FROM CONFERENCE CALL:

Eun Yang, biotech analyst at Jeffries & Co, asked management about emerging data suggesting there was a link between duration of Tysabri therapy and increased risk of developing PML.

“When you look at the patients who have been on the treatment for 24-months or longer, PML rate runs around 1 in 800, which is higher than what is in the [prescribing] label,” said Yang. “So, my question to you is what do you think would be the critical threshold of a PML rate where physicians or regulatory agencies would become more cautious on Tysabri?”

“I don’t want to speculate what makes regulators want to do things,” responded chief operating officer Bob Hamm, “but I can assure you that our current thinking is that the risk of PML even in that third year beyond 24-months is within the currently implied risk in the label.”

http://industry.bnet.com/pharma/10005050...

Who needs the credibility check: Jeffries or Biogen?