Hmm, very interesting comments on
1. Correlation between MRIs and disease progression, (there is one for RRMS), and
2. Relapse rate and EDSS scores (relapses generally increase EDSS scores).
This from the Biogen IDEC 30 Nov 04 R&D day, which can be listened to at this link:
http://phx.corporate-ir.net/phoenix.zht ... tID=924982
I don't know how long this link will be 'live' and its 4 hours! Transcript available at
The slides from this presentation can be viewed at
The following couple of questions are to Al Sandrock, VP of Medical Affairs for Biogen Idec (he may have another title, as my memory is failing me!):
Question from Frank Savrile: Al, I was struck on page 15 of your presentation in the distribution slide of new and newly enlarging T2 lesions, how there is a mirror image almost between drug relative to placebo in 0 new lesions versus greater than or equal to 3. And I’m wondering, from historical studies, if you are look at this marker relative to EDSS score changes at two years in historical data, what has been seen in the past and how tightly correlative are these, and what can you say about that?
Al Sandrock: That’s a tough question. First of all, I think the T2 lesion data with Tysabri is better than what we have seen with the interferons. Certainly, if you look at the mean number, the reduction in mean number, it is greater. The 80% number is greater than what we have seen with other drugs which are in the 60% range. The question about correlation between MRI measures of any type, actually, and EDSS is a tougher one. I think the correlation is modest. It partly depends on the stage of disease. If you take relapsing MS as we did in these trials, the correlation is much better than if you take, for example, people who have relapsing-secondary progressive MS where the correlation is quite poor. And those in the later stages of the disease, you can have a very strong effect on MRI and no effect on EDSS as we seen with the interferon trials in various stages of secondary progressive MS. I do think the correlation is pretty good in relapsing remitting MS which is largely what we studied here. That’s the best I can do with the answer at this point.
Q. Can you comment on the potential relationship between relapses and EDSS progression?
Al Sandrock: Again, we have examples of drugs that are on the market now that have achieved the relapse endpoint in their Phase III trials, but were not able to achieve their disability endpoint in Phase III trials. We’ve looked, there was a recent paper published by Cutter and I think it was Loveland, looking at the Silvia Lori center where they collected MS trial data from a number of trials. And they looked at how many of the relapses actually end up with EDSS progression. It turns out that about 45% or so of relapses lead to a .5 change in EDSS. And about a 25% or 30% (I believe the numbers are in that range) of relapses lead to a 1 point change in EDSS, sustained. So, given that we have a very strong effect on relapses, and given that there is some correlation between relapses and EDSS progression, at least as seen in that study which had looked at a huge database, I predict that it would be hard [not to see EDSS improvement] … If we don’t get an effect on EDSS, we are going to have to rethink how we think about MS, because it would just be quite a surprise.
Seems that they is some validity to looking at MRIs and relapse rates! And can anyone guess what a 66% reduction in relapse rate from Tysabri monotherapy did to EDSS? Also, in the presentation hospitilizations for the Tysabri group were reduced some 50+% relative to the placebo group (this from the slides).
Do you believe Sandrock? Up to you, but hard to believe he would be BSing in a public forum. But how this relates to the FDA-approved label is confusing with regard to the MRIs:
The exact relationship between MRI findings and the clinical status of patients is unknown. Changes in lesion area often do not correlate with changes in disability progression. The prognostic significance of the MRI findings in these studies has not been evaluated.
Confusing to me. Sandrock says MRI and EDSS correlate somewhat in RRMS, yet the Tysabri label does not say this. Big question, unless Sandrock is quoting this with the knowledge that 80% of the AFFIRM EDSS data are in and he knows the results (80% came from the Q&A listening to the link). This is ONLY MY SPECULATION.
Another good piece of news is that Biogen Idec confirmed that the AFFIRM (Tysabri monotherapy) EDSS data WILL be presented at the AAN meeting in early April, 2005.