New Alzheimer's Drugs Show Promise, But They're Only the Start

Two new drugs designed to treat Alzheimer's disease received FDA approval in 2024, marking the first medications that can actually slow the disease down rather than just manage its symptoms. Lecanemab arrived in January, and donanemab (sold as Kisunla) came later that year.

These approvals grew out of work by Sir John Hardy, a neuroscientist at University College London. In the 1990s, Hardy identified that a protein called amyloid builds up in the brains of Alzheimer's patients and damages them. For decades, scientists have been trying to create drugs to clear this buildup. These two new medications finally succeeded.

At a recent health conference, Hardy explained something important: these drug approvals are a major milestone, but they're not the finish line for treating dementia.

What the New Drugs Actually Do

Lecanemab and donanemab work by targeting amyloid and clearing it from the brain. In clinical trials, both drugs slowed memory loss — but they did not stop it entirely. Patients on these medications still experienced cognitive decline over time, just at a slower rate. Donanemab reduced thinking and memory problems by 29 percent compared to patients who received a placebo.

The results validated Hardy's original theory about amyloid's role while also exposing a hard truth: removing amyloid alone may not be enough to fully halt Alzheimer's progression.

The Real Bottleneck: Getting Patients Diagnosed and Treated

Hardy highlighted a major problem that pharmaceutical breakthroughs alone cannot solve. Many Alzheimer's patients are being misdiagnosed, and the infrastructure to identify and treat the disease remains inadequate.

Here is the scale of the challenge: clinical trials for Alzheimer's drugs need around 50,000 participants per year to keep the pipeline moving, yet only about 12,000 patients enroll annually. Polls show that most Americans would be willing to join Alzheimer's trials, so the barrier is not interest — it is logistics and access.

On top of that, patients need regular MRI brain scans to monitor for side effects. Donanemab can cause brain swelling and bleeding, which requires constant oversight. This adds cost and complexity to treatment. These risks also mean the drug is only safe for patients with mild cognitive impairment or early-stage Alzheimer's, not those further along in the disease.

The broader picture here is that approving a drug is only one step. Delivering that drug to patients who need it requires diagnostic expertise, imaging equipment, neurologists, and specialized infusion centers — resources that are spread unevenly across the country and the world.

More Drugs Are in Development

Scientists and pharmaceutical companies are now investigating 134 different potential Alzheimer's treatments across 171 ongoing studies — the biggest research effort in the field's history. Some of these candidates target different mechanisms beyond amyloid, such as a protein called tau that also accumulates in Alzheimer's brains, or inflammation in the brain itself.

This diversity of approaches reflects growing confidence that a single drug targeting one pathway may not be the complete answer. Instead, treatment may eventually involve multiple medications working together, much like how HIV treatment transformed in the mid-1990s when doctors discovered that one antiviral drug worked better as part of a combination.

Lecanemab has also been approved in China, and Kisunla in China as well, indicating that these treatments are moving beyond the U.S. market and generating real-world evidence from different populations.

What Needs to Happen Next

For these new drugs to genuinely help patients, healthcare systems will need to invest in more than just the medications themselves. Hospitals and clinics need more specialized imaging, more neurology expertise, and more infusion centers to deliver intravenous treatments. Another drug currently in trials, ALZ-801, could ease some of this burden — it is designed to be taken as a pill rather than an IV.

Looking at the path ahead, the real work now involves getting patients correctly diagnosed, building out the infrastructure to deliver these drugs, and continuing to develop new treatments that target other mechanisms. The approvals in 2024 prove that scientists can slow Alzheimer's. The next phase requires turning that scientific progress into actual patient access and outcomes.

Hardy's long career — from discovering the genetic basis of Alzheimer's in the 1990s to seeing drugs finally reach patients — illustrates how long it takes to move from laboratory discovery to treatments that work in the real world. We now have the proof of concept that Alzheimer's can be treated. Scaling that up into a genuine solution remains the work ahead.