The studies performed are the same ones, but companies submit it to the FDA first, who are more likely to approve, and approve faster than European regulators (the European Medicines Agency, EMA). The FDA are the most permissive regulator is what has been seen in the literature - there was a really good study looking at the same drugs (TKIs) submitted to various agencies (it's not the only one, but is the cleanest):
As for thalidomide, yep the FDA had an amazing employee who saved a lot of damage being done, and shows exactly why regulators exist, and assess the safety and efficacy before you can sell things!
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3769667/
As for thalidomide, yep the FDA had an amazing employee who saved a lot of damage being done, and shows exactly why regulators exist, and assess the safety and efficacy before you can sell things!