I do not think any list of risky biotech plays would be complete if it did not include what is (based on past events) probably the king of risky biotech plays - Elan.
1)The test for the virus related to PML should serve to mitigate the severity and frequency of cases of PML.
If the perceved safety of the drug improves as a result of less cases of PML and a reduction in the severity of the cases that do appear,Tysabri will be more prescribed in the treatment of both MS and Crohns disease.
2) Elan holds a 49.9% equity interest in JANSSEN Alzheimer Immunotherapy, and will be entitled to a 49.9% share of the profits and certain royalty payments upon the commercialization of (bapineuzumab), a potential first-in-class treatment that is
in phase 3 testing for Alzheimer's disease.
The phase 3 results should come out in the 2012-2013 timeframe.
JMHO and worth what you paid for it.