Why dementia therapy is beginning before severe symptoms

Alzheimer’s disease was long perceived as a condition in which medicine could mainly relieve symptoms, support daily function and slow the loss of independence through non-pharmacological methods. Such support remains important, but in recent years the approach has begun to change. Drugs have entered clinical practice that are directed not only at symptoms, but at one of the key biological features of the disease — the accumulation of amyloid beta in the brain. This does not mean that Alzheimer’s disease has become curable. However, the logic of treatment itself has changed: therapy is increasingly viewed as an intervention at an early stage, when the pathological process is already present, but severe dementia has not yet developed.

The main reason for this shift is the development of biomarkers. In the past, the diagnosis of Alzheimer’s disease was largely based on the clinical picture: memory impairment, decline in executive functions, behavioral changes and gradual loss of everyday independence. Today, the physician can use methods that show the presence of amyloid pathology and other signs of neurodegeneration. These include amyloid PET imaging, cerebrospinal fluid analysis and emerging blood tests for phosphorylated tau and other markers. This is especially important because new drugs require confirmation of amyloid pathology before treatment begins.

Anti-amyloid monoclonal antibodies have become the most discussed direction. They bind to forms of amyloid beta and help remove pathological deposits from the brain. This group includes lecanemab and donanemab. Such therapies are intended for patients at an early stage of the disease, usually mild cognitive impairment or mild dementia, because this is the population in which they were studied in clinical trials. This early-stage focus is essential: the goal is not to reverse advanced dementia, but to slow progression before extensive neuronal loss has occurred.

This emphasis on early disease is not accidental. If neurons have already been significantly lost, removing amyloid cannot restore dead cells or fully return cognitive function. Therefore, modern disease-modifying therapies are directed not at late dementia, but at the period when symptoms are still relatively mild. This changes the entire diagnostic pathway. A patient with memory complaints should not simply receive a general conclusion about age-related changes, but should undergo cognitive assessment, exclusion of reversible causes, evaluation of vascular factors, depression, sleep disorders, medication effects and, when indicated, biomarker confirmation of Alzheimer’s disease.

Donanemab has become another important drug in this direction. Like other anti-amyloid therapies, it requires confirmation of amyloid beta pathology before treatment begins and is used in a structured protocol with infusions, monitoring and risk assessment. This shows that treatment of Alzheimer’s disease is becoming not a simple symptomatic tablet therapy, but a complex medical pathway involving patient selection, biomarker testing, imaging follow-up and safety evaluation.

The clinical significance of these drugs should be described carefully. They do not stop the disease completely and do not restore memory that has already been lost. Their goal is to slow progression in a defined group of patients. Therefore, the conversation about treatment must be precise: it is about reducing the rate of decline, not returning the patient to their previous cognitive level. For the patient and family, this difference is fundamental. Even moderate slowing may matter if it preserves independence, communication and daily functioning for a longer period. But exaggerated expectations can lead to disappointment and misunderstanding of therapy.

One of the main risks of anti-amyloid antibodies is ARIA, or amyloid-related imaging abnormalities. These changes may appear as brain edema, microhemorrhages or superficial siderosis. In some patients, they are asymptomatic and detected only on MRI, but in certain cases they may be accompanied by headache, confusion, visual disturbances, seizures or more severe complications. For this reason, treatment requires not only confirmation of diagnosis, but also careful assessment of brain imaging findings and repeated monitoring during therapy.

The risk of ARIA is especially important in patients with certain genetic and vascular factors. APOE genotype, particularly the presence of APOE ε4, is significant because it is associated with a higher risk of Alzheimer’s disease and complications during antibody therapy. In addition, the physician must consider microhemorrhages on MRI, the need for anticoagulant therapy, previous strokes, cerebral amyloid angiopathy and other conditions that may increase the risk of bleeding. Therefore, treatment requires not only diagnostic confirmation, but also safety stratification. A patient may need MRI before therapy and repeated imaging during treatment.

The regulatory path of these drugs also shows how difficult the balance between benefit and risk remains. Anti-amyloid therapy has been assessed differently across healthcare systems, and access may depend on local regulatory decisions, reimbursement, availability of biomarker testing and MRI monitoring. The scientific community recognizes the importance of this new class of drugs, but at the same time continues to discuss the clinical magnitude of benefit, safety, cost, infrastructure requirements and the ability of healthcare systems to select patients correctly.

New treatments for Alzheimer’s disease cannot be considered separately from diagnosis. If therapy is effective only in early stages and requires confirmation of amyloid pathology, medicine must identify people with cognitive impairment earlier. This requires high-quality primary assessment, access to neuropsychological testing, referral pathways to specialists, biomarker diagnostics and exclusion of other causes of memory decline. In an older patient, cognitive symptoms may be related not only to Alzheimer’s disease, but also to vascular changes, depression, vitamin B12 deficiency, sleep disorders, hypothyroidism, medication side effects or a combination of several factors.

The emergence of blood tests for biomarkers may significantly change practice. If such tests become sufficiently accurate, accessible and standardized, they may help select patients for more complex confirmation methods, such as PET imaging or cerebrospinal fluid analysis. But a blood test should not be used as an isolated diagnosis without clinical context. A biomarker shows the probability of a certain pathological process; it does not replace assessment of symptoms, functional state and alternative causes of memory impairment. Results must be interpreted especially cautiously in people without symptoms, because the presence of biological pathology does not always mean rapid development of dementia.

Other therapeutic directions are also developing. Alzheimer’s disease is not limited to amyloid. Its pathogenesis involves tau pathology, neuroinflammation, vascular impairment, mitochondrial dysfunction, synaptic loss, disturbed protein clearance and metabolic factors. Therefore, future therapy will probably be combined. One patient may need anti-amyloid treatment, another vascular risk control, a third sleep therapy, hearing correction, physical activity, cognitive rehabilitation and treatment of comorbid depression. The more precise the biological classification of dementia becomes, the fewer universal solutions there will be.

Non-pharmacological interventions remain important even in the era of monoclonal antibodies. Blood pressure control, physical activity, treatment of sleep disorders, social engagement, correction of hearing and vision, diabetes management, stroke prevention and family support can influence quality of life and functional status. These measures are not a replacement for disease-modifying therapy, but they form the foundation of patient care. Alzheimer’s disease affects not only memory, but also safety, nutrition, sleep, emotional state, medication adherence, financial decisions and the burden on relatives.

The main change in recent years is that Alzheimer’s disease is increasingly viewed as a condition with a diagnostic and therapeutic window. In the past, the diagnosis was often made only when dementia was already pronounced. Now medical interest is shifting toward early symptoms and biological confirmation. This creates hope, but also requires caution. New drugs provide a limited but real change in the approach to the disease. Their use must be professional, strictly selected and accompanied by safety monitoring. The future of Alzheimer’s disease treatment will probably not lie in one drug, but in a combination of early diagnosis, biomarkers, targeted therapy, prevention of vascular risks and long-term support for the patient and family.