A cure for Alzheimer's disease isn't on the foreseeable horizon. The most promising research now focuses on attempts to prevent or forestall the illness rather than reverse it. That's the goal of a proposed set of rule changes by the U.S. Food and Drug Administration designed to make it easier to study medicines to combat the mind-robbing illness that afflicts 5 million Americans and is expected to grow in coming years.
The FDA has proposed -- and is seeking public comment about -- a roadmap that would facilitate research on drugs that effect markers for the brain damage that is the hallmark of Alzheimer's, rather than that demonstrate improvement in clinical symptoms. This shift in approach is crucial. By the time symptoms develop over a period of decades, irreversible brain damage has already occurred. To help those at risk for Alzheimer's, you need an intervention that stops symptoms before they start. Although specific drugs aren't identified, the new rules clearly are aimed at allowing access to several classes of experimental medicines that have failed in clinical trials to reverse or relieve symptoms for people with full-blown disease.
The FDA's proposal deserves strong support. Admittedly, these changes are controversial, especially since they may unleash drugs whose long-term use -- perhaps decades for pre-symptomatic patients identified as at high-risk for Alzheimer's -- may lead to as yet unknown side effects. And the cost of years of treatment could conceivably run into tens of billions of dollars, adding to the nation's already explosive growth in health care spending. That cost, of course, must be balanced against the staggering expense of caring for millions of patients with advanced dementia.
But consider a precedent. In the 1990s, AIDS activists pushed the FDA to expand access to treatments still in development in a groundbreaking way that didn't compromise patient safety or the quality of the science. At the time, people infected with HIV faced a death sentence, and they were willing -- through informed consent -- to try early, experimental treatments that had a limited track record of clinical efficacy.
This kind of expanded access led the FDA to speed up approval of the drugs by removal of red tape and other barriers. This creative approach proved so successful that the model has been used in approving drugs for other life-threatening ills, most especially cancer.
Like HIV/AIDS at the time, Alzheimer's is a sure killer. Many of the millions of Americans who are at risk of developing Alzheimer's based on genetics or family history would gladly volunteer to participate in studies of experimental drugs. We can move faster to address the looming catastrophe of Alzheimer's by offering genuine informed consent to those who participate, while working to minimize the risk as much as possible. Too much protection from the potential danger of research only denies people the opportunity to weigh for themselves the risk vs. a chance at preventing the onset of symptoms.
This same attitude is likely underpinning the FDA's new proposal. It is also certain the agency is acting under pressure not only from patient advocacy groups, but also from drug makers that have spent billions developing medicines that have yet to prove effective. Now researchers believe they may be able to identify people at risk of developing Alzheimer's years before its symptoms arise based on a person's genetics or other chemical markers present in spinal fluid or blood. But actually testing drugs on such people to see whether the risk of disease is reduced could take decades. We need to do those studies, but not only those studies. The FDA is suggesting it might approve drugs if companies can show in clinical trials that these experimental treatments can simply reverse or slow the accumulation of these biomarkers. That, of course, is a big if, as researchers have yet to show for certain that the biomarkers presage disease.
Yet, it is clear that by adopting new standards for approving Alzheimer's drugs, the FDA will inspire academic scientists and drug companies to speed up efforts to identify pre-symptomatic individuals. The FDA should be commended for helping fuel such research and helping to find and halt the disease before the ravages of dementia occur.
The approval of drugs based on their impact on markers instead of clinical symptoms is both risky and costly. In the end, it may turn out that attacking today's biomarkers may not prevent Alzheimer's. The answer, though, won't be known unless the FDA revises its rules, a gamble we may want to take given the alternative.
Dr. Tia Powell
Dr. Powell is a bioethicist and psychiatrist and is director of the Montefiore Einstein Center for Bioethics.
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