Identifying Patients Treated with Tysabri at Risk for PML

The risk for a rare brain infection called progressive multifocal leukoencephalopathy (PML) occurs in people using the drug Tysabri (natalizumab) to treat multiple sclerosis (MS) or Crohn’s disease (CD).

The Stratify JCV antibody enzyme-linked immunosorbent assay (ELISA), when used with other clinical data from the patient, can help health care providers determine the risk of developing PML in MS and CD patients.

Currently, there is no treatment, prevention, or cure for PML, and no certain way to predict who will develop it. This test, in conjunction with other factors, will enable physicians and patients to assess carefully the risks and benefits of continuing Tysabri treatment.

Risk factors have been identified that increase the chance of Tysabri-treated patients developing PML. These include the presence of anti-JCV antibodies, which reflects prior exposure to JCV, treatment with Tysabri for more than 2 years, and treatments with immunosuppressants before receiving Tysabri.

The US Food and Drug Administration (FDA; Silver Spring, MD, USA) permitted marketing of the first test, the Stratify JCV antibody ELISA to help determine risk of patients developing PML.

The Stratify JCV antibody ELISA test is manufactured by Focus Diagnostics (Cypress, CA, USA).

Related Links:
US Food and Drug Administration
Focus Diagnostics