European and US regulatory approval processes are very different. From what I understand, one of the bigger differences is that some EU regulatory bodies only r

European and US regulatory approval processes are very different. From what I understand, one of the bigger differences is that some EU regulatory bodies only require that a treatment be proven safe, not effective, whereas the US requires both. This means that in the EU it is sufficient to prove that your treatment is non-harmful, you are not required to prove that it actually works. In the US, you have to do both which can take much more effort. I'm sure there are other reasons and I'm not an expert, I just had a discussion with a friend of mine that is an AIDS researcher about the drug creation process and I was interested to learn of the difference.