The US Food and Drug Administration is dissatisfied with how the Laboratory Corporation of America clinically validated its homebrew OvaSure ovarian cancer test, which the agency considers a “high risk” product, according to a warning letter sent to the company.
The August 7 warning letter issued by the FDA suggests that the agency is reviewing LabCorp's multi-protein biomarker panel ovarian cancer test to determine if it is an in vitro diagnostic multivariate index assay that requires FDA clearance.
In the letter, the FDA's Office of In Vitro Device Evaluation and Safety asked LabCorp to discuss the utility of OvaSure, developed at Yale University and launched in June, after it learned that the test's performance characteristics were based on results of a study that does not represent the intended treatment population.
In that letter, OIVD Director Steven Gutman wrote that the scientific community would not view that study as sufficient to establish performance characteristics for high-risk women who may have ovarian cancer.
“Based on our review of your promotional materials and the research … we believe you are offering a high-risk test that has not received adequate clinical validation, and may harm the public health,” Gutman said in the letter. OIVD has requested that LabCorp discuss with the agency its strategies for validating the test.
LabCorp said in statement that it “shares the FDA’s determination to help assure that patients are protected without … imposing unnecessary regulatory burdens on new critically needed tests.”
The Burlington, NC-based firm added that it “ looks forward to working with the agency to review the clinical data related to this important test.”
Gutman told Pharmacogenomics Reporter he could not comment on the ongoing discussions with LabCorp.
A LabCorp spokesperson also declined to comment.
Last year, the FDA released a draft guidance explaining that in vitro diagnostic multivariate index assays are medical devices. Before this guidance, laboratory-developed tests such as the OvaSure were considered homebrews and overseen by the Centers for Medicare and Medicaid's less stringent CLIA rules.
“Based on our review of your promotional materials and the research … we believe you are offering a high-risk test that has not received adequate clinical validation, and may harm the public health.”
LabCorp claims that the six biomarker panel test discriminates between disease-free women and ovarian cancer patients with 99.4 percent specificity and 95.3 percent sensitivity. Greater than 99 percent sensitivity was shown in late-stage disease (stage III and stage IV). In early-stage disease (stage I and stage II), the assay demonstrated a sensitivity of 91.6 percent, yielding “a significant improvement” over CA-125 alone for ovarian cancer detection, the company reported.
According to LabCorp, Yale University studies have shown “comparable findings.”
In comments to Pharmacogenomics Reporter sister publication ProteoMonitor, LabCorp previously said that its test is accurate enough to begin offering it to physicians. “Although the data from the Phase III trial has not been published, our internal data that we’ve generated to date at LabCorp on OvaSure has been validated with 99-percent correlation to the performance characteristics in the Phase II trial,” Myla Lai-Goldman, executive vice president and chief medical officer of LabCorp, told ProteoMonitor.
OvaSure interrogates six protein biomarkers in a multiplex immunoassay. The markers are leptin, prolactin, osteopontin, insulin-like growth factor II, macrophage inhibitory factor, and CA-125. According to LabCorp, approximately 10 percent of women with benign ovarian masses may receive results from the test that says they have cancer.
LabCorp recommends “high-risk patients who are interpreted as 'positive' with the OvaSure assay be retested with a different specimen at least three weeks after the original sample was collected.”
In a separate case, the FDA is revisiting a decision it made in 2004 to suspend the sale of an ovarian cancer test made by Correlogic Systems.
According to Correlogic’s website, the company is currently discussing with the FDA the scope of the review that will be required to resume selling the OvaCheck test.
“FDA’s position has been that it has regulatory authority over OvaCheck and other tests of this nature — and that approval therefore is required,” Annette Fribourg, Correlogic’s VP of government and public relations, told Pharmacogenomics Reporter sister publication GenomeWeb Daily News in an e-mail last week.
“As a result, Correlogic has conducted extensive clinical trials on the test and we expect to make our submission to FDA shortly,” she said.
The FDA has so far cleared only three IVDMIAs since the agency issued its draft guidance in 2007: Agendia's 70-gene panel MammaPrint assay for breast cancer recurrence; Pathwork’s PathChip test for cancer of primary origin, which can simultaneously measure gene expression levels in 1,500 genes; and XDx's AlloMap multi-gene molecular expression test for heart transplant patients.