NCT07172815

PDE5 Inhibitor for Alzheimer's Disease

Evaluating the Safety and Efficacy of PDE-5 Inhibitor: Tadalafil as a Treatment for Early Stages of Alzheimer's Disease

• Status: Not Yet Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 244 (estimated)
• Sponsor: Imperial College London · Academic / Other
• Sex: All
• Age: 50 Years
• Healthy volunteers: Not accepted

Summary

Alzheimer's disease is the most common cause of dementia in the elderly population. The disease is characterised by the presence of abnormal proteins in the brain, primarily β-amyloid (Aβ) and tau. Recent evidence suggests that Phosphodiesterase-5 (PDE-5) enzyme inhibitors may hold therapeutic promise in the treatment of early AD. Findings showed that daily low-dose tadalafil (a PDE5 inhibitor that can cross the BBB) administration in patients with erectile dysfunction and MCI increased relative regional cerebral blood flow in the postcentral gyrus, precuneus, and brainstem. However, the long-term effects of tadalafil on AD progression and biomarkers are not known. However, there is limited evidence regarding its safety and efficacy in AD patients. The primary objective of this study is to assess the safety and tolerability of long-term (1 year) tadalafil treatment in patients who are Aβ-positive MCI and early AD based on NIA-AA criteria. Additionally, the secondary objective of this study is to assess the change in cognitive performance from baseline to follow-up, evaluated using neuropsychometric testing, in MCI and AD patients who are undergoing treatment with tadalafil for 1 year.

Conditions

• Alzheimer Disease

Interventions

Type	Name	Description
DRUG	tadalafil	Once daily dose of Tadalafil will be commenced at 10 mg for 2 weeks, followed by an increase to 20 mg for another 2 weeks and finally increased to 40 mg.
DRUG	Placebo	Matched Placebo will be taken once daily.

Timeline

• Start date: 2025-09-01
• Primary completion: 2028-08-01
• Completion: 2028-08-01
• First posted: 2025-09-15
• Last updated: 2025-09-15