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FDA- tysabri and a thought-
Posted: Tue Sep 22, 2009 8:43 am
by cheerleader
New warning from out this week from the FDA- PML seems to be a growing complication in only MS patients. But is not a concern in Crohns. If we consider PML within the CCSVI paradigm, we can see how slowed venous return and blood deposition into brain tissue could allow for a virus like PML to attack the brain. Shouldn't the docs be asking "Why no PML in other patients using Tysabri? Why is it only in MS?" If the immune system is the immune system thruout the body- what possible reason could there be that PML is only affecting MS patients???
Natalizumab (marketed as Tysabri)
Audience: Neurological healthcare professionals, patients
[Posted 09/17/2009] FDA continues to receive reports of progressive multifocal leukoencephalopathy (PML) in patients receiving Tysabri. Tysabri was approved by the FDA for the treatment of relapsing forms of multiple sclerosis (MS) in November 2004 and for moderately to severely active Crohn’s disease in January 2008. From July 2006, (when Tysabri marketing resumed) to September 8, 2009, 13 reported cases of Tysabri-related PML were confirmed worldwide in patients being treated for MS with Tysabri monotherapy. There have been no postmarketing reports of PML in patients treated with Tysabri for Crohn’s disease. Less than 2% of Tysabri use in the U.S. has been in patients with Crohn's disease. Based on available data from the U.S. and outside of the U.S., the current rate of PML in patients who have received at least 24 infusions ranges from 0.4 to 1.3 per 1,000 patients.
The risk for developing PML appears to increase with the number of Tysabri infusions received. At this time, the FDA is not requiring changes regarding PML to the Tysabri prescribing information or to the Tysabri risk management plan, called the TOUCH Prescribing Program.
[09/16/2009 - Information For Healthcare Professionals - FDA]
Posted: Tue Sep 22, 2009 9:12 am
by Loobie
Whoa. Hope I'm in the clear. I never liked those stats, and liked even less that Biogen quit reporting. It's been 14 weeks now since my last infusion, so hopefully it's washed out.
Posted: Tue Sep 22, 2009 9:41 am
by radeck
Could it be that Tysabri hasn't been given to enough patients with Crohn's to make the claim that it doesn't affect them? The citation mentions that only 2% of all patients treated with Tysabri in the US get it for Crohn's. The risk of getting PML in MS patients is 0.1%. I'm guessing that the number of Crohn's patients getting it is in the tens...It has to be 1000 on average before a single case with PML will occurr.
I agree with the principle that a person with slowed brain perfusion should be more likely to get PML, however are we able to tell from these data?
Posted: Tue Sep 22, 2009 10:05 am
by SarahLonglands
Best read this page:
http://www.ninds.nih.gov/disorders/pml/pml.htm
PML is most common among people with AIDS and also in people with Hodgkin's disease, lymphoma or even sarcoidosis. Do they have stenoses in their jugular veins? Because of their lowered immune defences, they can't fight the virus which causes PML, which most people carry without it causing any damage. Lew has no need to worry.
Sarah
Posted: Tue Sep 22, 2009 10:09 am
by cheerleader
your right, Radeck. The numbers aren't there.
And Lew, I wasn't putting this up to freak you out...seriously! We may learn in the future that what you did prior to stenting with tysabri was the right thing to do! I've talked to Dr. Cooke and Marie about this, and someday there will be a perfect protocol involving immune intervention, stenting and follow up care. We don't have it yet. In any event, now that your perfusion time and mean transit time have improved with better venous flow, I'm sure there are no worries.
I'm really more commenting on the fact that I haven't seen any medical research as to WHY PML occurs in MS brains. What's the mechanism of action? Why the brain? That's all.
Just saw Sarah's post...thanks for the clarification! It's just immune- as seen in HIV...nevermind!
cheer
Posted: Tue Sep 22, 2009 10:12 am
by mrhodes40
Good thought Rad,
TYSABRI STATS FROM PROSPECTUs
it appears there may be 100,000 on tysabri....in Aug of 08 it was already 32,000.
considerably more than a few crohn's patients then...... enough that one or two "should" have had PML if at the same rate as MS....still statistically really small