Certolizumab pegol: a polyethylene glycolated Fab' fragment of humanized anti-tumor necrosis factor alpha monoclonal antibody for the treatment of Crohn's disease.

Certolizumab pegol offers an alternative to the other biologic response modifiers for the treatment of Crohn's disease. Results from phase II dose-ranging studies were mixed because a number of the studies had high placebo response rates and a large number of patients with low C-reactive protein (CRP) levels. Phase III clinical trials have demonstrated induction of clinical responses and maintenance of remission for patients independent of whether baseline CRP levels were normal or elevated. Although concomitant immune suppressants reduced the immunogenicity, there were no differences in clinical response at 6 to 12 months for patients receiving immunosuppressives compared with those not receiving concomitant medications. There is also evidence that patients treated earlier in the course of disease may have improved responses and that patients who have lost response to infliximab will respond to certolizumab pegol.