LAUSANNE, Switzerland, April 2026
AC Immune SA announced continued progress in its Phase 1b/2 ABATE clinical trial evaluating ACI-24, an investigational anti-amyloid beta (Abeta) active immunotherapy for the treatment of Alzheimer’s disease (AD). The study is assessing ACI-24 in patients with prodromal AD and individuals with Down syndrome, with the expansion into Cohort AD4 marking a significant step forward in evaluating long-term safety, immunogenicity, and biomarker-driven efficacy. This development reinforces AC Immune’s strategy of precision prevention in neurodegenerative diseases, targeting early-stage disease mechanisms before irreversible damage occurs, and aligns with increasing industry focus on disease-modifying therapies in Alzheimer’s rather than symptomatic treatment.
ACI-24 Shows Strong Immunogenicity and Safety Profile
ACI-24 is designed to induce a robust immune response against toxic Abeta species, which are widely believed to drive amyloid plaque formation and disease progression in Alzheimer’s. By promoting plaque clearance and inhibiting further accumulation in the brain, the therapy has the potential to slow or delay cognitive decline.
Data from earlier cohorts (AD1, AD2, and AD3, involving 74 patients) indicate that ACI-24 is generally safe and well tolerated, with consistent antibody responses observed across all dose levels. Importantly, no safety concerns have been identified following multiple Data Safety Monitoring Board (DSMB) reviews, strengthening confidence in the therapy’s clinical profile. The upcoming 12-month data readouts expected in Q2 2026 are anticipated to provide deeper insights into its clinical efficacy and durability of response.
ABATE Trial Expansion Strengthens Clinical Evidence Base
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The addition of Cohort AD4, initially enrolling 36 patients with extended treatment and follow-up periods, is expected to significantly enhance the clinical and biomarker dataset, with potential expansion to approximately 112 total participants. The ABATE study is a randomized, double-blind, placebo-controlled trial, ensuring rigorous evaluation of ACI-24’s impact on disease progression and underlying pathology.
Patients enrolled meet strict diagnostic criteria, including amyloid-positive PET scans, ensuring accurate targeting of the intended population. This expanded dataset will be critical in determining the therapy’s ability to deliver meaningful disease modification in early Alzheimer’s, a key challenge in current treatment development.
Strategic Partnership and Commercial Potential
AC Immune’s collaboration with Takeda further strengthens the program’s development pathway, with Takeda holding the option to take over late-stage development, regulatory activities, and global commercialization.
The agreement includes a $100 million upfront payment and potential milestone payments of up to $2.1 billion, along with tiered double-digit royalties on global sales, highlighting strong commercial confidence in ACI-24’s potential. This partnership structure allows AC Immune to advance its innovative immunotherapy pipeline while leveraging Takeda’s global capabilities to accelerate market access.
The continued advancement of ACI-24 reflects a broader industry shift toward targeting underlying disease biology in Alzheimer’s, particularly through immune-based approaches that address amyloid pathology early in disease progression. By combining strong safety data, robust immunogenicity, and strategic clinical expansion, AC Immune is positioning ACI-24 as a potential next-generation disease-modifying therapy in a field where effective long-term treatments remain limited.
Source: AC Immune press release
