Repurposed Cancer Drug Sargramostim Shows Promise in Halting Brain Cell Death in Alzheimer's Disease
Key Insights
University of Colorado researchers found that sargramostim (Leukine), a 30-year-old cancer drug, reduced brain cell death markers by 40% in Alzheimer's patients during a clinical trial.
The study revealed that brain neuron death begins in early childhood and increases exponentially with age, with women showing higher rates of brain cell loss than men.
Patients treated with sargramostim showed improved cognition on one memory test, with benefits lasting even after treatment ended, unlike other approved Alzheimer's drugs that only slow disease progression.
Scientists at the University of Colorado Anschutz (search) have discovered that sargramostim, a synthetic form of the natural human protein GM-CSF that has been used for 30 years to treat cancer and other conditions, may offer new hope for halting brain cell death in Alzheimer's disease (search). The findings, published in Cell Reports Medicine, represent a potential breakthrough in treating neurodegenerative disease by targeting the underlying process of neuronal death rather than just slowing cognitive decline (search).
Drug Reduces Brain Cell Death Markers by 40%
In a randomized, placebo-controlled, double-blind study of more than 300 people, researchers found that patients with Alzheimer's disease (search) who received sargramostim for three weeks showed a dramatic 40% reduction in blood levels of UCH-L1 (search), a protein released from dying brain neurons. According to Huntington Potter, director of the University of Colorado Alzheimer's and Cognition Center and senior author of the study, this reduction brought brain cell death markers to levels "similar to those seen in early life."
"The people who were treated with Leukine or GM-CSF actually lost the ability to kill their nerve cells to such an extent that it reduced nerve cell death to what would be the equivalent of a normal person about five years old," Potter explained.
The study also demonstrated cognitive improvements, with patients showing better scores on the Mini-Mental State Exam (MMSE) compared to those taking placebo. Notably, this cognitive improvement persisted even 45 days after treatment ended, despite UCH-L1 (search) levels returning to pre-treatment concentrations.
Brain Cell Death Begins Early and Accelerates with Age
The research revealed new insights into the natural progression of brain aging. Through cross-sectional analysis of people across all age groups, scientists discovered that UCH-L1 (search) and another neuronal damage protein called NfL (search) are present at low concentrations in early life but increase exponentially each year through age 85.
The study found that brain inflammation (search), measured by GFAP (search) protein levels, begins around age 40 and increases more rapidly in women than men. Women also showed higher age-associated blood concentrations of both GFAP and UCH-L1 (search), though the reasons for this gender difference remain unclear.
"These findings suggest that the exponentially higher levels of these markers with age, likely accelerated by neuroinflammation, may underlie the contribution of aging to cognitive decline (search) and AD and that sargramostim treatment may halt this trajectory," Potter said.
Mechanism of Action and Safety Profile
Sargramostim works by stimulating the immune system to create new immune cells in the bone marrow and brain while modulating inflammation. In animal models, GM-CSF has been shown to reverse cognitive decline (search) and reduce the rate of neuron death after just a few weeks of treatment.
The drug's safety profile represents a significant advantage over other Alzheimer's treatments. "Leukine or GM-CSF has been FDA approved for decades and has been used to treat some 500,000 people with very little in the way of serious side effects," Potter noted. "It's one of the safest drugs that has been studied."
This contrasts with currently approved Alzheimer's drugs, which Potter emphasized "only slow the course of the disease" and often come with adverse side effects, while sargramostim appears to actually improve certain measures of cognition.
Future Research and Clinical Implications
A second, longer and more extensive clinical trial with sargramostim in mild-to-moderate Alzheimer's patients is currently underway. This 24-week study will provide researchers with better understanding of whether the drug can sustain its effects over longer treatment periods and potentially improve memory rather than just slowing its decline.
The research also raises questions about sargramostim's potential for treating age-related cognitive decline (search) in healthy individuals. Potter suggested it's "reasonable to assume the drug could halt brain cell death in those people and improve cognition but that further study is needed."
Important Safety Considerations
Despite the promising results, researchers emphasize that sargramostim should not be used off-label for Alzheimer's treatment. "No one should go out and try to take Leukine or prescribe it for Alzheimer's disease (search) until the studies are finished and the FDA has given its approval," Potter cautioned. "That would be potentially dangerous."
The findings represent preliminary results that require validation through ongoing clinical trials before the FDA can consider approval for Alzheimer's treatment. The research team, supported by funding from the University of Colorado Department of Neurology, the State of Colorado, the National Institutes of Health, and the Alzheimer's Association, continues to investigate this promising therapeutic approach.