NEW YORK – Delfi Diagnostics on Tuesday shared results from a proof-of-concept study at the annual meeting of the American Association for Cancer Research showing the potential applicability of the technology behind its FirstLook liquid biopsy lung cancer screening test in ovarian cancer.
The FirstLook lung cancer test uses whole-genome sequencing and machine learning to detect patterns of fragmented DNA in the blood that are associated with the presence of cancer cells. The test has a 99.8 percent predictive value for the likelihood of detecting lung cancer through low-dose CT imaging. Delfi launched the test in October 2023 for people at elevated risk for lung cancer who are eligible for screening.
In a webcast press briefing at AACR, Delfi Founder Victor Velculescu, also a professor of oncology at Johns Hopkins University, said the FirstLook lung cancer test has been validated in a prospective trial in nearly a thousand patients with and without cancer, and those results have been submitted for publication. Meanwhile, the company is turning its efforts to ovarian cancer, where there is a significant unmet need for early detection methods.
In the ovarian cancer study, researchers analyzed blood samples from nearly 600 women with ovarian cancer, benign lesions, or without any known ovarian lesions who had been screened at hospitals in the Netherlands or Denmark. They developed a classifier incorporating those results plus CA125 and HE4 protein markers. Then they validated the classifier in a similar cohort of patients from the US, finding that the cross-validated sensitivity of the test in the discovery cohort ranged from 72 percent for stage I disease to 100 percent for stage IV. In comparison, testing for CA125 alone detected 34 percent of stage I cancers and 100 percent of stage IV disease. Delfi estimates the positive predictive value of the test, dubbed Delfi-pro, at 16 percent, compared to 5 percent or lower for CA125 alone.
"Given the low prevalence of ovarian cancer and the risks of exploratory surgery, a [positive predictive value] of 10 percent is needed to justify population-wide screening for ovarian cancer in a way that balances the benefits of early detection against the potential harm from unnecessary surgical procedures," Velculescu said. "These analyses suggest that an accessible, high-adherence, sensitive, and specific assay like Delfi-pro could enable population-wide ovarian cancer screening."
Velculescu noted that this is only an initial analysis of the test, and the company has already begun follow-up studies in average-risk and high-risk patients who are genetically predisposed to ovarian and other cancers.