Clinical experience of natalizumab in Crohn's disease patients in a restricted distribution program

BACKGROUND Natalizumab (NAT) is a humanized monoclonal antibody against a4-integrin initially approved for the treatment of multiple sclerosis, and then withdrawn from the market in 2005 due to the risk of progressive multifocal leukoencephalopathy. NAT was approved for the treatment of Crohn's disease in the United States in 2008 under a restricted distribution program. There has been limited data on NAT since then. The purpose of this study was to review the experience with NAT in Crohn's disease patients at a tertiary inflammatory bowel disease center. METHODS A retrospective chart review was performed on all patients who received NAT for treatment of refractory Crohn's disease from January 2008 to August 2010 at Washington University Medical Center in St. Louis. RESULTS A total of 20 patients were identified and included in our study. Four patients did not complete induction therapy. Seven patients had a clinical response, with 5 patients continuing treatment up to 2012. Four patients had a partial response, 3 had adverse events, and 2 experienced loss of response. Two patients were pregnant while on NAT, and neither had significant adverse pregnancy outcomes. One patient dependent on total parenteral nutrition developed recurrent line sepsis while on NAT. Of the 5 patients on long-term maintenance therapy, 4 have a positive anti-JC virus antibody. No patients developed progressive multifocal leukoencephalopathy or other neurological complications. CONCLUSION NAT remains a valuable alternative treatment option for patients with refractory Crohn's disease under a restricted distribution program.