One of the many significant acts of my former advisor, Martin Karplus, was to help set up, in 1989, Vertex Pharmaceuticals - one of the first companies to use a design strategy based on "rational", structure-based approaches. Now, Kalydeco, designed by Vertex, is a glimpse into the future of personalized medicine. It is the first cystic fibrosis drug to treat the underlying cause of the disease, and works for those ~4% of patients with a certain mutation of an ion channel, which is potentiated by the drug. 4% amounts to about 2,000 patients, for whom this a wonder drug. However, Vertex has slapped a $300,000+ yearly price tag on this drug, making it one of the most expensive in existence, and this has led to an understandable outcry from various sources, including some scientists involved in the development of the drug itself. In retort, Vertex point out that they have spent $6.5 billion on R&D that needs to be recouped and that it has only two drugs on the market.
Given that personalized medicine is aimed at ever smaller numbers of patients, many fear that this approach will lead to ever more expensive drugs. But the one facet few seem to be talking about in this context is the origin of that $6.5 billion number above. Most of that outlay will have been researching failures. Many of us are now trying to develop fast and efficient ways of finding drug candidates that are more likely than before to have high efficacy and safety. This will get more personalized medicines to market quicker, with less R&D outlay. It stands to reason that if Vertex had discovered Kalydeco earlier, when its total R&D outlay had been only, say, $1 billion, then the price tag would have been lower.
It's not written in stone that personalized medicines will have to break the bank.