From historical perspectives to modern therapy: a review of current and future biological treatments for Crohn's disease.

Crohn's disease (CD) is a debilitating, systemic inflammatory disorder with both gastrointestinal and extraintestinal manifestations. Its existence predates modern medicine, but its precise etiology remains incompletely understood. Most authorities suggest a multifactorial pathogenesis owing to a mixture of genetic disorders, immunologic dysregulation, microbiota disequilibrium and environmental influences. Of these factors, the overactive immunologic response seen in CD appears to be the most promising target of medical therapy. Biological agents comprise a relatively new class of drugs that can induce and maintain remission in moderate to severe CD, as well as in ulcerative colitis. This review will provide an overview of CD, its history, clinical features, pathophysiology, and treatment options focusing on current and future biological agents with an emphasis on drug development, dosage and administration.