Placebo

A placebo is the term for a dummy drug, ie something that looks, smells and tastes like the compound or intervention that is being studied, but which has no active ingredient.

Using a placebo helps find out whether the active drug is really active. It also helps interpret side effects.

If 10% of people in the active drug group report having a headache and 2% of people in the placebo group report a headache, then it is reasonable to think that the active drug can cause headaches.

If 10% of the placebo group also reported a headache, then it is reasonable to think that the active drug doesn’t cause a headache.

An example of why placebo studies are still important was shown in the development of capravirine (an NNRTI). In a Phase IIb study people using capravirie plus a background combination did no better than people using the same regimen plus a placebo.

This stopped further development of the study drug. It protected other patients being put at risk from using an ineffective treatment in later trials.