pgnx - Why is this one up? Should I sell and cut my losses?

[computeraces]

I've been holding this one for a while. It's still below what I bought it, but it's up like 14% right now. I can't find out why it's up. Should I sell while it's up and cut my losses or is there a good reason it's up and going up more?

Thanks,
Cory

[bahroor]

http://biz.yahoo.com/ap/060822/wyeth_progenics.html?.v=2