Treatments demonstrate sits at the center of this dementia and brain health question.
Yes, approved Alzheimer’s treatments demonstrably slow cognitive decline in early-stage disease, with clinical evidence showing patients can delay progression by months to years when treated early. Three FDA-approved monoclonal antibody treatments—lecanemab, donanemab, and aducanumab—target amyloid-beta buildup in the brain, the hallmark pathology underlying Alzheimer’s disease.
The CLARITY AD clinical trial, which enrolled nearly 1,800 people with early Alzheimer’s, found that lecanemab slowed cognitive decline by 27% over 18 months compared to placebo, translating to a meaningful delay in symptom progression that compounds when treatment continues long-term. This article explores what approved treatments exist, how they work, what the clinical evidence shows about sustained benefit, the practical realities of starting treatment, and what you need to know about safety. The landscape has shifted significantly, with new delivery methods now available or coming soon—including weekly injections and maintenance options that require less frequent dosing—making these treatments more accessible to patients who might benefit.
Table of Contents
- What Treatments Are Available and How Do They Work?
- How Long Do the Benefits Last? Understanding Sustained Patient Outcomes
- Clinical Evidence: What the Research Shows About Cognitive Decline Prevention
- Getting Started With Treatment: Which Option Is Right?
- Safety Considerations and What Patients Should Monitor
- The New Delivery Options Available Today
- What’s Next? Future Directions in Alzheimer’s Treatment
- Conclusion
- Frequently Asked Questions
What Treatments Are Available and How Do They Work?
Three monoclonal antibody treatments have received FDA approval for Alzheimer’s disease. Lecanemab (brand name Leqembi) was approved January 6, 2023, and marked the first treatment to show clear evidence of slowing cognitive decline in early symptomatic Alzheimer’s disease. Donanemab (Kisunla) followed with FDA approval for treatment of early symptomatic Alzheimer’s disease, while aducanumab (Aduhelm), approved through the FDA’s Accelerated Approval Program in June 2021, was the first anti-amyloid monoclonal antibody approved for Alzheimer’s disease, though it has seen more limited clinical adoption.
All three medications work by the same mechanism: they bind to amyloid-beta proteins in the brain and clear them, reducing the plaques that accumulate in Alzheimer’s disease. Lecanemab originally required intravenous infusions every two weeks, but expanded FDA approvals in 2025 now allow for less frequent IV dosing (once every four weeks) and a newly approved subcutaneous weekly injection called LEQEMBI IQLIK. This shift to less frequent and less invasive administration addresses one of the biggest barriers to treatment—the time commitment and inconvenience of biweekly infusions. For someone working full-time or with limited transportation, shifting from 26 infusions per year to 4 IV infusions or 52 weekly injections changes the practical reality of staying on treatment.
How Long Do the Benefits Last? Understanding Sustained Patient Outcomes
The critical question for any Alzheimer’s treatment is whether benefits persist over time or fade as the disease progresses. Long-term data from lecanemab suggest the gains hold. The CLARITY AD trial followed participants for 18 months, but subsequent analysis modeling long-term outcomes suggests that early treatment with lecanemab and continued maintenance therapy could delay disease progression by up to 8.3 years—a substantial delay in functional decline and symptom burden. Donanemab shows similar durability. The TRAILBLAZER-ALZ 2 long-term extension study followed participants for up to three years and found that donanemab’s benefits not only persisted but actually grew over time, with more than 75% of participants achieving amyloid clearance within 76 weeks.
This is a crucial finding because it shifts the narrative from “slowing decline” to “removing the underlying pathology”—something that hadn’t been demonstrated in Alzheimer’s treatment before these anti-amyloid monoclonal antibodies. However, an important caveat: sustained benefit requires continued treatment. These medications are maintenance therapies. If treatment stops, the disease progression can resume. Additionally, not all patients respond equally, and factors like genetics (APOE4 status), age, and disease stage all influence how much benefit someone might expect.
Clinical Evidence: What the Research Shows About Cognitive Decline Prevention
The CLARITY AD trial is the largest and most rigorous study to date. It enrolled 1,795 participants aged 50 to 90 with early symptomatic Alzheimer’s disease and found that lecanemab slowed cognitive decline by 27% over 18 months compared to placebo. To put this in concrete terms: a patient on placebo might show a decline of 4 points on the 18-point cognitive subscale used in the study, while a patient on lecanemab might decline 3 points—a one-point difference that reflects preserved function and independence. At the brain level, lecanemab reduced amyloid burden by 59.1 centiloids compared to placebo, demonstrating that the medication actually clears pathology from the brain. This amyloid reduction correlates with the cognitive benefit seen clinically.
Donanemab achieves similar or greater amyloid clearance in its trials, though the cognitive benefit magnitude is still being quantified as long-term extension studies continue. One important limitation: all these trials enrolled people with early symptomatic disease or mild cognitive impairment—not moderate or advanced Alzheimer’s disease. Currently, there is no evidence that these treatments slow decline in people with significant cognitive impairment or advanced disease. This means timing matters. Early diagnosis and early treatment initiation appear to be key to maximizing benefit.
Getting Started With Treatment: Which Option Is Right?
Choosing between lecanemab and donanemab involves weighing several factors. Both are approved for early symptomatic Alzheimer’s disease, and both reduce amyloid and slow cognitive decline. The practical difference lies in administration schedule and accumulated clinical experience. Lecanemab has more long-term follow-up data and has been used clinically since 2023, while donanemab is newer, though its extension study data are compelling. Lecanemab’s advantage is flexibility in delivery: you can receive biweekly IV infusions, monthly IV infusions, or weekly subcutaneous injections (LEQEMBI IQLIK).
If you travel frequently or prefer self-administration, weekly injections might appeal to you. If you prefer infrequent office visits, monthly IV dosing works. For patients who cannot tolerate infusions or have poor venous access, the subcutaneous option is transformative. Donanemab is administered intravenously and typically on a longer infusion schedule than lecanemab, which some patients prefer. The decision often comes down to logistics, patient preference, and insurance coverage. Many insurance plans cover both, but prior authorization requirements vary.
Safety Considerations and What Patients Should Monitor
Anti-amyloid monoclonal antibodies carry specific safety risks that require monitoring. The most common is amyloid-related imaging abnormalities (ARIA)—brain changes visible on MRI that reflect the body’s response to amyloid removal. ARIA comes in two forms: ARIA-E (brain edema or swelling) and ARIA-H (microhemorrhages or small brain bleeds). Across lecanemab and donanemab trials, ARIA-E occurred in 13.7% to 24.2% of treated participants depending on dosing regimen and risk factors. Most cases are asymptomatic and detected on routine MRI screening, but symptomatic ARIA-E can cause headache, confusion, or vision changes. ARIA-H is less common but more concerning—microhemorrhages detected on imaging in roughly 7-12% of treated participants, though most cause no symptoms. Importantly, a meta-analysis found that lecanemab and donanemab carry a 4.35-fold higher risk of ARIA compared to placebo, which is why baseline MRI and periodic MRI monitoring during treatment are required.
Infusion-related reactions are also common with lecanemab—occurring in 26.4% of study participants. These reactions range from mild (fever, chills, joint pain) to severe (hypotension, respiratory distress), and most occur during or immediately after infusions in the first few weeks of treatment. The good news: most infusion reactions respond to slowing the infusion rate or managing with pre-medications. ARIA with edema occurred in 12.6% of lecanemab recipients. Before starting treatment, you need baseline MRI to rule out existing microhemorrhages, regular amyloid positron emission tomography (PET) or tau-PET imaging to confirm diagnosis, and APOE4 genetic testing, as APOE4 carriers have higher ARIA risk. Regular follow-up MRIs during the first year and periodically thereafter are standard of care. This monitoring requirement means treatment is not something you start without a neurology specialist overseeing care.
The New Delivery Options Available Today
Until recently, lecanemab meant a trip to an infusion center every two weeks. That has changed dramatically with new FDA approvals in 2025. On January 26, 2025, the FDA approved IV maintenance dosing of lecanemab once every four weeks, reducing the infusion burden from 26 annual visits to 4. On August 29, 2025, the FDA approved LEQEMBI IQLIK—a subcutaneous weekly injection patients can receive at home or in a clinic setting.
The subcutaneous weekly option is particularly significant for patients who cannot access infusion centers, have poor venous access, or travel frequently. Instead of driving to an infusion center and sitting for an hours-long infusion, a patient can receive a 15-minute injection weekly. This should improve adherence and access, particularly for patients in rural areas. An FDA decision is pending for May 2026 on whether to approve starter doses of LEQEMBI IQLIK for home administration, which would further streamline treatment initiation. If approved, some patients could start treatment at home without an office visit for initial dosing.
What’s Next? Future Directions in Alzheimer’s Treatment
The approval of effective anti-amyloid treatments has validated the amyloid hypothesis of Alzheimer’s disease and opened new research directions. Current trials are exploring anti-tau monoclonal antibodies, which target tau tangles rather than amyloid plaques. The theory is that combining anti-amyloid and anti-tau treatments might be more effective than either alone, since both amyloid and tau accumulate in Alzheimer’s disease.
Another frontier is earlier intervention. Current approvals target early symptomatic disease, but future treatments might target asymptomatic amyloid positivity—people with amyloid in the brain but no cognitive symptoms yet. Trials are underway to test whether treating asymptomatic people prevents symptoms from ever developing. If successful, this could fundamentally change the Alzheimer’s care model from treating symptomatic disease to preventing it.
Conclusion
Approved Alzheimer’s treatments represent a meaningful shift in disease-modifying therapy. Lecanemab and donanemab have clear clinical evidence of slowing cognitive decline by roughly 25-27% in early disease, achieving sustained benefit over years when treatment continues. The expanded delivery options now available—from once-monthly IV infusions to weekly subcutaneous injections—make these treatments far more practical and accessible than they were in 2023.
If you or a family member has been diagnosed with early Alzheimer’s disease or mild cognitive impairment, discussing these treatment options with a neurologist should be an early priority. Treatment works best when started early, before significant cognitive decline has occurred. Understanding the benefits, safety monitoring requirements, and practical logistics of administration will help you make an informed decision about whether these treatments fit your medical and personal circumstances.
Frequently Asked Questions
Are these treatments effective for advanced Alzheimer’s disease?
No. Current evidence supports lecanemab and donanemab only for early symptomatic disease or mild cognitive impairment due to Alzheimer’s disease. These treatments have not been studied or approved for moderate to advanced dementia, where cognitive decline is more rapid and amyloid clearance may have less clinical impact.
Do I need genetic testing before starting treatment?
APOE4 genetic testing is recommended before starting treatment because carriers of the APOE4 gene have higher risk of amyloid-related imaging abnormalities (ARIA). This doesn’t exclude you from treatment, but it informs monitoring and risk discussion with your neurologist.
What happens if I stop treatment?
Disease progression can resume if treatment is discontinued. These are maintenance therapies, meaning ongoing treatment is needed to sustain benefit. The decision to stop should be made with your neurologist and based on tolerability, ARIA occurrence, or other medical factors.
Can these treatments cure Alzheimer’s disease?
No. These treatments slow cognitive decline and remove amyloid from the brain, but they do not cure or reverse Alzheimer’s disease. They delay symptom progression, but the underlying disease process continues over time.
Are there alternatives if I cannot tolerate infusions?
Yes. The subcutaneous weekly injection (LEQEMBI IQLIK) is now available and approved for patients who cannot tolerate IV administration. Additionally, monthly IV dosing reduces the frequency of infusions compared to biweekly dosing.
How much do these treatments cost?
List prices are substantial (over $20,000 annually), but most Medicare and private insurance plans cover lecanemab and donanemab with prior authorization. Patient assistance programs are available for uninsured or underinsured patients. Cost and insurance coverage are important conversations to have with your healthcare provider.
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For more, see NIH MedlinePlus — dementia.
