The FDA's mission was to make sure treatments were "safe and effective". Now they're more concerned with the level of control they have and how much instant data companies should provide for them.
The best reason for the FDA requirements is found in cases where those requirements have been bypassed in the name of expedience.
Two examples:
1. Recall the big AZT acceleration for AIDS? The Lancet later published an article demonstrating that it caused more harm than good.
2. Recall the disaster announced last year in the clinical trials for fetal tissue implants to combat Parkinson's disease?
A "miracle cure" like this seems wonderful -- but it's also potentially a disaster: they're basically sending a virus to fight a virus. It'd be a Bad Thing if this ended up mutating into some deadly third virus.