Review article: biological drugs in Crohn's disease

Biological drugs have opened new therapeutic horizons for treating Crohn's disease (CD), but have also brought with them issues related to immunogenicity, long-term efficacy, safety and cost. At present, inhibitors tumour necrosis factor and adhesion molecules are the most advanced in use and development. When treating luminal disease with infliximab, two-thirds of patients respond initially. The ACCENT 1 study demonstrated that 28% of initial responders are in remission for 1 year. Infliximab has also had a major impact on the management of Crohn's anorectal fistulas. The ACCENT 2 study demonstrated initial response in two-thirds of patients. One-fifth of all treated patients were healed at 1 year. Infliximab diminished the need for further surgery. Magnetic resonance imaging scanning allows the extent of deep healing to be assessed and may influence the duration of treatment. The Mayo Clinic experience in 500 patients demonstrated 6% serious adverse events related to infliximab. The TREAT registry will provide long-term safety data on a larger group of patients. Concurrent immunosuppressive drugs and pre-infusion steroids can decrease antibody formation to infliximab. Screening for tuberculosis (TB) diminishes the rate of TB activation. Biological drugs can offer great therapeutic benefit, but their use must be considered in context.