Effect of PF-00547659 on Central Nervous System Immune Surveillance and Circulating β7+ T Cells in Crohn’s Disease: Report of the TOSCA Study

Abstract

In patients with active Crohn's disease, natalizumab therapy increases the risk for PML, and the increased risk is thought to be associated with iatrogenic leukopenia within the CNS. PML under PF-00547659 may be a lesser concern, as this agent did not reduce lymphocytes or T cell subsets in the cerebrospinal fluid.