PDL Just Got Riskier
"Tysabri was taken off the market in 2005 after it was linked to a potentially deadly infection of the brain called PML, but it was recently reapproved.

Most observers in the medical industry expect the reintroduction of Tysabri to progress slowly at first, but, considering the superior efficacy of the drug, if no more cases of PML are reported it could eventually become the blockbuster that was originally envisioned. PDL is certainly hoping for that scenario, considering it receives royalty payments on Tysabri......"