AC Immune (ACIU) Study Update summary

Study design and objectives

• Phase 2 trial of ACI-7104, an anti-alpha-synuclein active immunotherapy, in early Parkinson's disease, focused on safety, tolerability, immunogenicity, pharmacodynamics, and biomarker measures.

• Adaptive, biomarker-based, placebo-controlled design with interim analyses for safety, immunogenicity, and biomarker response.

• 34 subjects with early idiopathic Parkinson's disease, aged 40–75, Hoehn and Yahr stage 1 or 2, enrolled across 12 sites.

• Inclusion criteria: early PD (≤2 years from motor symptom onset), ages 40–75.

• Interim analysis not powered for active vs. placebo comparison but focused on trends and safety.

Safety and tolerability

• No clinically relevant or serious adverse events related to ACI-7104 observed; most common adverse events were mild and transient, including injection site reactions, headache, and fatigue.

• No significant MRI, lab, or ECG abnormalities reported.

Immunogenicity and antibody response

• 100% responder rate for anti-alpha-synuclein antibodies in serum, with robust, boostable, and sustained titers up to week 76.

• Antibody titers in both serum and CSF increased with successive immunizations, showing strong correlation and over 500-fold increase from baseline.