Author Topic: (AAN abst.) Tysabri therapy associated w/greater variability in JC virus antibody levels  (Read 53 times)

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Offline agate

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Presented at the annual AAN meeting in Boston, April 2017:

Natalizumab therapy is associated with greater variability in JC Virus Antibody levels

John Peters1, Eric Williamson1

Department of Neurology, University of Pennsylvania Perelman School of Medicine


To examine the variability of serial JC Virus (JCV) index measurements in patients with multiple sclerosis (MS) on natalizumab and other disease-modifying therapies (DMTs) in hopes of better understanding how to use this test in assessing risk for progressive multifocal leukoencephalopathy (PML). We aimed to quantify this variability over time and explore how it is impacted by various factors including age, gender, DMT, and timing of natalizumab infusions.


Positive antibody titers against JC Virus are one of several identified risk factors for PML for patients with multiple sclerosis being treated with natalizumab. Positive titers are also hypothesized to be helpful in assessing risk with other DMTs. Clinicians and patients use titer values to help decide whether to start, continue, or stop treatments, so assessing how indices vary over time for patients on DMTs may allow a patientís risk of PML to be better interpreted.


A retrospective analysis was conducted using medical records of MS patients with multiple JCV antibody index measurements exposed to therapy with natalizumab (N=171) or not (N=101). Variability was quantified by calculating the variance of multiple index values for each patient.


Variability of JCV antibody indices was found to be significantly higher for patients on natalizumab (p<0.05). For patients on natalizumab, infusion less than 14 days before JCV antibody testing was found to be associated with significantly higher antibody values (p<0.05).


JCV antibody levels vary over time and therapy with natalizumab is associated with greater variability. One potential contributing factor may be the timing of natalizumab infusion relative to antibody testing. These results suggest that therapy with natalizumab may influence the test being used to assess the risk of treatment with it.
« Last Edit: May 17, 2017, 12:12:21 pm by agate »
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SPMS, diagnosed 1980. Avonex 2001-2004. Copaxone 2007-2010.


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