Twenty-five years with companion diagnostics

For decades, pharmacotherapy has been hampered by significant patient variability, and the inability to predict outcomes at the individual patient level has negatively affected its value. However, progress in molecular medicine has led to an increased understanding of the pathophysiology and mechanisms of action of drugs, thereby enabling the development of predictive biomarkers. Companion diagnostics (CDx) belongs to the group of predictive biomarkers, which the Food and Drug Administration (FDA) defines as an in vitro diagnostic device that provides information that is essential for the safe and effective use of a corresponding therapeutic product. In September 1998, 25 years ago, the FDA approved the first CDx assay, the HercepTest, an immunohistochemical (IHC) assay for the detection of HER2 protein expression. This assay is linked to the use of the monoclonal antibody trastuzumab in the treatment of HER2 positive breast cancer. The HercepTest is not the only CDx developed. Currently, more than 60 drugs or drug combinations, primarily in hematology and oncology, have been approved by the FDA, with CDx assays linked to their use. The current article briefly discusses the subject of CDx and provides an overview of its evolution over the past 25 years, with particular emphasis on the United States.

Long-Term Exposure to AIR Pollution and COVID-19 Mortality and Morbidity in DENmark: Who Is Most Susceptible? (AIRCODEN)

INTRODUCTION

Early ecological studies have suggested a link between air pollution and Coronavirus Diseases 2019 (COVID-19); however, the evidence from individual-level prospective cohort studies is still sparse. Here, we have examined, in a general population, whether long-term exposure to air pollution is associated with the risk of contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and developing severe COVID-19, resulting in hospitalization or death and who is most susceptible. We also examined whether long-term exposure to air pollution is associated with hospitalization or death due to COVID-19 in those who have tested positive for SARS-CoV-2.

METHODS

We included all Danish residents 30 years or older who resided in Denmark on March 1, 2020. and followed them in the National COVID-19 Surveillance System until first positive test (incidence), COVID-19 hospitalization, or death until April 26, 2021. We estimated mean levels of nitrogen dioxide (NO2), particulate matter with an aerodynamic diameter <2.5 μm (PM2.5), black carbon (BC), and ozone (O3) at cohort participants' residence in 2019 by the Danish Eulerian Hemispheric Model/Urban Background Model. We used Cox proportional hazard models to estimate the associations of air pollutants with COVID-19 incidence, hospitalization, and mortality adjusting for age, sex, and socioeconomic status (SES) at the individual and area levels. We examined effect modification by age, sex, SES (education, income, wealth, employment), and comorbidities with cardiovascular disease, respiratory disease, acute lower respiratory infections, diabetes, lung cancer, and dementia. We used logistic regression to examine association of air pollutants with COVID-19-related hospitalization or death among SARS-CoV-2 positive patients, adjusting for age, sex, individual- and area-level SES.

RESULTS

Of 3,721,810 people, 138,742 were infected, 11,270 hospitalized, and 2,557 died from COVID-19 during 14 months of follow-up. We detected strong positive associations with COVID-19 incidence, with hazard ratio (HR) and 95% confidence interval (CI) of 1.10 (CI: 1.05-1.14) per 0.5-μg/m3 increase in PM2.5 and 1.18 (CI: 1.14-1.23) per 3.6-μg/m3 increase in NO2. For COVID-19 hospitalizations and for COVID-19 deaths, corresponding HRs and 95% CIs were 1.09 (CI: 1.01-1.17) and 1.19 (CI: 1.12-1.27), respectively for PM2.5, and 1.23 (CI: 1.04-1.44) and 1.18 (CI: 1.03-1.34), respectively for NO2. We also found strong positive and statistically significant associations with BC and negative associations with O3. Associations were strongest in those aged 65 years old or older, participants with the lowest SES, and patients with chronic cardiovascular, respiratory, metabolic, lung cancer, and neurodegenerative disease. Among 138,742 individuals who have tested positive for SARS-Cov-2, we detected positive association with COVID-19 hospitalizations (N = 11,270) with odds ratio and 95% CI of 1.04 (CI: 1.01- 1.08) per 0.5-μg/m3 increase in PM2.5 and 1.06 (CI: 1.01-1.12) per 3.6-μg/m3 increase in NO2, but no association with PM with an aerodynamic diameter <10 μm (PM10), BC, or O3, and no association between any of the pollutants and COVID-19 mortality (N = 2,557).

CONCLUSIONS

This large nationwide study provides strong new evidence in support of association between long-term exposure to air pollution and COVID-19.

The Different Roles of MET in the Development and Treatment of Cancer

This Special Issue features contributions from leading international researchers in the field of MET (hepatocyte growth factor (HGF) receptor) biology and therapeutics [...].

The Potential of Trastuzumab Deruxtecan as a Tissue Agnostic Drug

BACKGROUND

Many modern anticancer drugs are designed to target specific molecular alterations harbored by the cancer. If a specific drug is able to target these alterations, regardless of the organ or tissue in which the cancer originates, it will often be characterized as a tissue- or tumor agnostic drug. According to the Food and Drug Administration (FDA), a tissue-agnostic drug refers to a drug that targets a specific molecular alteration across multiple cancer types, as defined by organ, tissue, or tumor type.

SUMMARY

Over the last 6 years, the FDA has approved seven tissue-agnostic drugs, and more are anticipated in the future. One promising candidate for a tissue-agnostic classification is the antibody-drug conjugate trastuzumab deruxtecan (T-DXd). Currently, T-DXd is approved for the treatment of human epidermal growth factor receptor 2 (HER2)-positive and HER2-low breast cancer, HER2-positive gastric or gastroesophageal junction adenocarcinoma, and non-small cell lung cancer with activating HER2 mutations. Ongoing clinical research is exploring the potential of T-DXd in various solid tumors that harbor specific HER2 molecular alterations, and encouraging results, including the interim data from the DESTINY-PanTumor02 trial, have been published, which suggest a tissue-agnostic potential.

KEY MESSAGES

Published phase I data as well as the interim results from the phase II DESTINY-PanTumor02 trial indicates that patients with different HER2-positive advanced solid tumors may benefit from treatment with T-DXd. Based on the currently available data, it seems likely that T-DXd possesses pantumor activity. However, different clinical trials are ongoing, and it will be necessary to see the results from these trials before drawing a final conclusion. When discussing tissue-agnostic potential, it is important to add that for most of the patients enrolled in the DESTINY-PanTumor02 and other trials, few treatment alternatives seem to exist, and T-DXd might be able to cover an unmet medical need.

[Predictive biomarkers in medical treatment]

Use of predictive biomarkers plays a promising role in stratifying patients to a more effective medical treatment with less side effects. This review provides a brief overview in a Danish context of the potential of applying pharmacogenomics (PGx) including companion diagnostics (CDx) in daily clinical practice based on the current knowledge and regulation from the FDA and EMA, Summary of Product Characteristics (SPC), PharmGKB (pharmacogenomics knowledge resource providing clinical dosing guidelines) and partly promedicin.dk. Also, the barriers to more widespread use are being addressed.

Missing Companion Diagnostic for US Food and Drug Administration-Approved Hematological and Oncological Drugs

Within hematology and oncology, companion diagnostics (CDxs) play an increasing role in securing an optimal therapy for individual patients, and the US Food and Drug Administration (FDA) consider this type of assay essential for the safe and effective use of a corresponding therapeutic product. Most CDxs are developed prospectively using the drug-diagnostic codevelopment model, which normally secures the simultaneous approval of both drugs and diagnostics. A CDx assay is an important treatment decision tool that needs to be available simultaneously with the drug. However, within the past few years, several targeted drugs and new indications have been approved by the FDA without a CDx, despite the use of a predictive biomarker assay for patient selection during clinical development. A missing analytical and clinically validated CDx assay could affect the correct use of these drugs and ultimately patient safety. An alternative to FDA-approved or FDA-cleared CDxs could be to use a laboratory-developed test, which will normally miss documentation on the clinical validity. On the basis of the information available from different publicly available FDA databases, this article briefly discusses the issue of missing CDx assays in relation to the approval of hematological and oncological drugs and new indications.

Companion Diagnostics and Predictive Biomarkers for MET-Targeted Therapy in NSCLC

Simple Summary

MET is a receptor tyrosine kinase encoded by the MET proto-oncogene that has a significant role in cancer cell progression. Several drugs targeting MET are under development for the treatment of different cancers, including non-small-cell lung cancer (NSCLC). However, until now, relatively few of these drugs have shown sufficient clinical activity and obtained regulatory approval. One of the reasons for this could be the lack of effective biomarkers to select the right patients for treatment. In a number of clinical trials, different biomarkers have been studied, but so far, MET exon 14 skipping mutation is the only one that has shown sufficient predictive properties. Another interesting biomarker is MET amplification detected by fluorescence in situ hybridization (FISH), which has shown promising results in the treatment of patients with NSCLC. Future clinical research will show whether MET amplification by FISH is an effective predictive biomarker for MET-targeted therapy.

Abstract

Dysregulation of the MET tyrosine kinase receptor is a known oncogenic driver, and multiple genetic alterations can lead to a clinically relevant oncogenesis. Currently, a number of drugs targeting MET are under development as potential therapeutics for different cancer indications, including non-small cell lung cancer (NSCLC). However, relatively few of these drugs have shown sufficient clinical activity and obtained regulatory approval. One of the reasons for this could be the lack of effective predictive biomarkers to select the right patient populations for treatment. So far, capmatinib is the only MET-targeted drug approved with a companion diagnostic (CDx) assay, which is indicated for the treatment of metastatic NSCLC in patients having a mutation resulting in MET exon 14 skipping. An alternative predictive biomarker for MET therapy is MET amplification, which has been identified as a resistance mechanism in patients with EGFR-mutated NSCLC. Results obtained from different clinical trials seem to indicate that the MET/CEP7 ratio detected by FISH possesses the best predictive properties, likely because this method excludes MET amplification caused by polysomy. In this article, the concept of CDx assays will be discussed, with a focus on the currently FDA-approved MET targeted therapies for the treatment of NSCLC.

Oncology drug-companion diagnostic combinations

With the development of trastuzumab for metastatic breast cancer a new era began in cancer drug development. The drug-diagnostic codevelopment model with its clinical enrichment trial design has enabled development of target specific drugs for molecular defined subsets of patients. Since the simultaneous approval of trastuzumab and the HercepTest in 1998, the number of FDA-approved drug-companion diagnostic combinations within oncology and hematology have steadily increased. By June 2021, the number of drugs that have a companion diagnostic (CDx) linked to its use has reached 46. For these drugs, the CDx assays play an important role in defining the patient population likely to respond and without the assay they will often lose their value. This short article is based on an analysis of the FDA List of Cleared or Approved Companion Diagnostic Devices and relevant information in the Drugs@FDA, and will focus on the drug-CDx combinations, drug classes, clinical development, and the regulatory path and status.

A Companion Diagnostic With Significant Clinical Impact in Treatment of Breast and Gastric Cancer

The development of trastuzumab (Herceptin^®) was one of the most significant cancer drug development projects of the 20th century. Not only was it a scientific and medical achievement but it also paved the way for the drug-diagnostic codevelopment model, where a predictive biomarker assay is developed in parallel to the drug. One of the challenges in the development of trastuzumab was to select the right patient population likely to respond and here, it was critical to have access to an accurate, robust and reliable assay for detection of HER2 overexpression in tumors. In the clinical development of trastuzumab, a clinical trial assay (CTA), developed by Genentech, was used for selection of HER2 positive patients. However, during the phase III trial with trastuzumab, a new optimized IHC assay, HercepTest™ was designed and developed by Dako. In the final stage of its development, a comparative study with the CTA was conducted in order to show concordance between the two assays. In September 1998, the Food and Drug Administration (FDA) simultaneously granted approval to trastuzumab and HercepTest™. The assay has been used for patient selection in a number of significant breast cancer clinical trials such as the HERA, CLEOPATRA, EMILIA and more. In these trials, HercepTest™ demonstrated its clinical utility in the neoadjuvant, adjuvant, and metastatic setting as well as in relation to different types of HER2 targeted therapies. Likewise, the assay was used for selection of HER2 positive gastric cancer patients in the important ToGA trail. HercepTest™ was the first companion diagnostic ever approved by the FDA, and more than 20 years of use has documented its clinical impact.

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.

Predictive biomarkers and clinical evidence

Predictive biomarkers play an important role in our efforts to individualize pharmacotherapy, and within recent years, a number of different types of assays have been introduced. These biomarkers may potentially support the selection and dosage of specific drugs in order to maximize efficacy and minimize adverse reactions in the individual patient. However, in many instances, the scientific and clinical evidence is insufficient to support the prescribing decision. When predictive biomarkers are used to guide pharmacotherapy, it is important to secure that decisions are based on solid clinical evidence. Here, the regulatory authorities, especially the FDA, have been at the forefront in relation to regulate this type of biomarker assay in order to secure patient safety. The approval process for companion diagnostics is an example of this effort, where the scientific validity of the biomarker and assay is in focus. With the approaching implementation of the new IVD Regulation, greater attention will also be paid to analytical and clinical validity of biomarker assays in the EU. For any type of predictive biomarker assay, including pharmacogenetic and tumour profiling tests, the clinical evidence needs to be in place before they are used routinely in the clinic.

The current landscape of the FDA approved companion diagnostics

Predictive biomarker is an important element in the realization of precision medicine and with the introduction of the drug-diagnostic codevelopment model, the number of regulatory approved companion diagnostics (CDx) have steadily increased. This short perspective is based on an analysis of the FDA List of Cleared or Approved Companion Diagnostic Devices and focus on the biomarkers, drugs, clinical indications, analytical platforms, regulatory paths and status related to the different assays. By the end of 2020, the total number of CDx assays approved by the FDA had reached 44. These assays are almost exclusively linked to different hematological and oncological drugs. Without an accurate and reliable CDx assay these drugs will lose their value. The analytical platforms are diverse and cover technologies like immunohistochemistry, in situ hybridization, polymerase chain reaction, next generation sequencing, and imaging. CDx assays are high risk devices and the regulatory path almost exclusively requires submission of a Premarket Application (PMA); however, a relatively large group of the CDx assays is PMA approved Laboratory Developed Test.

MET deletion is a frequent event in gastric/gastroesophageal junction/esophageal cancer: a cross-sectional analysis of gene status and signal distribution in 1,580 patients

Background

MET gene aberrations are found in several human cancers including gastric, ovarian and lung. In a large multinational cohort of patients with gastric/gastroesophageal junction/esophageal (G/GEJ/E) adenocarcinoma we assessed the MET status with respect to amplification and deletion and correlate the results with the phenotypical gene signal distribution pattern.

Methods

Tissue specimens from 1,580 patients were analyzed using a novel fluorescence in situ hybridization (FISH) assay employing a MET/CEN-7 IQFISH Probe Mix. MET amplification and deletions were defined as a MET/CEN-7 ratio ≥2.0 and a MET/CEN-7 ratio <0.8, respectively. Furthermore, the link between the MET gene status and the phenotypical signal distribution was investigated.

Results

The prevalence of MET amplification and deletions was found to be 7.2% and 8.7%, respectively. Significant differences were observed with regard to geographic regions and sex. The Asian population had the highest percentage of MET amplification (9.4%) and the lowest percentage of deletions (3.2%). MET deletions was found more frequently among males (10.1%) compared to females (5.3%) and in esophagus (17.6%) compared to the stomach (5.7%). More than 50% of the patients who harbored MET gene amplification had a heterogeneous distribution of the FISH signals. Patients with a focal signal distribution were solely to be found among the MET amplified population. MET deletion were mainly observed in the group of patients with a homogenous signal distribution.

Conclusions

The screening data from this cross-sectional study showed that MET deletion and amplification are frequent events in G/GEJ/E cancer, which are linked to different phenotypical signal distribution patterns. The role of MET deletion in relation to tumor development is not fully understood but it is likely to play a role in the oncogenic transformation of the cells.

Site-agnostic biomarker-guided oncology drug development

INTRODUCTION

Advances within molecular diagnostics have enabled us to identify a number of oncogenic drivers across different cancers. Many cancers can now be divided into subgroups based on molecular characteristics, and an increasing number of targeted anticancer drugs have been developed together with a predictive biomarker assay using the drug-diagnostic codevelopment model. With the recent approval of entrectinib, larotrectinib, and pembrolizumab for site-agnostic indications, biomarker-guided drug development has entered into a new phase.

AREAS COVERED

The review focuses on the general principles of drug-diagnostic codevelopment, especially basket trials and site-agnostic drug development. Special attention is paid to entrectinib, larotrectinib, and pembrolizumab.

EXPERT OPINION

The recent approval of entrectinib, larotrectinib, and pembrolizumab must be regarded as a paradigm shift in biomarker-guided oncology drug development. For a site-agnostic indication, it is important to have in mind the central role of the companion diagnostic (CDx), as the assay defines the 'disease' and the patient population to be treated. A number of site-agnostic drugs are currently in development and here, it is important that CDx assay development is given high priority, so an analytical and clinical validated assay is available at the time of drug approval.

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.

A paradigm shift in biomarker guided oncology drug development

Over the past couple of decades, biomarker driven enrichment clinical trials have proven to be an important tool in clinical drug development, especially for targeted anti-cancer drugs. By the end of 2018, more than 30 drugs have been developed in conjunction with a biomarker test and have a regulatory approved companion diagnostic linked to their use. With the recent approval of larotrectinib (Vitrakvi, Loxo Oncology/Bayer) for patients with neurotrophic receptor tyrosine kinase (NTRK) gene fusion and pembrolizumab (Keytruda, MSD) for microsatellite instability-high (MSI-H) and mis-match-repair-deficient (dMMR) positive patients, we are experiencing a paradigm shift in biomarker guided drug development. In contrast to the previous drugs, they are not developed for a conventional cancer indication defined by tumor histology and anatomical location, but solely on their effect related to specific molecular aberrations. For larotrectinib efficacy was demonstrated across 12 different conventional cancer indications and for pembrolizumab the number was 15. Due to the low prevalence of the different molecular aberrations, data from several small "basket" trials was pooled in order to document the efficacy of the two drugs. With the approval of larotrectinib and the MSI-H/dMMR indication for pembrolizumab, the translational research methodology has demonstrated its potential in relation to drug development and made the way for a more precise and individualized anti-cancer therapy.

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.

Detection of MET amplification in gastroesophageal tumor specimens using IQFISH

Background

The gene mesenchymal epithelial transition factor (MET) is a proto-oncogene that encodes a transmembrane receptor with intrinsic tyrosine kinase activity known as Met or cMet. MET is found to be amplified in several human cancers including gastroesophageal cancer.

Methods

Here we report the MET amplification prevalence data from 159 consecutive tumor specimens from patients with gastric (G), gastroesophageal junction (GEJ) and esophageal (E) adenocarcinoma, using a novel fluorescence in situ hybridization (FISH) assay, MET/CEN-7 IQFISH Probe Mix [an investigational use only (IUO) assay]. MET amplification was defined as a MET/CEN-7 ratio ≥2.0. Furthermore, the link between the MET signal distribution and amplification status was investigated.

Results

The prevalence of MET amplification was found to be 6.9%. The FISH assay demonstrated a high inter-observer reproducibility. The inter-observer results showed a 100% overall agreement with respect to the MET status (amplified/non-amplified). The inter-observer CV was estimated to 11.8% (95% CI: 10.2-13.4). For the signal distribution, the inter-observer agreement was reported to be 98.7%. We also report an association of MET amplification and a unique signal distribution pattern in the G/GEJ/E tumor specimens. We found that the prevalence of MET amplification was markedly higher in tumors specimens with a heterogeneous (66.7%) versus homogeneous (2.0%) signal distribution. Furthermore, specimens with a heterogeneous signal distribution had a statically significantly higher median MET/CEN-7 ratio (2.35 versus 1.04; P<0.0001).

Conclusions

The novel FISH assay showed a high inter-observer reproducibility both with respect to amplification status and signal distribution. Based on the finding in the study it is suggested that MET amplification mainly is associated with tumor cells that is represented by a heterogonous growth pattern.

Gene Signal Distribution and HER2 Amplification in Gastroesophageal Cancer

Background: HER2 serves as an important therapeutic target in gastroesophageal cancer. Differences in HER2 gene signal distribution patterns can be observed at the tissue level, but how it influences the HER2 amplification status has not been studied so far. Here, we investigated the link between HER2 amplification and the different types of gene signal distribution.

Methods: Tumor samples from 140 patients with gastroesophageal adenocarcinoma where analyzed using the HER2 IQFISH pharmDx™ assay. Specimens covered non-amplified and amplified cases with a preselected high proportion of HER2 amplified cases. Based on the HER2/CEN-17 ratio, specimens were categorized into amplified or non-amplified. The signal distribution patterns were divided into homogeneous, heterogeneous focal or heterogeneous mosaic. The study was conducted based on anonymized specimens with limited access to clinicopathological data.

Results: Among the 140 analyzed specimens 83 had a heterogeneous HER2 signal distribution, with 62 being focal and 21 of the mosaic type. The remaining 57 specimens had a homogeneous signal distribution. HER2 amplification was observed in 63 of the 140 specimens, and nearly all (93.7%) were found among specimens with a heterogeneous focal signal distribution (p<0.0001). The mean HER2/CEN-17 ratio for the focal heterogeneous group was 8.75 (CI95%: 6.87 - 10.63), compared to 1.53 (CI95%: 1.45 - 1.61) and 1.70 (CI95%: 1.22 - 2.18) for the heterogeneous mosaic and homogeneous groups, respectively, (p<0.0001).

Conclusions: A clear relationship between HER2 amplification and the focal heterogeneous signal distribution was demonstrated in tumor specimens from patients with gastroesophageal cancer. Furthermore, we raise the hypothesis that the signal distribution patterns observed with FISH might be related to different subpopulations of HER2 positive tumor cells.

HER2 amplification and gene signal distribution in gastroesophageal cancer

e15600

Background: HER2 serves as an important therapeutic target in gastroesophageal cancer. Differences in HER2 gene signal distribution patterns can be observed at the tissue level, but how it influences the HER2 amplification status has not been studied so far. Here, we investigated the link between HER2 amplification and the different types of gene signal distribution. Methods: Tumor samples from 140 patients with gastroesophageal adenocarcinoma where analyzed using the HER2 IQFISH pharmDx™ assay. Specimens covered non-amplified and amplified cases with a preselected high proportion of HER2 amplified cases. Based on the HER2/CEN-17 ratio, specimens were categorized into amplified or non-amplified. The signal distribution patterns were divided into homogeneous, heterogeneous focal or heterogeneous mosaic. The study was conducted based on anonymized specimens with limited access to clinicopathological data. Results: Among the 140 analyzed specimens 83 had a heterogeneous HER2 signal distribution, with 62 being focal and 21 of the mosaic type. The remaining 57 specimens had a homogeneous signal distribution. HER2 amplification was observed in 63 of the 140 specimens, and nearly all (93.7%) were found among specimens with a heterogeneous focal signal distribution (p < 0.0001). The mean HER2/CEN-17 ratio for the focal heterogeneous group was 8.75 (CI95%: 6.87 – 10.63), compared to 1.53 (CI95%: 1.45 – 1.61) and 1.70 (CI95%: 1.22 – 2.18) for the heterogeneous mosaic and homogeneous groups, respectively, (p < 0.0001). Conclusions: A clear relationship between HER2 amplification and the focal heterogeneous signal distribution was demonstrated in tumor specimens from patients with gastroesophageal cancer. Furthermore, we raise the hypothesis that the signal distribution patterns observed with FISH might be related to different subpopulations of HER2 positive tumor cells.

Companion and Complementary Diagnostics: Clinical and Regulatory Perspectives

Nearly 20 years ago, the US Food and Drug Administration (FDA) approved the first companion diagnostic assay and, today, this type of test governs the use of 18 different drugs. With the appearance of PD-L1 immunohistochemistry (IHC) assays linked to the use of different PD-1/PD-L1 immune checkpoint inhibitors, a new class of predictive biomarker assays has emerged; the complementary diagnostics. These are predictive biomarker assays that aid the therapeutic decision process but are not a prerequisite for receiving a specific drug, as is the case with companion diagnostics. Both types of assay have the individual patient as a point of reference and they will be decisive for the move toward a more individualized pharmacotherapy. They are also considered important elements in the realization of precision medicine. Here, I discuss both companion and complementary diagnostics.

Companion diagnostics-a tool to improve pharmacotherapy

The variability of pharmacotherapy can be of a significant magnitude, and the main reason for this is often diseases heterogeneity. Patients who have similar diagnoses very often respond differently to the same pharmacological intervention, with great variability in both efficacy and safety outcome. Despite having discussed personalized medicine for more than a decade, we still see that most drug prescriptions for severe chronic diseases are largely based on 'trial and error' and not on solid biomarker data. However, with the advance of molecular diagnostics and a subsequent increased understanding of disease mechanisms, things are slowly changing. Within the last few years, we have seen an increasing number of predictive biomarker assays being developed to guide the use of targeted cancer drugs. This type of assay is called companion diagnostics and is developed in parallel to the drug using the drug-diagnostic co-development model. The development of companion diagnostics is a relatively new discipline and in this review, different aspects will be discussed including clinical and regulatory issues. Furthermore, examples of drugs, such as the ALK and PD-1/PD-L1 inhibitors, that have been approved recently together with a companion or complimentary diagnostic will be given.

Assessment of HER2 amplification status in breast cancer using a new automated HER2 IQFISH pharmDx™ (Dako Omnis) assay

In breast cancer the human epidermal growth factor receptor 2 (HER2) is an important target for a number of different HER2 inhibitors. Different slide-based assays are available for assessment of treatment eligibility, which include fluorescence in situ hybridization (FISH) or other in situ hybridization (ISH) methods for assessment of the HER2 gene status. Here we report a summary of the validation data on HER2 IQFISH pharmDx™ (Dako Omnis), a newly developed assay for the automated staining platform Dako Omnis. The assay uses a non-toxic buffer that significantly reduces the hybridization time, which results in a total turnaround time of 3½ to 4h from deparaffinization to counting of the gene and centromere signals. The data reported in the current summary covers method comparison, assessment of staining quality, observer-to-observer reproducibility as well as reproducibility within and between laboratories. Based on data from the different studies it was concluded that HER2 IQFISH pharmDx (Dako Omnis) is a reliable and robust assay with a high precision that is at least comparable to the manual HER2 IQFISH pharmDx™ assay and the PathVysion(®)HER-2 DNA Probe Kit.

Analysis of HER2 status in gastroesophageal tumor specimens using a new automated HER2 IQFISH pharmDx™ (Dako Omnis) assay

The human epidermal growth factor receptor 2 (HER2) is an important target for treatment of gastroesophageal cancer. Different slide-based assays are available for assessment of HER2 status. Overexpression of the HER2 protein is assessed by immunohistochemistry (IHC) whereas amplification of the HER2 gene is assessed by fluorescence in situ hybridization (FISH) or other in situ hybridization (ISH) methods. Here we report a summary of the validation data on HER2 IQFISH pharmDx™ (Dako Omnis), a newly developed assay for the automated staining platform Dako Omnis. This assay uses a non-toxic buffer that significantly reduces the hybridization time, which results in a total turnaround time of less than 4 hours from deparaffinization to counting of the gene and centromere signals. The data reported in the current summary cover method comparison, assessment of staining quality, observer-to-observer reproducibility as well as reproducibility within and between laboratories. Based on data from the different studies it was concluded that HER2 IQFISH pharmDx (Dako Omnis) is a reliable and robust assay, with high precision and at least comparable to the manual HER2 IQFISH pharmDx™ assay. The HER2 IQFISH pharmDx (Dako Omnis) assay is currently not commercially available outside the Europe Union.

Companion diagnostic assays for PD-1/PD-L1 checkpoint inhibitors in NSCLC

The immune checkpoint inhibitors pembrolizumab and nivolumab together with their diagnostic assays have recently been granted market authorization for treatment of advanced non-small-cell lung cancer in the USA. The two assays, PD-L1 IHC 22C3 pharmDx and PD-L1 IHC 28-8 pharmDx (both by Dako, Glostrup, Denmark), are the first PD-L1 IHC assays to obtain regulatory approval through the Premarket Approval process. This approval is supported by recent clinical studies that have shown a positive correlation between PD-L1 expression and the outcome following treatment with different PD-1/PD-L1 checkpoint inhibitors. These diagnostic assays are able to identify the group of non-small-cell lung cancer patients who will benefit most from treatment with the immune checkpoint inhibitors. However, so far, it is only the PD-L1 IHC 22C3 pharmDx assay, which is linked to the use of pembrolizumab, that has obtained regulatory status as a companion diagnostic.

Clinical application of companion diagnostics

Optimally, any prescription should rely on an in-depth understanding of the disease biology and the mechanism of action of the drug. However, despite the hype about precision medicine in recent years, the prescription of most drugs is still, except for a few anticancer drugs, largely based on 'trial and error' and not on solid pharmacogenomic biomarker data.

Companion diagnostics for targeted cancer drugs - clinical and regulatory aspects

Companion diagnostics (CDx) holds the promise of improving the predictability of the oncology drug development process and become an important tool for the oncologist in relation to the choice of treatment for the individual patient. A number of drug-diagnostic co-development programs have already been completed successfully, and in the clinic, the use of several targeted cancer drugs is now guided by a CDx. This central role of the CDx assays has attracted the attention of the regulators, and especially the US Food and Drug Administration has been at the forefront in relation to developing regulatory strategies for CDx and the drug-diagnostic co-development project. For an increasing number of cancer patients the treatment selection will depend on the result generated by a CDx assay, and consequently this type of assay has become critical for the care and safety of the patients. In order to secure that the CDx assays have a high degree of analytical and clinical validity, they must undergo an extensive non-clinical and clinical testing before release for routine patient management. This review will give a brief introduction to some of the scientific and medical challenges related to the CDx development with specific emphasis on the regulatory requirements in different regions of the world.

A changing landscape for companion diagnostics

2nd European Symposium of Biopathology Paris, France, 13-14 June, 2013 This report highlights some of the presentations and discussions at the second European Symposium of Biopathology, Paris, France, 13-14 June 2013. The symposium covered a wide range of topics in the space between molecular biology and pathology such as DNA sequencing, cancer genome interpretation, cell-free tumor DNA in plasma, molecular pathology, tissue biomarkers, biomarker discovery, companion diagnostics (CDx), drug-diagnostic co-development and targeted cancer therapy. However, in this short report, the focus will be on CDx and drug-diagnostic co-development in oncology, where a new landscape seems to emerge. As discussed at the symposium, we are slowly moving away from the 'one biomarker: one drug' scenario, which has characterized the first decades of targeted cancer drug development, toward a more integrated approach with multiple biomarkers and drugs. This 'new paradigm' will likely pave the way for the introduction of multiplexing strategies in the clinic using gene expression arrays and next-generation sequencing.

Companion diagnostics in oncology - current status and future aspects

A large number of targeted anticancer drugs are currently under development and most of them will have a companion diagnostic linked to their use. If a diagnostic assay is developed in conjunction with a targeted anticancer drug, such an assay will later end up determining the conditions for the use of the drug after its approval. The assay then becomes a kind of 'gatekeeper' in relation to which patients should be treated with the drug in question. This 'gatekeeper' role implies that companion diagnostic assays must live up to the same regulatory standards and requirements known from drug development. The assays must have proven to be analytically robust and reliable and to have demonstrated clinical utility before they are routinely used in the clinic. In the drug-diagnostic codevelopment model, several 'traditional' study designs have been used to demonstrate clinical utility. However, if we are to benefit from the increasing knowledge provided by molecular oncology, new ways should be developed to demonstrate the clinical utility of drug-diagnostic combinations. The development of such an approach will require a rethinking at different levels and is likely to include a number of ethical, regulatory and practical challenges.

A new manganese-based oral contrast agent (CMC-001) for liver MRI: pharmacological and pharmaceutical aspects

Manganese is one of the most abundant metals on earth and is found as a component of more than 100 different minerals. Besides being an essential trace element in relation to the metabolic processes in the body, manganese is also a paramagnetic metal that possesses similar characteristics to gadolinium with regards to T1-weighted (T1-w) magnetic resonance imaging (MRI). Manganese, in the form of manganese (II) chloride tetrahydrate, is the active substance in a new targeted oral contrast agent, currently known as CMC-001, indicated for hepatobiliary MRI. Under physiological circumstances manganese is poorly absorbed from the intestine after oral intake, but by the use of specific absorption promoters, L-alanine and vitamin D(3), it is possible to obtain a sufficiently high concentration in the liver in order to achieve a significant signal enhancing effect. In the liver manganese is exposed to a very high first-pass effect, up to 98%, which prevents the metal from reaching the systemic circulation, thereby reducing the number of systemic side-effects. Manganese is one of the least toxic trace elements, and due to its favorable safety profile it may be an attractive alternative to gadolinium-based contrast agents for patients undergoing an MRI evaluation for liver metastases in the future. In this review the basic pharmacological and pharmaceutical aspects of this new targeted oral hepatobiliary specific contrast agent will be discussed.

HER2 as a Prognostic Marker in Gastric Cancer - A Systematic Analysis of Data from the Literature

Through the recent conduct of the ToGA trial, HER2 has shown to be predictive for the treatment with trastuzumab in advanced gastric and gastro-oesophageal cancer. When it comes to the prognostic properties the situation is different. Despite the fact that it is more than 20 years ago since the first studies demonstrating an association between a positive HER2 status and poor prognosis were published the issue is still controversial. In this current systematic review a large number of studies on HER2 and gastric cancer have been reviewed. The studies included in this review should fulfill the following two criteria. First criterion: The number of patients in each study should be ≥ 100, and the HER2 status should have been determined either by immunohistochemistry (IHC) or in situ hybridization (ISH). Second criterion: The selected articles should include an analysis of the association between the HER2 status and survival or relevant clinicopathological characteristics. Forty-two publications with a total of 12,749 patients fulfilled the two criteria and were reviewed in detail. The majority of the publications (71%) showed that a HER2-postive status measured either by IHC or ISH was associated with poor survival and/or clinicopathological characteristics, such as serosal invasion, lymph node metastases, disease stage, or distant metastases. Based on the current analysis a clear trend towards a potential role for HER2 as a negative prognostics factor in gastric cancer was shown, suggesting that HER2 overexpression and/or amplification is a molecular abnormality that might be linked to the development of gastric cancer.

A challenging drug development process in the era of personalized medicine

After years of hesitation a larger number of pharmaceutical and biotech companies are now supporting the idea of a more individualized pharmacotherapy. The companies that are now involved in this research-demanding area will have to face several challenges. The key factor for success will be an in-depth molecular understanding of the pathophysiology and the mechanism of the drug under development. The one-disease-one-drug-one-target paradigm that has been prevailing for decades is history. Most diseases are heterogeneous and based on molecular profiling they can be divided into biological subgroups that each requires a specific pharmacological intervention.

High concordance between two companion diagnostics tests: a concordance study between the HercepTest and the HER2 FISH pharmDx kit

The present study was done to investigate the concordance between the HER2 status measured by immunohistochemical analysis (HercepTest, DAKO, Carpinteria, CA) and fluorescence in situ hybridization (FISH; HER2 FISH pharmDx, DAKO) in a large study cohort (n = 681) of patients with high-risk breast cancer. A high agreement between immunohistochemical and FISH results was demonstrated. For the whole study population, the agreement between the 2 assays was 93.1% with a corresponding κ coefficient of 0.85. When the equivocal immunohistochemical 2+ cases were excluded from the analysis (n = 79), the agreement increased to 95.0% with a κ coefficient of 0.90. When the cutoff value for amplified/nonamplified cases in the HER2 FISH assay was increased from 2.0 to 2.2 as recommended in the American Society of Clinical Oncology/College of American Pathologists guidelines, the concordance between the 2 assays was 94.3% with a κ coefficient of 0.87 in the whole study population. When the equivocal immunohistochemical 2+ cases were excluded from this analysis, the concordance is similar (95.7% with a κ coefficient of 0.91).

Hypoxia-inducible factors--regulation, role and comparative aspects in tumourigenesis

Hypoxia-inducible factors (HIFs) play a key role in the cellular response experienced in hypoxic tumours, mediating adaptive responses that allow hypoxic cells to survive in the hostile environment. Identification and understanding of tumour hypoxia and the influence on cellular processes carries important prognostic information and may help identify potential hypoxia circumventing and targeting strategies. This review summarizes current knowledge on HIF regulation and function in tumour cells and discusses the aspects of using companion animals as comparative spontaneous cancer models. Spontaneous tumours in companion animals hold a great research potential for the evaluation and understanding of tumour hypoxia and in the development of hypoxia-targeting therapeutics.

Targeted HER2 Treatment in Advanced Gastric Cancer

Amplification of the <i>HER2</i> gene and over-expression of the HER2 protein in gastric cancer have been shown in a large number of studies. HER2 positivity can be detected in approximately 20% of patients, which is a characteristic associated with poor prognosis. Preclinical in vitro and in vivo studies have demonstrated that both trastuzumab and lapatinib are effective in different gastric cancer models and have thus lead to the initiation of clinical studies. In the first phase III study, the ToGA trial, HER2-positive patients with advanced gastroesophageal and gastric adenocarcinoma were randomized to receive 5-fluorouracil/capecitabine and cisplatin either alone or in combination with trastuzumab. A statically significant gain in overall survival was seen in the patients who received the combined treatment of trastuzumab and chemotherapy. It is expected that the encouraging results from the ToGA trial will have an immediate impact on the management of patients and that routine HER2 testing of patients with advanced gastric cancer will be initiated within a relatively short period of time.

The new era of personalized medicine: 10 years later

The interest in personalized medicine has increased considerably over the last 10 years with an almost exponential growth in the number of publications since 1999 when the first article discussing the subject appeared. However, the foundation of what we perceive today as personalized medicine had already been created in the 1960s with the discovery of the estrogen receptor, and later on, with the development of the selective estrogen receptor modulator drug - tamoxifen. The key driver in today's personalized medicine is molecular diagnostics, but the need to improve the current pharmacotherapy also plays a very important role. Many of the frequently used drugs are not as effective and safe as they should be. The efficacy rate of drugs within major disease areas such as asthma, cancer, psychiatric illnesses and cardiovascular diseases are in the range of 25-60%. Drug safety is another critical issue which imposes burdens on both patients and society. In the European Union, it is estimated that 5% of all hospital admissions are due to side effects related to pharmacotherapy, thus resulting in nearly 200,000 deaths per year. The total cost related to side effects from therapeutic drugs in the European Union is €79 billion per year. This situation needs to be improved, and this can be achieved by taking differences in the individual patient's biologies into consideration when the drugs are dispensed. A more individualized pharmacotherapy by the implementation of pharmacodiagnostic testing will be an important aid in improving efficacy and reducing the frequency of serious side effects in the future. However, there are obstacles to be overcome with regard to the implementation of personalized medicine, and besides scientific and economic issues, it will be a challenge to address other aspects, such as regulatory requirements, reimbursement, education and logistics.