Reviewed by the Help Dementia Editorial Team — our editors review every article for accuracy against guidance from the National Institute on Aging, the Alzheimer’s Association, and peer-reviewed sources.
Amyloid drugs sits at the center of this question for families navigating dementia.
Lecanemab (Leqembi®) and donanemab (Kisunla™) represent the first disease-modifying treatments approved for early-stage Alzheimer’s disease, and they have generated considerable hope among families facing cognitive decline. However, the limits of these drugs are substantial and warrant serious consideration. While they have shown the ability to slow cognitive decline by 27–35% over 18 months in clinical trials, recent evidence—including a comprehensive 2026 Cochrane Review—indicates that this translates to minimal, clinically meaningful impact on patients’ actual day-to-day functioning, memory, or quality of life. For many families, the modest benefits must be weighed against significant safety risks, substantial costs, and strict eligibility requirements.
The reality is that these amyloid-targeting drugs represent a scientific milestone in addressing Alzheimer’s pathology, but they fall far short of being a cure or even a transformative treatment. Consider a 65-year-old woman diagnosed with mild cognitive impairment due to Alzheimer’s disease: lecanemab might slow her cognitive decline over 18 months, but the difference between her cognitive trajectory with the drug versus without it—measured by real-world tasks like managing finances or remembering conversations—would likely be imperceptible to her family. At the same time, she could experience brain swelling, infusion reactions, or a cascade of symptoms that require additional monitoring and management. Understanding what these drugs actually offer—and what they cannot—requires moving past the headlines and into the clinical data. Families deserve honest information about effectiveness, safety risks, costs, and who actually benefits from these treatments, which remain available primarily through clinical trial enrollment or specialized monitoring programs.
Table of Contents
- How Much Do Amyloid Drugs Actually Slow Cognitive Decline?
- The Safety Risks That Accompany Treatment
- Cost, Coverage, and Who Can Actually Access These Drugs
- Who Is Eligible, and Why the Restrictions Matter
- The Monitoring and Management Burden
- The Gap Between Trial Results and Real-World Benefit
- The Future of Alzheimer’s Treatment and Ongoing Questions
- Conclusion
How Much Do Amyloid Drugs Actually Slow Cognitive Decline?
The headline numbers sound promising: lecanemab slowed cognitive decline by 27% over 18 months, and donanemab achieved approximately 35% slower disease progression in the same timeframe. But these percentages mask a critical limitation—they describe relative, not absolute, slowing. In practical terms, this means a person who would have experienced a certain degree of cognitive loss experienced less, but the absolute difference is small. A patient on lecanemab might lose 2.45 cognitive points on a standard assessment scale over 18 months instead of 3.35 points. The remaining memory problems, the ongoing confusion, and the progressive difficulty with daily tasks continue largely unchanged.
The 2026 Cochrane Review, which analyzed evidence from multiple clinical trials, concluded that anti-amyloid drugs show “no clinically meaningful positive effects” on memory decline and dementia severity. This is a crucial distinction: the drugs may be statistically effective at slowing amyloid accumulation, but the impact on what patients actually experience—their ability to remember conversations, manage medications, recognize family members, or maintain independence—remains negligible. Researchers and clinicians in the dementia field remain “very skeptical” about these drugs’ ability to significantly alter disease progression, with many viewing the benefits as “very, very modest.” Some leading experts in the field have expressed concern that trial measures don’t capture what truly matters to people living with dementia and their families. In comparison, treatments for other progressive neurological conditions often provide more noticeable functional improvements. These amyloid drugs, by contrast, ask families to accept substantial costs, safety risks, and ongoing medical management for a delay in cognitive loss that may be measured in weeks rather than months. For many families, this represents an unfavorable trade-off.
The Safety Risks That Accompany Treatment
Brain swelling and related imaging abnormalities, collectively called ARIA (amyloid-related imaging abnormalities), are the most significant safety concern with amyloid-targeting drugs. Approximately 17.3% of lecanemab users experienced ARIA-edema—visible swelling in the brain on MRI scans—compared with only 9% in the placebo group. For donanemab, the risk is even more pronounced: up to 30.5% of participants showed brain imaging abnormalities compared with just 0.8–7.2% in placebo groups. While many cases of ARIA are detected on routine imaging before symptoms develop, this requires frequent MRI screening and creates considerable anxiety for families. When ARIA becomes symptomatic, patients may experience headaches, worsening confusion, dizziness, visual disturbances, nausea, and in rare cases, seizures.
These symptoms are typically temporary and resolve with medical intervention, but they represent a genuine medical crisis at the moment they occur. A family member might rush their loved one to the emergency room because of sudden confusion or a severe headache, only to learn that it’s a medication side effect detected on imaging. Some patients require dose reductions or discontinuation of treatment after developing symptomatic ARIA, which essentially ends their access to the drug’s potential benefits. Additionally, patients carrying the APOE ε4 gene—a genetic risk factor for Alzheimer’s disease—have significantly higher rates of adverse effects from these drugs, yet this genetic screening is not always performed before treatment begins. Micro-hemorrhages and infusion-related reactions have also been documented. These safety considerations mean that what appears, on paper, to be a straightforward treatment decision becomes far more complex when families must consider the possibility of neurological symptoms, repeated brain imaging, and potential hospitalization.
Cost, Coverage, and Who Can Actually Access These Drugs
Lecanemab costs $26,500–$27,000 per year, while donanemab carries an even steeper price tag of $32,000 annually. To contextualize this for families: that’s roughly the cost of a used car each year, in perpetuity, for a drug that may not noticeably change the patient’s experience of their disease. For uninsured or underinsured families, these prices are prohibitively expensive and out of reach entirely. Medicare coverage provides a critical limitation for seniors, the population most affected by Alzheimer’s disease. These drugs are not covered under standard Medicare Part B or Part D benefits.
Instead, coverage is available only when a patient is enrolled in a qualifying CMS-approved registry or clinical trial. This creates a paradoxical situation: the people most likely to benefit from these treatments—older adults with early Alzheimer’s disease—are also the least likely to have access to them unless they happen to live near a medical center offering enrollment. The Inflation Reduction Act of 2022 mandated that Medicare begin negotiating drug prices in 2026, which may eventually lower out-of-pocket costs, but this provides no help for families currently facing these prices. For families with private insurance, coverage policies vary widely, with many plans imposing strict prior authorization requirements, mandatory monitoring protocols, or exclusions based on APOE status or imaging findings. The practical reality is that access to amyloid drugs depends heavily on geography, insurance status, and the availability of specialized clinical monitoring centers—not solely on whether a patient would benefit from treatment.
Who Is Eligible, and Why the Restrictions Matter
FDA approval for both lecanemab and donanemab is limited to patients in the earliest stages of Alzheimer’s disease: those with mild cognitive impairment (MCI) or mild dementia stage only. This restriction exists because clinical trials did not demonstrate safety or efficacy in patients with moderate or advanced dementia. From a practical standpoint, this means that by the time many families receive a confirmed Alzheimer’s diagnosis—particularly if diagnosis is delayed—their family member may already be beyond the eligibility window for these treatments. The timeline matters enormously here. Many people with early cognitive changes don’t seek evaluation for months or years.
They might attribute memory problems to aging, stress, or lack of sleep. By the time a neurologist confirms mild cognitive impairment or mild dementia due to Alzheimer’s disease through cognitive testing and biomarker evidence (amyloid PET imaging or cerebrospinal fluid testing), the person may be progressing toward a more moderate stage. Additionally, the biomarker requirements—confirming the presence of amyloid pathology through imaging or spinal fluid analysis—add complexity and cost to the evaluation process. Not all primary care physicians routinely order these tests, and many patients may not have access to specialists who do. For families who do receive a timely diagnosis within the eligibility window, the decision-making process becomes another critical juncture. While families might initially hope that access to a disease-modifying drug represents a meaningful intervention, the modest benefits, safety risks, and ongoing monitoring burden must be carefully weighed against their specific situation, resources, and values.
The Monitoring and Management Burden
Treatment with amyloid-targeting drugs requires far more than a simple injection or infusion and walking away. Patients must undergo frequent MRI brain imaging—typically at baseline, during treatment, and at specific intervals—to screen for asymptomatic ARIA. These repeated MRI scans are themselves stressful medical procedures, particularly for older adults with anxiety or claustrophobia. They’re also expensive, adding to the overall cost of care even when the drug itself is covered by insurance. Patients also require regular infusions, either every two weeks (for lecanemab) or monthly (for donanemab), which means ongoing visits to a medical center, parking, wait times, and the physical demands of receiving intravenous medication.
For elderly patients with limited mobility, transportation difficulties, or who live in rural areas far from treatment centers, this becomes a substantial barrier. Some patients experience infusion-related reactions—fever, chills, shortness of breath—that require monitoring and sometimes emergency intervention. The cumulative burden of monitoring, infusions, and imaging is not trivial and can significantly impact quality of life, particularly for patients who are already managing other health conditions. Furthermore, if a patient develops symptomatic ARIA or experiences a serious infusion reaction, treatment must be interrupted or stopped entirely, and the patient may face hospitalization or emergency care. The expectation that patients will tolerate an ongoing regimen of frequent medical appointments, brain imaging, and infusions for a treatment offering minimal functional benefit is not realistic for all families, particularly those with limited resources or support systems.
The Gap Between Trial Results and Real-World Benefit
Clinical trials measure cognitive decline using standardized assessment scales administered by trained researchers in controlled settings. These scales are sensitive enough to detect small changes in memory and cognition—which is how lecanemab’s 27% slowing effect was measured. However, these same scales do not reliably capture what matters most to people living with dementia and their families: the ability to recognize loved ones, maintain conversations, manage daily self-care, remain independent, or enjoy activities that bring meaning and pleasure.
A patient’s family might not notice whether their loved one’s cognitive score declined by 2.45 points versus 3.35 points on a standardized test, but they would certainly notice if treatment prevented him from forgetting how to use the bathroom or remembering his children’s names. The clinical trials for amyloid drugs were not designed to measure these outcomes, so we simply don’t know whether the modest cognitive slowing translates to meaningful differences in activities of daily living, caregiver burden, or quality of life. This gap between what trial data shows and what patients and families actually experience is one of the most significant limitations of current evidence.
The Future of Alzheimer’s Treatment and Ongoing Questions
Amyloid-targeting drugs represent a shifting paradigm in Alzheimer’s research, moving away from the traditional focus on symptoms toward attempting to modify underlying pathology. However, the disappointing real-world effectiveness of lecanemab and donanemab has prompted serious scientific reflection about whether amyloid accumulation is the right treatment target, or whether other biological processes—inflammation, tau pathology, neurodegeneration, vascular disease—matter equally or more for how the disease progresses. Ongoing research continues to explore earlier intervention, combination therapies, and approaches targeting different aspects of Alzheimer’s pathology.
Some researchers are investigating whether treating amyloid at even earlier stages—before cognitive symptoms appear—might produce more meaningful results. Others are developing drugs targeting tau pathology or neuroinflammation. For families considering amyloid drugs today, it’s worth asking whether participating in research or waiting for next-generation treatments might be equally valid options, particularly given the current treatments’ modest benefits and notable risks.
Conclusion
Amyloid-targeting drugs like lecanemab and donanemab have earned FDA approval and represent a genuine scientific advance in understanding Alzheimer’s disease at the molecular level. However, families must understand their true limitations: these drugs slow cognitive decline in a relative sense, but produce no clinically meaningful benefit on the aspects of dementia that actually impact daily life. The safety risks—particularly brain swelling in up to 30% of donanemab users—the substantial costs, the frequent medical monitoring, and the strict eligibility requirements collectively mean these treatments are not the transformative interventions that headlines sometimes suggest.
For families facing an early Alzheimer’s diagnosis, the most important next step is to have a detailed, honest conversation with a neurologist or specialist who understands both the benefits and limitations of current amyloid-targeting drugs. This conversation should include a realistic assessment of what the drug might offer in your family member’s specific situation, a thorough discussion of safety risks and monitoring requirements, and an exploration of alternative approaches—whether that’s participation in clinical research, focus on modifiable risk factors like cognitive engagement and cardiovascular health, or careful planning for the progression that will likely occur despite treatment. Hope matters, but so does clarity about what we can and cannot expect from the tools currently available.
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For more on this topic, see NIH MedlinePlus — dementia.
