Alzheimer’s disease (AD) is the most common form of dementia, a chronic progressive disorder resulting in cognitive decline that significantly reduces quality of life. AD research receives up to $3.8 billion in federal funding every year; however, a cure has yet to be developed for AD. The first medication for AD was approved by the FDA in just 2023, and it is one of only two currently available medications approved to slow the progression of AD (as compared to merely alleviating the symptoms). In addition, it was primarily intended for patients with early-stage AD. Alternative medications and treatments for AD are still high in demand – and that’s exactly the demand addressed by a new study out of the University of California, San Francisco (UCSF) and Gladstone Institutes.
AD affects millions of older adults around the globe.
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In October 2025, the famed scientific journal, Cell, published a paper showing that two FDA-approved cancer medications, letrozole (a treatment for breast cancer in postmenopausal women) and irinotecan (a colorectal cancer treatment), reversed AD-associated gene expression in neurons and glia (the two primary cell types in the brain) in individuals with AD (including late-stage and more severe AD). In mouse models, the drug combination reduced tau clumps and even restored memory. Tau accumulation in the brain is a known hallmark of AD, so reducing the amount of tau in the brain is a significant feat for these cancer medications and signals the exciting possibility that these medications may also be used for AD treatment.
Of course, there are many questions still to be answered about these medications, such as if their effects last, how frequently the medications should be taken for optimal improvement of AD symptoms, and whether the medications can completely reverse AD. Extensive clinical trials will need to be completed before these medications can be used to treat AD. These findings are still important, though, as this study included individuals with late-stage AD, for which there are currently no FDA-approved medications. Perhaps for these individuals, letrozole and irinotecan could be the treatment they have been waiting for.
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