AC Immune SA announced the publication in JAMA Neurology1 of data showing that AC Immune's ACI-24 anti-Abeta vaccine was found to be safe and elicited immune response in a Phase 1b clinical trial in adults with DS. This is the first anti-Abeta vaccine study conducted with people living with DS. The landmark study was led by principal investigator Michael Rafii, MD, Ph.D., Professor of Neurology at Keck School of Medicine of the University of Southern California and Medical Director of the Alzheimer's Therapeutic Research Institute (ATRI).

The phase 1b multicenter, placebo-controlled clinical trial was a collaboration between AC Immune, the Alzheimer's Disease Cooperative Study (ADCS), and clinical investigators at Massachusetts General Hospital, Barrow Neurological Institute and University of California San Diego, with financial support from the National Institute on Aging, part of the National Institutes of Health, and the LuMind IDSC Down Syndrome Foundation. As presented in the JAMA Neurology article, the ACI-24 vaccine demonstrated immunogenicity along with pharmacodynamic and target engagement evidence as measured by a greater increase in plasma Abeta40 and Abeta42 in treated groups compared to placebo. Importantly, anti-Abeta antibody titers were not associated with any adverse findings.

An optimized formulation of ACI-24 has demonstrated strong immunogenicity, inducing a polyclonal response in non-human primates against Abeta and, importantly, high titers of antibodies targeting pyroGlutamate-Abeta (as published in Brain Communications). This neurotoxic species of Abeta found in amyloid plaques is a key driver of disease progression2. Additional data on the optimized formulation were presented at the AD/PD™ 2022, Alzheimer's & Parkinson's Diseases Conference held on March 15-20.