SAN FRANCISCO – Vectra DA, a multibiomarker blood test, can predict response to therapy for patients with rheumatoid arthritis, and it can also identify patients who can safely taper and discontinue disease-modifying antirheumatic drug (DMARD) therapy, according to two separate poster presentations at the annual meeting of the American College of Rheumatology.
Management of patients with RA is typically based on clinical criteria and lab test results. Vectra DA is the only multibiomarker panel available for assessing therapeutic response in RA. The test is Medicare-approved, and Medicare allows about $580 per test, according to a spokesperson for Crescendo Bioscience, the company providing the test. Currently, Vectra DA is used in about 20% of RA patients who are actively managed by a rheumatologist in the United States, and about 40% of U.S. rheumatologists use the test at least once per month, the spokesperson said.
Alice Goodman/Frontline Medical News
Rebecca J. Bolce and Dr. Juergen Rech
“Vectra DA can assess the risk of radiographic changes and track therapeutic response. Patients with low to moderate Vectra DA scores have a reduced risk of radiographic progression over the next year,” said a coauthor of the first study, Rebecca J. Bolce, an employee of Crescendo.
Response to subsequent therapy
This retrospective study analyzed multibiomarker disease activity score (that is, Vectra DA) in incomplete responders to 3 months of methotrexate monotherapy to predict response to subsequent triple therapy versus biologic therapies. The patient sample came from the SWEFOT (Swedish Farmacotherapy) study of patients with early RA.
After 3 months of methotrexate therapy, 157 nonresponders were randomized to triple therapy or methotrexate plus infliximab (biologic therapy). At the time of randomization, nonresponders were assessed with Vectra DA. Patients with low Vectra DA scores (that is, less than 30) were successfully treated with triple therapy; at 1 year, 88% of these patients achieved low disease activity (a 28-joint Disease Activity Score [DAS28] less than 3.2), compared with 18% assigned to biologic therapy (P = .006).
Patients with a high score on Vectra DA were more likely to respond to biologics. In this group, at 1 year, low disease activity was achieved in 58% of patients randomized to biologics versus 35% randomized to triple therapy (P = .04).
“At 1 year, the Vectra DA score at 3 months was a superior predictor of response to both conventional triple therapy and biologic therapy, compared with C-reactive protein, erythrocyte sedimentation rate, and DAS28,” Ms. Bolce said.
“These findings may help facilitate and improve the development of individualized and cost-effective treatment plans for individuals with RA,” Ms. Bolce said.
Tapering therapy
A second study analyzed the role of multibiomarker disease activity (Vectra DA score) in predicting relapses in RA patients in sustained remission when tapering disease-modifying antirheumatic drug therapy in the context of the RETRO randomized clinical trial.
On a scale from 0-100, Vectra DA scores of less than 30 are categorized as low, scores 30-44 are called moderate, and those greater than 44 are considered high. Scores were calculated and compared between 94 patients who were relapsing or in sustained remission while tapering DMARD therapy.
Patients were randomized to one of three arms: continuation of DMARD; reduction of DMARD by 50%; or reduction of DMARD by 50% for 6 months and then stopping therapy.
Moderate to high scores were found in one-third of RA patients in remission. Scores were twice as high in relapsing patients (58.3%), compared with those in stable remission (25%). Baseline scores were significantly higher in relapsing patients than in those in stable remission in the entire population, in tapering patients, and in those who stopped DMARDs.
A multivariate analysis found that Vectra DA scores were independent predictors of relapse next to anticitrullinated protein antibody (ACPA) status. Relapse rates were as follows: 13% in VECTRA-low/ACPA-low patients; about one-third in patients positive on one or the other test; and 76.4% in those with high VECTRA DA scores and high ACPA level.
“Vectra DA score improved the prediction of relapses in RA patients in stable remission undergoing DMARD tapering. Combined with ACPA testing, the score allowed a correct identification of relapse in more than 80% of patients,” stated lead author Dr. Juergen Rech of the University of Erlangen-Nuremberg, Germany.