, new research suggests
The nested case-control study included more than 200 participants with diseases such as rheumatoid arthritis, psoriasis, and Crohn’s disease. Results showed that exposure to TNF inhibitors was significantly associated with increased risk for demyelinating CNS events, such as multiple sclerosis, and nondemyelinating events, such as meningitis and encephalitis.
Interestingly, disease-specific secondary analyses showed that the strongest association for inflammatory events was in patients with rheumatoid arthritis.
Lead author Amy Kunchok, MD, of Mayo Clinic, Rochester, Minn., noted that “these are highly effective therapies for patients” and that these CNS events are likely uncommon.
“Our study has observed an association, but this does not imply causality. Therefore, we are not cautioning against using these therapies in appropriate patients,” Dr. Kunchok said in an interview.
“Rather, we recommend that clinicians assessing patients with both inflammatory demyelinating and nondemyelinating CNS events consider a detailed evaluation of the medication history, particularly in patients with coexistent autoimmune diseases who may have a current or past history of biological therapies,” she said.
The findings were published in JAMA Neurology.
Poorly understood
TNF inhibitors “are common therapies for certain autoimmune diseases,” the investigators noted.
Previously, a link between exposure to these inhibitors and inflammatory CNS events “has been postulated but is poorly understood,” they wrote.
In the current study, they examined records for 106 patients who were treated at Mayo clinics in Minnesota, Arizona, or Florida from January 2003 through February 2019. All participants had been diagnosed with an autoimmune disease that the Food and Drug Administration has listed as an indication for TNF inhibitor use. This included rheumatoid arthritis (n = 48), ankylosing spondylitis (n = 4), psoriasis and psoriatic arthritis (n = 21), Crohn’s disease (n = 27), and ulcerative colitis (n = 6). Their records also showed diagnostic codes for the inflammatory demyelinating CNS events of relapsing-remitting or primary progressive MS, clinically isolated syndrome, radiologically isolated syndrome, neuromyelitis optica spectrum disorder, and transverse myelitis or for the inflammatory nondemyelinating CNS events of meningitis, meningoencephalitis, encephalitis, neurosarcoidosis, and CNS vasculitis. The investigators also included 106 age-, sex-, and autoimmune disease–matched participants 1:1 to act as the control group.
In the total study population, 64% were women and the median age at disease onset was 52 years. In addition, 60% of the patient group and 40% of the control group were exposed to TNF inhibitors.
Novel finding?
Results showed that TNF inhibitor exposure was significantly linked to increased risk for developing any inflammatory CNS event (adjusted odds ratio, 3.01; 95% CI, 1.55-5.82; P = .001). When the outcomes were stratified by class of inflammatory event, these results were similar. The aOR was 3.09 (95% CI, 1.19-8.04; P = .02) for inflammatory demyelinating CNS events and was 2.97 (95% CI, 1.15-7.65; P = .02) for inflammatory nondemyelinating events.
Dr. Kunchok noted that the association between the inhibitors and nondemyelinating events was “a novel finding from this study.”
In secondary analyses, patients with rheumatoid arthritis and exposure to TNF inhibitors had the strongest association with any inflammatory CNS event (aOR, 4.82; 95% CI, 1.62-14.36; P = .005).
A pooled cohort comprising only the participants with the other autoimmune diseases did not show a significant association between exposure to TNF inhibitors and development of CNS events (P = .09).
“Because of the lack of power, further stratification by individual autoimmune diseases was not analyzed,” the investigators reported.
Although the overall findings showed that exposure to TNF inhibitors was linked to increased risk for inflammatory events, whether this association “represents de novo or exacerbated inflammatory pathways requires further research,” the authors wrote.
Dr. Kunchok added that more research, especially population-based studies, is also needed to examine the incidence of these inflammatory CNS events in patients exposed to TNF-alpha inhibitors.