After decades of research, American scientists may finally be closing in on new ways to fight Alzheimer’s disease.

But even the most promising discoveries can stall before they reach patients.

The obstacle is often the enormous cost of the final clinical trials needed to win approval.

Researchers call this funding gap the biotech “valley of death.”

Yet, President Donald Trump could make a difference by providing federal funding to help promising treatments through the valley and across the finish line.

For roughly three decades, Alzheimer’s research has concentrated heavily on amyloid plaques, the sticky protein deposits in the brain associated with the disease.

That work has deepened our understanding and produced new medicines.

But focusing on those deposits alone has not solved the problem.

Researchers are now targeting inflammation, toxic proteins and the loss of synapses, the connections that allow brain cells to communicate.

Those connections enable us to recognize a spouse, remember our children’s names and follow a conversation.

Some people retain those abilities despite substantial biological signs associated with Alzheimer’s in their brains.

Their ability to withstand damage offers an important clue: Strengthening that natural protection, known as synaptic resilience, may help preserve memory and cognition as the disease takes hold.

I have a direct stake in this work: I co-founded PharmatrophiX, whose Alzheimer’s drug candidate, LM11A-31, met its safety and tolerability goals in Phase IIa testing, with encouraging findings suggesting it may help preserve synaptic function and resilience.

The drug is being developed as a pill patients can take at home, without infusion visits or injections.

Today’s amyloid-targeting treatments can cause brain swelling and bleeding, requiring repeated brain scans to monitor for potentially serious complications.

Those side effects have not been observed with LM11A-31 in clinical testing to date.

These approved therapies are used in the earliest stages of Alzheimer’s, in patients with confirmed amyloid buildup.

Because LM11A-31 aims to protect brain cells and their connections, we believe it could ultimately help a broader range of patients.

So our goal goes beyond slowing Alzheimer’s: We seek to prevent the loss of those cells and connections.

But larger trials must establish whether LM11A-31’s early findings really do translate into meaningful benefits for most patients.

That brings us to the valley of death. Phase III, the final and most expensive clinical-trial hurdle before gaining approval, can cost hundreds of millions of dollars.

Even a company with strong science and respected researchers can spend years raising that kind of money.

Private investors are understandably cautious: Alzheimer’s drug development ranks among biotechnology’s most challenging fields, with many seemingly promising medicines falling short in expensive late-stage studies.

The National Institutes of Health and the National Institute on Aging have supported world-class research, including work on synaptic resilience.

Yet federal money today does not ensure that potential treatments have enough funds to make it through all the testing.

Washington should build on its investments by helping companies finance the testing needed to cross the finish line and bring treatments to patients.

For example, Advanced Research Projects Agency for Health, the federal agency created to support ambitious medical research that may be too risky for private investment alone, or similar public-private partnerships could provide direct funding for the final stages of testing.

The public funding could help smaller companies attract the private investment needed to complete those studies.

Such partnerships would also create networks that could recruit patients faster, standardize testing and make better use of biomarkers, including blood tests and brain imaging.

Smaller companies would gain access to resources they can’t acquire on their own.

Shared infrastructure could lower costs, accelerate testing and give investors stronger evidence on which to base funding decisions. 

Each treatment, of course, would still have to prove its merits.

The cost of Alzheimer’s and other dementias is estimated to reach about $409 billion in 2026 and will rise as the population ages.

Beyond medical and long-term-care bills, families face lost earnings and the relentless demands of caregiving.

The cost of fully testing promising new therapies could be far less than the cost of such burdens.

The Trump administration should bring federal research agencies, biotech companies and private investors together to fund promising clinical trials and the networks that support them.

Federal dollars could help draw private capital into Alzheimer’s research at the stage when it is hardest to secure and most urgently needed.

Promising discoveries deserve a fair test. Patients cannot afford more delays.

Dr. Frank Longo is a professor of neurology and principal investigator in Stanford University’s Department of Neurology and Neurological Sciences.