Real-World Study of ABBV-951 Subcutaneous Infusion to Assess Change in Disease Activity in Adult Participants With Parkinson's Disease

Inclusion Criteria:

• Eligibility for ABBV-951 therapy in accordance with the approved local label in theparticipating country and local reimbursement regulations, if applicable.

• Diagnosis of levodopa-responsive idiopathic Parkinson's Disease (PD).

• Participant must be either:

• Cohort A: Naïve to ABBV-951

• Cohort B: Pre-treated with ABBV-951, specifically, participants of Open-LabelExtension Studies M15-737 and M20-098 who completed these studies withoutsignificant protocol deviations and who did not experience an adverse event (AE) that in the investigator's opinion may indicate an unacceptable safetyrisk.

• Decision to treat with ABBV-951 (or continue the treatment in Cohort B) made by theclinician prior to any decision to approach the participant to participate in thisstudy.

• Prior to any study-related procedures being performed, the participant, or legalauthorized representative (LAR) has voluntarily signed an Authorization forUse/Disclosure of Data (AUDD)/informed consent form (ICF) according to nationalregulations after the study has been explained and the participant has had theopportunity to have questions answered.

Exclusion Criteria:

• Any condition included in the contraindications section of the approved localABBV-951 label in the participating country.

• Mini-Mental State Examination (MMSE) score < 24.

• If the participant has a score of 19-23, he/she can be included if based on theinvestigator´s judgment the participant is able to handle the therapy andfollow the study procedures with the help of a permanent caregiver.

• Participation in a concurrent interventional clinical trial from enrollment andthroughout the study.

• History of significant skin conditions or disorders per investigator´s judgment. Incase of temporary affections like recent sunburn, acne, scar tissue, tattoo, openwound, branding, or colorations, the participant should not be included if theinvestigator considers these as interfering with the infusion of study drug or withstudy assessments.