Brave New Visions

The promises and perils of imaging the brain

Bill Snyder
Published: February, 2006

In separate interviews with Lens editor Bill Snyder, Richard Hargreaves, Ph.D., vice president of Imaging at Merck Research Laboratories, and Judy Illes, Ph.D., Canada Research Chair in Neuroethics at the University of British Columbia, describe recent progress in the use of imaging technologies, their potential and challenges to further development of the field. Can imaging lower the cost of developing new drugs? Are there places we shouldn't go?

Hargreaves earned his Ph.D. in physiology from King’s College London. At Merck since 1988, he led the biology core for the discovery of Maxalt, an anti-migraine medication, and Emend, which helps prevent chemotherapy-induced nausea and vomiting. Illes received her doctorate in Hearing and Speech Sciences from Stanford University, specializing in experimental neuropsychology. She co-founded the Neuroethics Society, and formerly directed the Program in Neuroethics at the Stanford Center for Biomedical Ethics.

Interview 1: Richard Hargreaves, Ph.D.

Photo courtesy, Richard Hargreaves, Ph.D.
Imaging technologies are playing an increasingly important role in drug discovery.

Radiotracer imaging such as positron emission tomography (PET) allows scientists to see whether a molecule “engages” its target sufficiently to test for therapeutic efficacy. If the molecule doesn’t bind to its target, or saturates the target and yet fails the efficacy test, “then we can move on to a new therapeutic concept,” Hargreaves says.

In the early stages of drug discovery and development, imaging “actually increases the attrition in the number of molecules you test,” he says. “You actually throw more molecules away to get the best one.”

Can imaging reduce the cost of developing drugs?

Built into the cost of any drug are all the failures of the molecules you test along the way. If earlier on you can select the best development candidates, you improve your chances of moving through the development process in a more informed and efficient way.

Remember, too, that making early “go/no-go” decisions also has ethical implications for the human subjects who take part in clinical trials, since fewer will be exposed to potentially ineffective therapies.

If you get it right, you’ll bring good medicines to the market faster.

Is imaging improving treatment?

In oncology, PET radiotracers can be used to assess different aspects of tumor physiology, such as glucose metabolism, cell proliferation, angiogenesis (growth of new blood vessels), apoptosis (cell death) and oxygenation.

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