A friend of mine started a company that, among other things, runs clinical trials for generic versions of drugs.
He and his staff spent a lot of time in foreign countries, as it was much quicker, easier and cheaper to do clinical trials outside the US.
The companies developing generics don't always have the funding to run their trials in the US under FDA standards on top of all the other R&D and testing they performed. So, they outsourced most of the trials where they could afford it.
As long as the methodologies, standards and reporting requirements were met, the FDA had no problem with their business model. In fact, there's something to be said for bringing a competing drug to market faster which has already proven to be effective and safe, which can reduce prices for those drugs for everyone.