WASHINGTON, July 8 — The numbers arrive with the cold weight of an epidemic that refuses to recede. By 2024, an estimated 6.9 million Americans aged 65 and older were living with Alzheimer’s dementia, according to the Alzheimer’s Association 2024 Facts and Figures report. By 2050, that figure is projected to reach 13.8 million.
Alzheimer’s is the seventh leading cause of death in the United States. In 2022, the CDC recorded 121,499 deaths from the disease.
The financial toll is staggering: total payments for health care, long-term care, and hospice services for people with dementia are estimated at $345 billion in 2024. That includes $231 billion in Medicare and Medicaid costs. Globally, the World Health Organization put the cost of dementia at $1.3 trillion in 2019.
Breakthroughs in Clinical Trials
Two major clinical trials have delivered results that researchers describe as historic. Lecanemab’s Clarity AD trial, which enrolled 1,795 participants, showed a 27% reduction in cognitive decline on the CDR-SB scale at 18 months, with a p-value of 0.001. Donanemab’s TRAILBLAZER-ALZ 2 trial, with 1,736 participants, showed a 35% slowing on the iADRS scale at 18 months, with a p-value of less than 0.001.
These are not cures. But they represent the first generation of treatments that appear to slow the progression of the disease, rather than merely managing symptoms.
The FDA approved lecanemab in July 2023. Donanemab followed in July 2024.
Risks on the Horizon
The trials also documented significant risks. ARIA-E, or brain edema, occurred in 12.6% of patients taking lecanemab and in 24% of those on donanemab. These side effects require careful monitoring and have shaped the conversation around who should receive these treatments and under what conditions.
By nightfall, researchers and clinicians are still weighing the balance. The drugs are not for everyone.
But for a subset of patients in the early stages of the disease, they offer something that did not exist a few years ago: a measurable chance to slow the clock.
What Comes Next
The global cost of dementia, already at $1.3 trillion in 2019, is expected to rise sharply as populations age. The projected 13.8 million Americans with Alzheimer’s by 2050 will place immense pressure on health systems, families, and economies. But the approvals of lecanemab and donanemab have opened a new chapter.
The question now is not whether Alzheimer’s can be treated, but how far the treatments can go. The scene in research labs and memory clinics across the country is one of cautious optimism. Consult your doctor for medical advice.
