Anti‐tumour necrosis factor‐alpha (anti‐TNFα) agents have revolutionised; the management of numerous chronic inflammatory diseases such as rheumatoid arthritis (RA), ankylosing spondylitis (SpA); psoriatic arthritis (PsA) and inflammatory bowel disease (IBD) among others.

Patients receiving Enbrel for inflammatory diseases other than inflammatory bowel disease; have an increased risk for a diagnosis of Crohn’s disease or ulcerative colitis; according to study results. Data confirming these adverse events are limited as most accounts have case reports; or series with few broader investigations performed.

The association between psoriasis and treatment with an anti‐TNFα for RA; has been best studied using larger registries with adequate controls which support the strength of this finding as a risk of anti‐TNFα therapy; with estimates as high as 2.5% of patients treated.

Risk for IBD

With infrequent events in each subtype but with numerous subtypes in this broad category; such de novo autoimmune adverse events of anti‐TNFα might occur more frequently than recognize; while also being among the least studied and poorly understood.

Joshua Korzenik, MD, director of the Crohn’s and Colitis Center at Brigham and Women’s Hospital, and colleagues wrote in Alimentary Pharmacology & Therapeutics that anti-TNF treatments have made a significant impact on the management of autoimmune disease like rheumatoid arthritis and IBD. However, they do not come without risks.

“Paradoxically, these agents might provoke the development of de novo autoimmune disease; for which they are also utilized as therapy, such as de novo psoriasis and vasculitis,” they wrote. To further explore a potential risk for IBD when taking an anti-TNF for other inflammatory diseases; researchers performed a nationwide cohort study using Danish health registries.

Increased risk for CD

They included patients with diseases other than IBD, including rheumatoid arthritis; psoriasis, psoriatic arthritis, spondylitis and others, who received at least one dose of anti-TNF. Of 17,018 patients with an autoimmune disorder who received an anti-TNF, most received Remicade (infliximab, Janssen); Enbrel (etanercept, Amgen) or Humira (adalimumab, AbbVie). Researchers compared risk for IBD among these patients with 63,308 individuals who were not exposed to anti-TNF.

Investigators found that patients who received etanercept had an increased risk for CD (adjusted HR = 2; 95% CI, 1.4–2.8) and UC (aHR = 2; 95% CI, 1.5–2.8). They did not find an increased risk for de novo IBD among patients who received adalimumab or infliximab. Korzenik; and colleagues wrote they were uncertain about the reason for this link.

“This additional burden of disease is important to understand with regard to the insights; the phenomenon may provide into the pathogenesis of IBD, as well as these other diseases,” they wrote. “In addition, the recognition of these clinical problems is critical for physicians caring for individuals treat with anti-TNF alpha agents to minimize risk and provide optimal care.”