Stage-Dependent Effects of Rapamycin for Alzheimer’s Disease: Insights from Prevention and Treatment Trials

By Ai-Lin Ling from Cedars-Sinai Medical Center, Los Angeles:

Stage-Dependent Effects of Rapamycin for Alzheimer’s Disease: Insights from Prevention and Treatment Trials 2025

Rapamycin is the best-established longevity-promoting drug in animal models and has been shown to attenuate Alzheimer’s disease pathology in preclinical trials. Here we compare the findings of a prevention versus therapeutic clinical trial of rapamycin for Alzheimer’s disease and discuss implications for applying the geroscience hypothesis to Alzheimer’s disease. Two open-label pilot studies evaluated the safety and preliminary efficacy of short-term (4-12 week) low dose (1 mg/day) rapamycin treatment. The prevention trial enrolled cognitively unimpaired middle-aged APOE4 carriers and non-carriers, whereas the therapeutic trial enrolled older adults with mild cognitive impairment or dementia. Both studies examined changes in plasma inflammatory markers. The prevention study also examined cerebral blood flow, and the therapeutic study assessed Alzheimer’s disease biomarkers in cerebrospinal fluid (CSF). Baseline to post-treatment changes were evaluated using paired samples t-tests or Wilcoxon signed rank tests. The prevention study enrolled 9 APOE4 carriers (mean age 53 ± 8 years, 44% female) and 14 APOE-4 non-carriers (mean age 55 ± 6 years, 50% female). APOE4 carriers demonstrated reduced plasma cytokines and increased cerebral blood flow at post-treatment (all p < 0.05) that were not observed in non-carriers. In contrast, participants in the therapeutic trial displayed increased plasma cytokines and CSF phosphorylated tau 181, neurofilament light, and glial fibrillary acidic protein levels (FDR-corrected p-value<0.05). Overall, the results of the two trials suggest that rapamycin may have markedly divergent effects on inflammatory and Alzheimer’s disease biomarkers when administered for prevention versus treatment, highlighting the importance of tailoring geroscience-informed interventions for the appropriate disease stage.

Poke @Agetron

See also:

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This is the preprint: Rapamycin enhances neurovascular, peripheral metabolic, and immune function in cognitively normal, middle-aged APOE4 Carriers: genotype-dependent effects compared to non-carriers 2025 (by Ai-Lin Ling as well)

I think it is this one (University of Texas Health Science Center at San Antonio): Rapamycin treatment for Alzheimer’s disease and related dementias: a pilot phase 1 clinical trial 2025

That paper concluded:

Rapamycin is not detectable in the CSF before or after treatment, but several Alzheimer’s disease and inflammatory biomarkers increase after treatment. Our results highlight the need to better understand the biological effects and clinical impact of repurposing rapamycin for Alzheimer’s disease.

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Summary of those various studies by Gemini:

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Thanks Antoine :wink: for the heads up.
Great research results.

It’s tricky. Reminds me of how rapa increased certain area brain volumes in ApoE4 carriers, but not in ApoE3. The pathways rapa works along in these carriers might make it relevant or not. If, for example rapa tightens the BBB junctions, then it works to stop LPS infiltration through loose ApoE4 BBB, but makes no difference in ApoE3, where the BBB is intact. This brings us back to rapa brain penetrance controversy - it can have effects outside the brain that nonetheless affects the brain even if rapamycin itself doesn’t cross the BBB.

It’s therefore unsurprising if rapa works differently depending on the dementia stage and how the pathways are affected by the disease.

What we need are more studies.