AC Immune Positive Interim Phase 2 Data on ACI-7104.056 Support Potential Slowing of Progression of Parkinson's Disease

Core Insights - AC Immune SA announced positive interim results from the Phase 2 VacSYn trial for ACI-7104.056, an active immunotherapy targeting alpha-synuclein in early Parkinson's disease, indicating potential to slow disease progression [2][4][11] Interim Results - The VacSYn trial is a placebo-controlled, biomarker-based study involving 34 patients, with participants treated for at least 12 months [5] - Interim results demonstrated that all target criteria for immunogenicity were met, with a 100% responder rate for antibody production [6] - ACI-7104.056 showed a clear safety profile with no clinically relevant safety issues reported, and the most common adverse events were transient injection site reactions (56%), headaches (15%), and fatigue (12%) [10] Biomarker and Clinical Assessments - Disease-related biomarkers indicated stabilization of Parkinson's disease pathology, with total CSF alpha-synuclein levels stabilizing in the treatment group while decreasing in the placebo group [13] - Neurofilament light chain (NfL) levels remained stable in the treatment group, suggesting a potential slowing of neuronal damage, while increasing in the placebo group [13] - Clinical measures, including the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III scores, showed no meaningful progression in the treatment group compared to an expected increase in the placebo group [13] Expert Commentary - Dr. Andrea Pfeifer, CEO of AC Immune, emphasized the potential of ACI-7104.056 to transform Parkinson's disease treatment and indicated plans to discuss regulatory pathways for clinical development [4] - Dr. Werner Poewe highlighted the promising consistency of trends across multiple biomarkers and clinical assessments, supporting further development of the program [4] Future Plans - Based on the interim results, AC Immune aims to seek regulatory feedback to potentially accelerate the clinical development plan for ACI-7104.056 towards registration, with final data from Part 1 of the trial expected in mid-2026 [11]