The Three Kinds of Drug Studies
1. FDA Studies
Contrary to the name, these are not funded by the FDA but rather by the drug company that is interested in obtaining a new indication for their drug. However, the FDA does provide specific guidance regarding endpoints and methods, etc. These are typically well done multicenter trials for the purpose of getting a new indication. These are usually studies of Great Scientific Validity plus they are reviewed by the FDA and an independent review panel. These become FDA approved label indications (or not if the submitted data do not support the claim). Use TOES to grade these because even though they are very likely to be of high scientific validity they deserve rigorous review.
2. Marketing Studies
These are drug company sponsored studies for the primary purpose of marketing. The drug reps will show you these pieces as they try to convince you to use their product. These studies vary widely in their scientific validity. Best to use the grading system "TOES". Remember that just because something is statistically significant does not mean that it has much clinical significance.
What you have to ask yourself is this, "if the data were so compelling then why not get FDA approval". Also beware that the negative studies (the ones that don't show what the Drug company wanted) are not usually published.
3. Independent Studies
The Pharmaceutical industry controls 95% of all drug study funding (excluding cancer drug studies). It is very hard to get enough funding to perform a large INDEPENDENTLY FUNDED DRUG study. These are rare. These are usually small, open labeled studies. Occassionally there are some excellent Independent studies. Use TOES to grade these.