An Overview on the Clinical Development of Tau-Based Therapeutics

Tauopathies such as Alzheimer's disease (AD), frontotemporal lobar degeneration, or progressive supranuclear palsy constitute a group of brain disorders defined by neurodegeneration and the presence of tau aggregates in the affected brains regions. Tau is a microtubule-associated protein that accumulates in the cytosol under pathological conditions, steering the formation of aggregates or inclusions thought to be involved in the degeneration and neuronal death associated with these diseases. Despite a substantial and unmet medical need for novel, more effective disease-modifying therapies for the treatment of AD and tauopathies, the last couple of decades have seen numerous drug development undertakings primarily focused on β-amyloid, with disappointing results to date. On the other hand, tau-focused approaches have not received much attention until recently, notwithstanding that the presence of extensive tau pathology is fundamental for the disease and tau pathology shows a better correlation with impaired cognitive function than with amyloid pathology in AD patients. The last few years have brought us advances in our comprehension of tau biological functions beyond its well-established role as a microtubule-associated protein, unveiling novel physiological tau functions that may also be involved in pathogenesis and thus provide novel targets for therapeutic intervention. This review describes several emerging, encouraging therapeutic approaches aimed at tackling the underlying causes of tau pathology in AD and other tauopathies that have recently reached the clinical development stage.