1-22C3. Using a TPS of ≥50% as the cutoff, 26.1% of patients are positive using PDL1-E1L3N and 30.4% using PDL1-22C3. The PDL1-22C3 and PDL1-E1L3N assays are highly concordant and reveal a correlation coefficient of 0.925 (p < 0.0001). Patients with PDL1-E1L3N TPS > 50% have a significantly higher objective response rate than patients with PDL1-E1L3N TPS < 1% (p = 0.047), with a similar trend observed for PDL1-22C3 (p = 0.051). Consistent with PDL1-22C3, patients with higher PDL1-E1L3N expression (≥50%, 1-49%) have longer progression-free survival than those with PDL1-E1L3N TPS < 1%.

CONCLUSION

Our study provides clinical evidence on the concordance of PD-L1 TPS scores between clones E1L3N and 22C3. Moreover, the treatment responses to pembrolizumab are also comparable between the PDL1-E1L3N and PDL1-22C3. These findings indicate that E1L3N is a reliable and cost-effective assay and may serve as an alternative to 22C3.

Comparison of PD-L1 tumor cell expression with 22C3, 28-8, and SP142 IHC assays across multiple tumor types

BACKGROUND

Multiple PD-L1 immunohistochemistry (IHC) assays, including DAKO 22C3, DAKO 28-8, and Ventana SP142 PD-L1 IHC assays, have been approved by the Food and Drug Administration as a companion diagnostic (CDx) for various antiprogrammed death-1 and antiprogrammed death ligand 1 (PD-L1) based cancer immunotherapies. Here we present 22C3, 28-8, and SP142 analysis of 418 tumor specimens encountered in routine clinical practice.

METHODS

All specimens were tested with 22C3, 28-8, and SP142 assays following the manufacturer's established staining protocols.

RESULTS

The same PD-L1 status (defined as tumor cell expression (TC) scores with all three assays ≥1% or all &lt;1%) was observed in 60.0% (251/418) tumor specimens (45.9% (192/418) were triple negative and 14.1% (59/418) were triple positive). A total of 54.1% (226/418) tumor cases were positive with at least one IHC assay (94.2% (213/226), 77.0% (174/226), and 28.8% (65/226) of these were positive for 22C3, 28-8 and SP142, respectively). Among the 40.0% (167/418) tumor cases that showed a different PD-L1 status, 62.3% (104/167) were 22C3+/28-8+/SP142-, and 28.7% (48/167) were 22C3+/28-8-/SP142-. The same PD-L1 status with all three antibody clones was observed in 48.7% (97/199) of NSCLC cases, and among these, 54.6% (53/97) were triple negative and 45.4% (44/97) triple positive. A total of 73.4% (146/199) NSCLC cases were positive with at least one IHC assay (95.2% (n=139/146), 82.2% (n=120/146), and 32.2% (n=47/146) were positive for 22C3, 28-8, and SP142, respectively). Among the 51.3% (102/199) NSCLC cases that showed a different status among the three IHC assays, 67.6% (69/102) were 22C3+/28-8+/SP142-, and 23.5% (24/102) were 22C3+/28-8-/SP142-. A total of 81.1% (43/53) lung squamous cell carcinoma, 72.1% (88/122) of lung adenocarcinoma, 69.6% (16/23) of non-small cell lung cancer (NSCLC) not otherwise specified (NOS), and 50.0% (4/8) of small cell lung carcinoma cases were positive with at least one IHC assay.

CONCLUSIONS

Our data suggest that 22C3 is the most sensitive PD-L1 IHC assay for tumor cell expression, followed by 28-8 and in turn by SP-142. These findings represent an additional factor for clinical teams to consider when deciding which PD-L1 IHC assay (and in turn which CDx-associated PD-L1 based immunotherapy) is most appropriate for each individual patient.

Plasma-first: accelerating lung cancer diagnosis and molecular profiling through liquid biopsy

Introduction:

Molecular profiling of tumor tissue is the gold standard for treatment decision-making in advanced non-small cell lung cancer (NSCLC). Results may be delayed or unavailable due to insufficient tissue, prolonged wait times for biopsy, pathology assessment and testing. We piloted the use of plasma testing in the initial diagnostic workup for patients with suspected advanced lung cancer.

Methods:

Patients with ⩽15 pack-year smoking history and suspected advanced lung cancer referred to the lung cancer rapid diagnostic program underwent plasma circulating-tumor DNA testing using a DNA-based mutation panel. Tissue testing was performed per standard of care, including comprehensive next-generation sequencing (NGS). The primary endpoint was time from diagnostic program referral to cancer treatment in stage IV NSCLC patients (Cohort A) compared to a contemporary cohort not enrolled in the study (Cohort B) and an historical pre-COVID cohort referred to the program between 2018 and 2019 (Cohort C).

Results:

From January to June 2021, 20 patients were enrolled in Cohort A; median age was 70.5 years (range 33–87), 70% were female, 55% Caucasian, 85% never smokers, and 75% were diagnosed with NSCLC. Seven had actionable alterations detected in plasma or tissue (4/7 concordant). Fusions, not tested in plasma, were identified by immunohistochemistry for three patients. Mean result turnaround time was 17.8 days for plasma NGS and 23.6 days for tissue (p = 0.10). Mean time from referral to treatment initiation was significantly shorter in cohort A at 32.6 days (SD 13.1) versus 62.2 days (SD 31.2) in cohort B and 61.5 days (SD 29.1) in cohort C, both p < 0.0001.

Conclusion:

Liquid biopsy in the initial diagnostic workup of patients with suspected advanced NSCLC can lead to faster molecular results and shorten time to treatment even with smaller DNA panels. An expansion study using comprehensive NGS plasma testing with faster turnaround time is ongoing (NCT04862924).

Clinical validity and clinical utility of Ki67 in early breast cancer

Ki67 represents an immunohistochemical nuclear localized marker that is widely used in surgical pathology. Nuclear immunoreactivity for Ki67 indicates that cells are cycling and are in G1- to S-phase. The percentage of Ki67-positive tumor cells (Ki67 index) therefore provides an estimate of the growth fraction in tumor specimens. In breast cancer (BC), tumor cell proliferation rate is one of the most relevant prognostic markers and Ki67 is consequently helpful in prognostication similar to histological grading and mRNA profiling-based BC risk stratification. In BCs treated with short-term preoperative endocrine therapy, Ki67 dynamics enable distinguishing between endocrine sensitive and resistant tumors. Despite its nearly universal use in pathology laboratories worldwide, no internationally accepted consensus has yet been achieved for some methodological details related to Ki67 immunohistochemistry (IHC). Controversial issues refer to choice of IHC antibody clones, scoring methods, inter-laboratory reproducibility, and the potential value of computer-assisted imaging analysis and/or artificial intelligence for Ki67 assessment. Prospective clinical trials focusing on BC treatment have proven that Ki67, as determined by standardized central pathology assessment, is of clinical validity. Clinical utility has been demonstrated in huge observational studies.

From rough to precise: PD-L1 evaluation for predicting the efficacy of PD-1/PD-L1 blockades

Developing biomarkers for accurately predicting the efficacy of immune checkpoint inhibitor (ICI) therapies is conducive to avoiding unwanted side effects and economic burden. At the moment, the quantification of programmed cell death ligand 1 (PD-L1) in tumor tissues is clinically used as one of the combined diagnostic assays of response to anti-PD-1/PD-L1 therapy. However, the current assays for evaluating PD-L1 remain imperfect. Recent studies are promoting the methodologies of PD-L1 evaluation from rough to precise. Standardization of PD-L1 immunohistochemistry tests is being promoted by using optimized reagents, platforms, and cutoff values. Combining novel in vivo probes with PET or SPECT will probably be of benefit to map the spatio-temporal heterogeneity of PD-L1 expression. The dynamic change of PD-L1 in the circulatory system can also be realized by liquid biopsy. Consider PD-L1 expressed on non-tumor (immune and non-immune) cells, and optimized combination detection indexes are further improving the accuracy of PD-L1 in predicting the efficacy of ICIs. The combinations of artificial intelligence with novel technologies are conducive to the intelligence of PD-L1 as a predictive biomarker. In this review, we will provide an overview of the recent progress in this rapidly growing area and discuss the clinical and technical challenges.

Increased blood-based intratumor heterogeneity (bITH) is associated with unfavorable outcomes of immune checkpoint inhibitors plus chemotherapy in non-small cell lung cancer

BACKGROUND

The combination of immune checkpoint inhibitors (ICIs) and chemotherapy has been the standard first-line treatment for advanced non-small cell lung cancer (NSCLC) patients with driver-gene negative. However, efficacy biomarkers for ICIs-based combination therapy are lacking. We aimed to identify potential factors associated with outcomes of ICIs plus chemotherapy at baseline and dynamic changes in peripheral blood.

METHODS

We collected plasma samples of 51 advanced NSCLC patients without EGFR/ALK/ROS1 alteration at baseline and/or after two treatment cycles of ICIs plus chemotherapy. A blood-based intratumor heterogeneity (bITH) score was calculated based on the allele frequencies of somatic mutations using a 520-gene panel. bITH-up was defined as a ≥ 10% increase in bITH score from baseline, with a second confirmatory measurement after treatment.

RESULTS

At baseline, the number of metastatic organs and lung immune prognostic index (LIPI) were significantly associated with shorter progression-free survival (PFS) of ICIs plus chemotherapy, while bITH and other common molecular biomarkers, including ctDNA level, blood-based tumor mutational burden (bTMB), and PD-L1 expression, had no effect on PFS. LRP1B mutation at baseline was significantly associated with favorable outcomes to ICIs plus chemotherapy. There were 37 patients who had paired samples at baseline and after two cycles of treatment, with the median interval of 53 days. Intriguingly, patients with bITH-up had significant shorter PFS (HR, 4.92; 95% CI, 1.72-14.07; P = 0.001) and a lower durable clinical benefit rate (0 vs 41.38%, P = 0.036) than those with bITH-stable or down. Case studies indicated that bITH was promising to predict disease progression.

CONCLUSIONS

The present study is the first to report that increased bITH is associated with unfavorable outcomes of ICIs plus chemotherapy in advanced NSCLC patients.

PD-L1 assessment in cytology samples predicts treatment response to checkpoint inhibitors in NSCLC

BACKGROUND

Testing for tumor programmed death ligand-1 (PD-L1) expression was initially developed with histology specimens in non-small cell lung cancer (NSCLC). However, cytology specimens are widely used for primary diagnosis and biomarker studies in clinical practice. Limited clinical data exist on the predictiveness of cytology-derived PD-L1 scores for response to immune checkpoint inhibitor (ICI) therapy.

METHODS

We reviewed all NSCLC specimens clinically tested at the University Health Network (UHN) for PD-L1 with 22C3pharmDx, from 01/2013 to 04/2021. Treatment outcomes in patients treated with single agent ICI therapy were reviewed and compared according to cytology- and histology-derived PD-L1 scores.

RESULTS

We identified 494 and 1942 unique patients with cytology- and histology-derived tumor proportion scores, respectively, during the study period. Informative testing rates were 95 % vs 98 % for cytology and histology, respectively. Clinical data were available for 152 patients treated with single agent ICI: 61 cytology and 91 histology. Overall response rates (ORR) were similar for cytology and histology (36 % vs 34 %; p = 0.23), as well as median progression free survival (PFS) (4.9 vs 4.2 months; p = 0.99) and overall survival (23.4 vs 19.7 months; p = 0.99). The results remained similar even after adjusting for PD-L1 expression levels and line of ICI treatment (PFS HR 1.15; 95 %CI 0.78-1.70; p = 0.47).

CONCLUSIONS

Treatment outcomes to single agent ICI based on cytology-derived PD-L1 scores were comparable to histology controls. Our results support PD-L1 biomarker testing on both cytology and histology specimens.

Upfront Next Generation Sequencing in Non-Small Cell Lung Cancer

In advanced non-small cell lung cancer (NSCLC), patients with actionable genomic alterations may derive additional clinical benefit from targeted treatment compared to cytotoxic chemotherapy. Current guidelines recommend extensive testing with next generation sequencing (NGS) panels. We investigated the impact of using a targeted NGS panel (TruSight Tumor 15, Illumina) as reflex testing for NSCLC samples at a single institution. Molecular analysis examined 15 genes for hotspot mutation variants, including AKT1, BRAF, EGFR, ERBB2, FOXL2, GNA11, GNAQ, KIT, KRAS, MET, NRAS, PDGFRA, PIK3CA, RET and TP53 genes. Between February 2017 and October 2020, 1460 samples from 1395 patients were analyzed. 1201 patients (86.1%) had at least one variant identified, most frequently TP53 (47.5%), KRAS (32.2%) or EGFR (24.2%). Among these, 994 patients (71.3%) had clinically relevant variants eligible for treatment with approved therapies or clinical trial enrollment. The incremental cost of NGS beyond single gene testing (EGFR, ALK) was CAD $233 per case. Reflex upfront NGS identified at least one actionable variant in more than 70% of patients with NSCLC, with minimal increase in testing cost. Implementation of NGS panels remains essential as treatment paradigms continue to evolve.

PD-L1 Expression in Non-Small Cell Lung Cancer Specimens: Association with Clinicopathological Factors and Molecular Alterations

Immune checkpoint inhibitors (ICI) targeting programmed cell death-1 or its ligand (PD-L1) have improved outcomes in non-small cell lung cancer (NSCLC). High tumor PD-L1 expression, detected by immunohistochemistry (IHC) typically on formalin-fixed paraffin-embedded (FFPE) histological specimens, is linked to better response. Following our previous investigation on PD-L1 in cytological samples, the aim of this study was to further explore the potential impacts of various clinicopathological and molecular factors on PD-L1 expression. Two retrospective NSCLC cohorts of 1131 and 651 specimens, respectively, were investigated for PD-L1 expression (<1%/1−49%/≥50%), sample type, sample site, histological type, and oncogenic driver status. In both cohorts, PD-L1 was positive (≥1%) in 55% of the cases. Adenocarcinomas exhibited lower PD-L1 expression than squamous cell carcinomas (p < 0.0001), while there was no difference between sample types, tumor locations, or between the two cohorts in multivariate analysis (all p ≥ 0.28). Mutational status correlated significantly with PD-L1 expression (p < 0.0001), with the highest expression for KRAS-mutated cases, the lowest for EGFR-mutated, and the KRAS/EGFR wild-type cases in between. There was no difference in PD-L1 levels between different prevalent KRAS mutations (all p ≥ 0.44), while mucinous KRAS-mutated adenocarcinomas exhibited much lower PD-L1 expression than non-mucinous (p < 0.0001). Our data indicate that cytological and histological specimens are comparable for PD-L1 evaluation. Given the impact of KRAS mutations and the mucinous growth pattern on PD-L1 expression, these factors should be further investigated in studies on ICI response.

Distribution and concordance of PD-L1 expression by routine 22C3 assays in East-Asian patients with non-small cell lung cancer

Background

Currently, programmed death ligand-1 (PD-L1) expression has been widely applied in clinical trials and real-world clinical practice as a major biomarker for the efficacy of immune-checkpoint inhibitors. The purpose of this study is to reveal the distribution and concordance of PD-L1 expression in a large-scale consecutive cohort from East-Asian patients with non-small cell lung cancer (NSCLC).

Methods

PD-L1 testing was conducted using 22C3 assays, and cases were categorized into the high, low, and no expression of PD-L1 based on the tumor proportion score (TPS). Target-capture next-generation sequencing was used to identify molecular events.

Results

A total of 4550 patients and 4622 tests of PD-L1 expression were enrolled. There were 3017 (66.3%) patients with no PD-L1 expression (TPS < 1%), 1013 (22.3%) with low PD-L1 expression (TPS 1–49%), 520 (11.4%) with high PD-L1 expression (TPS ≥ 50%). Higher proportions of positive PD-L1 expression (TPS ≥ 1%) were observed in smokers, males, squamous cell carcinoma, and high-grade lung adenocarcinoma. Further analyses revealed fair agreement in primary and metastatic lesions (kappa = 0.533), poor agreement in multi-focal primary tumors (kappa = 0.045), and good agreement in biopsy and resection samples (kappa = 0.662) / two biopsy samples (kappa = 0.711). Mutational analyses revealed association between high PD-L1 expression (TPS ≥ 50%) and EGFR wild-type, KRAS mutation, ALK rearrangement, and TP53 mutation.

Conclusion

The study reveals the unique distribution pattern of PD-L1 expression in a large-scale East-Asian cohort with NSCLC, the concordance of multiple PD-L1 tests, and the association between PD-L1 expression and molecular events. The results shed a light on the optimization of PD-L1 testing in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02201-8.

The effect of neoadjuvant therapy on PD-L1 expression and CD8+lymphocyte density in non-small cell lung cancer

PD-L1 expression is the routine clinical biomarker for the selection of patients to receive immunotherapy in non-small cell lung cancer (NSCLC). However, the application and best timing of immunotherapy in the resectable setting is still under investigation. We aimed to study the effect of chemotherapy on PD-L1 expression and tumor infiltrating lymphocytes (TILs), which is to date still poorly understood. Our retrospective, single-centre neoadjuvant cohort comprised 96 consecutive patients with NSCLC resected 2000-2016 after neoadjuvant therapy, including paired diagnostic chemo-naïve specimens in 53 cases. A biologically matched surgical cohort of 114 primary resected cases was included. PD-L1 expression, CD8 + TILs density and tertiary lymphoid structures were assessed on whole slides and correlated with clinico-pathological characteristics and survival. Seven/53 and 12/53 cases had lower respectively higher PD-L1 expressions after neoadjuvant therapy. Most cases (n = 34) showed no changes in PD-L1 expression, the majority of these harboring PD-L1 < 1% in both samples (21/34 [61.8%]). Although CD8 + TILs density was significantly higher after chemotherapy (p = 0.031) in resections compared to diagnostic biopsies, this might be due to sampling and statistical bias. No difference in PD-L1 expression or CD8 + TILs density was detected when comparing the neoadjuvant and surgical cohort. In univariable analyses, higher CD8 + TILs density, higher numbers of tertiary lymphoid structures but not PD-L1 expression were significantly associated with longer survival. Increased PD-L1 expression after neoadjuvant chemotherapy was not significantly associated with shorter 5-year survival, but the number of cases was very low. In multivariable analysis, only pT category and age remained independent prognostic factors. In summary, PD-L1 expression was mostly unchanged after neoadjuvant chemotherapy compared to diagnostic biopsies. The sample size of cases with changed PD-L1 expression was too small to draw conclusions on any prognostic value.