Taltz (ixekizumab), an approved antibody treatment for plaque psoriasis, targets a cytokine that is thought to play a role in the development of inflammatory bowel disease (IBD). That connection has caused concerns that administration of the drug might increase occurrence of IBDs in patients with psoriasis. So, Eli Lilly and Company, the maker of Taltz, conducted a study to determine  if there was a significant correlation.

Results showed that rates of new IBD cases were observed in less than 1 percent of the psoriasis patients receiving Taltz. They reported that flares of pre-existing disease also were rare.

Titled “Inflammatory bowel disease among patients with psoriasis treated with ixekizumab: A presentation of adjudicated data from an integrated database of 7 randomized controlled and uncontrolled trials,” the study was published in the American Journal of Dermatology.

Taltz targets the cytokine interleulin-17 (IL-17). Previous studies have suggested a potential role of IL-17A in the pathogenesis (disease course) of IBD, although results have been inconclusive. According to a press release published in the Medical News Bulletin, trials using antagonists of IL-17A have failed to prove effective against IBDs.

The Eli Lilly study study included data from 4,029 patients with moderate-to-severe psoriasis who had received Taltz. Participants previously were enrolled in one of the seven clinical trials for Taltz already underway.

The study did have some limitations, including the fact that the study did not collect any information on the patients’ family histories before trial initiation, and the fact that there was no information collected on the duration of earlier therapies that could have led to IBD symptoms, namely before exposure to Taltz.

Because the trial is not fully conclusive, the authors recommend that dermatologists monitor patients with concomitant psoriasis and IBD who are receiving IL-17 antibody therapy and advocate for disclosing all the potential risks that IL-17A antagonist treatment could entail.

Plaque psoriasis is an inflammatory skin condition that is characterized by the appearance of raised red scales, which are often itchy and painful. The condition has a significant genetic overlap with IBD and patients often develop certain IBDs, like ulcerative colitis (UC) or Crohn’s disease, as co-morbidities.

In February 2015, research found that the genetic susceptibility to Crohn’s and psoriasis persisted for hundreds of thousands of years, dating back to pre-Neanderthals.