I don't see how this conception of personalized medicine would work. For many drugs, the binding sites aren't terribly different or different at all between individuals. I can see this being different for larger populations. More likely you'll see drugs created that very specifically target something so that the personalization will be at the level of the drug cocktail as opposed to synthesizing some new molecule. This isn't to mention the possibly wildly different effects you can get from changing something seemingly minor about the molecule. A sort of good example of this is methamphetamine (yes, I know chirality isn't minor but its a good layman's example).