Natalizumab is a specific humanised monoclonal antibody, which inhibits a4-integrins.

These affect the migration of leucocytes from the circulation into the tissues to set up inflammatory reactions.

A multi-centre trial of its effectiveness in severe Crohn’s disease was performed. After 2 infusions 71% of patients showed a response and 44% achieved clinical remission at 6 weeks. Inflammatory protein levels in the blood improved.

The long term effectiveness is as yet unknown and this remains an experimental treatment, which is not as yet generally available.

Further reading:NEJM 348 2003 24-32