Biosimilars: concept, current status, and future perspectives in inflammatory bowel diseases.

The inflammatory bowel diseases (IBD), which consist of Crohn's disease and ulcerative colitis, are chronic, incurable immunemediated inflammatory disorders of the intestine. As IBD incidence continues to increase globally and its mortality is low, prevalent cases of IBD are rapidly increasing, thereby leading to a substantial increase in health care costs. Although the introduction of biologic agents for IBD management has revolutionized the armamentarium of IBD therapy, the high cost of this therapy is concerning. With the expirations of patents for existing biologic agents (originals), biosimilars with cheaper costs have been highlighted in the field of IBD. Despite concerns regarding their short- and long-term efficacy, safety, immunogenicity, and interchangeability, increasing evidence via prospective observations and phase III or IV clinical trials, which aim to prove the "biosimilarity" of biosimilars to originals, has partly confirmed their efficacy, safety, and interchangeability. Additionally, although patients and physicians are reluctant to use biosimilars, a positive budget impact has been reported owing to their use in different countries. In the near future, multiple biosimilars with lower costs, and efficacy and safety profile similar to originals, could be used to treat IBD; thus, further consideration and knowledge dissemination are warranted in this new era of biosimilars.