The purpose of this study is to investigate the safety of a single dose of Lu AF82422, how well it is tolerated, how the drug effects the body and what the body does to the drug in healthy non-Japanese and Japanese subjects and in patients with Parkinson's disease

Inclusion criteria:

Healthy subjects:

- Men and women ≥18 and ≤55 years of age with a body mass index (BMI) ≥18 and ≤32 kg/m2 (non-Japanese subjects) and ≥18 and ≤28 kg/m2 (Japanese subjects)

Patients with Parkinson's disease:

• Men and women with a clinical diagnosis of idiopathic Parkinson's disease, Hoehn and Yahn (H&Y, stage 1-3)
• For a minimum of three months prior to enrolment, Parkinson's disease symptoms have been stable and is anticipated to be stable during the study duration as judged by the PI
• If on Parkinson's disease treatment the dose must be stable for a minimum of three months prior to enrolment and is anticipated to be stable during the study duration as judged by the PI
• ≥40 and ≤80 years of age
• BMI ≥18 and ≤35 kg/m2

Exclusion criteria:

• Atypical Parkinsonism
• Clinically relevant structural brain abnormality, as assessed using MRI
• Mild cognitive impairment, measured as a Montreal cognitive assessment (MoCA) score =<21
• Any past or current treatment with an active vaccine targeting alpha-synuclein
• Any past or current treatment with a monoclonal antibody within the last 12 months

Other in- and exclusion criteria may apply.