AC Immune Expands Vaccine Candidate to Down Syndrome

Alzheimers concept

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Interim data from the Phase Ib/II ABATE trial showed AC Immune’s anti-amyloid-beta vaccine candidate ACI-24.060 could safely elicit an antibody response in patients with Alzheimer’s disease, the company announced Thursday.

As the second part of ABATE ensues, AC Immune is looking to enroll patients with Down Syndrome. The company has also begun the second, higher-dose Alzheimer’s cohort of the trial.

ABATE is a double-blinded, randomized and placebo-controlled study to assess the safety, tolerability, pharmacodynamic profile and immunogenicity of ACI-24.060.

The trial has two parts: the first includes patients with early Alzheimer’s or mild cognitive impairment due to Alzheimer’s, while the second will enroll patients with Down Syndrome, who are at a heightened risk of developing Alzheimer’s.

In a statement, Dr. Johannes Streffer, chief medical officer, AC Immune, said ABATE’s inclusion of Down Syndrome patients will enable the company to potentially address an unmet medical need of an underserved patient subpopulation, “virtually all of whom will develop amyloid plaques and AD.”

In May 2022, AC Immune demonstrated that its anti-amyloid-beta vaccine was likewise safe and immunogenic in Down Syndrome patients, eliciting an increase in IgG levels without triggering meningoencephalitis, death, imaging-related abnormalities or other serious side effects.

The study, published in JAMA Neurology, marked the first to investigate an anti-amyloid-beta vaccine for Down Syndrome patients.

Derived from the company's proprietary SupraAntigen design platform, ACI-24.060 is a candidate designed to promote the formation of broad-spectrum antibodies.

In turn, the investigational vaccine could potentially inhibit the formation of amyloid plaques and facilitate the clearance of these plaques when they arise. Clinically, ACI-24.060 could slow or outright prevent the progression of Alzheimer’s.

A Buzz Around Amyloid

Ever since Biogen and Eisai’s lecanemab significantly slowed Alzheimer’s progression in a Phase III study last September 2022, the biopharma industry has experienced renewed excitement about the prospects of an anti-amyloid therapeutic for Alzheimer’s disease.

The FDA greenlit lecanemab, now marketed as Leqembi, earlier this month under its accelerated approval pathway.

Close on Biogen and Eisai’s heels is Eli Lilly, whose investigational antibody donanemab outperformed Aduhelm (aducanumab), also developed by Biogen and Eisai, in the industry’s first active-comparator study in the Alzheimer’s space.

However, the FDA  denied donanemab accelerated approval last week, citing the need for more data and lack of efficacy.

Though the rejection might be disappointing to some, others experts believe the FDA made the right call.

While donanemab successfully cleared amyloid plaques from the patients’ brains, Sharon L. Rogers, CEO of AmyriAD and an Alzheimer’s expert, previously told BioSpace there is not enough evidence to connect that with cognitive improvements.

Future studies in the field will also need to demonstrate meaningful improvements in patient function and quality of life.

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