LAUSANNE, Switzerland, August 11, 2026
AC Immune SA announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track designation and cleared the Investigational New Drug (IND) application for ACI-7104, the company’s wholly owned anti-alpha-synuclein active immunotherapy candidate for the treatment of early-stage Parkinson’s disease (PD). ACI-7104 is designed to stimulate the production of antibodies that preferentially recognize aggregated alpha-synuclein (α-syn) species associated with neuronal toxicity. The regulatory milestones will allow AC Immune to expand its ongoing VacSYn Phase 2 study to clinical sites in the United States. The company expects to report full Week-100 results from Part 1 of the study during the second half of 2026.
ACI-7104 Targets Pathological Alpha-Synuclein
ACI-7104 is an active immunotherapy designed to generate α-synuclein-specific antibodies against pathological forms of the protein, including toxic aggregated species. Alpha-synuclein aggregation is associated with neuronal dysfunction and degeneration in Parkinson’s disease and is believed to contribute to disease progression. By targeting pathological α-syn species, AC Immune aims to potentially interfere with the spread of toxic protein aggregates and downstream neurodegenerative processes. The candidate is being evaluated in an adaptive, biomarker-based Phase 2 study involving patients with early-stage Parkinson’s disease.
Interim Phase 2 Data Show Immunogenicity and Tolerability
The FDA’s Fast Track decision follows interim findings from Part 1 of the VacSYn Phase 2 trial, which AC Immune said demonstrated favorable safety, tolerability and immunogenicity through 76 weeks. The company reported no clinically relevant safety issues and a 100% responder rate for the immunogenicity target in the interim analysis. Early signals of potential activity were also reported, although these findings are preliminary and do not yet establish that ACI-7104 slows or modifies Parkinson’s disease progression. Full Week-100 results from Part 1 are expected in the second half of 2026 and will provide additional information on the candidate’s longer-term clinical profile.
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U.S. Expansion Supports Continued Clinical Development
Following FDA IND clearance, the VacSYn study is expected to expand to clinical sites in the United States, broadening the geographic scope of ACI-7104 development. AC Immune also recently received a $4 million research grant from the Vijay and Marie Goradia Charitable Foundation to support an extension of Part 1 of VacSYn, enabling assessment of the candidate’s long-term safety and efficacy for an additional two years. The company is developing ACI-7104 as a potential treatment for prodromal and early Parkinson’s disease while advancing other programs targeting misfolded proteins and inflammatory pathways involved in neurodegeneration. Fast Track designation and IND clearance do not constitute FDA approval, and the safety and efficacy of ACI-7104 remain under clinical evaluation.
Source:AC Immune, press release
