AC Immune released interim biomarker and safety data from its Phase II Vacsyn program targeting alpha‑synuclein in early Parkinson’s disease and reported signals consistent with potential disease modification. The company cited changes in cerebrospinal fluid alpha‑synuclein, neurofilament light (NfL) and other imaging markers that the firm interprets as supportive of slowing neurodegeneration. AC Immune said it will engage regulators to discuss pathways that could accelerate development based on the biomarker package. Analysts and external scientists cautioned that biomarker shifts do not yet prove clinical benefit and stressed the need for longer follow‑up and robust clinical endpoints. The data prompted share movement and renewed investor interest in active immunotherapy for synucleinopathies while highlighting the debate over surrogate endpoints in neurodegenerative disease trials.