The latest Alzheimer’s medications offer something previously unavailable: the ability to slow cognitive decline in the early stages of the disease. Lecanemab and donanemab, two disease-modifying monoclonal antibodies approved by the FDA in recent years, work by clearing amyloid plaques from the brain and have demonstrated measurable benefits in clinical trials. But their impact is measured in months, not years—and their benefits come with serious risks, steep costs, and strict eligibility requirements that exclude most people living with dementia today. These medications represent genuine medical progress, yet they are not a cure, not a prevention strategy, and not a substitute for the hands-on care that remains the foundation of dementia treatment.
Understanding what these new drugs can and cannot do is essential for families facing a diagnosis. A person with mild cognitive impairment (MCI) or mild dementia caused by Alzheimer’s pathology who starts lecanemab might see their cognitive decline slow by approximately five months over 18 months of treatment—a real benefit, but not a reversal. The medications work best when started early, before symptoms are severe, and they demand rigorous monitoring through MRI brain scans to catch dangerous side effects. For most people living with dementia today, these medications remain inaccessible due to cost, disease stage, or medical ineligibility. What truly sustains people with dementia is structured care, cognitive engagement, medical management of related conditions, and the presence of caregivers who understand their needs.
Table of Contents
- How Effective Are the New Alzheimer’s Medications?
- The Price Tag: Is Cost-Effectiveness Real?
- Serious Side Effects That Go Beyond the Label
- Who Can Actually Get These Medications?
- The Limitations of a Medical-Only Approach to Dementia
- New Options for Administration at Home
- What People Need to Know Before Deciding on Treatment
How Effective Are the New Alzheimer’s Medications?
Lecanemab received full FDA approval in 2023 and demonstrated its effects in a study of nearly 1,800 participants with MCI or mild dementia. The drug slowed cognitive decline by 27% over 18 months compared with placebo—which translates into approximately 5 months of slower progression on standardized cognitive scales. Donanemab, approved by the FDA in July 2024 and developed by Eli Lilly, showed a larger effect: 35% slower disease progression over 18 months, equivalent to a 4.5 to 7.5 month delay on clinical measures. In the TRAILBLAZER-ALZ 2 trial, 76.4% of donanemab-treated patients achieved amyloid clearance—meaning their brain scans showed successful removal of the plaques that drive Alzheimer’s damage. These numbers signal real biological activity and measurable slowing of decline, which is why they have been characterized as the most significant Alzheimer’s breakthrough in nearly two decades. However, the gap between slowing and stopping is critical to understand. Neither medication halts disease progression or restores lost cognitive function.
They work only in early stages—mild cognitive impairment and mild dementia—when amyloid plaques are confirmed by PET scan or cerebrospinal fluid testing. Once a person reaches moderate or severe dementia, these medications are no longer effective. They also require intensive monitoring: lecanemab demands monthly intravenous infusions, and both drugs require regular MRI scans to detect dangerous brain complications. A person must be cognitively able to tolerate the infusion process and comply with medical appointments, which limits who can realistically receive these treatments. The early-stage requirement also means most people currently living with dementia cannot take these medications. The Alzheimer’s Association estimates that many people are diagnosed only after significant cognitive decline has already occurred, placing them beyond the window when these drugs work. A family that notices memory problems at age 76 and gets a diagnosis at 78 may find that the person is no longer in the “mild” stage, and therefore ineligible. Conversely, a person with very mild MCI might begin a medication that provides five months of benefit, knowing that after the medication stops working or is discontinued, the disease will continue its natural progression.
The Price Tag: Is Cost-Effectiveness Real?
Lecanemab costs approximately $26,500 per year, while donanemab costs about $32,000 annually. These prices do not include the cost of the diagnostic PET or amyloid-tau PET scans required before treatment begins, the monthly or biweekly infusions, nursing visits, MRI monitoring scans every two weeks to eight weeks, and blood tests. For a patient with commercial insurance, copays and deductibles add thousands more out of pocket. For Medicare beneficiaries, the financial burden varies by plan, but many face substantial costs even with insurance. Uninsured patients and those with limited insurance coverage often cannot access these medications at all. Independent analyses published in medical literature suggest that lecanemab becomes cost-effective at a price point of $8,900 to $21,500 per year—significantly below its current price.
Researchers have argued that current pricing is inflated relative to the real-world benefit and that lower prices would make these medications genuinely affordable within healthcare budgets. Donanemab’s higher price point raises the same questions: does the marginally greater benefit (35% slowing versus 27%) justify a 21% higher cost? At current pricing, many insurers are restrictive about coverage, requiring prior authorization and limiting treatment to specific populations. Some Medicare Advantage plans and Medicaid programs have declined or limited coverage of these medications, effectively creating a two-tiered system where access depends on insurance type and financial resources. A family’s decision to pursue one of these medications often becomes a financial decision as much as a medical one. Some choose to pay out of pocket if their insurance refuses coverage, while others cannot afford to do so. Others delay diagnosis and testing to avoid learning they have Alzheimer’s while unable to pay for treatment. This reality means that for many people with early dementia, the new medications remain theoretical rather than practical.
Serious Side Effects That Go Beyond the Label
The most concerning side effects of lecanemab and donanemab are ARIA—amyloid-related imaging abnormalities—which manifest as brain swelling (amyloid-related imaging abnormality-edema, or ARIA-E) or microhemorrhages and microinfarcts (ARIA-H). These are not minor symptoms. Brain swelling can cause headaches, vision changes, confusion, nausea, and seizures. Microhemorrhages can cause stroke-like symptoms or silent brain bleeding that shows up only on imaging. In the lecanemab trial, 17.3% of the treatment group experienced brain swelling or hemorrhages detected on MRI, compared with 9% in the placebo group. In donanemab trials, amyloid-related imaging abnormalities occurred in up to 30.5% of treated participants versus 0.8% to 7.2% in placebo groups.
Most cases are asymptomatic—meaning they show up on brain scans but cause no noticeable symptoms—but some patients experience serious clinical events. In the donanemab trials, three deaths were attributed to the drug, though causality is debated. Several trial participants required hospitalization for symptoms related to brain swelling. Most people who experience ARIA continue the medication and recover without permanent damage, but the unpredictability of who will have a serious reaction and who will have none is a significant source of anxiety for patients and families. Certain patient characteristics increase ARIA risk: people with the APOE4 genetic marker, those over age 75, and those with existing cognitive impairment beyond mild dementia face higher risks. Regular MRI scans—required every two weeks to eight weeks—are designed to catch asymptomatic ARIA before symptoms develop, but this surveillance creates ongoing worry and represents a substantial burden for people already struggling with cognitive decline. For some, the thought of undergoing repeated MRI scans searching for silent brain damage is more stressful than the disease itself.
Who Can Actually Get These Medications?
Eligibility for lecanemab and donanemab requires meeting strict criteria. The person must have mild cognitive impairment or mild dementia caused by Alzheimer’s disease, confirmed by cognitive testing. They must have documented amyloid pathology, demonstrated through a PET scan showing amyloid accumulation, a tau PET scan, or amyloid-beta and phosphorylated tau testing in cerebrospinal fluid. These diagnostic tests are expensive and are not routinely performed; a person must first undergo a detailed neuropsychological evaluation, then imaging, then qualify by diagnosis stage, then receive additional clearance from insurance. The entire process can take months and may require seeing a specialist in a major medical center, which is not accessible to everyone. Once enrolled, a person must commit to frequent medical appointments: monthly or biweekly infusions, regular MRI scans, blood work, and neuropsychological testing to track cognitive status.
They must be cognitively able to comply with the treatment regimen and consent to the risk of brain complications. For a person with progressing dementia, the cognitive and logistical demands of treatment can become overwhelming. Missing appointments or being unable to tolerate the infusion process means stopping the medication, and there is limited evidence for restarting treatment after discontinuation. Age and genetic status also influence eligibility. Most trial participants were between 60 and 85 years old, raising questions about safety and efficacy in older adults. APOE4 carriers—people whose genetics put them at higher risk for Alzheimer’s—may be counseled to avoid or carefully consider these medications due to higher ARIA risk. A person with early Alzheimer’s disease and mild dementia who is 88 years old, has the APOE4 gene, and lives in a rural area may be perfectly aware of these medications but cannot realistically access them.
The Limitations of a Medical-Only Approach to Dementia
Medication alone does not treat dementia. Lecanemab and donanemab address one aspect of Alzheimer’s pathology—amyloid accumulation—but dementia is a complex brain disorder involving multiple pathologies: tau protein tangles, inflammation, vascular damage, and neurodegeneration. A person taking lecanemab may still experience cognitive decline due to tau tangles or other processes the medication does not address. They still need treatment for high blood pressure, diabetes, depression, sleep disorders, and other conditions that worsen dementia. They still need cognitive engagement, physical activity, social connection, and structured daily routines—the evidence-based non-pharmacological interventions that slow decline and maintain quality of life. The human dimensions of dementia care are not optional add-ons to medication.
Research consistently shows that people with dementia who have consistent caregivers, structured activities, meaningful social engagement, and regular physical activity maintain cognitive function better and experience fewer behavioral symptoms than those on medication alone in isolation. A person with mild dementia taking lecanemab but living alone without family contact and without cognitive engagement may decline faster than someone with mild dementia not on medication but surrounded by supportive family and engaged in daily meaningful activities. These factors cannot be reduced to a medication dose or a quarterly MRI scan. Dementia also demands practical support that no medication provides: help with finances, managing complex medical needs, making decisions, driving safely, medication management, nutrition, hygiene, and eventually activities of daily living. A family that invests entirely in pursuing the newest medication while neglecting other forms of support—education, respite care, planning for future decline, addressing behavioral symptoms, managing caregiver stress—often finds that their relative’s life quality declines despite pharmaceutical intervention. The new medications are tools, valuable ones, but they work best within the context of comprehensive, person-centered care.
New Options for Administration at Home
In August 2025, the FDA approved LEQEMBI IQLIK, a once-weekly subcutaneous injection that can be self-administered at home. This is a significant logistical advancement over the original lecanemab formulation, which requires monthly or biweekly intravenous infusions at a clinic or infusion center. For people living in rural areas far from infusion centers, people with transportation challenges, or people who experience anxiety around medical procedures, a self-administered injection at home is substantially more practical. It reduces the burden of frequent medical appointments and allows people to remain in their home environment rather than repeatedly traveling to healthcare facilities.
However, self-administration does not eliminate monitoring requirements. People taking LEQEMBI IQLIK still require regular MRI scans to detect ARIA, cognitive testing to measure treatment benefit, and blood work to monitor safety. The advantage is convenience in the infusion itself, not in overall monitoring burden. Some people will find that self-administration makes the treatment accessible when clinic-based infusions did not; others will find that home-based injection still requires learning a new skill and managing supplies and disposal of sharps. The medication’s cost, insurance coverage requirements, and diagnostic prerequisites remain unchanged.
What People Need to Know Before Deciding on Treatment
The conversation between a person with early Alzheimer’s disease and their doctor should address realistic expectations. A person considering lecanemab should understand that if they respond well, they may delay cognitive decline by approximately five months—that is the median benefit, and some people see slightly more, others slightly less. They should know that they will need to spend years on treatment to maintain this benefit, with no clear endpoint, and that stopping the medication means resumption of normal disease progression. They should be informed that one in six or more will have brain swelling or microhemorrhages on scan, and that a small percentage may experience stroke-like symptoms or require hospitalization. At the same time, a person in early stages of Alzheimer’s should know that doing nothing carries its own risks: untreated, their cognitive decline will progress at the natural rate, with no slowing. For some people, five months is worth the cost, risk, and medical burden. For others, the medical demands and ARIA risk are unacceptable trade-offs.
For still others, the cost is simply out of reach. There is no single correct answer, and the decision depends on individual circumstances, values, and access to care. What matters is that the decision is informed, not driven by marketing, hope, or pressure from family members or healthcare providers with financial incentives to pursue treatment. The medications also work best when the rest of someone’s life is structured for cognitive health: regular aerobic exercise, cognitive engagement through meaningful activities, strong social connections, management of sleep and mood, and control of cardiovascular risk factors. A person taking a new Alzheimer’s medication while living a sedentary, isolated life may experience less benefit than the clinical trials predict. Conversely, a person who cannot access the medication but who maintains physical activity, social engagement, and cognitive challenge may preserve function longer than expected. These human factors, in the end, matter as much as the pharmacology.
