Promises, problems with new FDA-approved Alzheimer’s drugs Aduhelm and Leqembi

The search for the best treatment for Alzheimer’s disease is an ongoing process. For years, families have supported their loved ones as they face the challenges of this cognition and memory-robbing illness. Current medications are only effective in managing the symptoms of the disease, while the root causes of Alzheimer’s remain largely unaddressed. Fortunately, new cutting-edge treatments are on the horizon, promising a brighter future, albeit with some roadblocks.

Aduhelm and Lecanemab offer new hope

Meet Aduhelm (aducanumab) and Leqembi (lecanemab), revolutionary FDA-approved medications that aim to treat one of the underlying causes of Alzheimer’s — the formation of beta-amyloid plaques. Aducanumab received FDA approval in June 2021, and lecanemab gained full approval in July 2023.

How Do These Medications Work?

Both aducanumab and lecanemab are injectable monoclonal antibodies designed to target beta-amyloid plaques in the brain. These plaques interfere with neuron communication, leading to memory loss and learning difficulties commonly seen in Alzheimer’s patients.

Who Can Benefit?

It’s crucial to note that these medications are approved only for patients with mild dementia or mild cognitive impairment. In clinical trials, they were tested only in this specific group. Also, not all Alzheimer’s cases involve beta-amyloid plaques; therefore, a proper work-up with diagnostic tests is essential.

Dementia, Alzheimer's, brain puzzle
More than 6 million Americans are living with Alzheimer’s. By 2050, this number is projected to rise to nearly 13 million. (© Orawan –

How effective are these new medications in treating Alzheimer’s?

Aducanumab showed a 59 and 71-percent reduction in beta-amyloid plaques in two Phase 3 clinical trials. Lecanemab also demonstrated promising results, reducing the progression to the next Alzheimer’s stage by 27 percent over 18 months in a Phase 3 trial.

Controversy surrounds the effectiveness of reducing beta-amyloid plaques in Alzheimer’s patients, as FDA experts and neurologists question whether it can lead to positive results.

“This is a very, very small change in memory function in a single clinical trial. And it’s so small that most patients probably would not be aware of the difference in their trajectory,” says Matthew Schragg, MD, PhD, in a statement. “You have to ask whether that difference that incredibly slight improvement is worse than negative consequences of the drug.”

Therefore, it is necessary to consider whether this insignificant improvement in memory is worth the adverse effects of the drug.

How do aducanumab and lecanemab compare?

Both treatments are often grouped because they are similar and manufactured by the same company. However, they haven’t been directly compared in clinical studies, so the question of which superiority remains unanswered. Here are some key points regarding each treatment to keep in mind:

Approved use: Both are for mild cognitive impairment or mild dementia.

Administration: Both are given as IV infusions in hospitals or clinics.

Dosing Frequency: Aducanumab is dosed every 4 weeks; Lecanemab every 2 weeks.

Side-effects: Both have similar side-effects, however, lecanemab seems to have less common side-effects. Main side-effects include infusion-related side-effects (flu-like symptoms, blood pressure changes, and nausea), headache, cough, diarrhea.

Less than 10% of patients eligible for new treatments

Despite the advancement in Alzheimer’s disease treatment through these new drugs, only a small fraction of older adults displaying the early stages of the disease are eligible to receive the latest monoclonal antibody treatments.

“There is hope that these new therapies for Alzheimer’s may slow progression of the disease for many people, although the fact remains that the drugs have only been studied in people with the earliest forms of the disease,” says study author Dr. Maria Vassilaki of the Mayo Clinic, a member of the American Academy of Neurology, in a media release.

“The inclusion and exclusion criteria of the clinical trials that led to FDA accelerated approval of these therapies form the basis of how people should be invited or discouraged from receiving one of these drugs. Our study estimates that only a small percentage of older people with early cognitive impairment due to Alzheimer’s may be eligible to be treated with monoclonal antibodies for amyloid-ß in the brain.”

Out of the 237 individuals between 50 and 90 with early Alzheimer’s symptoms in a recent study, only 19 (or 8%) would qualify for a lecanemab trial based on the clinical trial’s stringent criteria. Meanwhile, for aducanumab, 12 people (5%) met the criteria for eligibility.

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About the Author

Alexander Olumese, PharmD

Alexander Olumese is a DMV-based registered pharmacist and medical writer. He has over 10 years of experience with community and hospital pharmacies, as well as over 3 years within the pharmaceutical industry as a medical writer within medical affairs. He has a background in a variety of therapeutic areas. However, he specializes in cardiovascular disease, oncology, pain medicine, and infectious disease.

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