New Antibody Test from Quest Diagnostics Helps Stratify PML Risk in MS Patients

Quest Diagnostics has announced that the U.S. Food and Drug Administration (FDA) has granted a de novo classification petition to its STRATIFY JCV^TM Antibody ELISA testing service. The test is the first to be FDA market authorized for the detection of antibodies to the polyomavirus JC virus (JCV) for stratifying risk for progressive multifocal leukoencephalopathy (PML).

PML is a rare but often fatal infection which is characterized by progressive damage to multiple locations of the brain. The JC virus only causes disease when the immune system has been severely weakened, such as in patients with multiple sclerosis (MS) receiving TYSABRI^® (natalizumab), a highly effective therapy for relapsing forms of MS.

The market authorization follows FDA approval today of a product label change for TYSABRI. The new label identifies JCV antibody status as a PML risk factor; other risk factors include duration of treatment with TYSABRI and prior immunosuppressant therapy use. It is estimated that approximately 50 – 60% of MS patients have been infected by JCV.

The STRATIFY JCV Antibody ELISA testing service will be provided by Quest Diagnostics' Focus Diagnostics laboratory in the US. It is intended for the qualitative detection of antibodies to John Cunningham Virus in human serum or plasma. The assay is intended for use in conjunction with other clinical data, in multiple sclerosis and Crohn's disease patients receiving natalizumab therapy, as an aid in risk stratification for progressive multifocal leukoencephalopathy development. The assay is for professional use only and is to be performed only at Focus Diagnostics' Reference Laboratory.

"STRATIFY JCV is a great example of the capacity of pharmaceutical and diagnostic companies to collaborate to bring important medical innovations to market," said Kathy P. Ordonez, senior vice president, discovery and development, Quest Diagnostics. "The test has demonstrated its value as a tool that enhances PML risk assessment, and marks a significant step forward in the personalization of clinical management of MS patients who may benefit from natalizumab."