The trials investigates the changes of cerebral spinal fluid (CSF) soluble alpha-secretase
cleaved APP (APPsα) levels under oral therapy with acitretin 30mg daily in patients with mild
to moderate Alzheimer's disease (AD).The present study aims to demonstrate an enhancement of
the α-secretase activity by acitretin as measured by increased CSF APPSα levels in human AD.
Second, the safety and tolerability of acitretin in AD patients should be proven.