Researchers are mining the synovium for potential treasure: robust markers to bring precision medicine to the rheumatoid arthritis (RA) arena. The signs, according to a number of recent reports, point toward a gold strike via synovial tissue biopsy.
Dr. Harris R. Perlman
Dr. Harris R. Perlman
“I have no doubt about that – I am very confident that this concept of going straight to the tissue and using functional genomics will help us stratify our patients and will be a predictive model for patients with respect to therapy,” Harris R. Perlman, PhD, the Mabel Greene Myers Professor of Medicine and chief of the division of rheumatology at Northwestern University, Chicago, said in an interview.
Dr. Perlman is the principle investigator for the REASON (Rheumatoid Arthritis Synovial Tissue Network) study, and in a 2018 report on the network’s efforts to train participants across the United States in ultrasound-guided joint biopsy techniques and to collect and analyze synovial tissue samples submitted by the six participating centers, he and the coinvestigators explained why a precision approach can’t come soon enough.
“Currently, the standard of care for RA is to prescribe biologic therapy through a costly and time‐consuming trial‐and‐error process. Therefore, the utility of a biomarker to identify how a patient will respond to a particular therapy cannot be overstated,” they wrote (Arthritis Rheumatol. 2018 Jun;70[6]:841-54).
Since that REASON report was published, efforts by the investigators and others, such as those involved with the Accelerating Medicines Partnership (AMP) in RA and Lupus Network, to identify such biomarkers have continued to yield encouraging results.
In fact, data from the phase 4 R4-RA (Response, Relapse and Resistance to Rituximab Therapy in patients with RA) trial – the first randomized, controlled, biopsy-driven trial in RA – were reported in November 2019 at the annual meeting of the American College of Rheumatology. R4-RA demonstrated that patients with B cell–poor RA identified on synovial tissue biopsy (STB) responded better to tocilizumab (Actemra) than to rituximab (Rituxan), whereas those with B cell–rich RA on STB did not, Constantino Pitzalis, MD, head of the Centre for Experimental Medicine & Rheumatology at Queen Mary University of London said, noting that the findings could have “massive implications” for RA management and outcomes.
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Dr. Constantino Pitzalis
Numerous treatments exist for RA, but methods for determining which to use for a given patient are sorely lacking and the field of rheumatology lags behind others, like oncology, in bringing individualized medicine to the clinic, he explained.
Why STB?
Despite extensive efforts, blood testing has failed to yield markers sufficient for guiding RA treatment, and although the synovium has long been considered a potentially better source of information to guide treatment given the damage it sustains from RA, biopsies have generally been accessible only during arthroscopic or joint replacement surgery in patients with severe disease, which doesn’t reflect the population of patients who could benefit from early intervention, Dr. Perlman and colleagues explained in their 2018 report.