The Labyrinth of Product Development and Regulatory Approvals in Liquid Biopsy Diagnostics

Liquid Biopsy in the Clinical Management of Cancers

Liquid biopsy, a noninvasive diagnosis that examines circulating tumor components in body fluids, is increasingly used in cancer management. An overview of relevant literature emphasizes the current state of liquid biopsy applications in cancer care. Biomarkers in liquid biopsy, particularly circulating tumor DNA (ctDNA), circulating tumor RNAs (ctRNA), circulating tumor cells (CTCs), extracellular vesicles (EVs), and other components, offer promising opportunities for early cancer diagnosis, treatment selection, monitoring, and disease assessment. The implementation of liquid biopsy in precision medicine has shown significant potential in various cancer types, including lung cancer, colorectal cancer, breast cancer, and prostate cancer. Advances in genomic and molecular technologies such as next-generation sequencing (NGS) and digital polymerase chain reaction (dPCR) have expanded the utility of liquid biopsy, enabling the detection of somatic variants and actionable genomic alterations in tumors. Liquid biopsy has also demonstrated utility in predicting treatment responses, monitoring minimal residual disease (MRD), and assessing tumor heterogeneity. Nevertheless, standardizing liquid biopsy techniques, interpreting results, and integrating them into the clinical routine remain as challenges. Despite these challenges, liquid biopsy has significant clinical implications in cancer management, offering a dynamic and noninvasive approach to understanding tumor biology and guiding personalized treatment strategies.

liquid biopsy holds a promising approach for the early detection of cancer: Current information and future perspectives

Cancer is becoming a global pandemic, and its occurrence is increasing rapidly, putting a strain on people's families, health systems, and finances, in addition to their physical, mental, and emotional well-being. Many cancer types lack screening programs, and many people at high risk of developing cancer do not follow recommended medical screening regimens because of the nature of currently available screening tests and other compliance issues, despite cancer being the second leading cause of death worldwide. Furthermore, a lot of liquid biopsy methods for early cancer screening are not sensitive enough to catch cancer early. Cancer treatment costs increase with the time it takes to diagnose the disease; therefore, early detection is essential to enhance the quality of life and survival rates. The current status of the liquid biopsy sector is examined in this paper.

Leading the pack: Best practices in comparative canine cancer genomics to inform human oncology

Pet dogs develop spontaneous cancers at a rate estimated to be five times higher than that of humans, providing a unique opportunity to study disease biology and evaluate novel therapeutic strategies in a model system that possesses an intact immune system and mirrors key aspects of human cancer biology. Despite decades of interest, effective utilization of pet dog cancers has been hindered by a limited repertoire of necessary cellular and molecular reagents for both in vitro and in vivo studies, as well as a dearth of information regarding the genomic landscape of these cancers. Recently, many of these critical gaps have been addressed through the generation of a highly annotated canine reference genome, the creation of several tools necessary for multi-omic analysis of canine tumours, and the development of a centralized repository for key genomic and associated clinical information from canine cancer patients, the Integrated Canine Data Commons. Together, these advances have catalysed multidisciplinary efforts designed to integrate the study of pet dog cancers more effectively into the translational continuum, with the ultimate goal of improving human outcomes. The current review summarizes this recent progress and provides a guide to resources and tools available for comparative study of pet dog cancers.

Proof of concept: Detection of cell free RNA from EDTA plasma in patients with lung cancer and non-cancer patients

INTRODUCTION

Nucleic acid sequencing technologies have advanced significantly in recent years, thereby allowing for the development of liquid biopsies as new means to detect cancer biomarkers and cancer heterogenicity. Most of the assays available, clinically, focus on cell free DNA (cfDNA), however, cell free RNA (cfRNA) is also present. cfRNA has the potential to complement and improve cancer detection especially in cancers like lung cancer, which are usually only diagnosed at late stages and therefore have poor long-term survival outcomes.

METHODS

Remnant EDTA plasma was collected from lung cancer patients and non-cancer individuals at the University of Maryland Medical Center. RNA was extracted and processed for next generation sequencing with a tagmentation-based library preparation approach.

RESULTS

cfRNA was successfully extracted and sequenced from 52 EDTA-treated plasma samples with volumes as low as 1.5 mL. This quantity was sufficient to prepare libraries with the length of libraries averaging from 264 bp to 381 bp and resulted in over 2.2 to 3.6 million total sequence reads respectively. Sequential dilution of cfRNA samples from healthy individuals indicated that the starting cfRNA concentration influenced the detection of differentially expressed genes.

CONCLUSIONS

This proof-of-concept study provides a framework for screening cfRNA for identifying biomarkers for early detection of lung cancer (and other cancers), using minimal amounts of samples (1.5 mL) from standard EDTA 3-mL collection tubes routinely used for patient care. Further studies in large populations are required to establish limit of detection and other parameters including precision, accuracy, sensitivity, and specificity, to standardize this method.

Analytical device miniaturization for the detection of circulating biomarkers

Diverse (sub)cellular materials are secreted by cells into the systemic circulation at different stages of disease progression. These circulating biomarkers include whole cells, such as circulating tumour cells, subcellular extracellular vesicles and cell-free factors such as DNA, RNA and proteins. The biophysical and biomolecular state of circulating biomarkers carry a rich repertoire of molecular information that can be captured in the form of liquid biopsies for disease detection and monitoring. In this Review, we discuss miniaturized platforms that allow the minimally invasive and rapid detection and analysis of circulating biomarkers, accounting for their differences in size, concentration and molecular composition. We examine differently scaled materials and devices that can enrich, measure and analyse specific circulating biomarkers, outlining their distinct detection challenges. Finally, we highlight emerging opportunities in biomarker and device integration and provide key future milestones for their clinical translation.

Accelerating the Development and Validation of Liquid Biopsy for Early Cancer Screening and Treatment Tailoring

Liquid biopsy (LB) is a minimally invasive method which aims to detect circulating tumor-derived components in body fluids. It provides an alternative to current cancer screening methods that use tissue biopsies for the confirmation of diagnosis. This paper attempts to determine how far the regulatory, policy, and governance framework provide support to LB implementation into healthcare systems and how the situation can be improved. For that reason, the European Alliance for Personalised Medicine (EAPM) organized series of expert panels including different key stakeholders to identify different steps, challenges, and opportunities that need to be taken to effectively implement LB technology at the country level across Europe. To accomplish a change of patient care with an LB approach, it is required to establish collaboration between multiple stakeholders, including payers, policymakers, the medical and scientific community, and patient organizations, both at the national and international level. Regulators, pharma companies, and payers could have a major impact in their own domain. Linking national efforts to EU efforts and vice versa could help in implementation of LB across Europe, while patients, scientists, physicians, and kit manufacturers can generate a pull by undertaking more research into biomarkers.

Liquid Biopsy Using Cell-Free or Circulating Tumor DNA in the Management of Hepatocellular Carcinoma

Liver cancer (hepatocellular carcinoma [HCC]) is a fatal cancer worldwide and often is detected at an advanced stage when treatment options are very limited. This drives the development of techniques and platforms for early detection of HCC. In recent years, liquid biopsy has provided a means of noninvasive detection of cancers. By detecting plasma circulating tumor DNA (ctDNA) released from dying cancer cells, the presence of HCC can be detected in a noninvasive manner. In this review, we discuss the molecular characteristics of ctDNA and its various molecular landscapes in HCC. These include the mutational landscape, single-nucleotide variations, copy number variations, methylation landscape, end motif/coordinate preference, hepatitis B virus integration, and mitochondrial DNA mutations. The consistency between the plasma ctDNA and the tumor tissue genomic DNA mutational profile is pivotal for the clinical utility of ctDNA in the clinical management of HCC. With strategic use of genetic information provided from plasma ctDNA profiling and procedure standardization to facilitate implementation in clinical practice, better clinical management would become permissible through more efficient detection and diagnosis of HCC, better prognostication, precision-matched treatment guidance, and more reliable disease monitoring.

Recommendations for Specimen and Therapy Selection in Colorectal Cancer

INTRODUCTION

Next-generation sequencing has emerged as a clinical tool for the identification of actionable mutations to triage advanced colorectal cancer patients for targeted therapies. The literature is conflicted as to whether primaries or their metastases should be selected for sequencing. Some authors suggest that either site may be sequenced, whereas others recommend sequencing the primary, the metastasis, or even both tumors. Here, we address this issue head on with a meta-analysis and provide for the first time a set of sensible recommendations to make this determination.

METHODS

From our own series, we include 43 tumors from 13 patients including 14 primaries, 10 regional lymph node metastases, 17 distant metastases, and two anastomotic recurrences sequenced using the 50 gene Ion AmpliSeq cancer NGS panel v2.

RESULTS

Based on our new cohort and a meta-analysis, we found that ~ 77% of patient-matched primary-metastatic pairs have identical alterations in these 50 cancer-associated genes.

CONCLUSIONS

Low tumor cellularity, tumor heterogeneity, clonal evolution, treatment status, sample quality, and/or size of the sequencing panel accounted for a proportion of the differential detection of mutations at primary and metastatic sites. The therapeutic implications of the most frequently discordant alterations (TP53, APC, PIK3CA, and SMAD4) are discussed. Our meta-analysis indicates that a subset of patients who fail initial therapy may benefit from sequencing of additional sites to identify new actionable genomic abnormalities not present in the initial analysis. Evidence-based recommendations are proposed.

Extracellular Vesicle Molecular Signatures Characterize Metastatic Dynamicity in Ovarian Cancer

BACKGROUND

Late-stage diagnosis of ovarian cancer, a disease that originates in the ovaries and spreads to the peritoneal cavity, lowers 5-year survival rate from 90% to 30%. Early screening tools that can: i) detect with high specificity and sensitivity before conventional tools such as transvaginal ultrasound and CA-125, ii) use non-invasive sampling methods and iii) longitudinally significantly increase survival rates in ovarian cancer are needed. Studies that employ blood-based screening tools using circulating tumor-cells, -DNA, and most recently tumor-derived small extracellular vesicles (sEVs) have shown promise in non-invasive detection of cancer before standard of care. Our findings in this study show the promise of a sEV-derived signature as a non-invasive longitudinal screening tool in ovarian cancer.

METHODS

Human serum samples as well as plasma and ascites from a mouse model of ovarian cancer were collected at various disease stages. Small extracellular vesicles (sEVs) were extracted using a commercially available kit. RNA was isolated from lysed sEVs, and quantitative RT-PCR was performed to identify specific metastatic gene expression.

CONCLUSION

This paper highlights the potential of sEVs in monitoring ovarian cancer progression and metastatic development. We identified a 7-gene panel in sEVs derived from plasma, serum, and ascites that overlapped with an established metastatic ovarian carcinoma signature. We found the 7-gene panel to be differentially expressed with tumor development and metastatic spread in a mouse model of ovarian cancer. The most notable finding was a significant change in the ascites-derived sEV gene signature that overlapped with that of the plasma-derived sEV signature at varying stages of disease progression. While there were quantifiable changes in genes from the 7-gene panel in serum-derived sEVs from ovarian cancer patients, we were unable to establish a definitive signature due to low sample number. Taken together our findings show that differential expression of metastatic genes derived from circulating sEVs present a minimally invasive screening tool for ovarian cancer detection and longitudinal monitoring of molecular changes associated with progression and metastatic spread.

The regulatory landscape of precision oncology laboratory medicine in the United States - Perspective on the past 5 years and considerations for future regulation

The regulatory landscape for precision oncology in the United States is complicated, with multiple governmental regulatory agencies with different scopes of jurisdiction. Several regulatory proposals have been introduced since the Food and Drug Administration released a draft guidance to regulate laboratory-developed tests in 2014. Key aspects of the most recent proposals and discussion of central arguments related to the regulation of precision oncology laboratory tests provides insight to stakeholders for future discussions related to regulation of laboratory tests.

Real-life multidisciplinary treatment for unresectable colorectal cancer liver metastases including hepatic artery infusion with chemo-filtration and liquid biopsy precision oncotherapy: observational cohort study

BACKGROUND

Hepatic artery infusion (HAI) and drug selection by liquid biopsy precision oncotherapy are under investigation for the multidisciplinary treatment of unresectable colorectal liver metastases (CRCLM) in progression after systemic therapy. Here, we compare the safety and efficacy of third-line HAI followed by target therapy with drug regimes selected by liquid biopsy precision oncotherapy to third-line systemic therapy with drug regimes selected partly by tissue biopsy precision oncotherapy, in a retrospective real-life study of 106 unresectable CRCLM patients.

METHODS

Drug regimens for HAI/target therapy were selected by assessing the sensitivity of purified circulating tumor cell (CTCs) to 5-fluorouracil, carboplatin, cisplatin, oxaliplatin, irinotecan, doxorubicin, mitomycin, raltitrexed, and melphalan in-vitro and by real-time qRT-PCR gene expression assays, and for the Systemic therapy cohort were selected by age, comorbidity, performance status, and absence of RAS mutations. Therapeutic responses, adverse events, and quality of life were evaluated by RECIST 1.1, CTCAE 4.03, and ECOG criteria, respectively, and chemo-filtration performed following HAI to reduce systemic toxic effects.

RESULTS

HAI/target therapy with drugs selected by liquid biopsy precision oncotherapy (44 patients), resulted in 2.27% CRs, 38.63% PRs, 56.81% SD,s and 2.27% PDs; ECOG 2 to 1 improvement, but no infusion-related technical or vascular complications, or deaths. Systemic therapy (62 patients) resulted in 1.6% CRs, 17.74% PRs, 37.09% SDs, and 45.16% PDs; more grade 1-2 adverse events and 4.84% ECOG 1 to 2 worsening. The median 5 month PFS in the HAI/target therapy cohort was significantly longer than 3 months in the systemic cohort (P < 0.007) and the median 14 month survival in the HAI/target therapy cohort was longer than 8.5 months in the systemic therapy cohort but not statistically significant. Multivariate analysis identified ECOG grade 2 as the most unfavourable survival prognostic factor in both cohorts.

CONCLUSIONS

HAI plus chemo-filtration followed by target therapy, with drug regimens selected by liquid biopsy precision oncotherapy, is a safe and efficacious alternative therapeutic strategy for unresectable CRCLM in progression after two lines of systemic therapy and should be considered for a multicentre prospective phase III study, to fully confirm this potential.