Acumen Pharmaceuticals

Overview

Acumen Pharmaceuticals is a clinical-stage biopharmaceutical company focused on Alzheimer’s disease (AD). The company’s lead candidate, sabirnetug (ACU193), is an IgG2 monoclonal antibody designed to selectively bind soluble amyloid-β oligomers (AβOs) to neutralize their toxicity and slow disease progression in early AD. Key development programs include an AβO-targeted Enhanced Brain Delivery (EBD™) collaboration with JCR Pharmaceuticals and a subcutaneous formulation program with Halozyme. An IND for the EBD program is targeted for mid-2027.

Lead product candidate and clinical development

• Sabirnetug (ACU193)

  • Mechanism: Selectively binds soluble AβOs while avoiding binding to Aβ monomers and amyloid plaques.
  • Phase 1 (INTERCEPT-AD)
    • U.S.-based, multi-center study in early AD.
    • Enrolled 65 participants; 62 received at least one dose.
    • Evaluated safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and target engagement.
    • ARIA-E incidence 10.4%; ARIA-H 8.3%; one symptomatic ARIA-E (2.1%).
    • PET data showed dose-related reductions in amyloid plaque load; sabirnetug–AβO target engagement demonstrated; CSF biomarker changes observed (p-tau181, neurogranin, VAMP2).
    • Near-maximal target engagement observed at 25 mg/kg Q2W and 60 mg/kg Q4W.
  • Phase 2 (ALTITUDE-AD)
    • Randomized, double-blind, three-arm trial in 542 participants with mild cognitive impairment or mild dementia due to AD (up to 180 per arm).
    • Primary endpoint: Integrated Alzheimer’s Disease Rating Scale (iADRS) at 18 months.
    • Active doses: 35 mg/kg and 50 mg/kg IV every 4 weeks (with initial 35 mg/kg for the first two doses in the 50 mg/kg arm).
    • Enrollment completed March 2025; topline results expected in late 2026.
    • FDA Fast Track designation granted October 2022.

• Subcutaneous (SC) formulation option

  • Halozyme collaboration (non-exclusive) for ENHANZE® delivery technology to enable SC administration of sabirnetug.
  • Phase 1 study in healthy volunteers (16 subjects) evaluated four weekly SC doses of 1,200 mg and IV doses of 2,800 mg.
  • Injection-site reactions were common but mild; SC formulation produced systemic exposure suitable for further development.
  • Halozyme is the exclusive supplier of active ingredient for its PH20 product.

Collaborations, options and licenses

• JCR Pharmaceuticals (AβO-targeted EBD therapy)

  • Agreement reached July 2025 to develop an AβO-targeted EBD therapy for AD.
  • Acumen paid an upfront license; holds an exclusive option to develop up to two development candidates.
  • Option exercise payment: $9.25 million if exercised.
  • Milestones: up to $40.0 million in development milestones and up to $515.0 million in sales milestones (potential total up to $555.0 million), plus single-digit royalties on sales.
  • Goal: combine sabirnetug or other AβO-targeting antibodies with JCR’s J-Brain Cargo® BBB-penetrating technology to enhance brain delivery.

• Other collaborations and licenses

  • Merck (2003–2011): Acumen retained an exclusive, perpetual, irrevocable license to Merck’s sabirnetug-related patents after termination of the collaboration.
  • Northwestern University: License covering certain know-how; may require low single-digit royalties in the future.
  • Lonza (Nov 2, 2022): Worldwide non-exclusive license to use Lonza’s GS System for sabirnetug manufacturing; upfront payment of 1.0 million Swiss francs; ongoing royalties and annual country-by-country payments; term tied to first commercial sale in each country.
  • Halozyme (Nov 2023): Collaboration for SC delivery described above.
  • The JCR collaboration is intended to progress preclinical EBD candidates toward IND-enabling activities, targeting IND mid-2027.

Intellectual property

• Sabirnetug patent portfolio

  • Acquired exclusive rights from Merck covering sabirnetug composition and use.
  • As of March 27, 2025, Acumen licensed 1 issued U.S. patent and 18 issued foreign patents (including Brazil, China, Canada, Australia, Japan, South Korea, France, Germany, UK).
  • Patents are projected to expire in July 2031, exclusive of potential extensions.
  • Patent term extension may be available for one patent under applicable laws.

• Other IP and protections

  • Northwestern University license covers certain know-how with potential low single-digit royalties.
  • Trade secrets are protected through confidentiality agreements with employees, contractors, collaborators, and consultants.
  • The company manages ongoing patent prosecution and maintenance.

Manufacturing and supply

• Sabirnetug is manufactured by contract manufacturing organizations (CMOs); the company does not own manufacturing facilities.
• The Lonza GS System license provides a pathway to production; the Halozyme relationship supports the SC supply chain for PH20-enabled delivery devices.
• The company relies on third parties for scale-up, quality, supply continuity, and regulatory compliance (cGMPs).

Commercialization and market

• Sabirnetug has not been approved for commercial sale and has not generated product revenue to date.
• The company does not maintain an internal sales and marketing organization and intends to pursue partnerships with larger pharmaceutical companies for commercialization; it could build internal capabilities if required.
• Target population: patients with early AD (MCI or mild dementia due to AD with amyloid positivity).
• Reimbursement considerations include dependence on third-party payors and potential pricing and coverage pressures.

Financial position and capital needs

• Reported net losses: $121.3 million in 2025 and $102.3 million in 2024.
• Accumulated deficit: $446.5 million as of December 31, 2025.
• Cash and equivalents: $54.0 million; marketable securities: $62.9 million (as of December 31, 2025); total liquidity approximately $116.9 million.
• Runway: existing cash and marketable securities expected to fund operating expenses into early 2027.
• Debt and financing
  • November 2023: $30.0 million borrowed under a loan agreement with K2 HealthVentures LLC (K2HV); up to $20.0 million additional borrowing possible subject to lender approval.
  • Loan collateral: security interest in substantially all assets (excluding IP); the loan contains covenants and events of default that could restrict operations.
  • Interest rate: variable (the greater of 9.65% or prime + 1.15%).
  • The independent auditor’s report includes a note expressing substantial doubt about the company’s ability to continue as a going concern for at least 12 months post-issuance, based on recurring operating losses and the need for additional funding.
• Future funding needs will depend on ALTITUDE-AD results, the timing and size of clinical programs, regulatory pathways, manufacturing scale-up, potential collaborations, and ongoing R&D.

People and company information

• Employees: 61 total (60 full-time) as of March 25, 2026 — 40 in research and development; 21 in general and administrative functions.
• Incorporated in Delaware in 1996; principal offices in Newton, MA.

Summary

Acumen Pharmaceuticals is developing disease-modifying therapies for Alzheimer’s disease, with sabirnetug (ACU193) as its lead product candidate. Clinical data from Phase 1 show target engagement and biomarker signals, and the company is advancing a Phase 2 program (ALTITUDE-AD) with topline results expected in late 2026. Acumen is pursuing portfolio expansion through a BBB-penetrating EBD program with JCR and a subcutaneous administration pathway with Halozyme, supported by a set of collaboration and license agreements for development, manufacturing, and potential commercialization. The company continues to fund operations through cash, marketable securities, debt facilities, and potential future financings or partnerships.