12.03.16 Mary Yamin-Garone, DeMystifying Alzheimer’s
Good afternoon. Welcome to Demystifying Alzheimer’s. I’m your hostess Mary Yamin-Garone.
Today’s topic is “Treatments on the Horizon.”
Our understanding of Alzheimer’s has grown exponentially over the past two decades. Sophisticated knowledge, however, has yet to yield effective diagnostic tools or treatments, much less a cure for the disease. Per Ronald Petersen, MD, director of the Mayo Clinic Alzheimer’s Disease Research Center, AD is a “complex pathologic process” that involves genetic, biological and environmental factors. Scientists are now studying and targeting elements of that complex pathology with the hope of developing a combination of strategies to combat the disease.
Traveling on assignment in March 2007, NBC News chief science and health correspondent Robert Bazell received an outpouring of frantic voice and e-mail messages from editors trumpeting “a cure for Alzheimer’s disease.” The source of the excitement was Myriad Genetics, a biotechnology company then testing an experimental drug called Flurizan. It had shown some promise of treating memory loss and other Alzheimer’s symptoms in Phase II of clinical trials that had ended in 2006. The drug was being tested in Phase III trials, slated to end in 2008. Meanwhile, a company press release boasted more good news about Flurizan. It was described as a drug that “may be capable, not only of slowing the decline of Alzheimer’s disease, but of halting the disease in its tracks.” Myriad Genetics cited no data for these incredible claims, which several small media outlets reported as breakthrough news nonetheless.
Bazell, a veteran medical reporter who questions and verifies information before reporting it as fact, checked with the Alzheimer’s Association and trustworthy Alzheimer’s researchers to see if this was “dramatic, unexpected new research” or “yet another case of biotechnology hype.” It was the latter as it so often is, Bazell wrote later. He notes that only rarely does something entirely unexpected happen in science. Scientific and clinical studies proceed slowly and methodically and their progress is reported in medical journals and by organizations like the Alzheimer’s Association.
Myriad issued a press release to tell the world that 42 percent of 43 patients who had done well in the Phase II Flurizan trial didn’t get any worse during the following year. A study of 43 people is too small to reveal anything, much less a breakthrough in treatment for an intractable disease.
Research and development of Flurizan stopped in its tracks the following year when Phase III clinical trials showed the drug didn’t improve thinking and memory skills or the ability to carry out everyday tasks in a study of 1,700 men and women with mild cognitive impairment.
Flurizan is one of a handful of Alzheimer’s treatments whose red-hot hopes went cold once they reached the final phases of the clinical study.
Shortly before Myriad Genetics gave up on Flurizan, British researchers announced that an experimental vaccine designed to eliminate the amyloid plaques thought to cause dementia had worked but not the way it was supposed to. Researchers followed 64 patients with moderate Alzheimer’s for an average of six years in the vaccine study, during which time nine patients died. Autopsies of those patients showed that nearly all plaque was gone from their brains. Nevertheless, those patients still had developed severe dementia; the toxic plaques were gone but the disease wasn’t.
The trial was one of a growing number of studies that have caused some scientists to question whether the cause-effect relationship between amyloid and dementia is as straightforward as Alzheimer science has long assumed. Researchers, who still aren’t sure if plaque is a cause or an effect of AD, are learning that an overabundance of plaques, an Alzheimer’s hallmark, are less telling a symptom than is widely believed.
Researchers are pressing ahead with pharmaceuticals aimed at an array of targets. Some attack different phases of plaque formation; others immunize the body against amyloid. The more promising in late-stage investigative trials include:
- It is the first drug that directly attacks the tau protein tangles that form inside nerve cells in the brain and impair concentration and memory. The tangles first destroy the nerve cells linked to memory and then proceed to attack neurons in other parts of the brain. Researchers believe Rember may arrest that progression.
- Large clinical trials in the United States and Canada are studying Bapineuzumab, a form of immunotherapy treatment for mild to moderate Alzheimer’s. It’s designed to provide antibodies against amyloid-beta peptides directly to the patient. Those antibodies can bind to and remove amyloid peptide from the brain, eliminating plaque and inhibiting the damage it does.
- Originally developed and marketed in Russia as an antihistamine, Dimebon has emerged as a potential treatment for Alzheimer’s, Huntington’s disease and other neurodegenerative diseases. It stabilized AD for at least 18 months in a Russian study. Participants treated with the drug were reported to have better or not-much-worse mental function than those who were given placebo pills. Their symptoms got significantly worse.
Alzheimer’s experts warn that placebo-treated Alzheimer’s patients in Russia get different care than those in the U.S. That difference could make any effect of Dimebon seem greater compared with placebo. It also has been noted that patients’ actual improvement on Dimebon isn’t much different from improvement seen with the existing Alzheimer’s drugs Aricept, Razadyne and Exelon.
Inflammation seems to occur frequently in the brains of some Alzheimer’s sufferers. Several studies have looked at the effects of anti-inflammatory drugs, such as Advil, Aleve and Indocin, in treating or preventing AD. No anti-inflammatory has proven effective, though research continues.
Despite promising leads, new treatments for Alzheimer’s have been slow to emerge. Some AD specialists predict that many future treatments will focus on stopping the disease in people at risk. Some researchers predict that Alzheimer’s eventually will be treated with a drug cocktail or a multiple-step process, much the same way combination chemotherapy is administered.
Ever since my mother was diagnosed with Alzheimer’s nearly 20 years ago, I have prayed for a cure or—at the very least—a drug that would make her better if only for a little while. While a cure still is just out of reach, I am hopeful that one day this disease will be eradicated. It might not be in my lifetime but in my nieces’ and grandchildren’s.
That’s all for today. Thanks for listening. I hope this information was helpful.
Join me next time for more about Alzheimer’s treatments on the horizon.