No, the 40,000 number does not represent ALL the people who've ever been on Tysabri (i.e. including those from the trials) . . . BUT the 8 cases of PML does represent how many occurred (INCLUDING those from the trials). Apples and oranges, kinda.

In their Q4, 2008 report today, they are quoting the December announced numbers:

"At the end of the year and post-marketing setting, TYSABRI had over 10,000 patients with at least 18 months and 4,300 with at least two years of therapy."

http://seekingalpha.com/article/1190...nscript?page=1

So, the 8 people (including the trials) have gotten PML, and the total number of people that have used Tysabri for 18+ months, is:

10,700 - 18 mo (post-marketing)
4,300 - 24 mo (post-marketing)
1,800 - 18 mo (trials)
1,400 - 24 mo (trials)
18,200

This would amount to a current ratio of 8:18,200 or 1:2275 cases of PML.

(Now slightly higher than what I posted in January @ 1:2600 http://neurotalk.psychcentral.com/sh...Tysabri&page=2 . . . because it usually takes a few months for cases to be confirmed out of the previous quarter numbers).

Cherie