NEW YORK – Universal DX is planning for discussions with the US Food and Drug Administration as more positive data for its Signal-C liquid biopsy colorectal cancer early detection test emerges.
The Seville, Spain-based diagnostics firm presented results at the American Society of Clinical Oncology Gastrointestinal Cancers Symposium in January from an international cohort of patients who underwent testing with Signal-C. Christian Hense, chief operating officer of Universal DX, said the latest data helps make the case to eventually commercialize Signal-C globally.
"It looks at patient populations that we recruited in the US, in Spain, and in a couple of other European countries, and what we see is that the results are the same," Hense said. "We're getting similar accuracy for colorectal cancer detection and specificity across these different populations, which really stands out because it makes it a test that can be globally commercialized eventually."
While Hense did not disclose specifics on potential discussions with the FDA, he noted that the firm is currently working in parallel to report data from a large validation study of Signal-C later this year and start the FDA approval process.
Signal-C measures tumor-derived cell-free DNA (cfDNA) methylation status and fragmentation signals in blood. The biomarkers measured by Signal-C were identified in an earlier study using whole-genome bisulfite sequencing on tumor tissue, buffy coat, and plasma from patients with and without colorectal cancer. The researchers then developed a machine-learning model trained on the cfDNA methylation and fragmentation scores to identify these biomarkers associated with colorectal cancer in blood samples.
The data presented at the ASCO GI Symposium last month included results from a prospective, observational study of patient blood samples collected either prior to a scheduled colonoscopy screening or prior to surgery for colorectal cancer. There were 95 samples from patients with colorectal cancer and 204 matched control samples. Of the control group, 50 had negative colonoscopy results, 125 had benign colonoscopy findings, and 29 had non-advanced adenomas.
The ASCO GI data showed Signal-C had 92 percent sensitivity to detect colorectal cancer across all stages. The test had 91 percent sensitivity for stage I, 92 percent for stage II, 91 percent for stage III, and 93 percent for stage IV. It also had high sensitivity to detect different colorectal cancer locations, with 86 percent sensitivity for proximal colorectal tumors, 96 percent for distal colorectal cancers, and 89 percent for rectal tumors.
The test's overall specificity in this study was 94 percent. It correctly identified 97 percent of patients with non-advanced adenomas; 91 percent of patients with benign colonoscopy findings of diverticulosis, hemorrhoids, or hyperplastic polyps; and 96 percent of the group with negative colonoscopy findings.
Hense noted that these latest results were consistent with previous findings. "It's very reassuring for us that we're replicating similar accuracy on a completely new sample set, and that's important because it stands for the robustness of the technology and the approach," he said.
Beyond cancer detection, Universal DX is also exploring the prognostic value of methylation markers identified using Signal-C. In data presented at an American Association for Cancer Research Special Conference in November, researchers found that high expression of three genes associated with methylation status — FGF14, DPY19L2P1, and PTPRO — were associated with poorer overall survival among colorectal cancer patients. They concluded that methylation signals and their corresponding biomarkers could play a role in the development and progression of colorectal cancer. However, these findings require more validation.
As Universal DX looks toward potential approval in the cancer detection space, they're targeting the test for average-risk patients visiting their primary care physician, Hense said. This primary care space is likely to be a crowded market for colorectal cancer detection. Exact Sciences is already established in this market with its stool-based Cologuard test and is working on a blood-based version, and Guardant Health, which markets liquid biopsy tests to oncologists, is developing a blood-based test called Guardant Shield that the firm hopes to bring to the US market next year.
However, in December, Guardant reported 83 percent sensitivity for colorectal cancer detection but only 13 percent sensitivity for advance adenomas at 90 percent specificity for the blood-based assay. What that data means for FDA marketing clearance, as well as uptake of the assay when it reaches the market, remains to be seen.
Also at ASCO GI last month, CellMax Life presented positive data for its blood-based colorectal cancer detection assay, FirstSight. CellMax's test, which measures circulating epithelial cells, showed 92 percent sensitivity for colorectal cancer and 55 percent sensitivity for advanced adenomas at 91 percent specificity.
However, Universal DX sees space in this market for its Signal-C test. Hense estimates that the colorectal cancer screening market is about 120 million people in the US who would be tested every few years, depending on the screening method.
"We want to be in that primary care market," Hense said. "There's so many patients that are benefiting from colorectal screening overall, and I believe noninvasive testing is the way to go. Ultimately, there will be space for various modalities and approaches."
Outside of primary care, Universal DX is also considering commercializing the test in specialty medicine, such as gastroenterology and women's health, to reach even more patients, Hense said.
Hense also said the ability to detect pre-cancerous lesions, called advanced adenomas, is an important differentiating factor. Universal DX presented data in 2021 at the European Association of Cancer Research Congress showing Signal-C was able to detect colorectal advanced adenomas with 55 percent sensitivity and 90 percent specificity.
As the firm plans for regulatory discussions for Signal-C and another large data readout this year, Hense noted it has learned from previous entrants into the market, taking advantage of the precedent set by other diagnostics firms to move Signal-C through the process.
"The current tests in the colonoscopy or fecal-based areas have a couple of drawbacks that we can alleviate with the blood-based tests; patient compliance is probably the biggest one," Hense said. "With a blood-based test, you can just add it into your annual checkup. You add another tube and while you're getting tested for vitamins, cholesterol, and all of these other things, you also get tested for colorectal cancer."