Insights into post-marketing clinical validation of companion diagnostics with reference to the FDA, EMA, PMDA, and MFDS.

Companion diagnostics are increasing clinical demand globally, regulatory frameworks for clinical validation are strengthening. Post-marketing verification is an important aspect of providing high-quality, personalized treatment to patients because it can ensure long-term safety and effectiveness, while also generating effective risk management and performance evidence. Certain compliance issues related to the requirements for post-marketing clinical trials can potentially impact manufacturers, so it is essential to have a clear understanding of the regulatory process. In this study, we perform an institutional comparison as well as a case analysis by country (U.S. Food & Drug Administration, European Medicines Agency, Pharmaceuticals and Medical Devices Agency, and Ministry of Food and Drug Safety) on the post-marketing safety and effectiveness of companion diagnostics. We collected guidelines and guidance documents published by each regulatory agency and Post-marketing research case analysis examined the data collection items as well as the materials or templates required to be submitted. The results indicate that there are institutional differences in the post-marketing surveillance activities carried out by different regulatory authorities, and the data required may vary accordingly. The findings of this study are expected to provide new insights that can support manufacturers and developers of companion diagnostics in securing evidence regarding post-marketing safety and effectiveness.

Criteria for assessing evidence for biomarker-targeted therapies in rare cancers-an extrapolation framework.

Background: Advances in targeted therapy development and tumor sequencing technology are reclassifying cancers into smaller biomarker-defined diseases. Randomized controlled trials (RCTs) are often impractical in rare diseases, leading to calls for single-arm studies to be sufficient to inform clinical practice based on a strong biological rationale. However, without RCTs, favorable outcomes are often attributed to therapy but may be due to a more indolent disease course or other biases. When the clinical benefit of targeted therapy in a common cancer is established in RCTs, this benefit may extend to rarer cancers sharing the same biomarker. However, careful consideration of the appropriateness of extending the existing trial evidence beyond specific cancer types is required. A framework for extrapolating evidence for biomarker-targeted therapies to rare cancers is needed to support transparent decision-making. Objectives: To construct a framework outlining the breadth of criteria essential for extrapolating evidence for a biomarker-targeted therapy generated from RCTs in common cancers to different rare cancers sharing the same biomarker. Design: A series of questions articulating essential criteria for extrapolation. Methods: The framework was developed from the core topics for extrapolation identified from a previous scoping review of methodological guidance. Principles for extrapolation outlined in guidance documents from the European Medicines Agency, the US Food and Drug Administration, and Australia's Medical Services Advisory Committee were incorporated. Results: We propose a framework for assessing key assumptions of similarity of the disease and treatment outcomes between the common and rare cancer for five essential components: prognosis of the biomarker-defined cancer, biomarker test analytical validity, biomarker actionability, treatment efficacy, and safety. Knowledge gaps identified can be used to prioritize future studies. Conclusion: This framework will allow systematic assessment, standardize regulatory, reimbursement and clinical decision-making, and facilitate transparent discussions between key stakeholders in drug assessment for rare biomarker-defined cancers.

Guidance for securing approvals for new biomarkers: from discovery to clinical implementation.

The journey of translating a molecular discovery into the clinic involves multiple steps and requires planning, time, effort, and money. In this review, we provide a quick guide on the technical and clinical validation parameters that are necessary for successful commercialization of molecular and other markers. We also briefly address the different options for regulatory approvals. Successful clinical implantation depends on rigorous technical and clinical validation, and the ability to develop clear guidelines for the indications for testing (i.e. which patients are eligible to have this test), the frequency of testing, and also a clear interpretation of test results. Successful implementation requires providing evidence that the results of this test can be used to improve patient care. There are currently multiple routes for implementation of clinical molecular tests, which include regulatory agency- approved companion diagnostics, laboratory developed tests, or direct-to-consumer testing. Regulatory approval is considered the gold-standard, but it requires time and resources. There is an ongoing debate about the need for regulatory approval of laboratory developed testing. Ongoing oversight is maintained through lab accreditation and proficiency testing programs, which provide a common approach to ensuring high standards and consistent performance in clinical molecular labs. Before moving into the clinic, confirmation of both the clinical and analytic validity of a new molecular test is essential.

The life-saving benefit of dexamethasone in severe COVID-19 is linked to a reversal of monocyte dysregulation.

Dexamethasone is a life-saving treatment for severe COVID-19, yet its mechanism of action is unknown, and many patients deteriorate or die despite timely treatment initiation. Here, we identify dexamethasone treatment-induced cellular and molecular changes associated with improved survival in COVID-19 patients. We observed a reversal of transcriptional hallmark signatures in monocytes associated with severe COVID-19 and the induction of a monocyte substate characterized by the expression of glucocorticoid-response genes. These molecular responses to dexamethasone were detected in circulating and pulmonary monocytes, and they were directly linked to survival. Monocyte single-cell RNA sequencing (scRNA-seq)-derived signatures were enriched in whole blood transcriptomes of patients with fatal outcome in two independent cohorts, highlighting the potential for identifying non-responders refractory to dexamethasone. Our findings link the effects of dexamethasone to specific immunomodulation and reversal of monocyte dysregulation, and they highlight the potential of single-cell omics for monitoring in vivo target engagement of immunomodulatory drugs and for patient stratification for precision medicine approaches.

Twenty-five years with HER2 targeted therapy.

The development of trastuzumab is among the most significant cancer drug development projects in the 20th century. Trastuzumab became a gamechanger for the treatment of human epidermal growth receptor 2 (HER2) positive breast cancer, with a significant positive impact on disease recurrence and survival. The development of trastuzumab was the beginning of a new era of cancer drug development, which showed us the importance of understanding the molecular pathophysiology and drug mechanism of action. The drug-diagnostic codevelopment model, in which the drug is developed in parallel with a predictive biomarker assay, has had a significant impact on today's cancer drug development, and we are indebted to trastuzumab when it comes to the clinical enrichment trial design. Trastuzumab is not the only drug developed to target the HER2 protein. Over the past few decades, several new HER2 targeted therapies have been developed, including small-molecule tyrosine kinase inhibitors (TKI), monoclonal antibodies, and antibody-drug conjugates (ADC). In particular, the ADC trastuzumab deruxtecan seems to pave new avenues when it comes to HER2 targeted treatment not only for breast cancer, but also for gastric cancer and non-small cell lung cancer. With the development of trastuzumab as a reference point, this article will provide a brief summary of the efficacy of HER2 targeted therapy, including testing for HER2 positivity, as it has evolved over the past 25 years.

LiFT (a Lithium Fiber-Based Test): An At-Home Companion Diagnostics for a Safer Lithium Therapy in Bipolar Disorder.

This work presents LiFT (a lithium fiber-based test), a low-cost electrochemical sensor that can measure lithium in human saliva and urine with FDA-required accuracy. Lithium is used for the treatment of bipolar disorder, and has a narrow therapeutic window. Close monitoring of lithium concentration in biofluids and adjustment of drug dosage can minimize the devastating side effects. LiFT is an inexpensive, yet accurate and simple-to-operate lithium sensor for frequent at-home testing for early identification of lithium toxicity. The low cost and high accuracy of LiFT are enabled through an innovative design and the use of ubiquitous materials such as yarn and carbon black for fabrication. LiFT measures Li+ through potentiometric recognition using a lithium selective sensing membrane that is deposited on the ink-coated yarn. A detection limit of 0.97 µM is obtained with a sensitivity of 59.07±1.25 mV/decade for the Li+ sensor in deionized water. Moreover, the sodium correction extended LiFT's linear range in urine and saliva to 0.5 mM. The LiFT platform sends the test results to the patient's smartphone, which subsequently can be shared with the patient's healthcare provider to expedite diagnosis and prevention of acute lithium toxicity.

ImmunoPET imaging of Trop2 in patients with solid tumours.

Accurately predicting and selecting patients who can benefit from targeted or immunotherapy is crucial for precision therapy. Trophoblast cell surface antigen 2 (Trop2) has been extensively investigated as a pan-cancer biomarker expressed in various tumours and plays a crucial role in tumorigenesis through multiple signalling pathways. Our laboratory successfully developed two 68Ga-labelled nanobody tracers that can rapidly and specifically target Trop2. Of the two tracers, [68Ga]Ga-NOTA-T4, demonstrated excellent pharmacokinetics in preclinical mouse models and a beagle dog. Moreover, [68Ga]Ga-NOTA-T4 immuno-positron emission tomography (immunoPET) allowed noninvasive visualisation of Trop2 heterogeneous and differential expression in preclinical solid tumour models and ten patients with solid tumours. [68Ga]Ga-NOTA-T4 immunoPET could facilitate clinical decision-making through patient stratification and response monitoring during Trop2-targeted therapies.

ImmunoPET imaging of Trop2 expression in solid tumors with nanobody tracers.

PURPOSE: The high expression of the transmembrane glycoprotein trophoblast cell-surface antigen 2 (Trop2) was strongly associated with the progression of solid tumors, including pancreatic and gastric cancers. Our study aimed to construct Trop2-specific immuno-positron emission tomography (immunoPET) probes and assess the diagnostic abilities in preclinical pancreatic and gastric cancer models. METHODS: The expression of Trop2 in pancreatic cancer was determined by single-cell sequencing and immunohistochemistry on tissue microarray (TMA). Flow cytometry was used to screen the expression of Trop2 in pancreatic cancer cell lines. Two nanobodies (i.e., RTD98 and RTD01) targeting Trop2 were developed and labeled with gallium-68 (68Ga, T1/2 = 1.1 h) to construct immunoPET imaging probes. The agents were researched in cell-derived pancreatic and patient-derived gastric cancer models expressing varying Trop2. RESULTS: Single-cell sequencing results showed high expression of Trop2 in pancreatic ductal cells as well as acinar cells and immunohistochemical staining of TMA from pancreatic cancers showed significantly higher expression of Trop2 in cancerous than in paracancerous tissues. ImmunoPET utilizing [68Ga]Ga-NOTA-RTD98 could clearly delineate subcutaneous tumors, both in cell-derived pancreatic cancer models and patient-derived gastric cancer models, superior to imaging using [18F]-FDG or a non-specific probe [68Ga]Ga-NOTA-RTD161. Another probe with improved pharmacokinetics targeting Trop2, [68Ga]Ga-NOTA-RTD01, was further prepared and showed advantageous diagnostic capabilities in preclinical pancreatic cancer models. CONCLUSION: In the work, we reported two nanobody tracers targeting human Trop2 which may facilitate better use of Trop2-targeted therapeutics by noninvasively displaying expression dynamics of the target.

Accurate Detection of Multiple Tumor Mutations in Formalin-Fixed Paraffin-Embedded Tissues by Coupling Sequence Artifacts Elimination and Mutation Enrichment With MeltArray.

Formalin-fixed paraffin-embedded (FFPE) tissues are the primary source of DNA for companion diagnostics (CDx) of cancers. Degradation of FFPE tissue DNA and inherent tumor heterogeneity constitute serious challenges in current CDx assays. To address these limitations, we introduced sequence artifact elimination and mutation enrichment to MeltArray, a highly multiplexed PCR approach, to establish an integrated protocol that provides accuracy, ease of use, and rapidness. Using PIK3CA mutations as a model, we established a MeltArray protocol that could eliminate sequence artifacts completely and enrich mutations from 23.5- to 59.4-fold via a single-reaction pretreatment step comprising uracil-DNA-glycosylase excision and PCR clamping. The entire protocol could identify 13 PIK3CA hotspot mutations of 0.05% to 0.5% mutant allele fractions within 5 hours. Evaluation of 106 breast cancer and 40 matched normal FFPE tissue samples showed that all 47 PIK3CA mutant samples were from the cancer tissue, and no false-positive results were detected in the normal samples. Further evaluation of 105 colorectal and 40 matched normal FFPE tissue samples revealed that 11 PIK3CA mutants were solely from the cancer sample. The detection results of our protocol were consistent with those of the droplet digital PCR assays that underwent sequence artifact elimination. Of the 60 colorectal samples with next-generation sequencing results, the MeltArray protocol detected 2 additional mutant samples with low mutant allele fractions. We conclude that the new protocol provides an improved alternative to current CDx assays for detecting tumor mutations in FFPE tissue DNA.

Clinical Validation of the Unparalleled Sensitivity of the Novel Allele-Discriminating Priming System Technology-Based EGFR Mutation Assay in Patients with Operable Non-Small Cell Lung Cancer.

PURPOSE: Recently, we developed allele-discriminating priming system (ADPS) technology. This method increases the sensitivity of conventional quantitative polymerase chain reaction up to 100 folds, with limit of detection, 0.01%, with reinforced specificity. This prospective study aimed to develop and validate the accuracy of ADPS epidermal growth factor receptor (EGFR) Mutation Test Kit using clinical specimens. MATERIALS AND METHODS: In total 189 formalin-fixed paraffin-embedded tumor tissues resected from patients with non-small cell lung cancer were used to perform a comparative evaluation of the ADPS EGFR Mutation Test Kit versus the cobas EGFR Mutation Test v2, which is the current gold standard. When the two methods had inconsistent results, next-generation sequencing-based CancerSCAN was utilized as a referee. RESULTS: The overall agreement of the two methods was 97.4% (93.9%-99.1%); the positive percent agreement, 95.0% (88.7%-98.4%); and the negative percent agreement, 100.0% (95.9%-100.0%). EGFR mutations were detected at a frequency of 50.3% using the ADPS EGFR Mutation Test Kit and 52.9% using the cobas EGFR Mutation Test v2. There were 10 discrepant mutation calls between the two methods. CancerSCAN reproduced eight ADPS results. In two cases, mutant allele fraction was ultra-low at 0.02% and 0.06%, which are significantly below the limit of detection of the cobas assay and CancerSCAN. Based on the EGFR genotyping by ADPS, the treatment options could be switched in five patients. CONCLUSION: The highly sensitive and specific ADPS EGFR Mutation Test Kit would be useful in detecting the patients who have lung cancer with EGFR mutation, and can benefit from the EGFR targeted therapy.

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.

Necessity of strengthening the current clinical regulatory for companion diagnostics: An institutional comparison of the FDA, EMA, and MFDS.

Companion diagnostics (CDx), which is essential in precision medicine, is changing to a personalized treatment approach. CDx is a test that identifies patients who can benefit from a specific drug and those who experience side effects of drugs for safe and effective treatment. Conversely, when CDx has inadequate diagnostic performance or has not been adequately validated in a particular treatment, treatment prediction based on diagnostic results is not possible. Given the importance of CDx for the clinical use of biomarkers, strict regulation is essential. Regulators are providing more stringent regulations and are developing or revising guidelines. For example, the EU's In Vitro Diagnostic Regulation has defined CDx for the first time, raising awareness of the importance of CDx. However, if a new clinical performance test needs to be performed to meet the latest specifications or requirements for clinical data, problems such as securing clinical samples or institutions, cost, and time may occur. Therefore, an efficient clinical regulatory process may be required to meet stringent regulatory requirements. This study examines the need to strengthen the current clinical regulatory framework for CDx through an institutional comparison of regulatory agencies (FDA, EMA, and MFDS).

Toward Personalized Treatment of Depression: An Affordable Citalopram Test based on a Solid-Contact Potentiometric Electrode for at-Home Monitoring of the Antidepressant Dosage.

Citalopram (CTLP) is one of the most common antidepressants prescribed worldwide. It has a narrow therapeutic window and can cause severe toxicity and mortality if the dosage exceeds the safe level. Reports indicated that at-home monitoring of citalopram dosage considerably benefits the patients, yet there are no devices capable of such measurement of citalopram in biofluids. This work presents an affordable citalopram test for at-home and point-of-care monitoring of citalopram levels in urine, ensuring a safe and effective drug compliance. Our platform consists of a citalopram-selective yarn-based electrode (CTLP-SYE) that uses polymeric sensing membranes to provide valuable information about drug concentration in urine. CTLP-SYE is noninvasive and has a response time of fewer than 10 s. The fabricated electrode showed near-Nernstian behavior with a 52.3 mV/decade slope in citalopram hydrobromide solutions ranging from 0.5 µM to 1.0 mM, with a detection limit of 0.2 µM. Results also indicated that neither interfering ions nor pH affects electrode performance. We showed that CTLP-SYE could accurately and reproducibly measure citalopram in human urine (RSD 2.0 to 3.2%, error <12%) at clinically relevant concentrations. This work paves the way for the personalized treatment of depression and accessible companion diagnostics to improve treatment efficacy and safety.

Alternate Antimicrobial Therapies and Their Companion Tests.

New antimicrobial approaches are essential to counter antimicrobial resistance. The drug development pipeline is exhausted with the emergence of resistance, resulting in unsuccessful trials. The lack of an effective drug developed from the conventional drug portfolio has mandated the introspection into the list of potentially effective unconventional alternate antimicrobial molecules. Alternate therapies with clinically explicable forms include monoclonal antibodies, antimicrobial peptides, aptamers, and phages. Clinical diagnostics optimize the drug delivery. In the era of diagnostic-based applications, it is logical to draw diagnostic-based treatment for infectious diseases. Selection criteria of alternate therapeutics in infectious diseases include detection, monitoring of response, and resistance mechanism identification. Integrating these diagnostic applications is disruptive to the traditional therapeutic development. The challenges and mitigation methods need to be noted. Applying the goals of clinical pharmacokinetics that include enhancing efficacy and decreasing toxicity of drug therapy, this review analyses the strong correlation of alternate antimicrobial therapeutics in infectious diseases. The relationship between drug concentration and the resulting effect defined by the pharmacodynamic parameters are also analyzed. This review analyzes the perspectives of aligning diagnostic initiatives with the use of alternate therapeutics, with a particular focus on companion diagnostic applications in infectious diseases.

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.

A randomized, triple-blinded controlled clinical study with a novel disease-modifying drug combination in equine lameness-associated osteoarthritis.

Objective: This study aimed to test a novel treatment combination (TC) (equivalent to sildenafil, mepivacaine, and glucose) with disease-modifying properties compared to Celestone® bifas® (CB) in a randomized triple-blinded phase III clinical study in horses with mild osteoarthritis (OA). Joint biomarkers (reflecting the articular cartilage and subchondral bone remodelling) and clinical lameness were used as readouts to evaluate the treatment efficacy. Methods: Twenty horses with OA-associated lameness in the carpal joint were included in the study and received either TC (n = 10) or CB (n = 10) drug intra-articularly-twice in the middle carpal joint with an interval of 2 weeks (visit 1 & 2). Clinical lameness was assessed both objectively (Lameness locator) and subjectively (visually). Synovial fluid and serum were sampled for quantification of the extracellular matrix (ECM) neo-epitope joint biomarkers represented by biglycan (BGN262) and cartilage oligomeric matrix protein (COMP156). Another two weeks later clinical lameness was recorded, and serum was collected for biomarkers analysis. The overall health status was compared pre and post-intervention by interviewing the trainer. Results: Post-intervention, SF BGN262 levels significantly declined in TC (P = 0.002) and COMP156 levels significantly increased in CB (P = 0.002). The flexion test scores improved in the TC compared to CB (P =0.033) and also had an improved trotting gait quality (P =0.044). No adverse events were reported. Conclusion: This is the first clinical study presenting companion diagnostics assisting in identifying OA phenotype and evaluating the efficacy and safety of a novel disease-modifying osteoarthritic drug.

A Systematic Database Approach to Identify Companion Diagnostic Testing in Clinical Trials under the New In Vitro Diagnostic Medical Devices Regulation.

The European Union In Vitro Diagnostic Medical Devices Regulation (EU) 2017/746 (IVDR) introduces companion diagnostics (CDx) as a new legal term. CDx are applied in combination with a medicinal product to identify patient subgroups most likely to benefit from a treatment or who are at increased risk. This new regulation came into full effect on 26 May 2022 and represents the current development in personalized medicine. The implementation of IVDR and CDx is a regulatory challenge in the EU, requiring re-assessment of in vitro diagnostic medical devices (IVD) in terms of their CDx designation. To retrospectively identify IVD biomarker testing applied in clinical trials, a systematic search in the German PharmNet Clinical Trials database was developed. In total 3643 clinical trials conducted between 2004 and 2022 were identified. The results were analyzed in terms of medicinal products, biomarkers, and IVDs. Patient stratification based on biomarker testing mainly takes place in oncology-related trials, and the biomarkers most frequently tested are PD-L1 and HER2. Furthermore, there is a significant overlap between the collected data and non-European national authorities that have already implemented the CDx concept. This analysis could be indicatory of the medicinal products and corresponding IVD tests that could be CDx candidates under the IVDR.