A newly published scientific analysis is raising fresh doubts about the effectiveness of Leqembi and Kisunla, two Alzheimer’s medications approved in recent years and marketed as transformative advances in the fight against the disease. Researchers now say the clinical benefits may be far more modest than initial headlines suggested, while risks and costs remain substantial.
◉ Key Facts
- ►Leqembi (lecanemab), made by Eisai and Biogen, received full FDA approval in July 2023; Kisunla (donanemab), made by Eli Lilly, was approved in July 2024.
- ►Both drugs are monoclonal antibodies designed to clear amyloid plaques from the brain, a long-standing target of Alzheimer’s research.
- ►New analyses suggest the slowing of cognitive decline may be too small for patients and families to notice in daily life.
- ►Both treatments carry risks of brain swelling and bleeding — known as ARIA — which have been linked to patient deaths in clinical trials.
- ►Annual treatment costs run roughly $26,000 to $32,000 per patient, excluding infusion, imaging, and monitoring expenses.
The approval of Leqembi and Kisunla was widely described as a turning point after two decades of failed Alzheimer’s trials. Both drugs demonstrated, in large randomized studies, a statistically significant ability to slow the progression of early-stage Alzheimer’s disease by roughly 27 to 35 percent on standard cognitive rating scales over 18 months. That statistical success persuaded regulators to clear the treatments after the controversial 2021 accelerated approval of Aduhelm — Biogen’s earlier amyloid drug — collapsed amid concerns about efficacy and a congressional investigation into its approval process. But a growing number of neurologists and biostatisticians argue that the benefits observed in those trials, while real in a measurable sense, fall below the threshold that patients would actually perceive as meaningful. The difference between a treated and untreated patient after 18 months has been estimated at less than half a point on an 18-point cognitive-functional scale.
The safety profile has further complicated the picture. Amyloid-related imaging abnormalities, or ARIA, appeared in roughly 20 to 30 percent of patients receiving the drugs, manifesting as microbleeds or swelling visible on MRI scans. While most cases are asymptomatic, serious and fatal events have been recorded, particularly among patients carrying two copies of the APOE4 gene variant. That has prompted the FDA to require genetic testing and routine brain imaging as part of treatment protocols, adding layers of cost and logistical complexity. Rural patients, in particular, often face significant barriers in accessing the biweekly or monthly infusions and the specialized monitoring required. Medicare’s decision to cover the therapies under specific conditions has eased financial strain for many patients but has added billions to projected federal health spending.
📚 Background & Context
Alzheimer’s disease affects an estimated 6.9 million Americans aged 65 and older, a number projected to nearly double by 2050. The amyloid hypothesis — the theory that beta-amyloid plaque accumulation drives the disease — has dominated research for more than 30 years, and until recently had produced no successful disease-modifying treatments. The arrival of Leqembi and Kisunla was viewed as vindication of that framework, though critics have long argued the science may be more complex, involving tau proteins, inflammation, and vascular factors.
The debate now facing clinicians, regulators, and patients is whether incremental progress should be celebrated as a foundation to build upon or viewed with caution given the costs and risks involved. Several major health systems in Europe have declined to cover the therapies, with the European Medicines Agency initially rejecting Leqembi before later granting a conditional approval with narrow eligibility criteria. Researchers are already pursuing next-generation therapies — including anti-tau antibodies, GLP-1-based approaches, and combination regimens — that may eventually deliver larger benefits. In the near term, attention will focus on real-world outcome data from patients receiving the drugs outside trial conditions, as well as long-term follow-up studies that could clarify whether modest early gains compound meaningfully over years of treatment.
💬 What People Are Saying
Based on public reaction across social media and news platforms, here is the general consensus on this story:
- 🔴Many on the right emphasize concerns over Medicare spending on expensive therapies with uncertain benefits, and cite the story as evidence of overreach by federal drug regulators.
- 🔵Many on the left focus on pharmaceutical pricing and marketing practices, arguing that drugmakers overstated breakthroughs while charging patients and taxpayers premium prices.
- 🟠Across the political spectrum, patients and caregivers express a mixture of hope and frustration — grateful for any progress, but wary of overpromising in a disease area long marked by disappointment.
Note: Social reactions represent general public sentiment and do not reflect Political.org’s editorial position.
Photo: The U.S. Food and Drug Administration via Wikimedia Commons
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