medwireNews: Anti-carbamylated vimentin (anti-CarbV) antibodies may be associated with treatment response and structural damage progression among patients with rheumatoid arthritis (RA), shows a post-hoc analysis of data from the phase 3 RA-BEGIN trial.
By contrast, there was no such association with anti-mutated citrullinated vimentin (anti-MCV) antibodies, Pedro López-Romero (Eli Lilly & Company, Indianapolis, Indiana, USA) and colleagues report in Arthritis Research & Therapy.
The analysis included data for 570 biologic-naïve patients with active RA who also had no or limited prior treatment with conventional DMARDs. The patients were randomly assigned to receive methotrexate (n=203), baricitinib 4 mg/day (n=157), or baricitinib plus methotrexate (n=210) for 52 weeks.
The researchers found that, irrespective of treatment and other potential confounders, the improvement in SDAI from baseline to week 52 increased significantly with increasing baseline levels of both anti-CarbV immunoglobulin (Ig)A and IgG antibodies, and a similar association was observed for DAS28-CRP.
Conversely, high baseline titers of anti-CarbV IgM were associated with a poor SDAI response to methotrexate monotherapy, which the researchers describe as “a new and unexpected observation.”
They say that “if further studies confirm this result, anti-CarbV IgM titers could potentially be used as a prognostic biomarker to identify which patients with RA might not benefit from early treatment with [methotrexate].”
There was no significant association between anti-CarbV IgM levels and SDAI response to baricitinib and baricitinib plus methotrexate, but there was a trend towards a positive, rather than negative, correlation.
López-Romero et al also investigated the association between the autoantibody levels and structural damage progression as measured by mTSS. They found that each unit increase in anti-CarbV IgA was associated with a nonsignificant 0.2% increase in the odds of progression.
The authors conclude: “Our results suggest that high titers of anti-CarbV IgA and IgG antibodies could represent a useful prognostic biomarker for identifying the likelihood of both the response to treatment and the potential for structural damage progression in patients with RA.”
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