NEW YORK (GenomeWeb) – Crescendo Bioscience, a subsidiary of Myriad Genetics, this week announced the publication of a retrospective study in a medical journal that showed its Vectra DA molecular test can determine which newly diagnosed rheumatoid arthritis patients will be at low risk of radiographic progression, or joint damage as determined by imaging.
A more accurate assessment of which early RA patients will progress to have radiographic progression could help doctors direct them to the right types of treatments.
In the study, researchers from Crescendo and elsewhere led by Karen Hambardzumyan of the Karolinska Institute evaluated 235 patients with early RA from the Swedish Farmacotherapy (SWEFOT) trial. In that study, patients not previously treated with disease-modifying antirheumatic drugs (DMARDs) were treated with methotrexate for three months and then randomized to receive triple DMARD therapy or methotrexate plus TNF therapy.
Crescendo's Vectra DA is a blood-based test that measures the levels of 12 proteins associated with rheumatoid arthritis, yielding a test score between one and 100 that is intended to help doctors determine whether a patient has high, moderate, or low RA disease activity. In the latest study, using various quantitative measures and Vectra DA, researchers established patients' baseline disease characteristics at three months and then looked to see how well those assessments correlated with patients' radiographic progression at one year.
Vectra DA gave low scores to five patients and 29 moderate scores. No one from the low scoring group had radiographic progression, while one in the moderate score group had progression during the year. Meanwhile, 21 percent of 201 patients with a high Vectra DA score in the study had radiographic progression. Comparatively, one-year radiographic progression in the low/moderate Vectra DA group was 3.4 percent.
This retrospective study showed essentially that Vectra DA more accurately identifies early-stage RA patients at low risk of radiographic progression than traditional scoring measures. Using other disease scoring methods, researchers reported that around 15 percent of those with moderate or low scores still had radiographic progression. Additionally, "these findings build on earlier results from the Leiden Early Arthritis Cohort study published in Rheumatology, which showed that patients with a high Vectra DA score were at a six-fold higher risk of disease progression than those with a low Vectra DA score," Crescendo said in a statement announcing the publication of the latest study.
"With this test taken before anti-rheumatic therapies are started, the clinician will have more knowledge about the patient's prognosis to help inform decisions regarding treatment, an important step toward personalized medicine in the treatment of this important musculoskeletal disease." Ronald Vollenhoven of the Karolinska University and a lead study authors said in a statement.
"In patients with early RA, the [Vectra DA] score at baseline was a strong independent predictor of one year radiographic progression," Hambardzumyan and colleagues concluded in the study. "These results suggest that when choosing initial treatment in early RA the [Vectra DA] test may be clinically useful to identify a subgroup of patients at low risk of radiographic progression."
In past studies, Crescendo has shown that Vectra DA is significantly associated with other disease activity measures. To date, the company has largely focused on marketing the test as a disease monitoring tool, but has begun in recent months to build evidence on the test's ability to predict RA patients' risk of joint damage and their ability to respond to therapies.
In one study, called CAMERA, the Vectra DA score was found to be predictive of radiographic progression with "borderline significance," but Hambardzumyan and colleagues noted that study was limited by a very small sample size.
In the current study, with a bigger cohort than CAMERA, the negative predictive value of Vectra DA was high but the positive predictive value was very low, meaning that "though having relatively higher risk, the majority of patients with high [Vectra DA] score still did not progress radiographically over one year," the researchers wrote. The authors said this suggests that baseline Vectra DA scores can be used to identify patients at lower risk of progression and help inform treatment strategies for those with higher scores who may or may not progress to have joint damage.
Among the limitations of the current study was that the SWEFOT trial didn't include patients with low DAS28 and as such, the predictive value of Vectra DA in this subset of patients was not determined. Although researchers believe that SWEFOT was designed to be close to the real life early RA population, it "does not fully represent the RA population."
"It will be important to study the predictive value of the [Vectra DA] score at additional time points for even times of clinical and radiographic data," the study authors wrote.