Why do we need clinical trials?

• Does the new treatment work in humans? If it does, doctors are also looking for how well it works. Is it better than what’s now being used to treat a certain disease? If it’s not better, is it at least as good, while perhaps causing fewer side effects? Or does it work in some people who aren’t helped by current treatments? In other words, is it a step forward? A treatment that doesn’t offer anything new probably isn’t worth studying.
  
• Is the new treatment safe? This must be answered while realizing that no treatment or procedure – even one already in common use – is entirely without risk. But do the benefits of the new treatment outweigh the possible risks?
  

Answering these questions, while exposing as few people as possible to an unknown treatment, often requires several different clinical trials. They are usually grouped into “phases.” Clinical trials in each phase are designed to answer certain questions, while trying to make sure the people taking part are kept as safe as possible. Every new treatment is tested in 3 or more phases of clinical trials before being considered reasonably safe and effective.