Biologic Therapy in Inflammatory Bowel Disease-A Gastrointestinal Perspective

For inflammatory bowel diseases (IBD) that include Crohn's disease and ulcerative colitis, only limited therapeutic agents were available until the approval of infliximab in 1998. Since the introduction of the biological agents, which are antibodies to the cytokine tumor necrosis factor (TNF) alpha (anti-TNF), the therapeutic options have changed dramatically. Although side effects may occur, their clinical benefit is impressive and has changed the management and the expectations of treating IBD. Currently, 4 drugs have been approved by the Food and Drug Administration for the treatment of IBD, which include infliximab, adalimumab, certolizumab, and natalizumab. Their side effect profile seems to be safe when the physician follows recommended preventive pathways, including evaluation for hepatitis B and tuberculosis before treatment. There have been few reports about hepatosplenic T-cell lymphoma in young males on combination therapy with thiopurines and anti-TNFs. The risk for infection and malignancy does not seem to be increased. Natalizumab gained a negative reputation because of cases of progressive multifocal leukoencephalopathy. Tests for risk stratification including John Cunningham virus polymerase chain reaction in blood and antibody against John Cunningham virus may identify patients at higher risk for progressive multifocal leukoencephalopathy. Although, improvement of the patient's symptoms used to be the goal of therapy, this has shifted since the availability of anti-TNF therapy to mucosal healing as standard of care. In addition, as monitoring of drug levels and antibodies becomes more available, it will improve safety and efficacy of these agents.