NEW YORK (360Dx) – With additional data on the performance of its Videssa Breast proteomic breast cancer assay out this week, Provista Diagnostics is now prepping a new study to gather clinical utility and health economic data on the test.
The company is planning a retrospective study of patient data collected via physicians participating in its early-access program for Videssa, said Judy Wolf, the company's chief medical officer. The goal is to analyze data from around 100 to 150 patients across five sites to see how use of the test impacts physician decisions around patient care, she said, adding that the company will also use this data to model the test's potential economic impact.
The Videssa test is intended to aid physicians in the interpretation of mammograms, helping them to distinguish between benign and malignant lesions that appear during imaging and to interpret results in patients with dense breasts, which can be difficult to assess via mammography.
Mammogram findings are graded using the Breast Imaging-Reporting and Data System (BI-RADS), a 0 to 6 scale with likelihood of malignancy rising with the number grade. A score of 1, for instance, is considered negative, while a score of 6 is a proven malignancy. Scores in the 3 to 4 range can be challenging to interpret, though.
The Videssa test measures 15 proteins to rule out cancer in women with either a borderline BI-RADS score or where interpretation of a result is difficult due to dense breast tissue. The proteins are a mix of serum protein biomarkers and tumor-associated autoantibodies, some of which were initially discovered by the Biodesign Institute of Arizona State University's Joshua LaBaer and Karen Anderson, who also are members of Provista's advisory board.
In a study of 545 women under the age of 50 published this week in PLOS ONE, the test distinguished between malignant and benign BI-RADS 3 or 4 imaging findings with a sensitivity of 88.9 percent and specificity of 81.2 percent in women with dense breasts and sensitivity of 92.3 percent and specificity of 86.6 percent for women with non-dense breasts. Negative predictive value was 99.1 percent and 99.3 percent for the dense and non-dense groups, respectively.
Provista has also submitted for publication a study looking at use of the test in the 50- to 75-year-old population where, Wolf said, it exhibited similar levels of performance.
The company now aims to demonstrate that use of the test changes physician behavior. In theory, the ability to confidently rule out cancer in the case of indeterminate imaging findings could lead to a reduction in unnecessary biopsies and medical costs. According to the company, less than five percent of breast biopsies actually find a cancer.
Provista launched an early-adoption program for the test in 2016 and has since made it available to any US physicians interested in using it. The company offers the test out of its Scottsdale, Arizona-based CLIA facility.
Wolf said the company's commercialization efforts have focused thus far on regions with large population centers and high densities of breast-specific physicians. She said that there are around 30 to 40 sites around the country that regularly order the test.
These sites, she noted, have provided Provista with some early insights into how the test is being used in actual clinical practice.
At several sites, doctors are using the test to provide ease of mind to patients who might otherwise push for a biopsy despite the low likelihood that a finding is malignant, she said. "Getting a Videssa Breast that comes back low-protein signature can give some assurance to those patients and allow them to be calm and wait [for follow-up imaging] rather than go through a biopsy that's likely to be unnecessary."
Other clinicians, she said, are using the test to help distinguish between different grades of BI-RADS 4 ratings, which at some medical facilities are subdivided into 4A, 4B, and 4C with A being less likely to be malignant and C more likely.
A 4A classification is meant to indicate a slightly higher cancer risk than a BI-RADS 3 score, Wolf said, "but [a doctor] is still pretty darn sure that it is not going to be cancer."
"In the past, [doctors] have biopsied all of those, but now, instead, the radiologist [at some sites using the test] is recommending the patient have a Videssa Breast, and if it comes back low-protein signature, they aren't calling it a 4A, they are calling it a three, and following the patient [with a second round of imaging] in six months," she said.
"I believe that [these] sites are going to be able to show us that they are really able to reduce the number of biopsies in those women because the radiologist is putting the blood test and the imaging together, which is just how the test is meant to be used," she added.
In a prospective study published earlier this year in Clinical Breast Cancer of 561 women under the age of 50 who received biopsies after inconclusive imaging results, the company and collaborating researchers determined that use of the test could reduce unnecessary biopsies by up to 67 percent. In that patient population, 91 percent of the biopsies performed based on imaging results were negative.
The majority of the test's early users have come from the community setting, Wolf said, adding that the company hopes the release of the PLOS ONE study and the data it hopes to generate via its planned clinical utility study will help drive adoption among academic hospitals.