AC Immune's Alpha-Synuclein Immunotherapy Shows Promise in Slowing Parkinson's Disease Progression
核心洞察
AC Immune's ACI-7104.056 active immunotherapy demonstrated potential to slow Parkinson's disease (搜索) progression in interim Phase 2 VacSYn trial results, marking the first time an alpha-synuclein (搜索)-targeted active immunotherapy has shown such signals.
The treatment achieved 100% immunogenicity response rate and stabilized key disease biomarkers including alpha-synuclein (搜索) levels in cerebrospinal fluid and neurofilament light (搜索), suggesting reduced neuronal damage.
Clinical assessments using the MDS-UPDRS scale showed trends toward symptom stabilization in treated patients compared to placebo, with no clinically relevant safety issues reported.
Swiss biotech AC Immune has reported promising interim results from its Phase 2 VacSYn trial of ACI-7104.056, an alpha-synuclein (搜索)-targeted active immunotherapy for early-stage Parkinson's disease (搜索). The data represents the first demonstration that targeting underlying alpha-synuclein pathology with active immunotherapy could potentially slow disease progression.
Strong Immunogenic Response and Target Engagement
The adaptive, placebo-controlled Phase 2 study enrolled 34 patients randomized 3:1 to receive ACI-7104.056 or placebo. All participants in the interim analysis received treatment for at least 12 months, with 20 patients treated for up to 18 months.
ACI-7104.056 achieved a 100% responder rate for immunogenicity, with antibody titers in serum reaching over 500-fold higher levels than the placebo group at week 76. Importantly, antibodies crossed the blood-brain barrier, with cerebrospinal fluid (CSF) antibody levels also exceeding placebo by over 500-fold. The correlation between serum and CSF antibody titers was statistically significant (Spearman correlation at week 24 = 0.92, p<0.05; at week 76 = 0.85, p<0.05).
Biomarker Evidence of Disease Stabilization
The treatment demonstrated stabilization of multiple disease-related biomarkers suggesting potential disease modification. Total CSF alpha-synuclein (搜索) levels stabilized in the treatment arm while decreasing over time in the placebo group, as expected with natural disease progression (post-hoc analysis p=0.018). This indicates the desired effect of antibody binding to alpha-synuclein, leading to target stabilization or increased brain clearance.
Neurofilament light (搜索) (NfL) levels in CSF remained stable in the ACI-7104.056 group but increased in the placebo group. Since elevated NfL levels indicate ongoing neuronal damage in Parkinson's disease (搜索), this stabilization suggests potential slowing of neurodegeneration.
Additional markers including plasma glial fibrillary acidic protein (GFAP) and dopamine transporter (搜索) (DaT) SPECT imaging showed trends toward disease modification, tracking the activation of neuron-repairing glial cells and dopaminergic neuron loss, respectively.
Clinical Assessment Trends
Clinical measures using the Movement Disorder Society-Unified Parkinson's Disease (搜索) Rating Scale (MDS-UPDRS) Part III showed encouraging trends. At week 74, the ACI-7104.056 group did not demonstrate meaningful progression in mean total scores, while the placebo arm showed expected increases consistent with normal disease progression. The difference was further enhanced when stratified by levodopa ON/OFF state.
Safety Profile Supports Continued Development
The interim results continue to demonstrate that ACI-7104.056 is generally safe and well-tolerated. No clinically relevant or serious adverse events considered related to the study drug have been reported. The most common adverse events were transient injection site reactions (56%), headaches (15%), and fatigue (12%).
Expert Commentary and Regulatory Path Forward
Werner Poewe, emeritus Professor of Neurology at Innsbruck Medical University and leading Parkinson's expert, commented on the significance of the findings: "The remarkable consistency of the trends observed across multiple disease-related biomarkers and on clinical assessments in the treatment arm are very promising. For the first time, we are seeing signals that targeting the underlying pathology of Parkinson's with active immunotherapy could slow disease progression."
AC Immune CEO Dr. Andrea Pfeifer emphasized the potential impact: "The interim Phase 2 data shows the potential of our ACI-7104.056 active immunotherapy to slow the progression of Parkinson's disease (搜索) and hold the promise of a tremendous step forward for millions of patients."
Based on these results, AC Immune plans to seek regulatory feedback on a clinical development plan to potentially accelerate toward registration. Final data from Part 1 of the VacSYn trial are expected in mid-2026.
Context in Alpha-Synuclein Therapeutics
These positive results come after disappointing outcomes for antibody-based alpha-synuclein (搜索)-directed drugs, including Roche's prasinezumab and Biogen's cinpanemab in Parkinson's disease (搜索), and Lundbeck's AF82422 (搜索) in multiple system atrophy (搜索) trials.
Alpha-synuclein (搜索) is a protein that becomes misfolded and accumulates in clumps in the brains of patients with Parkinson's disease (搜索) and other neurodegenerative conditions like multiple system atrophy (搜索), functioning analogously to amyloid and tau proteins in Alzheimer's disease (搜索).
The company recently restructured its operations to focus on ACI-7104.056 and two Alzheimer's immunotherapies partnered with Takeda (搜索) and Johnson & Johnson, extending its cash runway to the third quarter of 2027. AC Immune's Nasdaq-listed shares rose approximately 10% following the announcement.