NCT04739423

Who might be able to join this trial:

For people with Parkinson's Disease (PD):

• You are between 40 and 80 years old at the time you agree to join the study.
• You have been diagnosed with Parkinson's Disease and also have a sleep condition called REM sleep behavior disorder.
• Your Parkinson's symptoms are in the mild-to-moderate range (stages 1–3 on a standard scale) based on records from the past 3 months or assessed at your screening visit.
• Your score on a standard memory and thinking test (MoCA) is between 18 and 28.

For people with Mild Cognitive Impairment (MCI):

• You are between 50 and 80 years old at the time you agree to join the study.
• You have been diagnosed with a specific type of memory-related Mild Cognitive Impairment (called amnestic MCI) according to recognised medical guidelines.
• Your score on a standard memory and thinking test (MoCA) is between 18 and 26.
• You do not have dementia.
• You, or someone close to you (such as a partner, family member, or carer), has noticed that your memory is not as good as it used to be.
• You score below the expected range for your age and education level on a specific attention and processing speed test (called the Digit Symbol Substitution Test) done at screening.
• Your cognitive decline is not mainly caused by a stroke, brain injury, or another medical condition.

For people with Dementia with Lewy Bodies (DLB) or Parkinson's Disease Dementia (PDD):

• You are between 50 and 80 years old at the time you agree to join the study.
• You have been diagnosed with Dementia with Lewy Bodies or Parkinson's Disease Dementia.
• You experience documented fluctuations in your thinking and alertness, confirmed by a specific assessment scale (confirm with trial site).
• Your score on a standard memory and thinking test (MoCA) is between 18 and 26.
• You have a carer or someone close to you who is willing to take part in the study with you, spends at least 12 hours a week with you, helps you with treatment, and can accompany you to study visits.
• Your movement symptoms are in the mild-to-moderate range (stages 1–3 on a standard scale) based on records from the past 3 months or assessed at screening.
• Any other medical or psychiatric conditions you have are considered stable in the opinion of the study doctor.

For everyone joining the trial:

• If you are male and not confirmed to be unable to produce sperm, you must agree to use a condom during the study when having sex with a woman who could become pregnant.
• If you are a woman who could become pregnant, you must have a negative pregnancy test at the start of the study and agree to use reliable contraception, be in a relationship with a confirmed sterile male partner, or abstain from sex, from screening through to 30 days after your last dose of study medication.
• If you are a woman who cannot become pregnant (due to menopause or surgery), you may still be eligible.
• Your body weight is at least 50 kg and your body mass index (BMI) is between 18 and 35 at screening.
• Any existing medical conditions (such as high blood pressure or high cholesterol) have been stable and well-managed for at least 3 months before screening.
• You are willing and able to follow all the study requirements and procedures.
• You are able to give your own consent to take part, or have a legally authorised person who can do so on your behalf.

Who may not be able to join:

• Your blood pressure is poorly controlled even with medication or lifestyle changes.
• You have a lung condition, including asthma that requires the use of a certain type of inhaler (a beta-2 bronchodilator), or you have significant breathing problems.
• You show signs of certain other brain or movement disorders (such as multiple system atrophy, corticobasal degeneration, or others), or have a history of stroke, significant head injury, or brain infection (confirm with trial site).
• You have a current or recent history (within the past 2 years) of epilepsy, a localised brain les