An FDA Perspective on the Regulatory Implications of Complex Signatures to Predict Response to Targeted Therapies

Defining clinically useful biomarkers of immune checkpoint inhibitors in solid tumours

Although more than a decade has passed since the approval of immune checkpoint inhibitors (ICIs) for the treatment of melanoma and non-small-cell lung, breast and gastrointestinal cancers, many patients still show limited response. US Food and Drug Administration (FDA)-approved biomarkers include programmed cell death 1 ligand 1 (PDL1) expression, microsatellite status (that is, microsatellite instability-high (MSI-H)) and tumour mutational burden (TMB), but these have limited utility and/or lack standardized testing approaches for pan-cancer applications. Tissue-based analytes (such as tumour gene signatures, tumour antigen presentation or tumour microenvironment profiles) show a correlation with immune response, but equally, these demonstrate limited efficacy, as they represent a single time point and a single spatial assessment. Patient heterogeneity as well as inter- and intra-tumoural differences across different tissue sites and time points represent substantial challenges for static biomarkers. However, dynamic biomarkers such as longitudinal biopsies or novel, less-invasive markers such as blood-based biomarkers, radiomics and the gut microbiome show increasing potential for the dynamic identification of ICI response, and patient-tailored predictors identified through neoadjuvant trials or novel ex vivo tumour models can help to personalize treatment. In this Perspective, we critically assess the multiple new static, dynamic and patient-specific biomarkers, highlight the newest consortia and trial efforts, and provide recommendations for future clinical trials to make meaningful steps forwards in the field.

Medical Relevance, State-of-the-Art and Perspectives of "Sweet Metacode" in Liquid Biopsy Approaches

This review briefly introduces readers to an area where glycomics meets modern oncodiagnostics with a focus on the analysis of sialic acid (Neu5Ac)-terminated structures. We present the biochemical perspective of aberrant sialylation during tumourigenesis and its significance, as well as an analytical perspective on the detection of these structures using different approaches for diagnostic and therapeutic purposes. We also provide a comparison to other established liquid biopsy approaches, and we mathematically define an early-stage cancer based on the overall prognosis and effect of these approaches on the patient's quality of life. Finally, some barriers including regulations and quality of clinical validations data are discussed, and a perspective and major challenges in this area are summarised.

Uveal melanoma: Recent advances in immunotherapy

Uveal melanoma (UM) is the most common primary intraocular cancer in adults. The incidence in Europe and the United States is 6-7 per million population per year. Although most primary UMs can be successfully treated and locally controlled by irradiation therapy or local tumor resection, up to 50% of UM patients develop metastases that usually involve the liver and are fatal within 1 year. To date, chemotherapy and targeted treatments only obtain minimal responses in patients with metastatic UM, which is still characterized by poor prognosis. No standard therapeutic approaches for its prevention or treatment have been established. The application of immunotherapy agents, such as immune checkpoint inhibitors that are effective in cutaneous melanoma, has shown limited effects in the treatment of ocular disease. This is due to UM's distinct genetics, natural history, and complex interaction with the immune system. Unlike cutaneous melanomas characterized mainly by BRAF or NRAS mutations, UMs are usually triggered by a mutation in GNAQ or GNA11. As a result, more effective immunotherapeutic approaches, such as cancer vaccines, adoptive cell transfer, and other new molecules are currently being studied. In this review, we examine novel immunotherapeutic strategies in clinical and preclinical studies and highlight the latest insight in immunotherapy and the development of tailored treatment of UM.

Tissue Age Affects Antigenicity and Scoring for the 22C3 Immunohistochemistry Companion Diagnostic Test

Programmed death-ligand 1 (PD-L1) antibody 22C3 is the approved companion diagnostic immunohistochemistry test for treatment with pembrolizumab and cemiplimab in multiple cancer types. The 22C3 and 28-8 antibodies target the extracellular domain (ECD) of PD-L1, which is known to contain N-glycosylation sites. We hypothesize that antigenicity could be affected by the degradation of the glycan part of the epitope and thus change the scoring of the assay over time. Here, we test samples over time and assess the effects of time and deglycosylation on PD-L1 signal by comparing an antibody with an ECD antigen to an antibody with an intracellular domain (ICD) antigen. Ten whole-tissue sections of non-small-cell lung cancer (NSCLC) from 2018 were selected for testing. Fresh-cut serial sections for each case were stained on DAKO Link48 for 22C3 according to the label. In parallel, a previously described laboratory-developed test using E1L3N (an ICD antibody) was performed on the Leica BondRX. Tumor proportion scores for 22C3 and E1L3N were read by a pathologist and compared to the previous clinical diagnoses. To determine the effect using a quantitative approach, a tissue microarray (TMA) cohort with 90 NSCLC cases was similarly assessed. Finally, to determine whether the possible effect of epitope glycosylation, antibodies were tested before and after enzymatic deglycosylation of specimens. We found that 6 of 7 archival positive samples showed a significant reduction in positive staining with 22C3 compared to the original diagnostic sample assessed 3 years earlier. In an older archival TMA cohort, a quantitative significant difference in signal intensity was noted when staining with 22C3 was compared to E1L3N. This loss of signal was not noted in the fresh cell line TMA consistent with a time-dependent degradation of staining. Finally, quantitative assessment of the fresh TMA showed a significant loss of signal after a deglycosylation procedure when stained with 22C3, which was not seen when stained with E1L3N. We believe that these data show that the glycan part of the 22C3 epitope is not stable over time, and that this issue should be considered when assessing archival tissue for diagnostic or research purposes.

Analytical validation of a multi-cancer early detection test with cancer signal origin using a cell-free DNA-based targeted methylation assay

The analytical validation is reported for a targeted methylation-based cell-free DNA multi-cancer early detection test designed to detect cancer and predict the cancer signal origin (tissue of origin). A machine-learning classifier was used to analyze the methylation patterns of >105 genomic targets covering >1 million methylation sites. Analytical sensitivity (limit of detection [95% probability]) was characterized with respect to tumor content by expected variant allele frequency and was determined to be 0.07%-0.17% across five tumor cases and 0.51% for the lymphoid neoplasm case. Test specificity was 99.3% (95% confidence interval, 98.6-99.7%). In the reproducibility and repeatability study, results were consistent in 31/34 (91.2%) pairs with cancer and 17/17 (100%) pairs without cancer; between runs, results were concordant for 129/133 (97.0%) cancer and 37/37 (100%) non-cancer sample pairs. Across 3- to 100-ng input levels of cell-free DNA, cancer was detected in 157/182 (86.3%) cancer samples but not in any of the 62 non-cancer samples. In input titration tests, cancer signal origin was correctly predicted in all tumor samples detected as cancer. No cross-contamination events were observed. No potential interferent (hemoglobin, bilirubin, triglycerides, genomic DNA) affected performance. The results of this analytical validation study support continued clinical development of a targeted methylation cell-free DNA multi-cancer early detection test.

Basket Trials: Review of Current Practice and Innovations for Future Trials

Advances in biology and immunology have elucidated genetic and immunologic origins of cancer. Innovations in sequencing technologies revealed that distinct cancer histologies shared common genetic and immune phenotypic traits. Pharmacologic developments made it possible to target these alterations, yielding novel classes of targeted agents whose therapeutic potential span multiple tumor types. Basket trials, one type of master protocol, emerged as a tool for evaluating biomarker-targeted therapies among multiple tumor histologies. Conventionally conducted within the phase II setting and designed to estimate high and durable objective responses, basket trials pose challenges to statistical design and interpretation of results. This article reviews basket trials implemented in oncology studies and discusses issues related to their statistical design and analysis.

Immune Checkpoint Inhibitors and Other Immune Therapies in Breast Cancer: A New Paradigm for Prolonged Adjuvant Immunotherapy

Background: Breast cancer is the most common form of cancer in women worldwide. Advances in the early diagnosis and treatment of cancer in the last decade have progressively decreased the cancer mortality rate, and in recent years, immunotherapy has emerged as a relevant tool against cancer. HER2+ and triple-negative breast cancers (TNBCs) are considered more immunogenic and suitable for this kind of treatment due to the higher rate of tumor-infiltrating lymphocytes (TILs) and programmed death ligand 1 (PD-L1) expression. In TNBC, genetic aberrations further favor immunogenicity due to more neo-antigens in cancer cells. Methods: This review summarizes the principal ongoing conventional and investigational immunotherapies in breast cancer. Particularly, immune checkpoint inhibitors (ICIs) and their use alone or combined with DNA damage repair inhibitors (DDRis) are described. Then, the issue on immunotherapy with monoclonal antibodies against HER-2 family receptors is updated. Other investigational immunotherapies include a new schedule based on the interferon beta-interleukin-2 sequence that was given in ER+ metastatic breast cancer patients concomitant with anti-estrogen therapy, which surprisingly showed promising results. Results: Based on the scientific literature and our own findings, the current evaluation of tumor immunogenicity and the conventional model of adjuvant chemotherapy (CT) are questioned. Conclusions: A novel strategy based on additional prolonged adjuvant immunotherapy combined with hormone therapy or alternated with CT is proposed.

The prevalence of mismatch repair deficiency in ovarian cancer: a systematic review and meta‐analysis

Ovarian cancer (OC) is the least survivable gynecological malignancy and presents late. Five‐year survival for OC is around 45% increasing the need for innovative treatments. Checkpoint inhibitors have shown significant clinical efficacy in mismatch repair deficient (MMRd) cancers and could be a powerful treatment in OC. However, their application in OC is limited due to the lack of data on the prevalence of MMRd. The aim of our study was to conduct a systematic review of the literature and meta‐analysis to provide an accurate estimate of the prevalence of MMRd in OC. We followed PRISMA guidelines throughout. Studies were identified by electronic searches of Medline, Embase, Cochrane CENTRAL and Web of Science followed by citation searching. Studies not written in English were excluded. All studies were reviewed by at least two independent reviewers. Proportions of test positivity were calculated by random and fixed‐effects meta‐analysis models. I² score was used to assess heterogeneity across studies. In total 54 studies were included with 17 532 analyzed for MMRd. The overall proportions of MMRd by immunohistochemistry and microsatellite instability analysis were 6.7% and 10.4%, respectively. MMRd was reported in all histotypes of epithelial OC but was most common in endometrioid OC. We estimate that on average 46.7% (95% CI: 28.8‐65.4) of ovarian carcinomas showing MMRd by IHC had a germline path_MMR variant identified. OC in those with Lynch syndrome seems to present at an earlier age and stage. Studies however were generally of low quality and there was a high degree of heterogeneity. A significant minority (up to 16%) of OC displays MMRd and, therefore, could be amenable to checkpoint inhibition therapy. However, the current literature base is of limited quality and therefore high‐quality prospective studies exploring MMRd in OC with the use of multimodal testing are required. In addition, trials researching efficacy of checkpoint inhibition in MMRd OC are needed.

Evaluation of Companion Diagnostics in Scientific Advice and Drug Marketing Authorization Applications by the European Medicines Agency

With the implementation of the new EU regulation on in vitro diagnostics (IVDR) in May 2022, notified bodies will be required to assess Companion Diagnostics (CDx). The EMA and national medicines agencies will be consulted on the performance and safety of CDx. In this paper, we report on our systematic review on how the EMA has dealt with CDx in dossiers for marketing authorization procedures, in 2017–2019, and in scientific advice procedures in 2016–2020, prior to the implementation of the new IVDR. Out of 167 medicines approved or refused by the EMA, CDx played a role for 20 medicines during assessment. Both European public assessment reports (EPARs) and the internal day 80 and day 120 assessment reports (ARs) of the EMA centralized marketing authorization procedures for these 20 medicines were analyzed in detail to determine how CDx were assessed. Likewise, in 46 of 159 cases in which scientific advice was provided, CDx were mentioned in the question-and-answer section of the scientific advice, and these were analyzed in an analogous manner. Our analysis indicates that clinical performance and analytical performance of the CDx were the most-discussed topics, being discussed 11 and seven times in the 20 EPARs and 59 and 29 times in the ARs, respectively. For scientific advice, clinical and analytical performance was discussed 65 and 22 times in the 46 retrieved mentions of scientific advice. Other aspects in relation to CDx were discussed as well, although at a lower frequency, in assessment reports and scientific advice. Overall, our analysis demonstrates that, despite the absence of an obligation from a legal point of view, EMA has gained experience on the assessment of CDx, most notably regarding its analytical and clinical performance. This experience may be useful in situations in which the EMA and national agencies of EU member states will formally be consulted by notified bodies regarding the performance and safety of CDx. In addition, the issues raised in the EPARs, ARs and scientific advice reports provide insight for applicants on aspects of CDx that need careful consideration.

Preventative and Disease-Modifying Investigations for Osteoarthritis Management Are Significantly Under-represented in the Clinical Trial Pipeline: A 2020 Review

PURPOSE

To conduct a review of active United States-based clinical trials investigating preventative, symptom resolution, and disease-modifying therapies for osteoarthritis (OA).

METHODS

We conducted a review of currently active clinical trials for OA using data obtained from the ClinicalTrials.gov database as of August 2020. The inclusion criteria were active studies registered in the United States that involved the prevention, symptom resolution, or disease modification of OA. Descriptive statistics were recorded and summarized.

RESULTS

A total of 3,859 clinical trials were identified, and 310 were included in the final analysis. Of the currently active trials, 89% (n = 275) targeted symptom resolution in patients with existing OA, 6% (n = 19) targeted OA disease-modifying therapeutics, and 5% (n = 16) targeted the prevention of OA in high-risk patients (P < .001). Primary interventions included medical devices (44%, n = 137), pharmaceutical drugs (14%, n = 42), surgical procedures (14%, n = 42), cellular biologics (13%, n = 41), and behavioral therapies (13%, n = 41). There was a significantly higher number of disease-modifying therapeutics for cellular biologics than pharmaceutical drugs (30% vs 14%) (P = .015). Most trials targeted the knee joint (63%, P = .042), with 38% of all trials evaluating joint arthroplasty. There were no significant differences between private sector and government funding sources (43% and 49%, respectively) (P = .288), yet there was a significantly lower rate of funding from industry (8%) (P = .026).

CONCLUSIONS

There was a significantly higher number of clinical trials investigating symptomatic resolution therapy (89%) for existing OA in comparison to preventative (5%) and disease-modifying (6%) therapies. The most common interventions involved medical devices and joint replacement surgery, with the knee joint accounting for more than 60% of the current clinical trials for OA. There was a significantly higher number of disease-modifying therapeutics for cellular biologics than pharmaceutical drugs. Funding of clinical trials was split between the private sector and government, with a low rate of reported funding from industry partners.

CLINICAL RELEVANCE

Identifying existing needs in the current market may help increase rates of research funding or optimize current funding pathways, in this study, specifically for targeting unaddressed focus areas in OA research. Our systematic review highlights the potential need for additional research and development regarding OA preventative and disease-modifying therapies.

An update on companion and complementary diagnostic assays for PD-1/PD-L1 checkpoint inhibitors in NSCLC

Introduction: Development within molecular medicine has given us an increased understanding of the pathophysiology of malignant diseases. This understanding has been the key to a development of a number of new effective target-specific drugs, including the PD-1/PD-L1 checkpoint inhibitors.Areas covered: This review will focus on the clinical validation and utility of the commercially available IHC PD-L1 expression assays linked to the different PD-1/PD-L1 checkpoint inhibitors indicated for treatment of NSCLC. For the discussion of this subject, mainly data from studies where the PD-1/PD-L1 checkpoint inhibitors have been given as monotherapy will be reported.Expert opinion: Although PD-L1 expression is not the perfect biomarker; the different IHC PD-L1 expression assays have had major impact on the clinical development of PD-1/PD-L1 checkpoint inhibitors for treatment of NSCLC. A number of clinical studies in NSCLC have shown that the efficacy of the PD-1/PD-L1 checkpoint inhibitors are positively correlated to the level of PD-L1 expression. Based on studies presented in this review, the recommendation is that monotherapy should mainly be used for treatment of NSCLC patients with a high PD-L1 expression, as defined by the cutoff values for the individual assays linked to the specific PD-1/PD-L1 checkpoint inhibitor.

Cancer Immunotherapy Update: FDA-Approved Checkpoint Inhibitors and Companion Diagnostics

Immune checkpoint inhibitors (ICIs) are considered a new standard-of-care across many cancer indications. This review provides an update on ICIs approved by the Food and Drug Administration (FDA), with focus on monoclonal antibodies that target the programmed cell death 1 (PD-1) or its ligand, PD-1 ligand 1 (PD-L1), including information on their clinical indications and associated companion diagnostics. The information is further discussed with strategies for identifying predictive biomarkers to guide the clinical use of PD-1/PD-L1-targeted therapies.

Neuropilin-1 is associated with the prognosis of cervical cancer in Henan Chinese population

Objective: Neuropilin-1 has been reported to be a valuable diagnostic biomarker in patients with cervical intraepithelial neoplasia (CIN) and early cervical cancer. The aim of this study was to investigate the association between Neuropilin-1 and the prognosis of cervical cancer in Henan Chinese population.

Methods: Tissues were collected in The Third Affiliated Hospital of Zhengzhou University between 2010 and 2012, determining the level and expression of Neuropilin-1 in different cervical lesions by immunohistochemistry. The cell proliferation assay, wound-healing assays and Transwell assay were performed to explore the ability of proliferation, migration and invasion for Hela and Caski cells after NRP-1 was knocked down by shRNA transfection. Western blotting was performed to investigate the role of NRP-1 in endothelial-to-mesenchymal transition (EndMT). Tumor xenografts model was used to evaluate the effect of NRP-1 on the tumor growth.

Results: The expression of NRP-1 was upregulated in the tumor tissues compared with the CIN and normal tissues (P<0.0001). The overall survival time of the high NRP-1 expression group was significantly shorter than that of the low NRP-1 expression group (P<0.0001); NRP-1-depleted cells had dramatically lower rate of proliferation, migration and invasion compared to control cells (all P<0.05). Depletion of NRP-1 significantly suppressed the growth of CaSki xenograft tumor in nude mice.

Conclusions: The current study demonstrated that NRP-1 expression is significantly correlated with the progression of CC. Notably, high NRP-1 expression is correlated with a poorer survival in patients with CC, and has been shown to be an independent prognostic factor.

Twenty Years with Personalized Medicine: Past, Present, and Future of Individualized Pharmacotherapy

On April 16, 1999, a short article appeared in The Wall Street Journal entitled "New Era of Personalized Medicine: Targeting Drugs for Each Unique Genetic Profile," and here, the public was introduced to the term "personalized medicine" for the first time. A few months after publication of the article, it was reprinted in The Oncologist. The article describes the formation of the Single Nucleotide Polymorphisms Consortium, which was established as a collaboration between a number of major pharmaceutical companies and several academic research institutions, with support from the Wellcome Trust Foundation. Reading the article today, one will find that several of the important arguments for an individualized therapy are described in a similar way as we have known it from the past 20 years of discussion. The article mentioned the poor efficacy of the current pharmacotherapy, disease heterogeneity, and genetic variability, a showdown with the "one-size-fits-all" approach, and the use of predictive safety and efficacy biomarkers. Today, personal medicine is in competition with other terms such as "precision medicine" and "stratified medicine" and is no longer the preferred term for describing the individualized health care approach. Even though personalized medicine arose from the idea of improving and individualizing pharmacotherapy, the concept has influenced most other areas of our health care system. No matter if we use the term precision medicine or personalized medicine, the ideas that originated 20 years ago have greatly impacted the way we develop and implement new initiatives in relation to diagnosis, prevention, and treatment today. IMPLICATIONS FOR PRACTICE: Since the publication of the ideas behind personalized medicine in The Wall Street Journal and The Oncologist 20 year ago, they have permeated medical research and innovation. This review will provide an overview of the background, definitions, and terminology and will describe some of the achievements in relation to the treatment of malignant diseases.

Development of a Diagnostic Programmed Cell Death 1-Ligand 1 Immunohistochemistry Assay for Nivolumab Therapy in Melanoma

Nivolumab is a monoclonal antibody that blocks the interaction between programmed cell death 1 (PD1) and programmed cell death 1-ligand 1 (PD-L1), resulting in enhanced antitumor activity by the immune system. Nivolumab is currently approved by the US Food and Drug Administration (FDA) for melanoma, non-small cell lung cancer (NSCLC), renal cell carcinoma, classical Hodgkin lymphoma, squamous cell carcinoma of the head and neck, and urothelial carcinoma. PD-L1 IHC 28-8 pharmDx is FDA-approved as a complementary diagnostic for immunohistochemical (IHC) detection of PD-L1 in non-squamous NSCLC and melanoma. We report validation of PD-L1 IHC 28-8 pharmDx for PD-L1 detection on formalin-fixed, paraffin-embedded human melanoma specimens using Autostainer Link 48. A prevalence assessment of 104 melanoma specimens indicated that PD-L1 was detected across the full expression level range (0% to 100% of tumor cells). Assay robustness and precision studies were conducted at Agilent Technologies, with additional reproducibility studies performed at 3 external laboratories. Precision studies evaluated at ≥1% and ≥5% expression levels revealed a range of average negative agreement from 89.5%, 95% CI (83.2, 93.6) to 100%, 95% CI (97.3, 100), and average positive agreement from 85.5%, 95% CI (77.6, 90.9) to 100%, 95% CI (97.9, 100). For external reproducibility, precise results were obtained. These results demonstrate PD-L1 IHC 28-8 pharmDx is a precise, robust, and reproducible assay for determining PD-L1 expression in melanoma. This is the first PD-L1 IHC test to receive FDA approval as a complementary diagnostic in melanoma patients whereby positive PD-L1 expression is correlated with the magnitude of nivolumab treatment effect.

PRRT genomic signature in blood for prediction of 177Lu-octreotate efficacy

BACKGROUND

Peptide receptor radionuclide therapy (PRRT) utilizes somatostatin receptor (SSR) overexpression on neuroendocrine tumors (NET) to deliver targeted radiotherapy. Intensity of uptake at imaging is considered related to efficacy but has low sensitivity. A pretreatment strategy to determine individual PRRT response remains a key unmet need. NET transcript expression in blood integrated with tumor grade provides a PRRT predictive quotient (PPQ) which stratifies PRRT "responders" from "non-responders". This study clinically validates the utility of the PPQ in NETs.

METHODS

The development and validation of the PPQ was undertaken in three independent ¹⁷⁷Lu-PRRT treated cohorts. Specificity was tested in two separate somatostatin analog-treated cohorts. Prognostic value of the marker was defined in a cohort of untreated patients. The developmental cohort included lung and gastroenteropancreatic [GEP] NETs (n = 72) from IRST Meldola, Italy. The majority were GEP (71%) and low grade (86% G1-G2). Prospective validation cohorts were from Zentralklinik Bad Berka, Germany (n = 44), and Erasmus Medical Center, Rotterdam, Netherlands (n = 42). Each cohort included predominantly well differentiated, low grade (86-95%) lung and GEP-NETs. The non-PRRT comparator cohorts included SSA cohort I, n = 28 (100% low grade, 100% GEP-NET); SSA cohort II, n = 51 (98% low grade; 76% GEP-NET); and an untreated cohort, n = 44 (64% low grade; 91% GEP-NET). Baseline evaluations included clinical information (disease status, grade, SSR) and biomarker (CgA). NET blood gene transcripts (n = 8: growth factor signaling and metabolism) were measured pre-therapy and integrated with tumor Ki67 using a logistic regression model. This provided a binary output: "predicted responder" (PPQ+); "predicted non-responder" (PPQ-). Treatment response was evaluated using RECIST criteria [Responder (stable, partial and complete response) vs Non-Responder)]. Sample measurement and analyses were blinded to study outcome. Statistical evaluation included Kaplan-Meier survival and standard test evaluation analyses.

RESULTS

In the developmental cohort, 56% responded to PRRT. The PPQ predicted 100% of responders and 84% of non-responders (accuracy: 93%). In the two validation cohorts (response: 64-79%), the PPQ was 95% accurate (Bad Berka: PPQ + =97%, PPQ- = 93%; Rotterdam: PPQ + =94%, PPQ- = 100%). Overall, the median PFS was not reached in PPQ+ vs PPQ- (10-14 months; HR: 18-77, p < 0.0001). In the comparator cohorts, the predictor (PPQ) was 47-50% accurate for SSA-treatment and 50% as a prognostic. No differences in PFS were respectively noted (PPQ+: 10-12 months vs. PPQ-: 9-15 months).

CONCLUSION

The PPQ derived from circulating NET specific genes and tumor grade prior to the initiation of therapy is a highly specific predictor of the efficacy of PRRT with an accuracy of 95%.

Considerations for Developing Targeted Therapies in Low-Frequency Molecular Subsets of a Disease

Advances in our understanding of the molecular underpinnings of disease have spurred the development of targeted therapies and the use of precision medicine approaches in patient care. While targeted therapies have improved our capability to provide effective treatments to patients, they also present additional challenges to drug development and benefit-risk assessment such as identifying the subset(s) of patients likely to respond to the drug, assessing heterogeneity in response across molecular subsets of a disease, and developing diagnostic tests to identify patients for treatment. These challenges are particularly difficult to address when targeted therapies are developed to treat diseases with multiple molecular subtypes that occur at low frequencies. To help address these challenges, the US Food and Drug Administration recently published a draft guidance entitled "Developing Targeted Therapies in Low-Frequency Molecular Subsets of a Disease." Here we provide additional information on specific aspects of targeted therapy development in diseases with low-frequency molecular subsets.

Clinical and Regulatory Aspects of Companion Diagnostic Development in Oncology

Nearly 20 years have passed since the US Food and Drug Administration (FDA) approved the first companion diagnostic and today this type of assay governs the use of 21 different anticancer drugs. The regulators deem these assays essential for the safe and effective use of a corresponding therapeutic product. The companion diagnostic assays are important both during the drug development process as well as essential treatment decision tools after the approval of the drugs.

Recent development in clinical applications of PD-1 and PD-L1 antibodies for cancer immunotherapy

Antibodies against programmed death (PD) pathway are revolutionizing cancer immunotherapy. Currently five antibodies against PD-1/PD-L1 have been approved. The clinical use of these antibodies is rapidly expanding. Incorporation of PD antibodies into chemotherapy regimens is in active clinical investigations. The combination of pembrolizumab with carboplatin and pemetrexed has been approved for the first line therapy of metastatic non-squamous non-small cell lung cancer. Combination of PD-1/PD-L1 antibodies with small molecule inhibitors such as tyrosine kinase inhibitors and IDO inhibitors are in active clinical trials. This review summarized recent development in clinical trials of PD-1 and PD-L1 antibodies for cancer immunotherapy.

Evaluating Molecular Biomarkers for the Early Detection of Lung Cancer: When Is a Biomarker Ready for Clinical Use? An Official American Thoracic Society Policy Statement

BACKGROUND

Molecular biomarkers have the potential to improve the current state of early lung cancer detection. The goal of this project was to develop a policy statement that provides guidance about the level of evidence required to determine that a molecular biomarker, used to support early lung cancer detection, is appropriate for clinical use.

METHODS

An ad hoc project steering committee was formed, to include individuals with expertise in the early detection of lung cancer and molecular biomarker development, from inside and outside of the Assembly on Thoracic Oncology. Key questions, generated from the results of a survey of the project steering committee, were discussed at an in-person meeting. Results of the discussion were summarized in a policy statement that was circulated to the steering committee and revised multiple times to achieve consensus.

RESULTS

With a focus on the clinical applications of lung cancer screening and lung nodule evaluation, the policy statement outlines categories of results that should be reported in the early phases of molecular biomarker development, discusses the level of evidence that would support study of the clinical utility, describes the outcomes that should be proven to consider a molecular biomarker clinically useful, and suggests study designs capable of assessing these outcomes.

CONCLUSIONS

The application of molecular biomarkers to assist with the early detection of lung cancer has the potential to substantially improve our ability to select patients for lung cancer screening, and to assist with the characterization of indeterminate lung nodules. We have described relevant considerations and have suggested standards to apply when determining whether a molecular biomarker for the early detection of lung cancer is ready for clinical use.

Societal challenges of precision medicine: Bringing order to chaos

The increasing number of drugs targeting specific proteins implicated in tumourigenesis and the commercial promotion of relatively affordable genome-wide analyses has led to an increasing expectation among patients with cancer that they can now receive effective personalised treatment based on the often complex genomic signature of their tumour. For such approaches to work in routine practice, the development of correspondingly complex biomarker assays through an appropriate and rigorous regulatory framework will be required. It is becoming increasingly evident that a re-engineering of clinical research is necessary so that regulatory considerations and procedures facilitate the efficient translation of these required biomarker assays from the discovery setting through to clinical application. This article discusses the practical requirements and challenges of developing such new precision medicine strategies, based on leveraging complex genomic profiles, as discussed at the Innovation and Biomarkers in Cancer Drug Development meeting (8th-9th September 2016, Brussels, Belgium).

Clinical applications of PD-L1 bioassays for cancer immunotherapy

Programmed death ligand 1 (PD-L1) has emerged as a biomarker that can help to predict responses to immunotherapies targeted against PD-L1 and its receptor (PD-1). Companion tests for evaluating PD-L1 expression as a biomarker of response have been developed for many cancer immunotherapy agents. These assays use a variety of detection platforms at different levels (protein, mRNA), employ diverse biopsy and surgical samples, and have disparate positivity cutoff points and scoring systems, all of which complicate the standardization of clinical decision-making. This review summarizes the current understanding and ongoing investigations regarding PD-L1 expression as a potential biomarker for clinical outcomes of anti-PD-1/PD-L1 immunotherapy.