Welcome to our dedicated page for Acumen Pharmaceuticals SEC filings (Ticker: ABOS), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
Acumen Pharmaceuticals, Inc. filings document a clinical-stage biopharmaceutical issuer focused on Alzheimer’s disease programs targeting toxic soluble amyloid beta oligomers. Its Form 8-K reports include operating and financial results, business highlights, Regulation FD presentation updates, clinical and nonclinical program disclosures, and material agreements related to Enhanced Brain Delivery development.
Proxy materials describe annual meeting voting matters, board elections, auditor ratification, and equity incentive plan approvals. The filing record also discloses ABOS common stock registered on the Nasdaq Global Select Market, emerging growth company status, governance changes, capital-structure matters, and clinical and regulatory disclosure categories tied to drug development.
Acumen Pharmaceuticals reported a larger full-year 2025 net loss while funding late-stage Alzheimer’s programs. For the year ended December 31, 2025, the company recorded a net loss of $121.3 million, compared with $102.3 million in 2024, driven mainly by higher research and development spending.
R&D expenses rose to $104.9 million from $93.8 million, reflecting manufacturing, clinical and Enhanced Brain Delivery (EBD™) research costs, while G&A expenses declined slightly to $18.9 million. Cash, cash equivalents and marketable securities totaled $116.9 million as of December 31, 2025, which management expects to fund current clinical and operational activities into early 2027. A $35.75 million private placement in March 2026 further supports development.
The company’s lead antibody sabirnetug (ACU193) is being tested in the Phase 2 ALTITUDE-AD trial in early Alzheimer’s disease, with topline results expected in late 2026. Acumen is also advancing an EBD program that showed markedly higher brain exposure in non-human primates, with an IND filing for a lead clinical candidate targeted for mid-2027.
Acumen Pharmaceuticals, Inc. reported that investment entities associated with RA Capital Management, L.P. acquired 6,060,606 shares of common stock at $3.30 per share in a grant or award transaction on March 16, 2026. The shares are held indirectly, including by RA Capital Healthcare Fund, L.P., with 19,103,785 shares reported as held following the transaction. Additional indirect holdings include 1,300,034 shares held by RA Capital Nexus Fund II, L.P. and 588,850 shares held in a separately managed account. The Adviser entities and managing members disclaim beneficial ownership beyond their respective pecuniary interests.
RA Capital Management and affiliates filed Amendment No. 4 to their Schedule 13D on Acumen Pharmaceuticals. They report beneficial ownership of 21,101,669 shares of common stock, or 29.5% of the company, including 19,103,785 shares held by RA Capital Healthcare Fund.
The filing reflects a March 2026 private placement in which Acumen sold 10,833,331 shares at $3.30 per share. RA Capital Healthcare Fund purchased 6,060,606 of those shares for total consideration of $19,999,999.80. Acumen agreed to register these PIPE shares for resale under a registration rights agreement.
Acumen Pharmaceuticals is raising about $35.75 million through a private placement of 10,833,331 common shares at $3.30 per share with institutional investors. The deal is expected to close on March 16, 2026, subject to customary conditions. The company plans to use the proceeds primarily to advance its Enhanced Brain Delivery (EBD™) program, including preclinical work to select a lead clinical candidate, and for working capital and general corporate purposes. Acumen also granted investors registration rights to resell the new shares after the company files and clears a resale registration statement.
Acumen Pharmaceuticals’ Chief Legal Officer Derek M. Meisner exercised employee stock options for 2,090 shares of common stock at $1.85 per share and sold the same 2,090 shares at $3.26 per share.
These transactions were carried out automatically under a pre-arranged Rule 10b5-1 trading plan adopted on March 29, 2025. After the sale, Meisner directly holds 173,999 shares of Acumen common stock, indicating this was a relatively small, routine liquidity event.
Acumen Pharmaceuticals reported a proposed sale of 2,090 common shares via a broker-assisted cashless exercise on 03/06/2026. The filing lists prior open-market sales by Derek Meisner across January–February 2026, including large blocks of 36,911 shares on 01/08/2026 and 15,085 shares on 01/26/2026.
Acumen Pharmaceuticals Chief Legal Officer Derek M. Meisner exercised employee stock options for 9,406 shares of common stock at a price of $1.85 per share and immediately sold 9,406 common shares in an open-market transaction at a weighted average price of $3.0099 per share. These sales occurred automatically under a Rule 10b5-1 trading plan adopted on March 29, 2025.
After these transactions, Meisner directly owned 173,999 shares of common stock and held 73,138 shares underlying employee stock options. The options vest in 48 equal monthly installments from the grant date, subject to continuous service.
Acumen Pharmaceuticals reported a Form 144 notice for the proposed sale of 9,406 shares of common stock on 02/27/2026. The filing identifies the sale method as a broker-assisted cashless exercise tied to employee stock options. The filing also lists multiple prior open-market dispositions by Derek Meisner during January 2026, with individual sales including 36,911 shares on 01/08/2026 and 15,085 shares on 01/26/2026.
Acumen Pharmaceuticals Chief Legal Officer Derek Meisner reported option exercises and related stock sales. On January 26 and 28, 2026, he exercised a total of 17,756 employee stock options at an exercise price of $1.85 per share, acquiring the same number of common shares.
On those same dates, he sold 17,756 common shares at weighted average prices of $3.0005 and $3.0016 per share under a pre-established Rule 10b5-1 trading plan. Following these transactions, he directly owned 173,999 common shares and retained vested and unvested stock options that vest in 48 equal monthly installments from the grant date.
Acumen Pharmaceuticals, Inc. insider plans to sell additional common stock under Rule 144. A notice covers the proposed sale of 2,671 shares of common stock through Merrill Lynch on 01/28/2026, with an aggregate market value of $8,017.29. The shares relate to an employee stock option exercise on the same date via a broker-assisted cashless transaction.
The filing also lists prior sales of Acumen Pharmaceuticals common stock by Derek Meisner over the past three months, including 4,000 shares for $7,838.00 on 01/05/2026 and 10,898 shares for $21,437.56 on 01/06/2026. Company shares outstanding are stated as 60,573,425, providing context for these transactions.