The main purpose of the study is to identify the best dose of V81444 to use in future trials in patients with Parkinson's disease. The study will also explore the effects of V81444 on brain activity and blood flow with tests of mental ability ("cognitive function tests"). It will also check how safe V81444 is and how well it is tolerated after dosing.
In this Phase I, single-centre, open-label, adaptive, single-dose study at multiple dose levels, the relationship between dose and plasma concentration of orally administered V81444 to brain A2A RO was investigated in 6 healthy male volunteers. In addition, the effects of V81444 on regional brain activity and perfusion during tests of cognitive function, and the safety and tolerability of V81444 were assessed. For each subject, the study consisted of a screening visit, a baseline visit, a treatment period, and a safety follow-up visit. The dose of V81444 and timing of scans performed were defined in the protocol for the first 2 subjects only. The dose, nature and timings of assessments for subsequent subjects were determined based on review of emerging receptor binding, pharmacokinetic (PK), pharmacodynamic (PD) and safety information. In each treatment period, subjects were admitted to the unit on the day before dosing (Day -1), received a single oral dose of V81444 on Day 1 and, subject to satisfactory medical review, were discharged a minimum of 12 h after dosing. Overall, 3 doses of V81444 were assessed (250 mg, 50 mg, and 100 mg), with 2 subjects included at each dose level. PD assessments were performed at baseline and after each dose of V81444 using PET (with the A2A radioligand, to measure brain A2A RO, as well as MRI techniques to investigate the effects of V81444 on regional brain activity and perfusion during cognitive function tests. PK parameters were assessed by assay of V81444 concentration in plasma. Safety and tolerability were assessed by monitoring physical examination findings, adverse events (AEs), vital signs, 12 lead electrocardiogram (ECG) and clinical laboratory safety tests.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
6
Single oral dose of V81444
Plasma concentration V81444 corresponding with 50% brain A2A receptor occupancy.
Plasma concentrations of V81444 and binding of \[11C\]SCH442416 radioligand to brain A2A receptors using PET before and after V81444 dosing to determine occupancy of A2A receptors by V81444.
Time frame: Up to 27 hours after a single dose
Cognitive function using functional MRI
Time frame: 5 hours after dosing
Change versus placebo in proportion of subjects with adverse events
Time frame: Up to 7 Days after last dose
Change versus placebo in proportion of subjects with abnormal laboratory findings
Time frame: Up to 7 Days after last dose
Change versus placebo in proportion of subjects with clinically significant abnormalities on vital signs
Time frame: Up to 7 Days after last dose
Change versus placebo in proportion of subjects with clinically significant abnormalities in 12-lead ECG
Time frame: Up to 7 Days after last dose
Change versus placebo in proportion of subjects with clinically significant abnormalities on physical examination
Time frame: Up to 7 Days after last dose
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