Corporate Presentation March 2024 1

Forward-Looking Statements 2 This presentation contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Any statement describing Acumen’s goals, expectations, financial or other projections, intentions or beliefs is a forward-looking statement and should be considered an at-risk statement. Words such as “believes,” “expects,” “anticipates,” “could,” “would,” “seeks,” “aims,” “plans,” “potential,” “will” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Forward-looking statements include statements concerning Acumen’s business, and Acumen’s ability to achieve its strategic and financial goals, including its projected use of cash, cash equivalents and marketable securities and the expected sufficiency of its cash resources into the first half of 2027, the therapeutic potential of Acumen’s product candidate, sabirnetug (ACU193), including against other antibodies, and the anticipated timeline for initiating a Phase 2 clinical trial of sabirnetug and a Phase 1 trial to support a subcutaneous dosing option of ACU 193. These statements are based upon the current beliefs and expectations of Acumen management, and are subject to certain factors, risks and uncertainties, particularly those inherent in the process of discovering, developing and commercializing safe and effective human therapeutics. Such risks may be amplified by the impacts of the COVID-19 pandemic. These and other risks concerning Acumen’s programs are described in additional detail in Acumen’s filings with the Securities and Exchange Commission (“SEC”), including in Acumen’s most recent Annual Report Form 10-K and future filings and reports by Acumen. Copies of these and other documents are available from Acumen. Additional information will be made available in other filings that Acumen makes from time to time with the SEC. These forward-looking statements speak only as of the date hereof, and Acumen expressly disclaims any obligation to update or revise any forward-looking statement, except as otherwise required by law, whether, as a result of new information, future events or otherwise. In this presentation, references to cash also include cash equivalents.

Positive Phase 1 clinical trial results presented in 2H 2023 3 Advancing a Potential Best-In-Class Antibody Targeting Toxic Amyloid Beta Oligomers (AβOs) for Early Alzheimer’s Disease (AD) Large market in need of additional treatment options Sabirnetug (ACU193): monoclonal antibody (mAb) highly selective for toxic AβOs Experienced leadership team with extensive AD drug development experience Strong balance sheet supporting clinical development plans for sabirnetug Expect to initiate Phase 2 (IV) and Phase 1 (subcutaneous) studies in 2024 $

Early AD Patient Population Represents Significant Market Opportunity 4 STAGES AND CHARACTERISTICS OF AD PROGRESSION Severe DementiaModerate DementiaMild Dementia Mild Cognitive Impairment (MCI) Preclinical AD ~5 Million1 ~2 Million1 Early Alzheimer’s Disease in the U.S. Acumen’s commercial priority Cognitive Decline Behavioral and Psychological Complications Functional Decline 1. 2021 Alzheimer's Association Uptake of first-generation, disease modifying, anti-amyloid beta treatment options is expected to increase, while significant unmet need and room for improvement will persist

AD, Amyloid & Abeta Oligomers

6 Amyloid Beta Oligomers (AβOs) in Alzheimer’s Disease Pathology

Amyloid Beta Oligomers (AβOs) are Widely Recognized as Highly Toxic Agents in AD Pathophysiology 7 1. Lacor et al., 2004 & 2007; Townsend et al., 2006; Batista et al., 2018 2. Cleary et al., 2005; Poling et al., 2008; Cline et al., 2019 3. De Felice et al., 2008; Zempel et al., 2010 • Impair synaptic function1 • Contribute to impairment of memory and cognition2 • Induce tau hyperphosphorylation3 Monomers Oligomers Protofibrils Fibrils Plaques Neurotoxic Soluble Amyloid Insoluble Amyloid Mature hippocampal neuron and toxic AβOs bound to dendritic spines Image Lacor et al., 2004.

8 AbOs May Consist of 2 to >200 Ab PeptidesWhat is an Aβ Oligomer? ____________________ Source: Kelley et al. J Chem Physics 2008. Figure 1. AbOs composed of 3 (a) and 18 (b) Ab peptides are depicted below. ____________________ Source: Relini et al. Biomolecules 2014. Figure 2. Atomic force microscopy images of representative steps of amyloid aggregation: (A) oligomers; (B) protofibrils; (C) mature fibrils. Scan size 1.0 µm. Z range (A) 8.0 nm; (B) 15 nm; (C) 20 nm. Quaternary structures of Aβ oligomers, protofibrils, and fibrils (a) (b)

Sabirnetug: Potential Best-in-Class Immunotherapy for Early AD Sabirnetug's High Selectivity for Toxic AβOs May Provide Meaningful Cognitive Efficacy and Improved Safety 9 Monomers Oligomers Protofibrils Fibrils Plaques Soluble Amyloid Insoluble Amyloid Humanized, affinity matured mAb developed to target toxic Aβ oligomers > 500-fold greater selectivity for AβOs over Aβ monomers > 85-fold greater selectivity for AβOs over Aβ fibrils IgG2 subclass mAb with reduced effector function Sabirnetug discovered in collaboration with Merck & Co. Acumen holds exclusive program rights with no future financial or other obligations due to Merck FDA Fast Track designation for the treatment of early Alzheimer’s disease FDA End of Phase 2 meeting in 4Q 2023 sabirnetug IgG2 Rationally Designed for Improved Efficacy & Safety Large Pharma Discovery Encouraging FDA Interactions

Sabirnetug: Value Proposition 10 The Alzheimer’s disease market is at a key inflection point with recent and expected approvals paving a new path for the treatment of AD … … and sabirnetug is well-positioned to emerge as a potential treatment of choice. Market will likely remain consolidated with Ab therapies emerging as the primary treatment option over the next few years Stakeholders are encouraged about the advancements in the AD treatment landscape and are working together to enable broader patient access With potential clinical and safety benefits conferred by AbO selectivity, sabirnetug has the opportunity to be a treatment of choice in the broader early AD population