AC Immune reported on September 23, 2026 that Part 1 of VacSYn, a randomized, double-blind, placebo-controlled Phase 2 trial in early Parkinson's disease, met all of its primary safety, tolerability, and immunogenicity endpoints through week 100. Thirty-four patients were randomized 3:1 to ACI-7104 or placebo; the company said 100% of patients developed antibodies against the PD01 antigen after three immunizations, antibodies reached the cerebrospinal fluid in all patients, and the vaccine was generally safe and well tolerated. ACI-7104.056 uses an eight-amino-acid peptide that mimics a C-terminal alpha-synuclein epitope, conjugated to keyhole limpet hemocyanin, according to Alzforum. AC Immune reported a CSF total alpha-synuclein signal consistent with target engagement but no clinical efficacy result, and plans FDA meetings in early 2027 before an expanded Phase 2.
The Alzheimer's Association International Conference (AAIC 2026) opens Sunday July 12 and runs through Wednesday July 15 at the ExCeL London, drawing approximately 12,000 researchers and health-care professionals from around the globe. The peptide-adjacent centerpiece already flagged in Wednesday's Vaccinex announcement is the Featured Research Session on Monday July 13 for pepinemab (humanized IgG4 anti-Semaphorin 4D monoclonal antibody), chaired by Elizabeth Evans, PhD, presenting new glial biomarker data from the Phase 1b/2 SIGNAL-AD study alongside plans for the expanded Phase 2b SIGNAL-AD2 trial. AC Immune (NASDAQ: ACIU) will present three programs from its Morphomer platform: a first-in-class TDP-43 PET tracer with encouraging early human imaging data in frontotemporal dementia and ALS, a novel brain-penetrant NLRP3 inhibitor in Phase 1 that supports an orally delivered CNS therapy profile, and an alpha-synuclein Morphomer showing potent, brain-penetrant inhibition of pathology with neuroprotective effects. Eisai will present 50-plus abstracts spanning the lecanemab (LEQEMBI) Alzheimer's disease portfolio, including biomarker, long-term safety, and clinical-utility readouts.