Head of the hive- clinical trials are very tightly regulated and the drug will at least have been through lab and animal testing before it even gets to phase 1.
My friend is a drug designer, and designs anti cancer drugs. In theory they all sound great, until you get them in a lab, or a mouse, and realise they just don't work, or have horrific side effects.
Plus, as an adult, you can make an informed choice as to whether to partake in a clinical trial, knowing the possible actions or non effects. Terminally ill people, and children, can't often make competent decisions.
Finally, the right to try will circumvent trials, and a whole lot of data will be lost. So long run, it won't be beneficial to the population as a whole, as we won't know if it works in a reasonable time frame, or what the side effects are. As always, one persons anecdote does not equal data.