Monday, March 19, 2012

Tysabri-PML Cases as of March 1, 2012

I've been following the reported incidence of cases of progressive multifocal leukoencephalopathy (PML) in patients who use Tysabri over the years.  For many months, reports of new cases were found in news publications such as Bloomberg.  However, public reports have been released less and less frequently. 

Biogen Idec has released the latest figures for PML cases and deaths following Tysabri infusions for multiple sclerosis.  The total number of cases have reached 212 PML cases and 46 deaths in Tysabri MS patients as of March 1, 2012.

I have updated the chart on the right to reflect this recent report. This chart is under copyright. Please do not reproduce without permission.

As of March 1, 2012, there have been 212 PML cases, of which 122 have been in the European Economic Area (EU), 80 in the United States and 10 in rest of world (other). 46 of the 212 patients with PML have died.

In 54 natalizumab-treated MS patients who developed PML and in whom serum samples were available 6-187 months prior to the onset of PML, all 54 patients had anti-JCV antibodies detected.

Samples were available from 86 patients at the time of PML diagnosis and all 86 tested positive for anti-JCV antibodies.

In addition, one sample, collected from a patient at the time of PML diagnosis following a cycle of plasma exchange (PLEX) tested negative for anti-JCV antibodies. Because this sample was collected immediately following PLEX, and PLEX removes antibodies from the circulation, the information obtained from this sample is unreliable.

One patient tested anti-JCV antibody positive two months before PML diagnosis. Previously, the patient had tested anti-JCV antibody negative 15 months prior to PML diagnosis, indicating that they had been exposed to the JC virus at some point between the two tests.

Source: Biogen Idec (16/03/12) as shared by Multiple Sclerosis Resource Centre.


  1. I only take only one drug for the MS headacheas.When I was diagnosed in Dec 03 my neurologist at the time said I had the highest count of any of his other MS patients.(the protein count) I lost him as a doc in 04,after he put me off work at the hospital where we both worked,numerous MRI's I was to high cost patient for THEIR insurance,lololo So now I take supplements(herbs) and glad to say I am glad I have.I am haivng issues with walking now,but at least I am alive,such as it is.Thank you for posting this,answers questions my huband and I talked about just today.And trust me MS patients are the most overlooked patients.I have a cousin who has suffered with it for yrs and lost another one who had MS last yr,odd isn't it,3 of us in the same family,

  2. Hi Lisa,

    Thanks for sharing your story. Sorry to hear that you lost your job due to MS. I hope that you are able to find a way to get the MS treatments you want and need at the appropriate time.

    Three MS patients in one family. Yes, that does seem to be a lot. wow. Hope you are doing well.