Personalized therapy might possibly not work for a really long time. Consider each drug to be a code change at heart of the most critical code running the code of your body. Clinical trials are the integration testing and ab testing equivalent of making sure this change doesn't have side effects. Personalized therapy means you have no way of testing in a comparable system. Unless you're gonna clone babies of yourself give them the same cancer and see if it treats them and doesn't kill them (and then pull a Prestige)