Risk of PML for patients on Tysabri has long been estimated as 1:1000 overall. Risk can now be stratified. To be at risk, patients must harbor the JC virus. The STRATIFY study has recently shown that 56% of MS patients are positive for the JCV antibody. 37/37 PML patients with serum available were JCV AB +, none negative.
45% of PML patients were previously treated with an immunosuppressive (IS), 20% not and the remainder unknown. Treatment before use of Tysabri with any IS confers a 4-fold higher risk of PML.
Risk is greatest between 24-30 months of therapy and may fall thereafter. No patient has developed PML at less than 12 months.
Risks are as follows:
- 2 yrs: 0.1/1000 = 1 in 10000 or less
- 2 yrs: same as <2 yrs
if JCV+ and no IS
- 2 yrs: 0.35/1000 = 1 in 2850
- 2 yrs: 2.8/1000 = 1 in 357
if JCV+ and IS
- 2 yrs: 1.2/1000 = 1 in 833
- 2 yrs: 8.1/100 = 1 in 123
A commercial JCV antibody assay is not yet available. STRATIFY sites will test any MS patient (whether or not on Tysabri) and forward results to the patient’s neurologist.
Look for the Stratify study at www.clinicaltrials.gov , then " search for trials", and type in JCV antibody assay and the study comes up.
Ref. Poster 0.3248, Sandrock et al, AAN, 2011.
National MS Society's Professional Resource Center
The Professional Resource Center houses the most comprehensive library of MS information in the world, and provides a variety of information and consultation services. Our goal is to partner with health care professionals to enhance quality of care and increase access to care for people with MS. The Professional Resource Center provides the following information:
- Professional Education – including conferences, CME programs, and self-study offerings
- Fellowship and Training Grants
- Pediatric MS
- Resources for clinicians
Two-thousand-ten marked an exciting year in MS research.
We saw the first disease-modifying oral drug come to market, new technologies and so much more. Here's to making even more progress in 2011!
BACK TO TOP
Did you know the National MS Society offers hundreds of programs and services each year to assist people living with MS in your community? Please tell your patients with MS to call on us and see how we can help them live their best life. If you would like more information on how we can help your patients living with MS, please contact us today to learn more.