PDE-5 inhibitor for AD
Research type
Research Study
Full title
Evaluating the safety and efficacy of PDE-5 inhibitor: tadalafil as a treatment for early stages of Alzheimer's disease
IRAS ID
1007098
Contact name
Paul Edison
Contact email
Sponsor organisation
Imperial College London
Research summary
Phosphodiesterase-5 (PDE-5) inhibitor, tadalafil, holds promise as a novel and an effective treatment for Alzheimer’s disease (AD). This repurposed drug has previously demonstrated safety and tolerability in patients with pulmonary hypertension and erectile dysfunction. For the first time, we will evaluate the long-term safety and efficacy of tadalafil in patients with early AD (mild AD and mild cognitive impairment [MCI]).
Alzheimer's disease is one of the leading causes of dementia worldwide. There are currently no effective approved treatments for that can delay its progression. Research into the disease suggests dysfunction in the barrier that separates blood and the brain (the blood-brain barrier) causing "leakage," due to neuroinflammation and reduced glucose metabolism within the brain. This dysfunction is suggested to contribute to increased levels of abnormal proteins (amyloid-beta proteins) associated with the disease.
PDE-5 inhibitors are currently licensed for arterial pulmonary hypertension and erectile dysfunction. The drug is able to cross the blood-brain barrier and administration of PDE-5 inhibitors in patients with erectile dysfunction and MCI increased relative regional cerebral blood flow and demonstrated significant improvements in cognitive function.
This is a 12-month study assessing the long-term effects of tadalafil, its interaction with the body and on cognitive performance. Participants will undergo medical examinations including Magnetic Resonance Imaging, Positron Emission Tomography, blood sampling, monitoring of vital signs (including 12-lead ECG), neuropsychometric testing (thinking/memory tests) and a optional lumbar puncture. 244 patients with mild Alzheimer’s disease or Mild Cognitive Impairment will enrol. Participants will undergo a screening Positron Emission Tomography scan to establish amyloid-beta positivity. Participants will be recruited from memory clinics and the Join Dementia Research website.REC name
London - Brent Research Ethics Committee
REC reference
24/LO/0822
Date of REC Opinion
4 Jun 2025
REC opinion
Further Information Favourable Opinion