Anti-JCV antibody status can aid in identifying Tysabri users’ risk for developing PML.
FDA approved a product label change for Biogen Idec and Elan’s multiple sclerosis therapy Tysabri® (natalizumab) to identify anti-JCV antibody status as a risk factor for the development of progressive multifocal leukoencephalopathy (PML). The new label change states that anti-JCV antibody negative status indicates that exposure to the JC virus has not been detected. The U.S. regulator concurrently granted Quest Diagnostics a de novo classification petition for its Stratify JCV antibody ELISA testing service. The European Commission has previously approved anti-JCV antibody status as an aid to stratifying patients at risk for developing PML.
The link between JC virus infection and the development of PML is particularly high in patients who have prior immunosuppressive therapy and been taking Tysabri for more than two years. Anaylses by Biogen Idec and Elan indicated that irrespective of prior therapy, about 55% of MS patients are anti-JCV positive.
The parallel FDA approval of Quest’s Stratify JCV test will enable neurologists to determine the JC virus infection status of their MS patients to aid in treatment decisions. The firms say the test is also the first blood test to be authorized by FDA for the qualitative detection of antibodies to the JC polyomavirus.
The Stratify JCV test was developed under an exclusive U.S. collaboration agreement with Biogen Idec. The assay will be offered through Quest’s Focus Diagnostics laboratory in the U.S.