11:06 pm - February 22, 2025
A New Era in Alzheimer’s Treatment: Exploring the Potential of Lecanemab and Donanemab
The diagnosis of mild cognitive decline due to Alzheimer’s disease can be life-altering, leaving patients and families searching for hope. Recent advancements in medical research have introduced two promising drugs: lecanemab (marketed as Leqembi) and donanemab (marketed as Kisunla). These medications aim to clear plaque-causing amyloid proteins from the brain, a hallmark of Alzheimer’s disease. While they offer a glimmer of hope, their benefits come with significant challenges, including time-consuming infusions, potential life-threatening side effects, and high costs. For patients, the decision to pursue these treatments hinges on the delicate balance of risks and rewards.
Understanding the Risks and Benefits
Both lecanemab and donanemab require biweekly or monthly infusions, which can be burdensome for patients. Additionally, these drugs carry risks of severe side effects, such as brain swelling or bleeding, which can be life-threatening. Despite these drawbacks, the potential benefits of delaying cognitive decline are substantial. A new study led by Dr. Sarah Hartz, a professor of psychiatry at Washington University School of Medicine, estimates that these drugs could extend independent living by several months to a few years, depending on the severity of the disease at the start of treatment.
The study analyzed data from 282 untreated Alzheimer’s patients to understand the natural progression of the disease. Researchers focused on four key functions: managing finances, driving, managing medications, and preparing meals. The loss of independence was defined as requiring assistance with at least three of these tasks. Untreated patients with mild cognitive decline were expected to live independently for about 29 months. Those treated with donanemab gained an additional eight months, while lecanemab added 10 months. For patients with more advanced symptoms, the benefits were even greater, with lecanemab extending independence by 26 months and donanemab by 19 months.
Putting the Benefits into Perspective
While the additional months of independence may seem modest, they can be meaningful for patients and their families. Dr. Hartz emphasizes that these estimates should not be taken as exact predictions but rather as a framework for discussions between patients and their doctors. “Patients want to know how long a drug will allow them to keep driving, pay their own bills, cook at home, and dress themselves,” she explains. These conversations are critical, as the decision to pursue treatment depends on individual priorities and circumstances.
The cost of these treatments is another important consideration. While the drugs are expensive—even for patients on Medicare—Dr. Hartz suggests that the cost should be weighed against the financial burden of residential care or nursing homes. For some, the extra months of independence may justify the investment. However, for others, the risks and costs may outweigh the benefits.
Expert Opinions and Limitations
Dr. Richard Isaacson, a neurologist and director of research at the Institute for Neurodegenerative Diseases, highlights the importance of using patient-centered language when discussing disease prognosis. He cautions, however, that these drugs are not miracle cures. “All that happens is that people get less worse over time—instead of declining by three years, they decline by two years,” he said. This nuanced perspective underscores the importance of realistic expectations for patients and families.
Another key concern is the methodology used in the study. Dr. Alberto Espay, a neurologist at the University of Cincinnati, points out that the assumption that changes in dementia scores can be equated to months of life has not been validated. He also notes that the drugs do not improve symptoms but rather slow decline. Patients must weigh the hope of a slower decline against the risk of severe side effects, such as brain swelling or bleeding.
The Side Effects and Challenges of Treatment
The potential side effects of lecanemab and donanemab are not insignificant. Clinical trials revealed that a small percentage of participants experienced ARIA-E (amyloid-related imaging abnormalities—edema), a condition involving brain swelling and bleeding. For example, 2.8% of lecanemab participants and 2.9% of donanemab participants experienced this serious side effect. These risks are particularly concerning for individuals with two copies of the APOE-4 gene, which increases the likelihood of Alzheimer’s and the risk of ARIA-E.
To mitigate these risks, patients on these medications must undergo regular brain scans and close medical monitoring. Despite these precautions, the potential for serious complications remains a critical factor in treatment decisions. Additionally, side effects such as allergic reactions, confusion, dizziness, and flu-like symptoms can significantly impact quality of life.
The Broader Context: The Urgent Need for Alzheimer’s Treatments
The development of lecanemab and donanemab comes at a time when Alzheimer’s disease is reaching epidemic proportions. According to the U.S. Centers for Disease Control and Prevention, the number of Americans living with Alzheimer’s is projected to grow from 6.7 million in 2023 to nearly 14 million by 2060. This staggering trend underscores the urgent need for effective treatments. While these drugs are not perfect, they represent a step forward in the fight against Alzheimer’s.
However, not all experts are convinced that the benefits of lecanemab and donanemab outweigh their risks. When the U.S. Food and Drug Administration fast-tracked the approval of these drugs, some doctors expressed skepticism. Clinical trials showed that lecanemab slowed cognitive decline by 27% over 18 months, while donanemab reduced the risk of progression by 35% over the same period. These results, while promising, are modest, and the risks of serious side effects cannot be ignored.
Moving Forward: Informed Decision-Making and Hope for the Future
The study’s findings highlight the importance of individualized decision-making in Alzheimer’s treatment. Patients and their families must carefully consider their unique circumstances, including the severity of symptoms, genetic risk factors, and personal priorities. While lecanemab and donanemab are not miracle drugs, they offer a new option for slowing disease progression and preserving independence.
Dr. Hartz stresses that the purpose of her study was not to advocate for or against these medications but to provide context that can inform personal choices. As research continues, the hope is