Inclusion Criteria:

• The participant is capable of communicating with the site staff.
• The participant is able to read and understand the Informed Consent Form.
• The participant has signed the trial-specific Informed Consent Form
• The participant’s caregiver is able to read and understand the Caregiver’s Informed Consent Form.
• The participant’s caregiver has signed the Caregiver’s Informed Consent Form.
• The participant is  ≥40 and ≤ 75 years of age at the Screening Visit.
• The participant has a reliable caregiver who will be available throughout the trial to complete caregiver observer questionnaires (at site visit or in a remote setting) when carer/observer-reported outcomes are performed. A caregiver is defined as a person who spends approximately 3 hours or more with the participant per week and can inform on the participant’s level of functioning.
• The participant and the participant’s caregiver are willing and able to attend trial appointments within the specified time windows.
• The participant has a diagnosis of clinically established MSA-P or MSA-C, or clinically probable MSA-P or MSA-C, according to the 2022 MDS criteria for the diagnosis of MSA at the Screening Visit.
• The participant had onset of motor MSA symptoms within 5 years prior to the Screening Visit in the judgement of the investigator.
• The participant has an anticipated survival of >3 years, in the opinion of the investigator, at the Screening Visit.
• The participant has an UMSARS Part I score ≤16 (omitting item 11 on sexual function) at the Screening Visit.
• The participant has a cognitive performance score ≥22, evaluated by the MoCA at the Screening Visit. Add one point for an individual who has 12 years or less of formal education.
• The participant has suitable peripheral venous access for IMP administration and blood sampling 
• The man must:
  • have been surgically sterilised (bilateral surgical vasectomy or bilateral orchiectomy) prior to the Screening Visit
  • OR
  • remain sexually abstinent, when this is in line with his preferred and usual lifestyle
  • OR
  • engage exclusively in same-sex relationships
  • OR
  • engage in sexual relationships with a partner who is a woman of non-childbearing potential, defined as:
    • a woman who had her last natural menstruation ≥12 months prior to the Screening Visit
    • OR
    • a woman who was surgically sterilised (bilateral fallopian tubal ligation, bilateral salpingo-oophorectomy, or bilateral oophorectomy) or had a hysterectomy prior to the Screening Visit
  • OR
    • agree to avoid impregnating his partner, if the partner is considered to be of childbearing potential, from the Screening Visit until ≥5 months after the last dose of IMP by using contraception as specified below
  • AND
    •  not donate sperm from the Screening Visit until ≥5 months after the last dose of IMP
• Contraception Methods to Be Used by Men and Their Partners who are Women of Childbearing Potential:
  • By the man: condom (to avoid the risk of drug exposure through the ejaculate [which also applies to a vasectomised male] to the sexual partner, including a pregnant partner)
  • By the woman of childbearing potential: contraception is recommended
• The woman, if considered to be of childbearing potential,* must:
  • remain sexually abstinent when this is in line with her preferred and usual lifestyle
  • OR
  • engage exclusively in same-sex relationships
  • OR
  • have a male partner who was surgically sterilised (bilateral surgical vasectomy or bilateral orchiectomy) prior to the Screening Visit
  • OR
  • agree to avoid becoming pregnant from the Screening Visit until ≥5 months after the last dose of IMP by using a highly effective method of contraception as specified below
  • AND
  • not donate ova from the Screening Visit until ≥5 months after the last dose of IMP
  • Contraception Method:
    • Highly effective contraception is defined as one that results in a low failure rate (that is, <1% per year) when used consistently and correctly, for example, combined (oestrogen-and progesterone-containing) hormonal contraception associated with inhibition of ovulation (oral, intra-vaginal, or transdermal), progesterone-only hormonal contraception associated with inhibition of ovulation (oral, injectable, implantable), intrauterine device, intrauterine hormone-releasing system.
    • * The woman is considered to be of non-childbearing potential if she:
      •  has not had her menses for ≥12 months without an alternative medical cause; if this needs to be confirmed, a FSH test can be used, unless the participant is taking hormonal replace therapy or using hormonal contraception. 
      • OR
      • was surgically sterilised (bilateral fallopian tubal ligation, bilateral salpingo-oophorectomy, or bilateral oophorectomy) or had a hysterectomy prior to the Screening Visit.

Exclusion Criteria:

• The participant is a member of the site staff or of their immediate families or is a subordinate (or immediate family member of a subordinate) to any of the site staff.
• The participant has previously been enrolled in this trial.
• The participant has previously been dosed with Lu AF82422.
• The participant has taken any IMP < 3 months or < 5 years prior to the first dose of IMP.
• The participant is pregnant, breastfeeding, intends to become pregnant, or is of childbearing potential and not willing to use adequate contraceptive methods.
• The participant has a history of severe drug allergy, anaphylaxis or hypersensitivity or known or suspected hypersensitivity or intolerance to the IMP, or its excipients.
• The participant has 2 or more blood relatives with a history of MSA.
• The participant, if of MSA-P subtype, has unexplained anosmia (not explained by other common causes such as allergic rhinitis or smoking, nasal structural lesions, or nasal surgery) on olfactory testing at the Screening Visit.
• The participant has contraindications for MRI scanning.
• The participant has evidence (clinically or on MRI) and/or history of any clinically significant disease or condition other than MSA, that is, in the investigator’s opinion, likely to affect CNS functioning, e.g., serious neurological disorder, other intracranial or systemic disease. Abnormalities (space-occupying lesions, vascular lesions, tumours, stroke, etc.) on MRI are to be discussed with the Lundbeck Medical Expert or the CRO Medical Monitor before the patient is enrolled.
• The participant has a current diagnosis of movement disorders that could mimic MSA, e.g., Parkinson’ disease, dementia with Lewy bodies, essential tremor, progressive supranuclear palsy, spinocerebellar ataxia, spastic paraparesis, corticobasal degeneration, or vascular, pharmacological, or post-encephalitic parkinsonism, per investigator discretion. Participants who have previously been incorrectly diagnosed with Parkinson’s disease will not be excluded.
• The participant has a history of neurosurgical procedures including deep brain stimulation that could, in the investigator’s opinion, interfere with the assessments of safety or.
• The participant has a history of cancer, other than basal cell or Stage 1 squamous cell carcinoma of the skin or adequately treated cervical intraepithelial neoplasia, that has not been in remission for >5 years prior to the first dose of IMP.
• The participant has any other disorder for which the treatment takes priority over treatment of MSA or is likely to interfere with the study treatment or impair treatment compliance.
• The participant takes or has taken concomitant medication that is disallowed or allowed with restrictions, or it is anticipated that the participant will require treatment with at least one of these medications during the trial.
• The participant has an abnormal ECG that is considered clinically significant by the investigator at the Screening Visit.
• The participant has one or more clinical laboratory test values outside the reference range, based on the blood and urine samples taken at the Screening Visit, or has a disease or takes medication that could, in the opinion of the investigator, interfere with the assessments of safety, or tolerability, or interfere with the conduct or interpretation of the trial.
• The participant is at significant risk of suicide based on medical history, mental status, investigator judgement, or the C-SSRS (answer of ‘yes’ to suicidal ideation question 4 or 5 or any suicidal behaviour during the last 6 months prior to the Screening Visit).
• The participant is, in the opinion of the investigator, unlikely to comply with the Clinical Trial Protocol or is unsuitable for any reason

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 07/30/2024. Questions regarding updates should be directed to the study team contact.