Personalized medicine

Yesterday the Wall Street Journal (WSJ) ran an article on the first regulations to come out about “pharmacogenomics,” personalized medicine to you and me. The article’s right down the line with what I heard at BIOSILICO and explains it well. Unfortunately, I can’t link to it because the WSJ isn’t accessible without a subscription. But, I think a liberally excerpted summary will do as well.

Researchers are increasingly finding ties between people’s genes and their responses to certain medications. The field, called pharmacogenomics, ultimately holds the promise of “personalized medicine,” in which doctors would tailor drug regimens to patients’ individual genetic signatures.

“It gives us the possibility of only treating the people who stand to benefit, and weeding out the people who could have serious reactions,” says Janet Woodcock, FDA.

Genetic tests are already being used to guide some drug treatments. Doctors can give a genetic test to breast cancer patients, for example, to determine if they should receive the Genentech Inc. medicine Herceptin

Furthermore, the FDA already has begun approving new drugs with labeling that includes genetic test information. Strattera, an Eli Lilly & Co. treatment for attention deficit disorder approved last November, says on its label that a genetic test is available that can help show whether patients are likely to metabolize the drug more slowly, which may cause them to experience its effects a bit more strongly.

“We’re moving from a one-size-fits-all paradigm to a targeted paradigm,” says Mitch Martin…at Roche Holdings AG’s pharmaceutical unit. For the majority of the drugs it is developing, Roche has concurrent programs designed to find genetic or other markers that might help tailor use of the medicine to individual patients.

Let me explain that the genetic testing is a double-edged sword for the drug companies. They’ve made billions on “blockbuster” drugs, the one-size-fits-all drugs. It used to work because we didn’t know that these drugs worked ineffectively or had bad side-effects, probably because of genetic differences among recipients. And it gave the drug companies the latitude to sell it to the broadest possible patient population. So the edge of the sword they don’t like is that genetic testing could narrow the market for a drug or require expensive development of differentiated drugs. Ouch!

Drug companies that don’t have big diagnostic testing businesses are concerned that genetic testing could upset the business models behind many of their most successful products. Even as the drug companies have begun to experiment with pharmacogenomics, they fear that the FDA could use the data they gather to limit the target patient population for potential blockbuster drugs.

But there’s the other edge of the sword. Some drugs that have been tested for approval and failed (at great expense) to benefit a broad enough segment of the patient population might be effectiveness to be sold if they can be shown to work with a population with a specific genetic profile. Aah!

On the other hand, by identifying narrower target groups that react well to a drug, genetic tests could salvage more limited uses for medicines that don’t appear to be effective among the general population.

In the drug approval process, the FDA says it plans to continue using its traditional criteria, evaluating the drug’s safety and effectiveness in “the overall indicated population” even if there are also genetic testing results that show variations in effectiveness for certain groups. So far, the agency has tended to use the genetic-test information on the drug’s label in language that describes its implications and points out precautions.

But if a drug company develops a genetic test along with the medicine and wants to target the drug only at people with certain genetic signatures, the FDA will also consider those applications, the draft guidelines say.

This is all just getting started. In the long run the whole notion about who should have a drug will very likely change.