Good News for Tysabri Users Who Are JCV Positive

Good News for Tysabri Users Who Are JCV Positive


One of the many disease-modifying therapies (DMTs) that I’ve been on over the many years of my treatment for MS is Tysabri (natalizumab). It worked well, holding the progression of my MS at bay for the several years that I received the infusions. I’d probably still be on it today, were it not for the possibility of PML.

Progressive multifocal leukoencephalopathy (PML) is a rare brain infection that usually leads to severe disability or death. Most adults are already infected with a virus called the John Cunningham (JC) virus, which is usually acquired in childhood. People who carry the JC virus are susceptible to PML, but most don’t develop it. However, Tysabri and some other therapies that suppress the immune system are known to increase the risk of PML for those who are JCV-positive after a certain period.

I’m positive for the virus (JCV+). Even so, my neurologist, believing that the PML risk is low at the time a patient begins Tysabri infusions, prescribed the treatment for me. After two years, however, she reduced my infusions from monthly, which is the standard treatment, to every other month. That’s because studies indicated that the PML risk begins to increase after two years of Tysabri infusions.

Longer gaps between infusions may lessen the risk

Now there’s a study that confirms the wisdom of my neurologist’s treatment modification. Researchers at the New York University Langone MS Comprehensive Care Center report that extending the length of time between doses of Tysabri from every four weeks to every five to 12 weeks “significantly reduced the risk of developing” PML. This Langone study didn’t look at whether reducing the treatment frequency impacted the effectiveness of the therapy. However, previous work by the same researchers found that extending the dose up to eight weeks did not negatively affect the medication’s efficacy.

The Langone study’s primary author, Lana Zhovtis Ryerson, MD, considers this a potential treatment changer. “Our safety findings are clinically and statistically significant, and we believe that extending the dosing schedule of natalizumab is practice changing and may save lives,” Ryerson says.

That’s good news for patients who may have ignored a useful MS DMT because of its PML risk. And it proves to me that my neuro knows her stuff.

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  1. Becca says:

    I’m doing the 8-week infusions, too. I’ve gone 6 months with this schedule, and so far so good. I haven’t found anything (rebif, copaxone, tecfidera, etc) to work near as well as tysabri so this is welcome news!

  2. Mayvår Sjøberg says:

    I reacted to the first dose, so we pushed time between doses to 6 weeks and infused over two hours with IV fluids prior (and pre-meds). I’ve been fine since. I’m glad to have a neurologist like mine!

  3. Cynthia says:

    I was on Tysabri for 6 years and was JCV positive. I went monthly up until June 1, 2018. My numbers from the blood work was good that test for the JCV. He told me that I had to stop because the FDA stated that I have gone past the required doses (72). The medicine was working for me really good. I cried because he placed me on a drug that I did not like because it smelled like marijuana every time I broke the seal. so now I am not on anything because I am JCV Positive.

    • Ed Tobias says:

      Hi Cynthia,

      There are about 15 disease-modifying therapies available in the US. For most of them being JCV positive isn’t a concern. Have you asked your neurologist about any others?


  4. NIQUE says:

    If I have to go extend the days before I get my next infusion, I would be disheartened. A week and a few dsys before my next treatment my symptoms are extremely worse.

    • Ed Tobias says:

      Hi Nique,

      You’re not alone. I’ve heard of many people who feel poorly just before they’re due for their next Tysabri infusion. Fortunately, I didn’t have that problem so extending the time between infusions didn’t bother me. Eventually, however, my JCV titer score rose to a level where I needed to switch to a different DMT.


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