AC Immune has reported results from a mid-stage clinical trial of its immunotherapy for Parkinson’s disease, suggesting the therapy may slow progression of the condition. The company tested its anti-alpha-synuclein active immunotherapy, ACI-7104.056, against a placebo in 34 patients with early-stage Parkinson’s disease for at least one year as part of the first segment of its Phase II VacSYn trial. Of those participants, 20 remained on treatment for 18 months.
Interim analysis showed that ACI-7104.056 stabilized biomarkers associated with Parkinson’s and neurodegeneration, including alpha-synuclein and neurofilament light chain. According to AC Immune’s press release, brain imaging after treatment indicated “trends toward disease modification,” while patient-reported movement scores also suggested stabilization. Additionally, all patients developed a strong antibody response by week 76.
Shares of AC Immune increased by 14% in pre-market trading before stabilizing once markets opened.
Werner Poewe, emeritus Professor of Neurology at Innsbruck Medical University and expert in Parkinson’s disease, commented: “For the first time, we are seeing signals that targeting the underlying pathology of Parkinson’s with active immunotherapy could slow disease progression.” He added that further evidence is required to demonstrate impact on the underlying disease but described today’s results as “highly encouraging.”
Chief Executive Officer Andrea Pfeifer said these findings “hold the promise of a tremendous step forward for millions of patients.”
Earlier this year, AC Immune reduced its pipeline and cut approximately 30% of its workforce to extend funding into the third quarter of 2027 and prioritize key assets such as ACI-7104.056. Another priority program is ACI-24.060—an Alzheimer’s vaccine currently anticipated to have data available in the first half of 2026.
