Hippocrates’ most famous dictum—primum non nocere—is not part of The Physician’s Oath; it appears in his treatise on epidemics. “As to diseases make a habit of two things,” he advised, “to help, or at least, to do no harm.” As any practicing physician knows, however, this is harder than it sounds. What is nominally the same disease differs, often markedly, from one patient to another. And sometimes a drug that works well in most people causes unexpected side effects, with devastating results. The dream of personalized medicine is, first of all, to use the advanced tools of molecular genetics to predict how patients will respond to drugs, reducing harm and increasing benefit. Beyond this, it is to produce a personal medical profile that can guide an individual to stave off diseases before they manifest themselves.

 

As with much modern medicine, though, the technology is ahead of the healthcare system. Recently the Institute of Medicine (IOM) estimated that in the United States medical errors—doctors making simple mistakes, like prescribing the wrong medication—accounts for some 80,000 deaths a year. And the number of patients who are injured is far higher. Standard treatment for patients after a heart attack calls for aspirin, but the IOM found that almost 40 percent of the time physicians failed to administer it.

 

Harvard Business School professor Clayton Christensen has written at length about the relationship between breakthrough technologies and the social and market systems that enable them to flourish or perish. RCA developed color television in the 1950s, but no network was available to broadcast color until RCA itself acquired NBC and forced the market to adapt. At the same time, vacuum tube televisions were sold by independent dealers who made most of their profits on repairs and, in consequence, had no interest in selling innovative transistor TVs produced by Sony. K Mart, however, had lots of stores and no repairmen, and quickly revolutionized the distribution system, selling the new technology and driving the dealers out of business.

 

And so, as we consider how the powerful combination of diagnostic and treatment technologies at the heart of personalized medicine will transform healthcare, we should pay careful attention to the barriers and opportunities embedded in the present system. How will the regulatory process adapt? How will government and private insurers respond? How will medical education change? And how will doctors accustomed to one style of practice be encouraged to take up new ways of treating patients? History suggests that while the new technology will triumph, the process will be neither as smooth nor as rapid as we might hope.