Tau aggregation inhibitors are therapeutic agents designed to prevent or reverse the pathological aggregation of tau protein into neurofibrillary tangles (NFTs), a hallmark of Alzheimer's disease and other tauopathies. These compounds target various stages of the tau aggregation process, from monomeric tau to pre-fibrillar oligomers and mature tangles. [1]
In tauopathies, tau protein undergoes: [2]
Tau aggregation inhibitors aim to block steps 2-4, preventing the formation of toxic species. [3]
These compounds bind directly to tau, preventing β-sheet formation and filament assembly. [4]
Key Mechanisms: [5]
Leuco-methylthioninium (LMTM/LMTX) [6]
Methylthioninium chloride (MTC) [7]
Other compounds indirectly inhibit aggregation by: [8]
LMTM (leuco-methylthioninium bishydromethanesulfonate) is the most advanced tau aggregation inhibitor in clinical development. [9]
Tideglusib is a non-selective GSK-3β inhibitor that reduces tau phosphorylation. [10]
Davunetide (AL-108) is a peptide that enhances microtubule stability and reduces tau pathology. [11]
Nilotinib is a BCR-ABL inhibitor being repurposed for AD. [12]
| Feature | Small Molecule Inhibitors | Immunotherapy | [13]
|---------|--------------------------|----------------| [14]
| Mechanism | Intracellular target engagement | Extracellular antibody-mediated | [15]
| BBB Penetration | Generally good | Limited; relies on FcRn transport | [16]
| Target | Cytosolic tau aggregates | Extracellular tau, NFTs |
| Administration | Oral | Intravenous/subcutaneous |
| Frequency | Daily | Every 2-4 weeks |
| Immunogenicity | Not an issue | Anti-drug antibodies possible |
| Onset of Action | Potentially faster | May require time for antibody levels |
Tau aggregation inhibitors may be combined with:
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Wischik CM, et al. Mechanisms of action of methylene blue derivatives in tauopathies. Neurobiol Aging. 2014;35(Suppl 1):S31. 2014. ↩︎
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Cho JW, et al. Nilotinib for Alzheimer's disease: A phase 2 study. Nat Med. 2019;25(1):4-7. 2019. ↩︎
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Cai T, et al. Small molecule tau aggregation inhibitors: Progress and challenges. J Med Chem. 2022;65(12):8048-8071. 2022. ↩︎
Moussa CE-H. Commentary on nilotinib phase 2 results. J Alzheimers Dis. 2020;73(3):893-897. 2020. ↩︎