There have now been 35 cases of PML in Tysabri patients:

http://www.businessweek.com/news/201...ase-cases.html

They're saying that the risk is still within the expected range, and so Tysabri is still considered safe.

Here is a link to an article coming out in "The Lancet" in March 2010 on the JC virus, PML, Tysabri and the immune system.

http://www.thelancet.com/journals/la...006-5/abstract

It was good to read that 11 of the 35 are in the US. I'm pretty sure that 2/3 of the people on Ty are in the US with a little less than 1/3 getting pml.
Linda

http://clinicaltrials.gov/ct2/show/N...m=Elan&rank=36



http://clinicaltrials.gov/ct2/show/N...ntibody&rank=1

That's great news!! BUT....my question is this: the time frame for the studies is 2 years so does that mean this assay will not be commercially available until 2-3 years from now?

I think we will be the people testing it, Natalie...

The trials are what Biogen/Elan have to do to get the JC Virus antibody assay into the label for Tysabri as reducing the PML risk.

Oh, so the doctors will soon have the test in their office and sign everyone up for the clinical trials? Since I'm now on the 8 week Tysabri cycle I hope I can still get a test. Oh, and if they test us, will Biogen even tell us whether we are positive or negative? I worry they won't because they don't want people dropping off of Tysabri if they are positive.

I am still confused!

Had a friend who is involved in MS research look at this article and tell me what it means...

Basically, Tysabri caused an increase in the proliferation of the viruses but the body's humoral response remained stable. This means that the body wasn't making any antibodies to the viruses so it wasn't launching an attack. This is why it said that although there was an increase in the viruses there was no sign of reactivation. One only would see symptoms of reactivation if the immune system was launching an attack as that is what creates the symptoms. If the virus actually gets so concentrated it will interfere with function and then of course you have morbidity which can be fatal. The viruses were being proliferated in the body but the immune system wasn't launching an attack and that certainly is not good!

There still appears to be so much we don't know about PML and it's connection with Tysabri. Hopefully this test will become available soon.

Harry

Not sure how your friend came up his summary as it appears to be totally opposite to what the investigators determined.

This is what the scientific experts concluded in the paper "Interpretation
Natalizumab increases cellular immune responses specific to viruses and myelin proteins in the peripheral blood after 1 year, without evidence of viral reactivation."