Researchers at the University of California, San Francisco (UCSF) have identified two FDA-approved cancer drugs, letrozole and irinotecan, that not only slowed the progression of Alzheimer’s pathology in mouse models but actually reversed it, restoring memory and learning abilities. They began by matching Alzheimer’s-driven gene expression changes in brain cells to drugs that could reverse those patterns. From a database of 1,300 medications, the team narrowed it down to these two, which had already been prescribed safely for cancer patients, and then validated their findings in laboratory mice. The full study has been published in the journal Cell.
In the mouse models, the combination therapy cleared toxic tau protein clumps, prevented brain degeneration, corrected abnormal gene activity in neurons and glial cells, and produced measurable improvements in memory and cognition. The New York Post described the effects as “stunning,” with memory function restored even in mice with advanced stages of the disease. Looking at patient data from 1.4 million people, the researchers also found that those who had been treated with these drugs for cancer had a noticeably lower risk of developing Alzheimer’s. These medications are already in use in the NHS for cancer care, which could fast-track any transition to dementia-related trials.
Why this could change everything, and what we still don’t know
This research is so promising because both drugs are already approved for human use, which means clinical trials for Alzheimer’s could potentially move more quickly than for brand-new medications. The UCSF team used a computational approach, leveraging massive databases of existing drugs and human gene expression data to identify unexpected treatment candidates. According to ScienceAlert, this model could change the way drug discovery is done, by starting with the data and working backward.
There are caveats, though. Both letrozole and irinotecan are chemotherapy drugs, which means they come with side effects, particularly when taken at high doses. Researchers will need to explore whether smaller, carefully calibrated doses can still deliver benefits in the brain without causing harm elsewhere. There’s also the question of how well the findings in mice will translate to humans—a challenge every Alzheimer’s researcher is familiar with.
But this is far from the only exciting development. A Canadian team recently found that a compound called GL‑II‑73 reversed memory loss in mice by targeting specific GABA receptors in the hippocampus. That work, led by the Centre for Addiction and Mental Health, is now moving into human trials. It’s part of a growing push to actually reverse cognitive decline rather than just manage symptoms.
Could this be a new direction for dementia care?
In the UK, current treatments like donepezil and rivastigmine offer only modest symptom relief and don’t slow down the underlying disease. A therapy that could halt or even reverse brain damage would be transformative, especially with the number of people living with dementia expected to surpass 1.4 million by 2040.
While it’s far too early to talk about cures, this type of research offers hope. More importantly, it signals a shift in how scientists are thinking about Alzheimer’s, not as an inevitable decline to be managed, but as a condition that might be fundamentally treatable. If human trials confirm what the mouse studies suggest, we could be on the verge of a much-needed breakthrough.
As with anything in medicine, more evidence is needed. But for now, it’s an encouraging step, and one that could open the door to smarter, faster ways of finding treatments hidden in plain sight.