This Phase 1 clinical trial investigates the repurposing of nucleoside reverse transcriptase inhibitors (NRTIs) — traditionally used for HIV treatment — for Alzheimer's disease. The trial is being conducted at National University Hospital Singapore and represents an innovative approach targeting the endogenous retroviral element hypothesis of neurodegeneration [1].
Trial Details
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Overview
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This Phase 1 clinical trial investigates the repurposing of nucleoside reverse transcriptase inhibitors (NRTIs) — traditionally used for HIV treatment — for Alzheimer's disease. The trial is being conducted at National University Hospital Singapore and represents an innovative approach targeting the endogenous retroviral element hypothesis of neurodegeneration [1].
Trial Details
| Parameter | Value | |-----------|-------| | Trial ID | NCT07210528 | | Phase | Phase 1 | | Status | Recruiting | | Participants | 48 | | Location | National University Hospital, Singapore | | Intervention | Emtricitabine + Descovy (FTC/TDF) | | Indication | Alzheimer's Disease | | Sponsor | National University of Singapore |
Background and Rationale
The Viral Hypothesis of Alzheimer's Disease
The endogenous retroelement hypothesis proposes that human endogenous retroviruses (HERVs) may contribute to Alzheimer's disease pathogenesis. These are remnants of ancient viral infections incorporated into the human genome over millions of years of evolution [2].
Key HERVs Implicated in AD:
HERV-K (HML-2): Most active endogenous retrovirus, expresses viral proteins in AD brain
HERV-W: Associated with neuroinflammation and demyelination
ERVWE1: Syncytin-1, involved in cell fusion and neuroinflammation
Evidence Supporting the Hypothesis
Increased HERV Expression in AD:
Post-mortem brain studies show elevated HERV-K RNA and protein in AD temporal cortex
HERV-K envelope proteins detected in neurons and glia of AD patients
CSF HERV-K DNA levels correlate with disease severity
Mechanistic Links to AD Pathology:
HERV activation can trigger neuroinflammatory cascades
Reverse transcriptase activity may interfere with amyloid processing
Mitochondrial toxicity (though minimized with modern NRTIs)
Limited efficacy if HERV hypothesis incorrect
Unknown optimal dosing for AD
Future Implications
If Successful
Proof of concept for viral hypothesis of AD
Novel therapeutic class for AD
Potential for combination with amyloid/tau-targeted therapies
Broader application to other neurodegenerative diseases
If Unsuccessful
Would not definitively disprove viral hypothesis
May need different NRTI or combination
Suggests need for more direct antiviral approaches
Highlights complexity of AD pathogenesis
Summary
This Phase 1 trial represents an innovative approach to Alzheimer's disease treatment based on the endogenous retroelement hypothesis. By repurposing established HIV drugs, the study tests whether suppressing HERV activation can modify AD progression. With 48 participants over 12 weeks of treatment followed by 24 weeks of follow-up, this trial will provide initial safety and efficacy data for this novel therapeutic approach [1][2].