In a study recently published in PLoS ONE, researchers used specimens from the ITN RAVE trial to investigate angiopoietin-2 as a potential biomarker in ANCA-associated vasculitis (AAV), a highly variable and serious disease without reliable markers to help predict disease outcome.
In this study, Paul Monach, MD (Boston University) and colleagues assessed angiopoietin-2 as a potential biomarker of disease activity and relapse in AAV. Angiopoietin-2 is a protein that renders the vascular endothelial barrier susceptible to inflammation and has been previously shown in a small number of patients to be correlated with disease severity. Using samples collected from the ITN RAVE study and from the Vasculitis Clinical Research Consortium (VCRC) Longitudinal Study, the investigators measured angiopoietin-2 levels in the same patients during active disease and during remission, as well as compared angiopoeitin-2 levels across patients with varying disease states. The results showed that angiopoietin-2 was unable to predict response to treatment in those with active disease, was not strong enough to distinguish active disease from remission and was not able to predict time to flare for those in remission.
The use of high-quality samples collected from 162 patients in the ITN RAVE study enabled the investigators to conduct a rigorous biomarker investigation rather than rely on anecdotal evidence among a few patients. This study helps confirm that angiopoietin-2 should not be pursued as a predictive tool in AAV. In a similar ITN-supported biomarker study using RAVE samples, researchers were able to demonstrate that metalloproteinase-3 (MMP-3), an enzyme involved in angiogenesis, was able to distinguish active disease from remission in AAV (results here), and should be further explored as a potential biomarker to assist in AAV evaluation and management.