Study of ARO-ATXN2 Injection in Adults With Spinocerebellar Ataxia Type 2

Inclusion Criteria:

• Non-pregnant, non-lactating

• Diagnosis of symptomatic SCA2 and ≥33 CAG repeats in the ATXN2 gene based on sourceverifiable medical records or genetic testing at Screening

• Scale of Assessment and Rating of Ataxia (SARA) score ≤14

• Subjects of childbearing potential must agree to use highly effective contraceptionin addition to a condom during the study and for at least 90 days following the endof the study or last dose of study drug, whichever is later. Subjects must notdonate sperm or eggs during the study and for at least 90 days following the end ofthe study or last dose of study drug whichever is later

Exclusion Criteria:

• Uncontrolled hypertension (blood pressure >160/100 mmHg)

• History of having received stem cell therapy

• Clinically significant cardiac, liver, or renal disease

• Human immunodeficiency virus (HIV) infection (seropositive at Screening)

• Seropositive for hepatitis B (HBV) or hepatitis C (HCV) at Screening

• Intellectual disability or significant behavioral neuropsychiatric manifestation

• Any contraindications to lumbar puncture, including INR >1.4, platelet count <100,000, and use of anticoagulant or antiplatelet medications that cannot be safelyinterrupted

• Presence of an implanted shunt for drainage of CSF or an implanted central nervoussystem (CNS) catheter

Note: Additional inclusion/exclusion criteria may apply per protocol.