Accurate blood-based clinical laboratory testing for cancer promises to encourage more people to undergo early screening for deadly diseases
One holy grail in diagnostics is to develop less-invasive specimen types when screening or testing for different cancers. This is the motivation behind the creation of a new assay for colorectal (colon) cancer that uses a blood sample and that could be offered by clinical laboratories. The data on this assay and its performance was featured in a recent issue of the New England Journal of Medicine(NEJM).
The company developing this new test recognized that more than 50,000 people will die in 2024 from colon cancer, according to the American Cancer Society. That’s primarily because people do not like colonoscopies even though the procedure can detect cancer in its early stages. Similarly, patients tend to find collecting their own fecal samples for colon cancer screening tests to be unpleasant.
But the clinical laboratory blood test for cancer screening developed by Guardant Health may make diagnosing the deadly disease less invasive and save lives. The test “detects 83% of people with colorectal cancer with specificity of 90%,” a company press release noted.
“Early detection could prevent more than 90% of colorectal cancer-related deaths, yet more than one third of the screening-eligible population is not up to date with screening despite multiple available tests. A blood-based test has the potential to improve screening adherence, detect colorectal cancer earlier, and reduce colorectal cancer-related mortality,” the study authors wrote in the NEJM.
As noted above, this is the latest example of test developers working to develop clinical laboratory tests that are less invasive for patients, while equaling or exceeding the sensitivity and specificity of existing diagnostic assays for certain health conditions.
“I do think having a blood draw versus undergoing an invasive test will reach more people, My hope is that with more tools we can reach more people,” Barbara H. Jung, MD (above), President of the American Gastroenterological Association, told NPR. Clinical laboratory blood tests for cancer may encourage people who do not like colonoscopies to get regular screening. (Photo copyright: American Gastroenterology Association.)
Developing the Shield Blood Test
Colorectal cancer is the “third most common cancer among men and women in the US,” according to the American Gastrological Association (AGA). And yet, millions of people do not get regular screening for the disease.
To prove their Shield blood test, Guardant Health, a precision oncology company based in Redwood City, Calif., enrolled more than 20,000 patients between the ages of 45-84 from across the US in a prospective, multi-site registrational study called ECLIPSE (Evaluation of ctDNA LUNAR Assay In an Average Patient Screening Episode).
“We assessed the performance characteristics of a cell-free DNA (cfDNA) blood-based test in a population eligible for colorectal cancer screening. The coprimary outcomes were sensitivity for colorectal cancer and specificity for advanced neoplasia (colorectal cancer or advanced precancerous lesions) relative to screening colonoscopy. The secondary outcome was sensitivity to detect advanced precancerous lesions,” the study authors wrote in the NEJM.
In March, Guardant completed clinical trials of its Shield blood test for detecting colorectal cancer (CRC) in men and women. According to the company press release, the test demonstrated:
83% sensitivity in detecting individuals with CRC.
88% sensitivity in detecting pathology-confirmed Stages I-III.
Additionally, the Shield test showed sensitivity by stage of:
65% for pathology-confirmed Stage I,
55% for clinical Stage I,
100% for Stage II, and
100% for Stage III.
“The results of the study are a promising step toward developing more convenient tools to detect colorectal cancer early while it is more easily treated,” said molecular biologist and gastroenterologist William M. Grady, MD, Medical Director, Gastrointestinal Cancer Prevention Program at Fred Hutchinson Cancer Center and corresponding author of the ECLIPSE study in the press release. “The test, which has an accuracy rate for colon cancer detection similar to stool tests used for early detection of cancer, could offer an alternative for patients who may otherwise decline current screening options.”
Are Colonoscopies Still Needed?
“More than three out of four Americans who die from colorectal cancer are not up to date with their recommended screening, highlighting the need for a more convenient and less invasive screening method that can overcome barriers associated with traditional options,” Daniel Chung, MD, gastroenterologist at Massachusetts General Hospital and Professor of Medicine at Harvard Medical School, said in the Guardant press release.
Barbara H. Jung, MD, President of the American Gastroenterological Association, says that even if Guardant’s Shield test makes it to the public the “dreaded colonoscopy” will still be needed because the procedure is used to locate and test polyps. “And when you find those you can also remove them, which in turn prevents the cancer from forming,” she told NPR.
There is hope that less invasive clinical laboratory testing will encourage more individuals to get screened for cancer earlier and regularly, and that the shift will result in a reduction in cancer rates.
“Colorectal cancer is highly treatable if caught in the early stages,” said Chris Evans, President of the Colon Cancer Coalition, in the Guardant press release.
Guardant Health’s ECLIPSE study is a prime example of the push clinical laboratory test developers are making to create user-friendly test options that make it easier for patients to follow through with regular screening for early detection of diseases. It echoes a larger effort in the medical community to think outside the box and come up with creative solutions to reach wider audiences in the name of prevention.
This comprehensive white paper is designed to be your go-to guide, providing invaluable insights into critical success factors and essential functions crucial for maintaining compliance and delivering reliable results. Tailored for clinical molecular laboratory staff, this resource delves into the tangible aspects of compliant method validation, offering practical strategies for proving the accuracy and efficacy of laboratory-developed tests (LDTs).
Prior to that, however, the FDA had already announced its intention to issue a proposed rule giving the agency regulatory oversight of LDTs.
“The FDA has continually supported the passage of the VALID Act by Congress,” attorney Charles Dunham IV, a Shareholder at Greenberg Traurig LLP in Houston, told Dark Daily. “In fact, there is speculation that the VALID Act will be attached to the Pandemic and All Hazards Preparedness Act as it moves through Congress.”
“The FDA may not actually proceed with promulgating rules to regulate LDTs if it is concerned it will not be successful in court if the rules are challenged, which would happen,” said attorney Charles Dunham IV (above), a Shareholder at Greenberg Traurig, LLP. Clinical laboratory leaders can learn more from Dunham during a panel discussion at next week’s 2023 Executive War College on Diagnostics, Clinical Laboratory, and Pathology Management in New Orleans. (Photo copyright: Greenberg Traurig LLP.)
Arguments For and Against FDA LDT Regulation of LDTs
Supporters of the VALID Act contend that putting LDTs under FDA regulation will lead to improved patient safety and less review for low-risk tests. Their argument is that LDTs should undergo the same FDA review and approval process as other medical devices.
Hospital laboratory managers and pathologists—particularly in academic medical center laboratories—have largely opposed FDA regulation of LDTs. They prefer to keep the current setup under which lab-developed tests are validated under the Clinical Laboratory Improvement Amendments of 1988 (CLIA). They argue that FDA intervention will slow down development of new tests.
In response, an FDA official indicated during the American Clinical Laboratory Association’s (ACLA) annual meeting on March 1 that the federal agency plans to issue a proposed rule to regulate LDTs, BioWorld reported. That rulemaking has not yet emerged. It’s possible the FDA will wait and see what happens in Congress with the VALID Act.
“Some legal experts have suggested that one significant new legal challenge FDA may face is the Supreme Court’s West Virginia v. EPA decision last summer that limited the ability of the EPA to cap power plant emissions by regulation due to the EPA’s lack of explicit congressional authority to do so,” said Gee, who also will appear on the Executive War College legal panel next week.
“The West Virginia v. EPA ruling provides support for those in the clinical lab industry who point to the FDA’s lack of clear statutory authority to regulate LDTs and therefore fundamentally disagree with FDA’s longstanding position that LDTs are medical devices subject to FDA’s authority to regulate,” he added.
Actions Clinical Laboratory Managers Can Take
Clinical laboratory managers who want to share their thoughts about the future of LDT regulation may want to take one or both of the following actions:
Contact their representatives in Congress.
Find out whether any trade associations they belong to have taken a position on the VALID Act.
Clinical laboratory professionals should monitor the VALID Act’s progress while also paying attention to industry groups and manufacturers that support or oppose the bill.
Doing so will provide a clearer indication of who has the most to gain or lose should the legislation be passed. Pathologists and medical laboratory managers should also remain alert for further efforts by the FDA to issue proposed rulemaking to regulate LDTs.
But even though the College of American Pathologists (CAP) and nine other organizations signed a December 12 stakeholder letter to leaders of key House and Senate committees urging passage of legislation that would enable some regulation of LDTs, the VALID Act was ultimately omitted from the year-end omnibus spending bill (H.R. 2617).
That may be due to pressure from organizations representing clinical laboratories and pathologists which lobbied hard against the bill.
Responding to criticism of its stance on FDA oversight of LDTs, in a May 2022 open letter posted on the organization’s website, anatomic pathologist and CAP president Emily Volk, MD, said “we at the CAP have an honest difference of opinion with some other respected laboratory organizations. … We believe the VALID Act is the only viable piece of legislation addressing the LDT issue. … the VALID Act contains many provisions that are similar to policy the CAP has advocated for regarding the regulation of laboratory tests since 2009. Importantly, the current version includes explicit protections for pathologists and our ability to practice medicine without infringement from the Food and Drug Administration (FDA).” (Photo copyright: College of American Pathologists.)
Organizations on Both Sides Brought Pressure to Bear on Legislators
The AAMC and AMP were especially influential, Bucshon told ProPublica. In addition to spending hefty sums on lobbying, AMP urged its members to contact legislators directly and provided talking points, ProPublica reported.
“The academic medical centers and big medical centers are in every state,” Bucshon said. As major employers in many locales, they have “a pretty big voice,” he added.
Discussing CAP’s reasoning behind its support of the VALID Act in a May 26 open letter and podcast, CAP president Emily Volk, MD, said the Valid Act “creates a risk-based system of oversight utilizing three tiers—low, moderate and high risk—in order to target the attention of the FDA oversight.”
While acknowledging that it had room for improvement, she lauded the bill’s three-tier risk-based system, in which tests deemed to have the greatest risks would receive the highest level of scrutiny.
She also noted that the bill exempts existing LDTs from an FDA premarket review “unless there is a safety concern for patients.” It would also exempt “low-volume tests, modified tests, manual interpretation tests, and humanitarian tests,” she wrote.
In addition, the bill would “direct the FDA not to create regulations that are duplicative of regulation under CLIA,” she noted, and “would require the FDA to conduct public hearings on LDT oversight.”
Pros and Cons of the VALID Act
One concern raised by opponents relates to how the VALID Act addressed user fees paid by clinical laboratories to fund FDA compliance activities. But Volk wrote that any specific fees “would need to be approved by Congress in a future FDA user fee authorization bill after years of public input.”
During the May 2022 podcast, Volk also cast CAP’s support as a matter of recognizing political realities.
“We understand that support for FDA oversight of laboratory-developed tests or IVCTs is present on both sides of the aisle and in both houses of Congress,” she said. “In fact, it enjoys wide support among very influential patient advocacy groups.” These groups “are very sophisticated in their understanding of the issues with laboratory-developed tests, and they do have the ear of Congress. There are many in the laboratory community that believe the VALID Act goes too far, but I can tell you that many of these patient groups don’t believe it goes far enough and are actively pushing for even more restrictive paradigms.”
Also urging passage of the bill were former FDA commissioners Scott Gottlieb, MD, and Mark B. McClellan, MD, PhD. In a Dec. 5 opinion piece for STAT, they noted that “diagnostic technologies have undergone considerable advances in recent decades, owing to innovation in fields like genomics, proteomics, and data science.” However, they wrote, laws governing FDA oversight “have not kept pace,” placing the agency in a position of regulating tests based on where they are made—in a medical laboratory or by a manufacturer—instead of their “distinctive complexity or potential risks.”
In their May 22 letter, opponents of the legislation outlined broad areas of concern. They contended that it would create “an onerous and complex system that would radically alter the way that laboratory testing is regulated to the detriment of patient care.” And even though existing tests would be largely exempted from oversight, “the utility of these tests would diminish over time as the VALID Act puts overly restrictive constraints on how they can be modified.”
CLIA Regulation of LDTs also Under Scrutiny
The provision to avoid duplication with the Clinical Laboratory Improvement Amendments (CLIA) program—which currently has some regulatory oversight of LDTs and IVCTs—is “insufficient,” opponents added, “especially when other aspects of the legislation call for requirements and activities that lead to duplicative and unnecessary regulatory burden.”
Opponents to the VALID Act also argued that the definitions of high-, medium-, and low-risk test categories lacked clarity, stating that “the newly created definition of moderate risk appears to overlap with the definition of high risk.”
The opponents also took issue with the degree of discretion that the bill grants to the US Secretary of Health and Human Services. This will create “an unpredictable regulatory process and ambiguities in the significance of the policy,” they wrote, while urging the Senate committee to “narrow the discretion so that stakeholders may better evaluate and understand the implications of this legislation.”
Decades ago, clinical laboratory researchers were allowed to develop assays in tandem with clinicians that were intended to provide accurate diagnoses, earlier detection of disease, and help guide selection of therapies. Since the 1990s, however, an industry of investor-funded laboratory companies have brought proprietary LDTs to the national market. Many recognize that this falls outside the government’s original intent for encouragement of laboratory-developed tests to begin with.
Proteins in human saliva make up its proteome and may be the key to new, precision medicine diagnostics that would give clinical pathologists new capabilities to identify disease
Clinical pathologists may soon have an array of new precision medicine diagnostic tools based on peoples’ saliva. There are an increasing number of “–omes” that can be the source of useful diagnostic biomarkers for developing clinical laboratory tests. The latest is the world’s first saliva protein biome wiki.
Called the Human Salivary Proteome Wiki (HSP Wiki), the “public data platform,” which was created by researchers at the University of Buffalo, is the “first of its kind,” according to Labroots, and “contains data on the many thousands of proteins present in saliva.”
The HSP Wiki brings together data from independent studies on proteins present in human saliva. One of the researchers’ goals is to speed up the development of saliva-based diagnostics and personalized medicine tools.
In “The Human Salivary Proteome Wiki: A Community-Driven Research Platform,” published in the Journal of Dental Research, the researchers wrote, “Saliva has become an attractive body fluid for on-site, remote, and real-time monitoring of oral and systemic health. At the same time, the scientific community needs a saliva-centered information platform that keeps pace with the rapid accumulation of new data and knowledge by annotating, refining, and updating the salivary proteome catalog.
“We developed the Human Salivary Proteome (HSP) Wiki as a public data platform for researching and retrieving custom-curated data and knowledge on the saliva proteome. … The HSP Wiki will pave the way for harnessing the full potential of the salivary proteome for diagnosis, risk prediction, therapy of oral and systemic diseases, and preparedness for emerging infectious diseases,” they concluded.
“This community-based data and knowledge base will pave the way to harness the full potential of the salivary proteome for diagnosis, risk prediction, and therapy for oral and systemic diseases, and increase preparedness for future emerging diseases and pandemics,” Stefan Ruhl, DDS, PhD (above right, with Omer Gokcumen, PhD, Associate Professor of Biological Sciences on left), Professor, Department of Oral Biology, University of Buffalo, and lead researcher of the study, told Labroots. Development of precision medicine clinical laboratory diagnostics is part of their research goals. (Photo copyright: University of Buffalo.)
Where Does Saliva Come From?
Saliva is a complex biological fluid that has long been linked to oral health and the health of the upper gastrointestinal tract. Only recently, though, have scientists begun to understand from where in the body saliva proteins originate.
The authors wrote: “Salivary proteins are essential for maintaining health in the oral cavity and proximal digestive tract, and they serve as potential diagnostic markers for monitoring human health and disease. However, their precise organ origins remain unclear.
“Through transcriptomic analysis of major adult and fetal salivary glands and integration with the saliva proteome, the blood plasma proteome, and transcriptomes of 28+ organs, we link human saliva proteins to their source, identify salivary-gland-specific genes, and uncover fetal- and adult-specific gene repertoires,” they added.
“Our results pave the way for future investigations into glandular biology and pathology, as well as saliva’s use as a diagnostic fluid,” the researchers concluded.
Saliva plays a crucial role in digestion by breaking down starches. It also provides a protective barrier in the mouth. When salivary glands malfunction, patients can face serious health consequences. Although clinicians and scientists have long understood the importance of saliva to good health, the question now is whether it contains markers of specific diseases.
“The Human Salivary Proteome Wiki contains proteomic, genomic, transcriptomic data, as well as data on the glycome, sugar molecules present on salivary glycoproteins. New data goes through an interdisciplinary team of curators, which ensures that all input data is accurate and scientifically sound,” noted Labroots.
The graphic above “shows the interconnectedness of the thousands of salivary proteins originating from blood plasma, parotid glands, and submandibular and sublingual glands. The diagram is one of many tools available to researchers and clinicians through the Human Salivary Proteome Wiki,” noted a UBNow blog post. (Graphic copyright: University of Buffalo.)
Omics and Their Role in Clinical Laboratory Diagnostics
Proteomics is just one of several hotly-researched -omics that hold the potential to develop into important personalized medicine and diagnostics tools for pathologists. Genomics is a related area of research being studied for its potential to benefit precision medicine diagnostics.
However, unlike genomes, which do not change, proteomes change constantly. That is one of the main reasons studying the human salivary proteome could lead to valuable diagnostics tools.
Combining the study of the -omes with tools like mass spectrometry, a new era of pathology may be evolving. “With the rapid decrease in the costs of omics technologies over the past few years, whole-proteome profiling from tissue slides has become more accessible to diagnostic labs as a means of characterization of global protein expression patterns to evaluate the pathophysiology of diseases,” noted Pathology News.
Saliva and the Age of Precision Medicine
The study of the -omes may be an important element in the evolution of precision medicine, because of its ability to provide information about what is happening in patients’ bodies at the point of care.
Thus, a full understanding of the proteome of saliva and what causes it to change in response to different health conditions and diseases could open the door to an entirely new branch of diagnostics and laboratory medicine. It is easy and non-invasive to gather and, given that saliva contains so much information, it offers an avenue of study that may improve patients’ lives.
It also would bring us closer to the age of precision medicine where clinical laboratory scientists and pathologists can contribute even more value to referring physicians and their patients.
