Natalizumab for the treatment of multiple sclerosis and Crohn's disease.

OBJECTIVE

To review the pharmacology, pharmacokinetics, safety, and pivotal clinical trials for natalizumab in the treatment of multiple sclerosis (MS) and inflammatory bowel disease.

DATA SOURCES: A PubMed/MEDLINE search was conducted (1966-June 2005), and information was obtained from Iowa Drug Information Services. Additional data sources included meeting abstracts, bibliographies from identified articles, and information from the manufacturer.

STUDY SELECTION AND DATA EXTRACTION: Studies and review articles examining natalizumab were evaluated. All published, randomized clinical trials evaluating natalizumab in MS and IBD were included in this review.

DATA SYNTHESIS: Natalizumab is the first drug in a new class of agents called selective adhesion molecule inhibitors. It has shown promising results in MS and inflammatory bowel disease and appears superior compared with current therapies in reducing relapse rates. However, 3 recent, confirmed case reports of progressive multifocal leukoencephalopathy (PML) create concern about natalizumab's use in combination with existing therapies or in undefined patient subgroups. Natalizumab was voluntarily withdrawn from the market in March 2005 while the drug's safety is further evaluated.

CONCLUSIONS

Although long-term efficacy and safety of natalizumab have not been established, available data indicate that it is a novel drug for patients with MS or inflammatory bowel disease. Analysis of its possible association with PML will determine the risk-benefit evaluation and eventual place in therapy for natalizumab.