Acumen’s Alzheimer’s Candidate Enters Key Trial Phase, Targeting Toxic Brain Proteins

NEW YORK, NY – November 17, 2025 – Acumen Pharmaceuticals (NASDAQ: ABOS) has dosed the first participant in the open-label extension (OLE) portion of its Phase 2 ALTITUDE-AD trial, marking a significant step forward for its lead candidate, sabirnetug. The trial focuses on a distinctly different approach to Alzheimer’s disease treatment – targeting soluble amyloid beta oligomers (AβOs) believed to be key drivers of the disease.

A Novel Target in Alzheimer's Research

For decades, Alzheimer's research has largely centered around amyloid plaques – the dense, insoluble deposits in the brain linked to cognitive decline. However, an increasing body of evidence suggests that soluble amyloid beta oligomers – smaller, more mobile forms of the protein – are the primary neurotoxins. These oligomers disrupt communication between neurons, leading to synapse loss and ultimately, cognitive impairment.

“The conventional wisdom has been that plaques are the villains,” explained one industry analyst. “But the emerging view is that they're more of a consequence of the disease, while the soluble oligomers are the real instigators.”

Acumen’s sabirnetug is a humanized monoclonal antibody specifically designed to selectively target and neutralize these toxic AβOs. The ongoing Phase 2 ALTITUDE-AD trial, enrolling 542 participants with early Alzheimer’s, aims to demonstrate the efficacy and safety of this approach. The OLE allows all participants completing the initial 18-month placebo-controlled trial to receive sabirnetug for another 52 weeks, providing valuable long-term safety and efficacy data.

Financial Implications and Competitive Landscape

The initiation of the OLE is not only a scientific milestone but also a crucial step for Acumen’s financial stability. The company, which reported approximately $265.4 million in cash as of September 30, 2023, relies on positive clinical data to attract further investment and potentially secure partnerships with larger pharmaceutical companies.

“This extension provides a longer window for investors to assess the drug's impact and provides the company with more time to collect data,” said a financial analyst familiar with the biotech sector. “Positive results from this extension could significantly increase the company’s valuation.”

The Alzheimer’s drug market is intensely competitive, with recent approvals like lecanemab (Leqembi) and donanemab demonstrating the potential for amyloid-targeting therapies. However, Acumen differentiates itself by focusing on soluble oligomers, a strategy experts believe may offer a more targeted and potentially more effective approach. Several other companies are also exploring different mechanisms to address Alzheimer's, including therapies targeting tau protein, neuroinflammation, and synaptic health.

Patient Impact and Long-Term Prospects

The OLE offers hope to patients with early Alzheimer’s, providing them with continued access to a potentially disease-modifying therapy. The trial’s extended duration will allow researchers to assess the long-term effects of sabirnetug on cognitive function, daily living activities, and biomarkers of disease progression.

“For patients in the early stages of Alzheimer’s, even a modest slowing of disease progression can make a significant difference in their quality of life,” said a neurologist specializing in Alzheimer's research. “The opportunity to participate in a trial like this, and potentially receive a treatment that could help preserve their cognitive function, is incredibly valuable.”

Acumen anticipates reporting topline results from the full Phase 2 ALTITUDE-AD trial in late 2026. While the road to approval is long and challenging, the company’s unique approach and the promising early data suggest that sabirnetug could represent a new frontier in the fight against Alzheimer’s disease. The company's commitment to a selective approach toward the AβO target, along with the robust safety profile demonstrated in the Phase 1 INTERCEPT-AD trial, suggests potential for success. The trial indicated that ACU193 reduced amyloid plaque load significantly, indicating the potential for the drug to slow disease progression. As it moves into longer trials, the company is optimistic about its potential to bring much needed treatment to the millions affected by the disease.

The OLE phase will be critical to monitor the impact on patients and potentially prepare a submission for FDA approval, as well as demonstrate the safety and efficacy of a treatment that targets the disease at the earliest stages.