AC Immune shares jump 13.98% premarket after positive Phase 2 data shows Parkinson's progression slowdown potential.

AC Immune surged 13.98% in premarket trading following the release of positive interim Phase 2 data for its Parkinson’s disease immunotherapy ACI-7104.056. The trial demonstrated a 100% responder rate in immunogenicity, with biomarkers such as cerebrospinal fluid alpha-synuclein and neurofilament light chain stabilizing in treated patients compared to the placebo group. Clinical assessments also indicated potential disease stabilization. The therapy’s favorable safety profile, including no serious adverse events, further supported its development. AC Immune plans to engage regulators to accelerate registration pathways, with final Phase 2 data expected in mid-2026. The results, described by experts as a "tremendous step forward," validate the company’s approach to targeting Parkinson’s pathology via active immunotherapy, driving immediate optimism among investors.