AC Immune disclosed interim biomarker data from its Phase 2 Vacsyn trial of active anti–α‑synuclein immunotherapy, reporting directional changes in a coherent biomarker suite including CSF α‑synuclein, neurofilament light (NfL), GFAP and DaT‑SPECT imaging. The company described the profile as consistent with a potential disease‑modifying effect and said it plans to seek regulatory feedback to accelerate an approval pathway. AC Immune presented the biomarker dossier alongside safety and tolerability data; while clinical efficacy endpoints remain immature, management characterized the biomarker constellation as an encouraging signal to advance discussions with health authorities. The firm intends to use the dataset to define the next pivotal strategy and regulatory submission timeline. Biotech investors and PD researchers will closely watch whether regulators accept biomarker-driven evidence for expedited development in synucleinopathies, a contentious area where disease modification claims depend heavily on surrogate and imaging endpoints.