Alzheimer’s Disease: New Drugs & Research Discoveries
Alzheimer’s is a terrifying and cruel disease, gradually robbing people of their memories, minds and ability to function in everyday life. While there is no cure for Alzheimer’s disease, dramatic progress has been made in recent years—including the availability of two new drugs that can slow down the disease, plus new blood tests that can detect Alzheimer’s. In addition, promising new research is being published all the time, as scientists continue to learn more and more about Alzheimer’s.
Alzheimer’s disease is a degenerative brain disease and the most common cause of dementia. More than 7 million Americans have Alzheimer’s disease, which kills more people than breast cancer and prostate cancer combined, according to a 2025 report from the Alzheimer’s Association. Globally, 55 million people have Alzheimer’s and other dementias.
What Causes Alzheimer’s Disease?
The most studied and most-understood causes of Alzheimer’s are higher levels of amyloid plaques and tau tangles in the brain.
Despite knowing about the tau and beta-amyloid connection, researchers don’t fully understand how or why abnormal amyloid or tau buildup happens.
Both amyloid and tau are important types of proteins in the brain. But when they are not cleared from the brain properly, they can cause problems. When tau proteins become abnormal, they start to tangle inside the neurons, which disrupts the usual function of the neuron and causes difficulty in cell communication. Meanwhile, an accumulation of abnormal beta-amyloid clumps (or “plaques”), which happens outside the cells in the brain, causes inflammation and also likely interrupts communication between cells. These two problems can lead to Alzheimer’s disease.
Despite knowing about the tau and beta-amyloid connection, researchers don’t fully understand how or why abnormal amyloid or tau buildup happens. Furthermore, they don’t know how to prevent or get rid of this accumulation.
“What we think is that the amyloid begins to build up 10 or 15 years” before a clinical diagnosis of dementia, said neurologist Reisa Sperling, MD, a professor of neurology at Harvard Medical School, director of the Center for Alzheimer Research and Treatment at Brigham and Women’s Hospital, and co-principal investigator of the Harvard Aging Brain Study.
“Amyloid is associated with a loss of synapses—or the important connections between nerve cells,” Dr. Sperling explained. “But, probably most importantly—in a way that I will say we don’t fully understand—amyloid accelerates the likelihood that you’ll have spreading of tau tangles, and that tangle spreading is what’s more imminently associated with cognitive decline.”
New Alzheimer’s Drugs
Until recently, the only Alzheimer’s drugs available were “symptomatic” therapies. While helpful for many Alzheimer’s patients, these drugs treat the symptoms, not the underlying cause of the disease. They often work by boosting or improving chemicals in the brain that help with memory and thinking.
Two new FDA-approved drugs work by slowing down amyloid plaque accumulation. “They are not perfect drugs, meaning they only slow cognitive decline by about 30% [over 18 months], and what we all want is to slow it by 100%.” —Reisa Sperling, MD
However, in the past two years, two new drugs that focus on one cause of Alzheimer’s have been approved by the U.S. Food and Drug Administration (FDA). The new drugs are anti-amyloid drugs, meaning they work by slowing down amyloid plaque accumulation.
Lecanemab (brand name: Leqembi) was approved in July 2023. Donanemab (brand name: Kisunla) was approved in July 2024. Both drugs are given regularly as IV infusions and are approved for use in people with mild cognitive impairment (MCI) and mild dementia due to Alzheimer’s disease. These are the first drugs to ever be approved for use in MCI. There isn’t enough research data to show whether the drugs help in patients with moderate-to-severe dementia.
Medicare Part B covers both drugs in people who meet certain criteria, but patients may still faces thousands of dollars per year in out-of-pocket costs, currently limiting access to those who can afford one of the drugs and who have a physician who can administer it, along with the required ongoing tests.
“They are not perfect drugs, meaning they only slow cognitive decline by about 30% [over 18 months], and what we all want is to slow it by 100%,” Dr. Sperling said. However, that delay is “extremely clinically meaningful” to patients, she added. “That’s an extra five months out of the 18 months before people hit the same degree of impairment.”
Neuropsychologists and others are now examining what “clinical meaningfulness” means to patients. In other words, if the drugs work to slow down the progression of amyloid plaques, how does that help a person in their day-to-day life? This will be discussed at the November National Academy of Neuropsychology conference in the session “Clinical Meaningfulness in Alzheimer’s Disease Therapeutic Trials and Real-World Practices: An Exciting New Era.”
Neuropsychologists—who are experts in the assessment and treatment of brain injuries and disorders—play an important role, along with physicians, in helping to verify an accurate, early diagnosis and develop personalized treatment for people with Alzheimer’s.
“These drugs are biologically efficacious—they do what they’re supposed to do. Now, what’s the clinical impact?” said neurologist Ronald C. Petersen, MD, PhD, director of the Mayo Clinic Alzheimer’s Disease Research Center and the Mayo Clinic Study of Aging in Rochester, Minnesota. “It’s important for us to emphasize to our patients and families that these drugs do not stop the disease, they do not make the person better, but they slow down the rate of progression.”
A 30% slowdown can be hard to explain to patients in real-world terms, Dr. Petersen added. “This means that if this drug is effective for you, and it removes amyloid from your brain, that we will try to keep you at your current level of functioning for a longer period of time,” he said.
No drug has been developed and approved by the FDA that attacks tau tangles directly. “What [the new drugs] do now is decrease the amyloid, which is thought to slow the tangle spreading, and that is thought to be really important for slowing the cognitive decline,” Dr. Sperling explained.
But a drug that targets the tau tangles would likely be more effective at treating or slowing down Alzheimer’s than the anti-amyloid drugs, she said. That’s because of how the two proteins work in sequence: First you get amyloid, then the tau begins to spread throughout the brain. The more amyloid you develop, the more likely the tau will begin to spread throughout the brain.
“We call this sometimes ‘cataustrophe’ because there’s this period of rapid tau spreading that is associated with this imminent cognitive decline. The cataustrophe begins a year or two right before people develop mild cognitive impairment,” Dr. Sperling said. That’s why it’s important to focus prevention on the time before the cataustrophe begins.
“For a long time, there has been a laser focus on amyloid, and there is no question that amyloid is important. But we will need more than amyloid-directed therapy to treat Alzheimer’s disease because it arises from many biological pathways going awry.”
—Sarah A. Kremen, MD
Other Causes of Alzheimer’s Disease
Although amyloid and tau are important to focus on, they are likely not the only factors that lead to an Alzheimer’s diagnosis. For one, people who have the APOE-e4 gene have a higher risk of the disease. In addition, vascular components—like clogged arteries, poor circulation, blood clots and strokes—and metabolic factors—like diabetes, high blood pressure and high cholesterol—probably play a role in developing Alzheimer’s disease symptoms as well.
Vascular and metabolic factors “seem to actually interact with the amyloid to drive faster tau,” Dr. Sperling said, “which is really important because that means if we could also lower stroke risk and vascular risk at the same time that we’re starting to lower amyloid, we might have more of an effect on tau and cognitive decline.”
Research on Alzheimer’s disease continues on many fronts. A 2025 analysis showed that there are 182 clinical trials studying 138 potential Alzheimer’s drugs. That’s an increase from 2024’s drug development pipeline, which saw 164 clinical trials assessing 127 drugs.
One of the most exciting things about these studies is how diverse they are, said neurologist Sarah A. Kremen, MD, associate professor and director of the Neurobehavior Program at the Jona Goldrich Center for Alzheimer’s and Memory Disorders at Cedars-Sinai in Los Angeles.
The current studies are looking at 15 different types of disease processes. “For a long time, there has been a laser focus on amyloid, and there is no question that amyloid is important,” Dr. Kremen said. “But we will need more than amyloid-directed therapy to treat Alzheimer’s disease because it arises from many biological pathways going awry.”
In Rochester, Minnesota, Dr. Petersen, as director of the Mayo Clinic Study of Aging, examines how Alzheimer’s disease and diagnosis acts in the real world—not just in a controlled clinical trial focused only on one disease.
By studying people in the Rochester community, Mayo researchers can learn how a multitude of health conditions and diseases interact with and affect Alzheimer’s disease. “Alzheimer’s disease frequently does not exist alone,” Dr. Petersen said.
New Blood Test Diagnoses Alzheimer’s Disease
In May 2025, the FDA approved the first and only blood test to diagnose Alzheimer’s disease. The test is not for everyone—and should be used only by physicians. But it’s a giant leap forward, and several other diagnostic blood tests are still being researched.
Known as Lumipulse G pTau217, the test can detect and measure the amount of amyloid and tau proteins in a person’s blood. Lumipulse G pTau217 is meant only for adults 55 and older who are showing signs and symptoms of Alzheimer’s disease.
Blood tests are less invasive, less expensive and likely easier to access than PET (positron emission tomography) scans, which are still the primary way to diagnose Alzheimer’s. “The blood tests are not quite as precise as the amyloid and tau PET imaging, but they’re pretty good,” Dr. Sperling said.
Diagnosing Alzheimer’s by a certain type of PET scan has only been around for a few years, even though the medical community has known about Alzheimer’s for more than 100 years. In 1906, Dr. Alois Alzheimer noticed signs of dementia in a female patient. After the patient died, an autopsy showed plaques and tangles in her brain. In the 1980s, tau and beta-amyloid proteins were discovered to be key components of developing Alzheimer’s. But until recently, the disease could only be officially diagnosed after a person died and an autopsy was performed to look inside the brain.
PET is the only type of imaging that can show the existence of amyloid and tau in the brain. A PET scan uses radioactive dye to show organs and tissues and any abnormalities or cellular changes. This differs from a CT (computed tomography) scan, which uses X-rays, or an MRI (magnetic resonance imaging), which uses magnets and radio waves. (A spinal tab is also sometimes conducted to confirm Alzheimer’s diagnosis.)
Ongoing Alzheimer’s Disease Research
Let’s take a look at a handful of the ongoing promising research focused on Alzheimer’s disease.
Dr. Sperling is a leader in the AHEAD study, a large clinical trial across the U.S. and Canada that is studying whether lecanemab—one of the current anti-amyloid drugs—will work in preventing Alzheimer’s symptoms. Participants in the AHEAD study have not developed cognitive impairment due to Alzheimer’s disease, but they have “preclinical Alzheimer’s disease”—meaning they have either intermediate or elevated levels of amyloid in their brain, as shown through PET scans and blood tests.
The research studies that led to lecanemab’s FDA approval showed that the group that was at the beginning stage of Alzheimer’s had the greatest delay in progression of the disease, Dr. Sperling said. Therefore, she is excited to see if using the drug before a person develops Alzheimer’s symptoms can prevent the disease. The four-year AHEAD study finished enrolling participants in October 2024, so final results will be available in 2028.
“We have to wait and see what these trials show, but I’m tremendously excited that we will hopefully get answers over the next few years,” Dr. Sperling said. “There are several trials going—and another big one that will start next year. So I’m really excited for being able to one day hopefully prevent dementia.”
A few other promising studies to watch are:
- The EVOKE/EVOKE+ study is a Phase 3 trial studying whether the drug semaglutide is safe and effective at treating mild cognitive impairment due to Alzheimer’s disease. Semaglutide is a GLP-1 inhibitor currently used for diabetes management and weight loss. Study results are expected in December 2025. (Phase 3 is the final stage of a trial before applying for FDA approval.)
- The Brainshuttle AD study announced results of its successful Phase 2 study of trontinemab in July 2025. Trontinemab is a new drug that targets amyloid similar to lecanemab and donanemab, but it has an extra molecule that allows it to attach to a receptor at the blood-brain barrier. This allows the drug to more easily cross the blood-brain barrier, allowing more medication to get to the brain. Phase 3 is expected to launch by the end of 2025.
- The Alzheimer’s Association U.S. POINTER Study is the first large-scale, randomized controlled clinical trial to “demonstrate that an accessible and sustainable healthy lifestyle intervention—a combination of diet, exercise, heart health, and cognitive challenge and social engagement—can protect cognitive function in diverse populations in communities across the United States.”
POINTER results presented in July 2025 showed that a structured lifestyle intervention of regular moderate- to high-intensity physical exercise, adherence to the MIND diet (a combination of the Mediterranean diet and the Dietary Approaches to Stop Hypertension, or DASH, diet), cognitive challenge and social engagement, and cardiovascular health monitoring greatly improved cognitive function over two years. Participants will continue to be followed for four more years.
