Tuesday, June 3, 2008

MS Awareness

It's MS Awareness Week here in Australia so I've heard and seen some new information that I'd like to share and comment about.

In the recent budget the Government put a new MS drug on the PBS list that will allow more people to access it from July 1st. It called Tysabri and it's manufactured by Biogen-Idec.

I did a search on the net and this is what I found out about it. Tysabri was originally issued in the US in 2004. It was removed a year later after a few people taking the drug contracted PML (progressive multifocal leukoencephalopathy) and died. It was then allowed back onto the market in 2006 after "appropriate steps" were taken.

In July 2007 it was approved by the Australian Therapeutic Goods Administration. At that time anyone taking it had to pay $33000 per year for the priviledge. The recent PBS listing brings that price down to an affordable level, however (and I quote) "due to the emergence of the link to PML in the clinical trials, specific safety procedures and patient tracking systems for adverse events have been put in place worldwide." I assume that is what they meant by appropriate steps.

What does Tysabri do?

It's designed to hamper the movement of immune cells from the bloodstream across the blood-brain barrier into the brain and spinal cord. It does this by attaching itself to a protein in the T-cell (immune cell) to prevent it going in.

Ok, let's look at the big picture here. MS is an auto-immune disease, which means that it's the body's own immune system attacking the myelin coating on nerves. The more frequently this happens the more damage occurs, therefore the worse the prognosis. So, Tysabri changes the chemistry of the T-cells and prevents them from crossing over from the blood to the brain and spinal cord, reducing the possiblity of the T-cells being destructive.

Is this a good thing? (From here I'm going to be totally subjective so if you're expecting an unbiased argument then you may as well tune out at this point)

IF I had an aggressive relapsing/remitting form of MS (which I don't) and I was feeling totally depressed and disillusioned about life then, and only then, I MIGHT choose to invest in this sort of insurance policy, because that's all it is. It seems to adopt a "shoot the messenger" approach because no one knows who or what is sending the messages in the first place.

Does anyone really know what role the T-cells play in the brain and spinal cord? If you do then please tell me. I assume that the lack of T-cells in the people on the trial who died may have allowed a killer virus to get into the brain. What other consequences might there be if there are no T-cells getting to the brain? Is there some sybiotic relationship between T-cells and some other brain component that has a role to play in thought processes or memory? I assume that we don't know this, which is why I wouldn't want to experiment with my own brain chemistry.

If you have any view on what I've written then please leave a comment and I'll be happy to discuss it with you.

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