•The treatment of advanced non–small cell lung cancer (NSCLC) represents a substantial unmet need.•The programmed death 1 (PD-1) was a promising target for novel therapies.•Approval of anti–PD-1 ...antibodies resulted in a paradigm shift in treatment.•Pembrolizumab has shown efficacy in both first- and second-line treatment of NSCLC.
Non–small cell lung cancer (NSCLC) is one of the most prevalent cancers and is responsible for a large proportion of all cancer-related deaths. Current treatment options are inadequate, reflecting a substantial unmet clinical need. Increasing knowledge regarding the mechanisms and genetic aberrations underlying tumor development and growth has heralded a new era of therapy in oncology, moving away from indiscriminate cytotoxic chemotherapy toward more finely focused, targeted medicine. The development of small-molecule drugs and monoclonal antibodies directed toward specific components of dysfunctional molecular or immune pathways, and mutated genes specific to particular cancer types, is leading the field to more personalized and less toxic treatment options, many of which have demonstrated greater efficacy and survival benefits than their chemotherapeutic counterparts. Particularly successful examples are agents that interfere with the programmed death 1 (PD-1) pathway, which many tumors can hijack to avoid immune surveillance and editing. Pembrolizumab, a monoclonal antibody directed at PD-1 that blocks the engagement between PD-1 and its ligands, has been explored as a treatment for solid tumors, and demonstrated survival benefits in several studies. The use of PD-1 inhibitors such as nivolumab and pembrolizumab in advanced cancers is widespread, and pembrolizumab is available in more than 60 countries for at least one of the following: advanced melanoma, PD-L1–expressing NSCLC, head and neck squamous cell carcinoma, and adult and pediatric patients with refractory classical Hodgkin’s lymphoma. This work provides a brief overview of the role of pembrolizumab in the treatment of advanced (recurrent/metastatic) NSCLC.
The 2021 WHO Classification of Thoracic Tumours was published earlier this year, with classification of lung tumors being one of the chapters. The principles remain those of using morphology first, ...supported by immunohistochemistry, and then molecular techniques. In 2015, there was particular emphasis on using immunohistochemistry to make classification more accurate. In 2021, there is greater emphasis throughout the book on advances in molecular pathology across all tumor types. Major features within this edition are (1) broader emphasis on genetic testing than in the 2015 WHO Classification; (2) a section entirely dedicated to the classification of small diagnostic samples; (3) continued recommendation to document percentages of histologic patterns in invasive nonmucinous adenocarcinomas, with utilization of these features to apply a formal grading system, and using only invasive size for T-factor size determination in part lepidic nonmucinous lung adenocarcinomas as recommended by the eighth edition TNM classification; (4) recognition of spread through airspaces as a histologic feature with prognostic significance; (5) moving lymphoepithelial carcinoma to squamous cell carcinomas; (6) update on evolving concepts in lung neuroendocrine neoplasm classification; (7) recognition of bronchiolar adenoma/ciliated muconodular papillary tumor as a new entity within the adenoma subgroup; (8) recognition of thoracic SMARCA4-deficient undifferentiated tumor; and (9) inclusion of essential and desirable diagnostic criteria for each tumor.
The approval of anti-programmed death receptor (PD)-1 therapies for non-small cell lung cancer has directed the spotlight on programmed death ligand-1 (PD-L1) immunohistochemistry as the latest ...predictive biomarker potentially required in this disease. Several other drugs in this class will likely be approved in the future and each has been developed with a unique anti-PD-L1 immunohistochemistry test. The prospect of 5 drugs competing in the same treatment area, each possibly requiring PD-L1 immunohistochemistry testing, presents a challenge for pathologists unlike any previously faced. The key issue is whether laboratories will attempt to deliver the trial-validated assays for one or more of these treatments, or introduce instead one or more laboratory developed tests, or attempt to provide a single PD-L1 immunohistochemistry assay for all possible anti-PD-1 and anti-PD-L1 treatments that may be used. This paper discusses some of the issues, challenges, hazards, and possible solutions that have recently emerged in this most complex interface between cancer therapeutics and laboratory biomarker testing.
The Blueprint Programmed Death Ligand 1 (PD-L1) Immunohistochemistry (IHC) Assay Comparison Project is an industrial-academic collaborative partnership to provide information on the analytical and ...clinical comparability of four PD-L1 IHC assays used in clinical trials.
A total of 39 NSCLC tumors were stained with four PD-L1 IHC assays (22C3, 28-8, SP142, and SP263), as used in the clinical trials. Three experts in interpreting their respective assays independently evaluated the percentages of tumor and immune cells staining positive at any intensity. Clinical diagnostic performance was assessed through comparisons of patient classification above and below a selected expression cutoff and by agreement using various combinations of assays and cutoffs.
Analytical comparison demonstrated that the percentage of PD-L1–stained tumor cells was comparable when the 22C3, 28-8, and SP263 assays were used, whereas the SP142 assay exhibited fewer stained tumor cells overall. The variability of immune cell staining across the four assays appears to be higher than for tumor cell staining. Of the 38 cases, 19 (50.0%) were classified above and five (13%) were classified below the selected cutoffs of all assays. For 14 of the 38 cases (37%), a different PD-L1 classification would be made depending on which assay/scoring system was used.
The Blueprint PD-L1 IHC Assay Comparison Project revealed that three of the four assays were closely aligned on tumor cell staining whereas the fourth showed consistently fewer tumor cells stained. All of the assays demonstrated immune cell staining, but with greater variability than with tumor cell staining. By comparing assays and cutoffs, the study indicated that despite similar analytical performance of PD-L1 expression for three assays, interchanging assays and cutoffs would lead to “misclassification” of PD-L1 status for some patients. More data are required to inform on the use of alternative staining assays upon which to read different specific therapy-related PD-L1 cutoffs.
•Molecular testing determines appropriate targeted therapies for advanced NSCLC.•Country-specific differences exist in molecular testing availability across Europe.•Molecular tumour board and reflex ...molecular testing strategies are desirable.•Next-generation sequencing permits comprehensive molecular testing.•Cell-free DNA-based analysis facilitates re-testing to guide subsequent treatment.
The discovery of oncogenic driver mutations rendering non-small cell lung cancer (NSCLC) targetable by small-molecule inhibitors, and the development of immunotherapies, have revolutionised NSCLC treatment. Today, instead of non-selective chemotherapies, all patients with advanced NSCLC eligible for treatment (and increasing numbers with earlier, less extensive disease) require fast and comprehensive screening of biomarkers for first-line patient selection for targeted therapy, chemotherapy, or immunotherapy (with or without chemotherapy). To avoid unnecessary re-biopsies, biomarker screening before first-line treatment should also include markers that are actionable from second-line onwards; PD-L1 expression testing is also mandatory before initiating treatment.
Population differences exist in the frequency of oncogenic driver mutations: EGFR mutations are more frequent in Asia than Europe, whereas the converse is true for KRAS mutations. In addition to approved first-line therapies, a number of emerging therapies are being investigated in clinical trials. Guidelines for biomarker testing vary by country, with the number of actionable targets and the requirement for extensive molecular screening strategies expected to increase. To meet diagnostic demands, rapid screening technologies for single-driver mutations have been implemented. Improvements in DNA- and RNA-based next-generation sequencing technologies enable analysis of a group of genes in one assay; however, turnaround times remain relatively long. Consequently, rapid screening technologies are being implemented alongside next-generation sequencing.
Further challenges in the evolving landscape of biomarker testing in NSCLC are actionable primary and secondary resistance mechanisms to targeted therapies. Therefore, comprehensive testing on re-biopsies, collected at the time of disease progression, in combination with testing of circulating tumour DNA may provide important information to guide second- or third-line therapies. Furthermore, longitudinal biomarker testing can provide insights into tumour evolution and heterogeneity during the course of the disease. We summarise best practice strategies for Europe in the changing landscape of biomarker testing at diagnosis and during treatment.
Although most primary cancers of the lung carry a heavy mutational load and will potentially present many "nonself" antigens to the immune system, there are a wide range of possible mechanisms for ...tumors to avoid so-called immune surveillance. One such mechanism is the adoption of immune checkpoints to inhibit the host immune response. Immune checkpoint inhibitors show great promise in the treatment of advanced non-small cell lung cancer.
To discuss the possibility of biomarker selection of patients for these therapies. This is becoming a much debated issue, and the immunohistochemical detection of Programmed Death Ligand 1 (PD-L1), the ligand for the inhibitory Programmed Death receptor 1 (PD-1) checkpoint, is one possible biomarker. Data so far available show some conflicting results, but PD-L1 immunohistochemistry looks likely to be introduced into clinical use for selecting patients for treatment with anti-PD-1 or anti-PD-L1 therapies. Given that there are 4 such drugs rapidly approaching regulatory approval, each with its own independent PD-L1 immunohistochemistry biomarker test, both oncologists and pathologists face some significant challenges.
Peer-reviewed literature and meeting proceedings, especially during the last 12 months, were used.
The biology of PD-1/PD-L1 is complex, the clinical data for these drugs show considerable variation, the selection performance of the PD-L1 biomarker test is not perfect, and the existence of 4 drug/test combinations adds significantly to the problems faced. This article addresses some of the background to this therapeutic problem and discusses some of the issues ahead.
Immune-checkpoint inhibitors targeting PD-1 or PD-L1 have already substantially improved the outcomes of patients with many types of cancer, although only 20-40% of patients derive benefit from these ...new therapies. PD-L1, quantified using immunohistochemistry assays, is currently the most widely validated, used and accepted biomarker to guide the selection of patients to receive anti-PD-1 or anti-PD-L1 antibodies. However, many challenges remain in the clinical use of these assays, including the necessity of using different companion diagnostic assays for specific agents, high levels of inter-assay variability in terms of both performance and cut-off points, and a lack of prospective comparisons of how PD-L1
disease diagnosed using each assay relates to clinical outcomes. In this Review, we describe the current role of PD-L1 immunohistochemistry assays used to inform the selection of patients to receive anti-PD-1 or anti-PD-L1 antibodies, we discuss the various technical and clinical challenges associated with these assays, including regulatory issues, and we provide some perspective on how to optimize PD-L1 as a selection biomarker for the future treatment of patients with solid tumours.
The Blueprint (BP) Programmed Death Ligand 1 (PD-L1) Immunohistochemistry Comparability Project is a pivotal academic/professional society and industrial collaboration to assess the feasibility of ...harmonizing the clinical use of five independently developed commercial PD-L1 immunohistochemistry assays. The goal of BP phase 2 (BP2) was to validate the results obtained in BP phase 1 by using real-world clinical lung cancer samples.
BP2 were conducted using 81 lung cancer specimens of various histological and sample types, stained with all five trial-validated PD-L1 assays (22C3, 28-8, SP142, SP263, and 73-10); the slides were evaluated by an international panel of pathologists. BP2 also assessed the reliability of PD-L1 scoring by using digital images, and samples prepared for cytological examination. PD-L1 expression was assessed for percentage (tumor proportional score) of tumor cell (TC) and immune cell areas showing PD-L1 staining, with TCs scored continuously or categorically with the cutoffs used in checkpoint inhibitor trials.
The BP2 results showed highly comparable staining by the 22C3, 28-8 and SP263 assays; less sensitivity with the SP142 assay; and higher sensitivity with the 73-10 assay to detect PD-L1 expression on TCs. Glass slide and digital image scorings were highly concordant (Pearson correlation >0.96). There was very strong reliability among pathologists in TC PD-L1 scoring with all assays (overall intraclass correlation coefficient ICC = 0.86–0.93), poor reliability in IC PD-L1 scoring (overall ICC = 0.18–0.19), and good agreement in assessing PD-L1 status on cytological cell block materials (ICC = 0.78–0.85).
BP2 consolidates the analytical evidence for interchangeability of the 22C3, 28-8, and SP263 assays and lower sensitivity of the SP142 assay for determining tumor proportion score on TCs and demonstrates greater sensitivity of the 73-10 assay compared with that of the other assays.
Kerr K M (2011) Histopathology 60, 531–546 Personalized medicine for lung cancer: new challenges for pathology
Recent advances in non‐small‐cell lung cancer (NSCLC) therapy mean the relatively ...simple discrimination between small‐cell and ‘non‐small‐cell’ carcinoma is insufficient to determine the best treatment for individual patients. Safety, efficacy and prescribing requirements mandate more specific subtyping of NSCLC for several new drugs: practice made difficult by the tumour heterogeneity combined with the paucity of tissue in most diagnostic samples. Immunohistochemical approaches have emerged as accurate predictors of probable tumour histotype. P63 and/or cytokeratins 5 and 6 and thyroid transcription factor 1 (TTF1) are among the best predictors, respectively, of squamous and adenocarcinoma histology. Molecular characteristics may predict response to both newer molecular targeted agents and traditional cytotoxic agents. Specific mutations in the epidermal growth factor receptor (EGFR) gene as predictors of response to EGFR tyrosine kinase inhibitors (erlotinib, gefitinib) is the first example of markers which predict response to targeted agents. Actual drug targets e.g. thymidilate synthase (TS) – pemetrexed or markers of the tumour’s ability to repair cytotoxic drug‐induced damage e.g. excision repair cross‐complementation group 1 (ERCC1) – cisplatin may well also complement NSCLC diagnosis. This extended diagnostic requirement from increasingly limited material provided by minimally invasive biopsy techniques poses major challenges for pathology.
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