AC Immune SA announced the first interim safety, tolerability and immunogenicity findings from the Phase 1b/2 ABATE trial of its anti-amyloid-beta (Abeta) vaccine ACI-24.060 in patients with prodromal Alzheimer's disease (AD). ABATE will now be expanded, as planned, to include individuals with Down syndrome (DS) and to evaluate higher doses in Alzheimer's patients. Targeting Abeta using antibodies has recently been validated with FDA approvals of new monoclonal antibody treatments for patients with AD.

By eliciting polyclonal anti-Abeta antibodies, the ACI-24.060 anti-Abeta vaccine development program aims to ultimately deliver significant benefits to patients, their caregivers, and healthcare systems in terms of potential safety and tolerability, low frequency dosing, low overall costs and durable responses. Early results from the first cohort of AD patients in ABATE showed that low dose ACI-24.060 could elicit an anti-Abeta antibody response as soon as week 6 (2 weeks after the second injection). The data show that ACI-24.060 vaccination has been safe and well tolerated to date.

As a result, dosing in ABATE's second, higher dose AD cohort has now begun and the trial is cleared to begin screening individuals with DS for part 2 of the study. The ABATE study is a Phase 1b/2, multicenter, adaptive, double-blind, randomized, placebo-controlled study to assess the safety, tolerability, immunogenicity, and pharmacodynamic effects of ACI-24.060 in subjects with prodromal Alzheimer's disease and in adults with Down syndrome. All participants in the trial must have brain Abeta pathology confirmed by a positron emission tomography (PET) scan.

The trial begins with a dose escalation phase in AD patients, during which various doses/dosing regimens may be evaluated, and also includes individuals with DS. ACI-24.060, derived from AC Immune's SupraAntigen® platform, has been shown in preclinical studies to induce a strong polyclonal antibody response that matures and is maintained against both oligomeric and pyroglutamate-Abeta species, key pathological forms of Abeta believed to drive Abeta plaque formation and disease progression. ACI-24.060 is designed to enhance the formation of broad-spectrum protective antibodies with the same safety and tolerability previously demonstrated in the ACI-24 program in Phase 1 and 2 trials.

This investigational candidate has the potential to efficiently inhibit plaque formation and increase plaque clearance, and thereby may reduce or prevent disease progression.