The Paradox of Precision Medicine

Precision medicine sounds like an inarguably good thing. It begins with the observation that individuals vary in their genetic makeup and that their diseases and responses to medications differ as a result. It then aims to find the right drug, for the right patient, at the right time, every time. The notion certainly has its supporters among medical experts. But for every one of them, there is another who thinks that efforts to achieve precision medicine are a waste of time and money. With a multimillion-dollar government-funded precision medicine initiative currently under way, debate is intensifying over whether this approach to treating disease can truly deliver on its promise to revolutionize health care.

Ask scientists who favor precision medicine for an example of what it might accomplish, and they are likely to tell you about ivacaftor, a new drug that has eased symptoms in a small and very specific subset of patients with cystic fibrosis. The disease stems from any of several defects in the protein that regulates the passage of salt molecules into and out of cells...