Natalizumab update

Abstract

The pharmacology, pharmacokinetics, indications, clinical efficacy, adverse effects, drug interactions, and dosage and administration of natalizumab are reviewed. Natalizumab, the first commercially available selective adhesion-molecule inhibitor, is approved as monotherapy for the treatment of patients with relapsing forms of multiple sclerosis (MS). Natalizumab exerts its immunologic effects by targeting the alpha4 integrin receptor, the site responsible for the migration of leukocytes from the blood into inflamed tissues. Because of the increased risk of progressive multifocal leukoencephalopathy (PML), natalizumab is generally recommended for patients who have had an inadequate response to or are intolerant of alternative MS therapies. Data evaluating the efficacy and safety of natalizumab for the treatment of MS are available from published Phase II and III trials. The most common adverse effects reported include headache, fatigue, urinary-tract infection, depression, arthralgia, and lower respiratory-tract infection. The recommended dosage of natalizumab for the treatment of relapsing forms of MS is 300 mg administered by i.v. infusion over one hour once every four weeks. Natalizumab is available only through a risk-minimization program run by the manufacturer. Natalizumab offers an effective treatment option for patients with MS who have had an inadequate response to or are intolerant of alternative MS therapies. Because of its potential to increase the risk of PML, the risks and benefits should be carefully weighed before initiating natalizumab therapy in patients with MS. Natalizumab should not be used to treat Crohn's disease or any other unapproved indication until more postmarketing safety data are available.