["The safety and efficacy of maintenance therapy with the anti-tumor necrosis factor certolizumab pegol has not been reported beyond 6 months. We assessed the long-term efficacy, safety, and immunogenicity of continuous versus interrupted maintenance therapy with subcutaneous certolizumab pegol in patients with Crohn's disease.", "Patients who responded to induction therapy at week 6 of the PEGylated Antibody Fragment Evaluation in Crohn's Disease: Safety and Efficacy (PRECiSE) 2 trial were assigned randomly to groups given certolizumab pegol (continuous) or placebo (drug-interruption) during weeks 6 to 26. Patients who completed PRECiSE 2 were eligible to enter PRECiSE 3, an ongoing, prospective, open-label extension trial in which patients have received certolizumab pegol (400 mg) every 4 weeks for 54 weeks to date, and were not offered the option to increase their dose. Disease activity was measured by the Harvey-Bradshaw Index.", 'Harvey-Bradshaw Index responses at week 26 for the continuous and drug-interruption groups were 56.3% and 37.6%, respectively; corresponding remission rates were 47.9% and 32.4%, respectively. Of patients responding at week 26, response rates at week 80 after the start of PRECiSE 2 in the continuous and drug-interruption groups were 66.1% and 63.3%, respectively; among patients in remission at week 26, week 80 remission rates were 62.1% and 63.2%, respectively. More patients in the drug-interruption group developed antibodies against certolizumab pegol (and had lower plasma concentrations of certolizumab pegol) than the continuously treated group.'] Does continuous therapy with certolizumab pegol maintain remission of patients with Crohn 's disease for up to 18 months?