PASTIS: investigating the impact of tadalafil on cerebral blood flow in small vessel disease

Atticus Hainsworth, St George’s University of London, London, UK, discusses the PASTIS trial (NCT02450253) - a double-blind, placebo-controlled, cross-over trial investigating tadalafil, a PDE5 inhibitor, as a potential therapeutic in small vessel disease. As small vessel disease is the main cause of vascular cognitive impairment in older adults, it was hoped the widely used vasodilator would impact cerebral blood flow (CBF). In total, 65 older people were recruited and administered one dose of tadalafil (20mg) or placebo on two visits, 7 days apart (randomized to order of treatment). The primary endpoint of the trial was a change in subcortical CBF. Dr Hainsworth explains that the observed treatment effects were not statistically significant. To detect treatment effects may require different dosing regimens. He suggests if they were to carry out the trial again to focus only on those aged 65 years and above, as the strongest indication of treatment effect was seen in this population. This interview took place at the Alzheimer’s Association International Conference (AAIC) 2022 in San Diego, CA.