PML with Tysabri using increased dose periods

As someone who takes the drug tysabri, I am always interested to read articles and studies in the effectiveness of this particular drug. 

Tysabri is a very effective drug for people with highly active types of relapse remitting MS. When I was first diagnosed, my MS fell into this category and probably still would if I didn’t take this medicine. I have to say that this drug has been a lifesaver for me! 

There aren’t many down sides or side effects, however it does carry a risk of a pretty severe brain infection called PML (progressive multi focal leukoencephalopathy). There are a number of procedures in place to significantly reduce the number of people that get PML, such as regular blood testing and MRI scans. However, it was been impossible to reduce the risk completely. 

There have been about three or four studies which have looked into the effectiveness of tysabri and the risks of PML when the dosing is increased from the standard 4 weeks to six or more. 

I have even been offered this during some of my appointments. 

Was this a money saving exercise?

At first I thought it was due to the NHS trying to save money! For someone who receives tysabri every 4 weeks, the patient will receive a total of 13 treatments in year. With someone on a 6 week regimen, this is reduced to around 9 treatments. You can clearly see that there is a cost incentive to do so. 

What does the research say?

From data collected through the TOUCH programme which monitors tysabri and PML risk, around 35,000 people who were at risk of developing PML were reviewed. Researchers compared the extended dosing to the standard dosing of 4 weeks and discovered that those who were treated by extended dosing were significantly less likely to progress to PML. The risk of developing PML was in fact between 90-95% lower on the extended regime compared with the standard regime. 

As someone who has a very low risk on the standard regime, this isn’t something that I am personally concerned about at the moment. However with every year that goes on being treated by tysabri, my risk technically increases. There are some people who are on the drug who have a much higher risk of getting PML. I ask them why they continue to be on the drug, and how they weigh up the risks and benefits. 

One of the people I receive treatment with said 

“I’d rather have an increased risk of getting PML which might kill me, and live a better life on tysabri than the life I had before when I was really struggling with my MS” 


Is it still effective at 6 weeks?

One of the factors that I’d consider if they were going to increase my drug regime from four to six weeks would be whether it was still effective or not. Reviewing some Italian research, 360 people who had been on tysabri for some time were classified into standard and extended regimes. It was identified that there was no difference in efficacy between the standard dose and the extended one. 

To be honest, this is food for thought for me. Although I feel as though my treatment wears off and I feel ready for a boost around 4 weeks, perhaps this is just all psychological and in fact I could go longer between dosing. Would a regime of 6 weeks work for me? Would I be able to manage the changed time table after 5 years of having this regular 28 day routine? 

Do people feel it wears off?

A lot of people report that they have increased cognitive problems and fatigue near the time when they are due the next infusion. Researchers in the Netherlands concluded that more than half of the group experienced the drug wearing off towards the infusion date. Interestingly, the wearing off was more prevalently reported in the standard regime than the extended one!! Most importantly, there was no reduction in the blood levels of tysabri with either of these different dosing types before the next dose. 

Really this does give me something to think about. More than the anecdotal evidence of the patients not feeling as though the drug was wearing off, but the hard evidence of the drug still being equally present in the blood after the 6 week time. 

What does this mean for me on my Ty journey?

Well it suggests that the gap between infusions from 4 to 6 weeks will reduce the risk of PML fairly significantly without any loss in the efficacy of the drug. This is especially promising news. 

I am going to think this one over for myself and

Consider what it means for me as a patient and someone who receives tysabri. 

Are you someone who receives the drug. Does this make any difference to how you will go forward in your treatment? 

Let me know, I’d love to hear from you. 

2 thoughts on “PML with Tysabri using increased dose periods

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