Efficacy of Probucol on cognitive function in Alzheimers disease: Study protocol for a double-blind, placebo-controlled, randomised phase II trial (PIA Study)
Preclinical, clinical and epidemiological studies support the hypothesis that aberrant systemic metabolism of amyloid-beta (Aβ) in the peripheral circulation is causally related to the development of Alzheimers disease (AD). Specifically, recent studies suggest that increased plasma concentrations of lipoprotein-Aβ compromises the brain microvasculature, resulting in extravasation and retention of the lipoprotein-Aβ moiety. The latter results in an inflammatory response and neurodegeneration ensues. Probucol, a historic cholesterol-lowering drug, has been shown in murine models to suppress lipoprotein-Aβ secretion, concomitant with maintaining blood-brain-barrier function and suppressing neurovascular inflammation. Probucol has also been shown to protect cognitive function in dietary-induced amyloidogenic mice. This protocol details the Probucol in Alzheimers Study (PIA-study), a double-blind, randomised, placebo-controlled drug intervention trial investigating if Probucol attenuates cognitive decline in patients with mild-to-moderate AD. Objectives: The primary objective of the 104-week study is to assess whether Probucol supports cognitive function and delays brain atrophy in AD patients. A secondary objective is to determine whether Probucol treatment will reduce cerebral amyloid burden.