In a significant breakthrough, scientists from the University of California, San Francisco (UCSF) and Gladstone Institutes have identified two FDA-approved cancer drugs that may help reverse brain changes associated with Alzheimer’s disease, a condition affecting more than 55 million people worldwide.
Researchers identified letrozole and irinotecan, drugs currently approved for breast, colon, and lung cancers, as promising candidates for repurposing as Alzheimer’s treatments. The team began by analysing how Alzheimer’s alters gene expression in the brain. Using a database known as the Connectivity Map, they identified drugs that could reverse these genetic changes.
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Clinical records of cancer patients who had taken letrozole or irinotecan showed a reduced likelihood of developing Alzheimer’s, prompting further investigation. The researchers then tested the drugs in mouse models of Alzheimer’s disease.
The tests revealed that the two drugs, when used together, significantly reduced tau protein buildup in the brain, a key marker of the disease, and led to improvements in memory and learning. The study also found that letrozole and irinotecan act on different brain cell types, potentially offering a dual-action approach to treatment.
Researchers emphasised that, although these drugs are already approved by the US Food and Drug Administration (FDA), they still carry side effects and have not yet been tested on humans for Alzheimer’s.
“Alzheimer’s disease comes with complex changes to the brain, which has made it tough to study and treat,” said Dr. Marina Sirota, computational biologist at UCSF. “But our tools opened up the possibility of tackling this complexity directly.”
Dr. Yadong Huang, neuroscientist and co-author, added, “Alzheimer’s is likely the result of numerous gene and protein alterations. That’s why a multi-drug, multi-target approach may work better than a single-compound therapy.” The full study has been published in the journal Cell.
Alzheimer’s disease affects over 55 million people globally, a number expected to more than double in the coming decades. Researchers say these findings could pave the way for more effective, personalised treatment strategies.
