Alzheimer’s research is more active and more diverse than at any point in history. As of 2025, there are 192 clinical trials testing 158 different drugs, spanning everything from antibodies that clear toxic proteins to repurposed diabetes medications to vaccines designed to prevent the disease entirely. The field has also shifted dramatically in the last decade: amyloid-targeting drugs, once the dominant strategy, now make up only about 20% of the pipeline, while inflammation-focused and tau-focused approaches have each grown from 6% to roughly 20%.
Anti-Amyloid Drugs: First Approvals, Mixed Results
The most high-profile Alzheimer’s research of the past few years centers on drugs that use lab-made antibodies to strip amyloid plaques from the brain. Two of these drugs have received FDA approval: lecanemab and donanemab. In clinical trials, donanemab slowed cognitive decline by about 22% compared to placebo. That’s a real, measurable effect, but it’s modest. Patients still declined, just a bit more slowly. These drugs also carry serious risks, including brain swelling and microbleeds, and require regular IV infusions and brain scans to monitor safety.
The bigger significance of these drugs may be what they proved: that removing amyloid from the brain can change the course of the disease, even if it doesn’t stop it. That confirmation has fueled research into combining amyloid removal with drugs targeting other aspects of the disease.
Tau-Targeted Therapies
Tau is a protein that, in Alzheimer’s, forms tangled clumps inside brain cells and kills them. While amyloid plaques build up between neurons, tau tangles spread through the brain in a pattern that closely tracks with symptom progression, making it a compelling drug target. Tau-focused agents have grown from a small sliver of the research pipeline to about 20% of all drugs in trials.
One of the most ambitious efforts is the Alzheimer’s Tau Platform, a Phase 2 trial testing multiple tau-directed therapies, both alone and in combination with the amyloid-clearing drug donanemab. The trial enrolls adults aged 50 to 80 who are in the earliest stages of the disease, before significant symptoms appear. The idea is to hit both amyloid and tau simultaneously and earlier than previous trials have attempted. The platform design allows researchers to test several tau drugs within the same study framework, which speeds up the process of figuring out which approaches work.
Inflammation and the Brain’s Immune System
The brain has its own immune cells called microglia, and they play a complicated role in Alzheimer’s. Early in the disease, microglia try to clean up amyloid and other debris. But over time, they can become chronically activated, pumping out inflammatory signals that damage healthy neurons. About 20% of the current drug pipeline targets this inflammatory process.
Researchers are pursuing several angles. One involves a protein on the surface of microglia that essentially tells them to stand down and stop cleaning up amyloid. Blocking this protein could restore the microglia’s ability to clear toxic buildup. Another line of research focuses on a signaling pathway that, when triggered by cellular stress signals, activates an inflammatory chain reaction producing compounds that damage surrounding brain tissue. Drugs that interrupt this chain could reduce the collateral damage from chronic brain inflammation.
A genetic discovery has added urgency to this area. Variants of a gene called TREM2 are among the strongest genetic risk factors for late-onset Alzheimer’s. TREM2 sits on the surface of microglia and helps them respond to damage. People with certain TREM2 variants have microglia that don’t function properly, leading to impaired cleanup and increased inflammation. Several programs are now trying to enhance TREM2 signaling as a potential treatment.
Repurposed Diabetes Drugs
One of the more surprising areas of Alzheimer’s research involves GLP-1 receptor agonists, a class of drugs originally developed for type 2 diabetes and now widely prescribed for weight loss. The logic connecting these drugs to Alzheimer’s is straightforward: brains affected by the disease show insulin resistance, reduced energy metabolism, inflammation, and poor clearance of toxic proteins. GLP-1 drugs favorably affect all of these processes.
In animal models, these drugs reduce brain inflammation, improve energy production in brain cells, and help clear the toxic proteins that define Alzheimer’s. Human data is still early but encouraging. A 26-week trial of liraglutide found that the drug prevented a decline in the brain’s ability to use glucose for energy, a key early marker of Alzheimer’s progression, even though cognition didn’t change over that short period. Longer follow-up from the same trial showed that liraglutide slowed brain shrinkage in regions critical for memory, though the study’s primary endpoint wasn’t met. Separately, a large diabetes trial found that patients taking dulaglutide showed modestly slower cognitive decline compared to placebo, though those findings were exploratory.
The main concern with these drugs in Alzheimer’s patients is their side effect profile. Nausea and weight loss, common and often welcome effects in diabetes and obesity patients, can be a real problem for frail or underweight people with dementia. Dropout rates in Alzheimer’s trials have been notably higher among participants receiving the active drug.
Vaccines Against Alzheimer’s
Several groups are developing vaccines that would train the immune system to attack amyloid, tau, or both. Unlike antibody drugs that must be infused repeatedly, a successful vaccine could potentially provide lasting protection with just a few shots.
The most novel candidate in early testing is DUVAX, a first-in-human Phase 1 vaccine that targets both amyloid and tau simultaneously. The trial is enrolling healthy adults aged 40 to 65, giving three injections over about six months, and monitoring immune responses and safety for a year after the final dose. This dual-target approach is a departure from earlier vaccine attempts that focused on amyloid alone. Phase 1 trials are primarily about safety, so it will be years before researchers know whether the vaccine actually affects the disease.
Blood Tests That Could Change Early Detection
Diagnosing Alzheimer’s with certainty used to require either an expensive PET brain scan or an invasive spinal tap. A blood test measuring a specific form of tau protein called p-tau217 is changing that. As a standalone test, it identifies Alzheimer’s brain pathology with 81% accuracy. When doctors confirm positive results with a follow-up PET scan, accuracy rises to 91%.
This matters for research as much as for clinical care. Enrolling the right patients in clinical trials has been one of the biggest bottlenecks in Alzheimer’s drug development. Up to 30% of participants in some past amyloid trials turned out not to have amyloid in their brains at all, diluting the results. A cheap, accessible blood test means researchers can screen large populations quickly, identify people in the earliest stages of the disease, and enroll them in trials before significant brain damage has occurred.
Lifestyle Interventions
Not all Alzheimer’s research involves drugs. The FINGER study, conducted in Finland, tested whether a combination of exercise, diet changes, cognitive training, and management of heart health risk factors could prevent cognitive decline in older adults at elevated risk. After two years, the control group had a 30% greater risk of developing cognitive impairment compared to the group receiving the intervention.
That finding launched a global network of similar trials, now running in more than 60 countries, adapted to local diets, cultures, and health systems. The goal is to determine whether lifestyle interventions work across diverse populations and whether they can be scaled up as a public health strategy. This line of research is particularly important because even a modestly effective drug will likely need to be paired with lifestyle changes to produce meaningful results, and lifestyle interventions are available right now to anyone willing to adopt them.
The Shift Toward Combination Approaches
The clearest trend across all of this research is a move away from single-target strategies. Alzheimer’s involves amyloid buildup, tau tangles, inflammation, metabolic dysfunction, and vascular damage, often all at once. The current pipeline reflects a growing consensus that no single drug is likely to be enough. About 73% of drugs in trials are classified as disease-targeting therapies aimed at the underlying biology, while 18% focus on improving cognition and 10% address behavioral symptoms like agitation and sleep disruption.
The combination trial testing tau drugs alongside donanemab is one example of this philosophy in action. Researchers are increasingly designing platform trials that can test multiple drugs, alone and together, within a single study structure. This is faster and cheaper than running separate trials for each combination, and it reflects lessons learned from cancer research, where combination therapy transformed outcomes over the past two decades.