IL17A and inflammatory bowel disease: While some biologics are approved for the treatment of IBD (i.e., certolizumab pegol, subcutaneous golimumab, adalimumab, infliximab, vedolizumab, and natalizumab), biologic therapies with certain mechanisms of action, such as IL-17 antagonists and etanercept, have been linked with an increased risk of new onset IBD or exacerbation of existing IBD.