http://www.newscientist.com/article/...al-horror.html
Apparently the drug was much less selective than other monoclonal antibodies.
Ironically, this news story seems to have made healthy, young men in Britain more interested in participating in trials because it has highlighted that they pay well and usually don't have much effect on volunteers.
Perhaps drugs companies should test such powerful drugs like they do cancer drugs: the first human trials only happen in someone with the disease who has exhausted other treatments and only one person at a time gets the treatment, at least at the start of the trial.