ACI-24 (anti-Abeta vaccine) - (ABATE)

June 30, 2026: AC Immune SA (NASDAQ: ACIU) reported interim 12‑month data from the Phase 1b/2 randomized, double-blind, placebo-controlled ABATE trial of ACI-24, an anti-amyloid beta (Abeta) active immunotherapy, in prodromal Alzheimer’s disease. Across the first three AD cohorts (AD1–AD3; part of 74 prodromal AD patients), ACI-24 was generally safe and well tolerated, with no evidence of amyloid-related imaging abnormalities-edema (ARIA-E). Anti-Abeta antibody responses were detected at all dose levels, showing a dose-response relationship.

AC Immune said an additional adjuvant is being evaluated to enhance immunogenicity; this is being tested in the recently initiated ABATE Cohort AD4.

The release also notes ABATE includes adults with Down syndrome (DS); recruitment into the third DS cohort (DS3) has concluded (NCT05462106). Multiple DSMB reviews have raised no safety concerns to date, with no evidence of ARIA.

Under AC Immune’s option and license agreement with Takeda covering anti-Abeta active immunotherapies including ACI-24, AC Immune received $100 million upfront and a $12 million milestone upon dosing the first patients in AD4; additional potential milestones up to ~$2.1 billion and tiered double-digit royalties are described.