NEW YORK – As populations age throughout the world, one of them most prominent topics in doctors’ offices and family meetings is Alzheimer’s disease. Throughout human history, few people lived past the age of 50, and even in the late 20th century the proverbial “three score and ten” was the longest lifespan most people could aspire to. But along with the joys of longevity that accompany medical breakthroughs in many areas come the risks and realities of diseases that rarely show up before 70 – like Alzheimer’s.

Until recently, it was easy to ignore the disease until it began to rear its ugly head in our own or family members’ lives, because diagnosis and prognosis were muddy at best, and usually impossible. That is changing dramatically. An article in the Washington Post this week notes that, “simple blood tests for Alzheimer’s disease, long coveted by doctors and researchers, have hit the market, representing a potentially powerful tool to help diagnose the devastating, memory-robbing illness, which afflicts 6.5 million Americans. The tests detect tiny amounts of abnormal proteins in the blood, including a sticky version called amyloid beta, to determine whether the pathological hallmarks of Alzheimer’s are present in the brain.”

Gil Rabinovici, a neurologist at the University of California at San Francisco, says, “if you had asked me five years ago if we would have a blood test that could reliably detect plaques and tangles in the brain, I would have said it was unlikely…I am glad I was wrong about that.”

Laurie McGinley, the author of the article, notes that, “in coming years, the blood tests could transform the way Alzheimer’s is researched, diagnosed and treated, experts say. Already, the tests, which are being used mostly in clinical trials, are expediting research. In regular patient care, doctors can prescribe the tests, but that happens infrequently, in part because of a lack of effective treatments if the tests are positive. In addition, the tests, which cost hundreds of dollars or more, often are not covered by insurance.”

But the tests will become more widely used, “providing clarity for a disease that is notoriously difficult to diagnose and helping determine which patients should get new treatments – if federal regulators approve therapies now under review,” McGinley writes.

She then focuses on the raging debate over scientific and ethical questions: “Who should get them and when? How accurate are they? Do patients want to know whether they have Alzheimer’s? Should people who do not have symptoms be tested?”

Beyond the medical ethics debates are the practical argument about what we really know and how effective are potential treatments.

Regarding the tests, skeptical doctors will change their minds as more data about their efficacy comes in, and, and McGinley writes that, “the blood tests are emerging just as major developments in treatment may be on the horizon. In September, data showed an experimental drug, called lecanemab, modestly slowed cognitive and functional decline. The medication, from Japanese drugmaker Eisai and its American partner, Biogen, was the first Alzheimer’s drug to clearly slow deterioration in a well-executed clinical trial. The data has not been peer-reviewed, and more information is expected later this month. The FDA is scheduled to decide whether to approve the drug by Jan. 6.”

But the picture may not be on the verge of getting clearer. “The lecanemab success bolstered hope for drugs that remove amyloid plaques from the brain. But in recent days, a Roche drug failed in clinical trials, raising questions about the therapies. Results from an Eli Lilly drug are expected next year,” the article notes.

Still, Reisa Sperling, director of the Center for Alzheimer Research and Treatment at Brigham and Women’s Hospital in Boston,” notes that, “if there is a therapy that clearly demonstrates a clinical benefit, demand for these blood tests could skyrocket,” as the prospects for tests and treatments for Alzheimer’s are intertwined,

So, as McGinley notes, while “many neurologists are taking a wait-and-see approach even for patients with cognitive impairment… other physicians plan to use the tests as soon as they are covered by Medicare and other insurance.”

Unfortunately, there is still disagreement about the precise causes and progression of the disease, “specifically, whether removing brain amyloid can slow or stop Alzheimer’s. While the ‘amyloid hypothesis’ has many supporters, it has yielded repeated drug failures,” the article explains.

McGinley, Demetrius M. Maraganore, chairman of the neurology department at the Tulane University School of Medicine in New Orleans, believes that “combinations of drugs ultimately will be needed to defeat Alzheimer’s.” But Maraganore added, “we have to start someplace… We have to create a runway. You can’t land a plane without a runway.”

(Material from the Washington Post was used in this article.)