It's not a cure, but it slows what was once unstoppable
Pela primeira vez na história da medicina, o Brasil aprova um medicamento capaz de alterar o curso biológico do Alzheimer — não de curá-lo, mas de retardar sua marcha inexorável. A Anvisa autorizou o lecanemabe, um anticorpo monoclonal que remove placas de amiloide do cérebro, oferecendo aos pacientes em estágio inicial uma modesta mas inédita margem de tempo. A chegada dessa terapia ao país carrega, porém, o peso das contradições que acompanham tantos avanços médicos: um benefício real, acessível a poucos, cercado de riscos que exigem vigilância constante.
- Após décadas sem nenhum tratamento capaz de modificar o Alzheimer, o lecanemabe representa a primeira ruptura biológica real — uma redução de 27% na velocidade do declínio cognitivo em 18 meses de ensaios clínicos.
- Os riscos não são abstratos: hemorragias cerebrais, edemas graves e mortes registradas em ensaios clínicos tornam a seleção criteriosa dos pacientes uma exigência médica e ética inegociável.
- O custo estimado de 143 mil reais por ano coloca o medicamento fora do alcance do SUS e da maioria dos brasileiros, repetindo um padrão doloroso em que inovações chegam ao país sem chegar às pessoas.
- A diversidade genética da população brasileira levanta dúvidas legítimas sobre a eficácia e segurança de um fármaco testado predominantemente em populações norte-americanas e europeias.
- Sem data de lançamento definida e sem preço máximo estabelecido pela CMED, a aprovação é, por ora, uma promessa regulatória à espera de se tornar realidade clínica.
A Anvisa aprovou o lecanemabe — comercializado como Leqembi pelos laboratórios Biogen e Eisai — para o tratamento do Alzheimer em estágio inicial, tornando o Brasil um dos primeiros países a autorizar essa nova classe de medicamentos. O fármaco atua removendo as placas de amiloide que se acumulam ao redor dos neurônios e são consideradas centrais no desenvolvimento da doença. Administrado em infusão intravenosa quinzenal, ele reduziu em 27% a velocidade do declínio cognitivo ao longo de 18 meses nos ensaios clínicos — um resultado modesto, mas historicamente significativo: foi a primeira vez que qualquer medicamento demonstrou alterar o curso da doença, e não apenas atenuar seus sintomas.
Nem todos os pacientes poderão recebê-lo. O lecanemabe é indicado apenas para adultos com comprometimento cognitivo leve ou demência inicial confirmada por exames de imagem que detectem placas amiloides no cérebro. Portadores da mutação genética APOE-e4 estão excluídos, pois apresentam risco muito maior de efeitos adversos graves. Entre eles estão hemorragias cerebrais e edemas que, em casos severos, podem ser fatais — realidade que exige triagem rigorosa e acompanhamento contínuo durante todo o tratamento.
O custo é outro obstáculo de peso. Estimado em cerca de 143 mil reais por ano no Brasil, o medicamento está muito além do que o SUS poderia absorver. Para comparação, o donanemabe — aprovado em abril passado e já disponível em alguns hospitais privados — custa mais de 200 mil reais anuais, com eficácia ligeiramente superior, de 35% de redução no declínio. O neurocientista Mychael Lourenço, da UFRJ, avalia que qualquer proposta de incorporação pública seria rejeitada diante dos custos, da elegibilidade restrita e da ausência de cura.
Há ainda uma questão científica em aberto: os ensaios clínicos foram conduzidos majoritariamente com populações norte-americanas e europeias, geneticamente menos diversas do que a brasileira. Avaliar como esses medicamentos se comportam na população do país será essencial à medida que entram na prática clínica. Ainda assim, Lourenço reconhece o valor simbólico e científico do momento: depois de anos sem novas opções terapêuticas, a ciência demonstrou que o Alzheimer pode ser modificado. O avanço é real — mesmo que, por ora, chegue a poucos.
Brazil's health regulator, Anvisa, has approved lecanemab for early-stage Alzheimer's disease, marking the arrival of a new class of treatment that can slow—but not stop—the disease's relentless progression. The drug, sold under the brand name Leqembi by manufacturers Biogen and Eisai, joins donanemabe as the only medications to meaningfully interfere with Alzheimer's at its biological root. Yet its arrival in Brazil comes with significant caveats: no launch date has been set, the cost will be staggering, and the risks are real enough to demand careful patient selection and constant medical vigilance.
Lecanemab works by binding to and clearing amyloid plaques—the protein accumulations that form around neurons in Alzheimer's patients and are believed to drive the disease. It is administered as an intravenous infusion lasting about an hour, given once every two weeks in a hospital setting. In clinical trials spanning 18 months, the drug slowed the rate of cognitive decline by 27 percent—a modest but meaningful improvement in a disease where decline has long been inevitable. When these results were published in 2022, it was the first time any medication had actually altered the disease's course rather than merely managing its symptoms.
Not every Alzheimer's patient will be eligible. The drug is approved only for adults with mild cognitive impairment or mild dementia caused by Alzheimer's—the earliest stages—and only if they have confirmed amyloid plaques in the brain. Critically, patients carrying the APOE-e4 gene mutation cannot receive the drug. This mutation increases Alzheimer's risk but also dramatically raises the likelihood of severe side effects from lecanemab itself. The screening process is therefore not a simple matter: patients must undergo testing and imaging to confirm amyloid pathology and rule out genetic contraindications before treatment can begin.
The side effects are sobering. Brain hemorrhages, infusion-related complications, and headaches appeared regularly in clinical trials. More alarming are the cases of brain edema—swelling of the organ itself—which in some instances proved fatal. As Mychael Lourenço, a neuroscientist at the Federal University of Rio de Janeiro who studies Alzheimer's, explained, these edemas may cause nothing more than a headache, but in severe cases they can be deadly. This reality demands rigorous clinical screening and close monitoring throughout treatment.
Cost presents another barrier. In the United States, lecanemab costs approximately $26,500 annually, or roughly 143,000 reais at current exchange rates. Brazil's drug pricing authority, CMED, has not yet set a maximum price for the Brazilian market. For comparison, donanemabe—the competing drug approved in Brazil last April and already available in some hospitals and clinics—sells for about 24,000 reals per month, exceeding 200,000 reals yearly. Donanemabe shows slightly better efficacy, reducing cognitive decline by 35 percent over 18 months, but both drugs remain far too expensive for coverage by Brazil's public health system, the SUS. Lourenço predicted that any proposal to incorporate either drug into public coverage would be rejected on grounds of cost, limited patient eligibility, and the fact that neither offers a cure.
Another consideration complicates the picture: most clinical trials for these drugs were conducted in the United States and Europe with genetically homogeneous populations. Brazil's population is far more genetically diverse, raising legitimate questions about how effectively and safely these medications will work in Brazilian patients. Lourenço emphasized that evaluating the drugs' efficacy and safety in the Brazilian population will be essential as they enter clinical practice.
Yet despite these limitations, Lourenço views the approvals as a genuine advance. After years without meaningful new therapeutic options for Alzheimer's, these drugs represent a shift in what is biologically possible. They do not cure the disease, and their benefits are modest. But they demonstrate that science is moving in the right direction—that the disease can be modified, that its progression can be slowed. For a condition that has long offered patients and families nothing but decline, that represents progress worth acknowledging, even as we reckon honestly with its constraints.
Notable Quotes
It's not a cure, but it provides a delay in the patient's clinical progression. Together with donanemabe, it brings the best benefit for patients so far.— Mychael Lourenço, neuroscientist, Federal University of Rio de Janeiro
These edemas may result in nothing, cause only a headache, but in some severe cases can lead to death. Clinical screening must be done very carefully.— Mychael Lourenço, neuroscientist, Federal University of Rio de Janeiro
The Hearth Conversation Another angle on the story
Why does it matter that lecanemab slows decline by 27 percent when it doesn't stop the disease?
Because for decades, there was nothing. Patients and families watched decline happen with no intervention that actually changed the biology. A 27 percent slowdown means more time—more months or years of preserved memory, independence, recognition. It's not a cure, but it's the first real interruption of the disease's course.
The side effects sound serious. Brain edema that can be fatal—how do doctors decide who gets the drug?
That's the hard part. They have to screen carefully: genetic testing, brain imaging, cognitive assessment. Some patients are ruled out entirely because of their genetics. Others might be candidates but the risk-benefit calculation is different for each person. It requires specialists and ongoing monitoring, which is why it can't be a mass treatment.
You mentioned the trials were mostly in the US and Europe. Why does that matter for Brazil?
Genetic diversity. The populations in those trials were more homogeneous than Brazil's. We don't yet know if the drug works the same way, or carries the same risks, in a more genetically mixed population. That's an open question that will only be answered through use here.
At 143,000 reals a year, who can actually afford this?
Wealthy patients with private insurance, essentially. It won't be covered by the public system—the cost is prohibitive and the drug only helps a narrow slice of Alzheimer's patients. So it becomes another treatment available only to those who can pay, which is a real limitation in a country like Brazil.
Does the approval change anything for patients right now?
Not immediately. There's no launch date set yet. The regulatory approval is the first step, but the drug still needs to be brought to market, priced, and made available. For now, it's a signal that something is coming—a new option, with all its promise and complications.