Reproducibility of PD-L1 assessment in non-small cell lung cancer-know your limits but never stop trying to exceed them

WhARIO: whole-slide-image-based survival analysis for patients treated with immunotherapy

Purpose

Immune checkpoint inhibitors (ICIs) are now one of the standards of care for patients with lung cancer and have greatly improved both progression-free and overall survival, although < 20 % of the patients respond to the treatment, and some face acute adverse events. Although a few predictive biomarkers have integrated the clinical workflow, they require additional modalities on top of whole-slide images and lack efficiency or robustness. In this work, we propose a biomarker of immunotherapy outcome derived solely from the analysis of histology slides.

Approach

We develop a three-step framework, combining contrastive learning and nonparametric clustering to distinguish tissue patterns within the slides, before exploiting the adjacencies of previously defined regions to derive features and train a proportional hazards model for survival analysis. We test our approach on an in-house dataset of 193 patients from 5 medical centers and compare it with the gold standard tumor proportion score (TPS) biomarker.

Results

On a fivefold cross-validation (CV) of the entire dataset, the whole-slide image-based survival analysis for patients treated with immunotherapy (WhARIO) features are able to separate a low- and a high-risk group of patients with a hazard ratio (HR) of 2.29 (CI 95 = 1.48 to 3.56), whereas the TPS 1% reference threshold only reaches a HR of 1.81 (CI 95 = 1.21 to 2.69). Combining the two yields a higher HR of 2.60 (CI 95 = 1.72 to 3.94). Additional experiments on the same dataset, where one out of five centers is excluded from the CV and used as a test set, confirm these trends.

Conclusions

Our uniquely designed WhARIO features are an efficient predictor of survival for lung cancer patients who received ICI treatment. We achieve similar performance to the current gold standard biomarker, without the need to access other imaging modalities, and show that both can be used together to reach even better results.

c-Met immunohistochemistry as reflex test at diagnosis for non-small cell lung cancer: a real-world experience from a monocentric case series

AIMS

Recent clinical trials have shown promising results with drugs targeting the hepatocyte growth factor receptor (c-Met) for advanced non-small cell lung cancers overexpressing c-Met. We assessed reflex testing of c-Met immunohistochemistry (IHC) at diagnosis for NSCLC in the real-world.

METHODS

We retrospectively collected clinical, pathological and molecular data of cases diagnosed with NSCLC in our institution from January 2021 to June 2023. We performed c-Met IHC (SP44 clone) and scored the expression using a H-score and a three-tier classification.

RESULTS

391 cases with interpretable c-Met IHC staining were included. The median age at diagnosis was 70 years (range 25-89 years) including 234 males (male/female ratio 1:5). 58% of the samples came from surgical resections, 35% from biopsies and 8% from cytological procedures. 52% of cases were classified as c-Met-positive (H-score≥150) and 19% were classified as c-Methigh (≥50%, 3+). 43% of the c-Metneg presented with lymph node and/or visceral metastases at diagnosis vs 55% for c-Methigh (p=0.042). 23% of the adenocarcinomas showed c-Methigh expression vs 3% for squamous cell carcinomas (p=0.004). 27% of the c-Metneg cases had a high PD-L1 expression vs 58% of c-Methigh cases (p<0.001). MET ex14 skipping was present in 8% of the c-Methigh cases.

CONCLUSIONS

Systematic c-Met testing in daily routine for NSCLC patients is feasible, highlighting a potential correlation with clinicopathological and molecular features.

Transcriptional and post-transcriptional regulation of checkpoint genes on the tumour side of the immunological synapse

Cancer is a disease of the genome, therefore, its development has a clear Mendelian component, demonstrated by well-studied genes such as BRCA1 and BRCA2 in breast cancer risk. However, it is known that a single genetic variant is not enough for cancer to develop leading to the theory of multistage carcinogenesis. In many cases, it is a sequence of events, acquired somatic mutations, or simply polygenic components with strong epigenetic effects, such as in the case of brain tumours. The expression of many genes is the product of the complex interplay between several factors, including the organism’s genotype (in most cases Mendelian-inherited), genetic instability, epigenetic factors (non-Mendelian-inherited) as well as the immune response of the host, to name just a few. In recent years the importance of the immune system has been elevated, especially in the light of the immune checkpoint genes discovery and the subsequent development of their inhibitors. As the expression of these genes normally suppresses self-immunoreactivity, their expression by tumour cells prevents the elimination of the tumour by the immune system. These discoveries led to the rapid growth of the field of immuno-oncology that offers new possibilities of long-lasting and effective treatment options. Here we discuss the recent advances in the understanding of the key mechanisms controlling the expression of immune checkpoint genes in tumour cells.

Multiplex Immunofluorescence and Multispectral Imaging: Forming the Basis of a Clinical Test Platform for Immuno-Oncology

As immuno-oncology (I/O) emerges as an effective approach in the fight against cancer, multispectral imaging of multiplex immunofluorescence (mIF) is maturing as an analytical platform. The timing is fortuitous. Due to health economic considerations surrounding the use of I/O, there is an urgent need for tests that accurately predict response to the growing list of available therapies. Multispectral mIF provides several advantages over other biomarker modalities by enabling deeper interrogation of the intricate biology within the tumor microenvironment, including detection of cell-to-cell spatial interactions that correlate with clinical outcomes. It also provides a practical path for generating reliable and reproducible results in a clinically suitable, high-throughput workflow. In this article, we (1) describe the principles behind multispectral mIF; (2) provide advice and recommendations on assay development and optimization and highlight characteristics of a well-performing assay; and (3) discuss the requirements for translating this approach into clinical practice.

Prospective evaluation of EBUS-TBNA specimens for programmed death-ligand 1 expression in non-small cell lung cancer patients: a pilot study

OBJECTIVE

EBUS-TBNA cytological sampling is routinely performed for pathological diagnosis, mediastinal staging, and molecular testing in lung cancer patients. EBUS-TBNA samples are not formally accepted for testing programmed death-ligand 1 (PD-L1) expression. The objective of the study was to compare the feasibility, reproducibility, and accuracy of PD-L1 expression assessment in cytological specimens and histological samples.

METHODS

We prospectively collected histological (transbronchial forceps biopsy) and cytological (EBUS-TBNA) samples from peribronchial neoplastic lesions during an endoscopic procedure at the same target lesion for the pathological diagnosis and molecular assessment of stage IV non-small cell lung cancer (NSCLC).

RESULTS

Fifteen patients underwent the procedure. Adequate cytological samples (at least 100 neoplastic cells) were obtained in 12 cases (92.3%). Assessment of PD-L1 expression was similar between histological and cytological samples (agreement rate = 92%). Sensitivity and diagnostic accuracy of EBUS-TBNA cytological specimens were 88.9% and 100%, respectively.

CONCLUSIONS

The evaluation of PD-L1 expression in EBUS-TBNA cytological specimens is feasible and presents good reproducibility when compared with routine histological samples. EBUS-TBNA cytological samples could be used for the assessment of PD-L1 expression in patients with NSCLC as a minimally invasive approach in stage IV NSCLC cancer patients.

Transcriptional Spatial Profiling of Cancer Tissues in the Era of Immunotherapy: The Potential and Promise

Intratumoral heterogeneity poses a major challenge to making an accurate diagnosis and establishing personalized treatment strategies for cancer patients. Moreover, this heterogeneity might underlie treatment resistance, disease progression, and cancer relapse. For example, while immunotherapies can confer a high success rate, selective pressures coupled with dynamic evolution within a tumour can drive the emergence of drug-resistant clones that allow tumours to persist in certain patients. To improve immunotherapy efficacy, researchers have used transcriptional spatial profiling techniques to identify and subsequently block the source of tumour heterogeneity. In this review, we describe and assess the different technologies available for such profiling within a cancer tissue. We first outline two well-known approaches, in situ hybridization and digital spatial profiling. Then, we highlight the features of an emerging technology known as Visium Spatial Gene Expression Solution. Visium generates quantitative gene expression data and maps them to the tissue architecture. By retaining spatial information, we are well positioned to identify novel biomarkers and perform computational analyses that might inform on novel combinatorial immunotherapies.

Economic Burden of Checkpoint Inhibitor Immunotherapy for the Treatment of Non-Small Cell Lung Cancer in US Clinical Practice

PURPOSE

The efficacy of checkpoint inhibitor (CPI) immunotherapy in patients with non-small cell lung cancer (NSCLC) is limited by a lack of strongly predictive response markers, subjecting patients to potential underutilization of alternative effective treatments, increased risk for futile care, and unnecessary costs. Here, we characterize the extent to which basic molecular tumor-marker testing has been performed for NSCLC therapy selection in the United States, and compare medical resource utilization and costs in CPI-treated patients versus CPI-eligible patients treated with other therapies.

METHODS

We identified a cohort of CPI-treated patients with NSCLC and a propensity score-matched cohort of CPI-eligible patients with NSCLC treated with non-CPI therapies (3095 patients in each group), using US administrative claims data covering the pre- and postinitial FDA-approval period for nivolumab, pembrolizumab, and atezolizumab (October 2012 to September 2017). We describe the utilization of recommended baseline molecular testing for CPI selection (pre-index date for CPI or other anticancer therapy), including programmed death ligand 1 (PD-L1) immunohistochemistry, ALK rearrangement and EGFR mutation testing, and pre- and postindex treatment patterns. All-cause medical resource utilization and semiannual total reimbursement (costs) were compared between CPI-treated and non-CPI-treated patients.

FINDINGS

At baseline, in the propensity score-matched CPI- and non-CPI-treated patient cohorts, mean PD-L1 immunohistochemistry test utilization for CPI selection was moderate (0.6 vs 0.7 per patient, respectively). However, we observed much lower mean utilization of testing for EGFR mutations (0.1 vs 0.1 per patient) and ALK rearrangements (0.1 vs 0.2 per patient). Postindex, the use of both chemotherapy and ALK- and EGFR-targeted therapies were decreased in both cohorts. The CPI-treated group had significantly higher mean medical resource utilization in nearly all categories in the postindex period, and total per-patient semiannual costs, than did the CPI-eligible patients who received other therapies (141,537 vs 75,429 US dollars [USD]; P < 0.0001), driven by CPI drug reimbursement. Median (interquartile range) time on CPI was longest with pembrolizumab (113 [106-127] days), followed by nivolumab (105 [97-106] days) and atezolizumab (64 [50-85] days). Despite being associated with the lowest drug cost and the shortest treatment duration, atezolizumab was associated with the highest mean total per-patient semiannual costs (160,540 USD) compared with pembrolizumab (153,003 USD) and nivolumab (138,542 USD).

IMPLICATIONS

The advent of CPI treatment for NSCLC has added substantial care-related costs for patients and payers, concurrent with underutilization of minimum recommended molecular testing for therapy selection. Broad uptake of panel-based comprehensive targeted-therapy and immunotherapy profiling can promote optimal treatment selection and sequencing, reduce the likelihood of futile treatment, and further improve patient outcomes.

Implementation of PD-L1 22C3 IHC pharmDxTM in Cell Block Preparations of Lung Cancer: Concordance with Surgical Resections and Technical Validation of CytoLyt® Prefixation

BACKGROUND

Programmed death ligand-1 (PD-L1) assessed by immunohistochemistry (IHC) is used as biomarker for pembrolizumab therapy in advanced stage lung cancer patients. However, data permitting direct performance comparison between cytology and surgical specimen types are limited since both specimens from a single tumor site are infrequently available. In addition, alcohol fixation used with cytology specimens requires technical validation of the PD-L1 IHC assay before clinical use. We here report our experience with implementation of the PD-L1 22C3 IHC pharmDxTM assay for cytologic samples at a large tertiary cancer center.

STUDY DESIGN

Archival formalin-fixed (FF), paraffin-embedded cell blocks (CBs) and subsequent lung tumor resections (LTRs) from the same anatomical site were used for a direct comparison of PD-L1 tumor proportion scores (TPSs). TPS values were independently determined by one surgical lung pathologist and two cytopathologists blinded to the specimen pairs. An interim analysis was performed to facilitate the pooling of expertise among observers. After PD-L1 22C3 IHC pharmDxTM implementation for FF cytology specimens, dual-processed samples were used for a prospective technical validation of CytoLyt® prefixation (CF). Digital image analysis was performed for a subset of dual-processed specimens.

RESULTS

Eighty-one CBs and LTRs were included for comparison of the specimen types. PD-L1 assessment in CBs had an accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 88.9/72.8, 66.7/73.5, 95.2/72.3, 80.0/65.8, and 90.9/79.1% for the ≥50/≥1% cutoff, respectively. The intraclass correlation coefficient was 0.84 (95% confidence interval [CI]: 0.76, 0.90), and it improved after interim analysis (before: 0.79 and after: 0.92). The overall concordance between CF and FF for the categories defined by the ≥50/≥1% cutoff values was 90.4% (95% CI: 79.0, 96.8). Similar assay performance was confirmed by digital analysis.

CONCLUSIONS

PD-L1 22C3 IHC pharmDxTM shows good reliability if used with CB preparations. CF does not impact assay results significantly. Clinical validation with outcome data is needed, and digital methods of assessment should be further investigated.

PD-L1 Expression and Clinical Outcomes to Cabozantinib, Everolimus, and Sunitinib in Patients with Metastatic Renal Cell Carcinoma: Analysis of the Randomized Clinical Trials METEOR and CABOSUN

PURPOSE

Programmed death-ligand 1 (PD-L1) status by IHC is prognostic in metastatic renal cell carcinoma (mRCC), and its role as a potential predictive biomarker is under investigation. Using tumor tissue from the METEOR (NCT01865747) and CABOSUN (NCT01835158) clinical trials, we explored whether PD-L1 expression and the extent of the immune cell infiltrate can serve as prognostic and/or predictive biomarkers for cabozantinib and other targeted agents.

EXPERIMENTAL DESIGN

IHC double staining for PD-L1 and CD45/CD163 (immune cell markers) was performed on tumor tissue from METEOR (n = 306) and CABOSUN (n = 110) clinical trials. Immune cell density and MET expression levels were also analyzed. Our primary aim was to correlate progression-free survival (PFS) by independent central review with PD-L1 status in patients treated with cabozantinib, everolimus (METEOR), or sunitinib (CABOSUN). Overall survival (OS) was also interrogated.

RESULTS

Tumor cell (TC) PD-L1 expression (≥1% cutoff) was detected in 29% and 23% of tumors from patients in the METEOR and CABOSUN trials, respectively. On univariate analysis, patients with PD-L1-positive TC had poorer PFS and OS than patients with PD-L1-negative TC on both trials, independent of therapy. On multivariable analysis and when combining the two trials, the association between TC PD-L1 expression and OS was statistically significant for all patients (P = 0.034) and for patients treated with cabozantinib only (P = 0.038). Cabozantinib was associated with improved PFS (HR < 0.70) and OS (HR < 0.85) compared with everolimus and sunitinib irrespective of PD-L1 expression.

CONCLUSIONS

Higher PD-L1 expression results in worse clinical outcomes in mRCC treated with targeted therapy. Furthermore, PD-L1 expression is not predictive of response to cabozantinib therapy.

Using 22C3 Anti-PD-L1 Antibody Concentrate on Biopsy and Cytology Samples from Non-small Cell Lung Cancer Patients

Pembrolizumab monotherapy has been approved for the first- and second-line treatment of patients with PD-L1-expressing advanced non-small cell lung cancer (NSCLC). Testing for PD-L1 expression with the PD-L1 immunohistochemistry (IHC) 22C3 companion diagnostic assay, which gives a tumor proportion score (TPS), has been validated on tumor tissue. We developed an optimized laboratory-developed test (LDT) that uses the 22C3 antibody (Ab) concentrate on a widely available IHC autostainer for biopsy and cytology specimens. The PD-L1 TPS was evaluated with 120 paired whole-tumor tissue sections and biopsy samples and with 70 paired biopsy and cytology samples (bronchial washes, n = 40; pleural effusions, n = 30). The 22C3 Ab concentrate-based LDT showed a high concordance rate between biopsy (~100%) and cytology (~95%) specimens when compared to PD-L1 IHC expression determined using the PD-L1 IHC 22C3 companion assay at both TPS cut points (≥1%, ≥50%). The optimized LDT presented here, using the 22C3 Ab concentrate to determine the PD-L1 expression in both tumor tissue and in cytology specimens, will expand the ability of laboratories worldwide to assess the eligibility of patients with NSCLC for treatment with pembrolizumab monotherapy in a reliable and reproducible manner.