Educating MSers about natalizumab-associated PML; keeping it simple.

PML risk education; keeping it simple. #MSBlog #MSResearch

“I am now aware that most MSers don’t want to wade through detailed slide decks to get their heads around the risks and benefits of natalizumab therapy. We therefore asked Alison Thomson, a designer in our group to come up with something simple; our very own visual guide. We have now tested this visual guide in our infusion unit and performed a clinical audit to see if the tool can make a difference.”

The following are the headline results of our audit:

  1. Overall the degree of knowledge of the risk of PML increases
    after using the tool. However, the knowledge decreased at 6 weeks.
  2. Before the MSers were shown the tool, only 20% got the answer correct to “Do you know how many cases of PML
    have been reported so far?”
    asked after the tool was used 90% got it
    correct and when asked 6 weeks later only 40% got it correct.
  3. All MSers said they were aware of the risk of PML
    when on natalizumab but only 30% knew the overall risk of PML. This was
    increased to 40% after use of the tool.
  4. Importantly, all MSers see the same nurse for their
    infusions and all feel that the implications of the JC virus are
    adequately explained to them.
  5. All people said they were satisfied with the service they are
    receiving at Barts Health NHS Trust.

“Do you think keeping it simple with this simple visual guide is an improvement on the detailed monthly slide shows I have been posted on the blog?”

CoI: multiple

About the author

Prof G

Professor of Neurology, Barts & The London. MS & Preventive Neurology thinker, blogger, runner, vegetable gardener, husband, father, cook and wine & food lover.


  • Re: "Why is the risk higher if you have been on Tysabri longer? Is that a real risk?"

    Yes, it is a real risk the data speaks for itself. Why it occurs probably relates to the fact that the strain of virus that causes PML is a mutant virus and it has to escape from the immune system. The average mutant virus has mutations in its regulatory region and its coat protein that is responsible for it being able to infect glial cells within the brain. I assume this mutations take time to accumulate, which is why treatment duration is a risk factor.

  • If you have been on tysabri for 2 years and in month 24 of treatment you test positive for JC virus (having previously tested negative), is your risk 1 in 94 at the point, or is it the length of tysabri use AFTER testing positive that counts?

  • is that an error, or is your risk off pml LESS if you have been on immunomodifying therapy, than if you haven't? 1 in 92 if you have, 1 in 194 if you haven't.

By Prof G



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