Acumen Pharmaceuticals, Inc.

Previous wording

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our unaudited condensed financial statements and related notes included elsewhere in this Quarterly Report on Form 10-Q and in the audited financial statements and notes thereto as of and for the year ended December 31, 2024 and the related Management’s Discussion and Analysis of Financial Condition and Results of Operations, included in our Annual Report. This discussion, particularly information with respect to our future results of operations or financial condition, business strategy and plans and objectives of management for future operations, includes forward-looking statements that involve risks and uncertainties as described under the heading “Special Note Regarding Forward-Looking Statements” in this Quarterly Report on Form 10-Q. You should review the disclosure under the heading “Risk Factors” in the Annual Report for a discussion of important factors that could cause our actual results to differ materially from those described in or implied by these forward-looking statements.

Current wording

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our unaudited condensed financial statements and related notes included elsewhere in this Quarterly Report on Form 10-Q and in the audited financial statements and notes thereto as of and for the year ended December 31, 2025 and the related Management’s Discussion and Analysis of Financial Condition and Results of Operations, included in our Annual Report. This discussion, particularly information with respect to our future results of operations or financial condition, business strategy and plans and objectives of management for future operations, includes forward-looking statements that involve risks and uncertainties as described under the heading “Special Note Regarding Forward-Looking Statements” in this Quarterly Report on Form 10-Q. You should review the disclosure under the heading “Risk Factors” in the Annual Report for a discussion of important factors that could cause our actual results to differ materially from those described in or implied by these forward-looking statements contained in the following discussion and analysis.

Previous wording

We are a clinical-stage biopharmaceutical company developing a novel disease-modifying approach to target what we believe to be a key underlying cause of Alzheimer’s disease, or AD. Alzheimer’s disease is a progressive neurodegenerative disease of the brain that leads to loss of memory and cognitive functions and ultimately results in death. Our scientific founders pioneered research on soluble amyloid-beta oligomers, or AßOs, which are globular assemblies of the amyloid-beta, or Aß, peptide that are distinct from Aß monomers and amyloid plaques. Based on decades of research and supporting evidence, AßOs have gained increasing scientific acceptance as a primary toxin involved in the initiation and propagation of AD pathology. We are currently focused on advancing a targeted immunotherapy drug candidate, sabirnetug, in our Phase 2 ALTITUDE-AD clinical trial. We completed enrollment in March 2025 and expect to announce top-line results for ALTITUDE-AD in late 2026. ALTITUDE-AD is a randomized, double-blind, placebo-controlled, three-arm clinical trial designed to evaluate the clinical efficacy, safety and tolerability of sabirnetug with up to 180 participants per arm for a total of 542 participants with mild cognitive impairment or mild dementia due to AD. We plan to use the Integrated Alzheimer’s Disease Rating Scale at 18 months as the primary outcome measure. The active doses for ALTITUDE-AD are 35 mg/kg and 50 mg/kg, dosed intravenously every four weeks. These dose levels and frequency were selected based on extensive pharmacokinetic and pharmacodynamic modeling of our Phase 1 INTERCEPT-AD clinical trial of sabirnetug. Sabirnetug is a recombinant humanized immunoglobulin gamma 2, or IgG2, monoclonal antibody, or mAb, that was designed to selectively target AßOs. In July 2023, we announced topline results from INTERCEPT-AD, which demonstrated that sabirnetug met the primary and secondary objectives of this clinical trial in 62 participants with early AD.

Current wording

We are a clinical-stage biopharmaceutical company developing a novel disease-modifying approach targeting what we believe to be a key underlying cause of Alzheimer’s disease, or AD. Alzheimer’s disease is a progressive neurodegenerative disease of the brain that leads to loss of memory and cognitive functions and ultimately results in death. Our scientific founders pioneered research on soluble amyloid-beta oligomers, or AßOs, which are globular assemblies of the amyloid-beta, or Aß, peptide that are distinct from Aß monomers and amyloid plaques. Based on decades of research and supporting evidence, AßOs have gained increasing scientific acceptance as a primary toxin involved in the initiation and propagation of AD pathology. We are currently focused on advancing a targeted immunotherapy drug candidate, sabirnetug, in our Phase 2 ALTITUDE-AD clinical trial. We plan to announce top-line results in late 2026. Top-line results are expected to include the difference after 18 months as measured by the Integrated Alzheimer’s Disease Rating Scale, or iADRS, our primary clinical efficacy endpoint, as well as key secondary endpoints, such as Clinical Dementia Rating – Sum of the Boxes, or CDR-SB, certain safety measures such as adverse event rates, including amyloid-related imaging abnormalities, or ARIA rates, and key biomarkers. ALTITUDE-AD is a randomized, double-blind, placebo-controlled, three-arm clinical trial designed to evaluate the clinical efficacy, safety and tolerability of sabirnetug with up to 180 participants per arm for a total of 542 participants with mild cognitive impairment or mild dementia due to AD. We plan to use iADRS at 18 months as the primary outcome measure. The active doses for ALTITUDE-AD are 35 mg/kg and 50 mg/kg, dosed intravenously every four weeks. These dose levels and frequency were selected based on extensive pharmacokinetic and pharmacodynamic modeling of our Phase 1 INTERCEPT-AD clinical trial of sabirnetug. Sabirnetug is a recombinant humanized immunoglobulin gamma 2, or IgG2, monoclonal antibody, or mAb, that was designed to selectively target AßOs. In July 2023, we announced top-line results from INTERCEPT-AD, which demonstrated that sabirnetug met the primary and secondary objectives of this clinical trial in 62 participants with early AD.

Previous wording

In July 2025, we entered into a collaboration, option and license agreement with JCR Pharmaceuticals Co. Ltd., or JCR, to develop an Aß oligomer-targeted EBDTM therapy for AD. Under the terms of the agreement, in addition to an upfront license payment that we paid to JCR, if we exercise our exclusive option to develop up to two development candidates, JCR will be eligible for an option exercise payment of $9.25 million. Our option can be exercised when there is a preclinical candidate data package, inclusive of a non-human primate study, which is expected in early 2026. JCR will also be eligible to receive future milestone payments of up to $40 million related to development, and up to $515 million related to sales, for a total of up to $555 million, as well as single-digit percentage royalties on sales of any products that emerge from the collaboration. The combination of sabirnetug or additional, novel, AβO-selective antibodies with JCR’s blood-brain barrier-penetrating technology, J-Brain Cargo®, strengthens Acumen’s portfolio of AβO-targeted therapies. The partnership is designed to advance potential next-generation treatment options for people living with AD, by targeting the development of products with enhanced efficacy, safety and convenience.

Current wording

In addition, we are investigating a blood-brain barrier-penetrating, Aß oligomer-targeted Enhanced Brain Delivery (EBD™) therapy for the treatment of AD. In March 2026, we announced certain preclinical data from EBD candidates, includingin vitro, in vivo and non-human primate study results, supporting the advancement of the EBD program: (1) EBD candidates achieved 14-40x higher brain levels in non-human primates compared to native antibodies 24 hours after dosing; (2) hematology data in non-human primates indicated low potential for anemia, including that, at 24 hours after subcutaneous dosing, EBD candidates demonstrated no observed change in red blood cell count, hematocrit, hemoglobin or reticulocyte count; and (3) favorable stability profile and enhanced brain delivery support a path to subcutaneous administration with low-volume devices. Based on this data, an investigational new drug, or IND, application is targeted for mid-2027. In July 2025, we entered into a collaboration, option and license agreement with JCR Pharmaceuticals Co. Ltd., or JCR, to develop an Aß oligomer-targeted EBD therapy for the treatment of AD. Under the terms of the agreement, in addition to an upfront license payment that we paid to JCR, if we exercise our exclusive option to develop up to two development candidates, JCR will be eligible for an option exercise payment of $9.25 million. We currently anticipate that we will exercise our option to license two compounds developed as part of our collaboration with JCR during the second quarter of 2026. JCR will also be eligible to receive future milestone payments of up to $40.0 million related to development, and up to $515.0 million related to sales, for a total of up to $555.0 million, as well as single-digit percentage royalties on sales of any products that emerge from the collaboration. The combination of sabirnetug or additional, novel, AβO-selective antibodies with JCR’s blood-brain barrier-penetrating technology, J-Brain Cargo®, strengthens Acumen’s portfolio of AβO-targeted therapies. The partnership is designed to advance potential next-generation treatment options for people living with AD, by targeting the development of products with enhanced efficacy, safety and convenience.

Previous wording

During the nine months ended September 30, 2025, no shares of common stock were issued under our at-the-market offering program, or the ATM. In January 2024, we issued 2,068,246 shares of our common stock under the ATM, for net proceeds of $7.9 million, or $3.84 per share.

Current wording

During the three months ended March 31, 2026 and 2025, no shares of our common stock were issued under our at-the-market offering program, or the ATM. Since inception, we have issued 2,068,246 shares of our common stock under the ATM, for net proceeds of $7.9 million, or $3.84 per share.

Previous wording

We have incurred net losses and negative cash flows from operations since our inception. Our net losses were $96.2 million and $65.2 million for the nine months ended September 30, 2025 and 2024, respectively. Approximately $84.4 million, or 88%, of the net loss for the nine months ended September 30, 2025 was due to research and development spending. As of September 30, 2025, we had an accumulated deficit of $421.3 million. Our net losses and cash flows from operations may fluctuate significantly from quarter-to-quarter and year-to-year, depending on the timing of nonclinical studies, clinical trials and our expenditures on other research and development activities. We expect our expenses and operating losses will increase substantially for the foreseeable future as we advance sabirnetug in clinical development, seek to expand our product candidate portfolio through developing additional product candidates, and incur additional costs associated with operating as a public company. It is likely that we will seek third-party collaborators for the future commercialization of sabirnetug or any other product candidate that is approved for marketing. Should we seek to commercialize our products at our own expense, we would incur significant additional expenses for marketing, sales, manufacturing and distribution. We will not generate revenue from product sales unless and until we successfully complete clinical development and obtain regulatory approval for our product candidates.

Current wording

We have incurred net losses and negative cash flows from operations since our inception. Our net losses were $20.7 million and $28.8 million for the three months ended March 31, 2026 and 2025, respectively. Approximately $16.5 million, or 79%, of the net loss for the three months ended March 31, 2026 was due to research and development spending. As of March 31, 2026, we had an accumulated deficit of $467.2 million and cash and cash equivalents and marketable securities of $128.4 million. We expect our expenses and operating losses will increase substantially for the foreseeable future as we advance sabirnetug in clinical development, seek to expand our product candidate portfolio through developing additional product candidates, and incur additional costs associated with operating as a public company. It is likely that we will seek third-party collaborators for the future commercialization of sabirnetug or any other product candidate that is approved for marketing. Should we seek to commercialize our products at our own expense, we would incur significant additional expenses for marketing, sales, manufacturing and distribution. We will not generate revenue from product sales unless and until we successfully complete clinical development and obtain regulatory approval for our product candidates.

Previous wording

As a result, we will need substantial additional funding to support our continuing operations and pursue our growth strategy. Until we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of public or private equity offerings and debt financings or other sources, such as potential collaboration agreements, strategic alliances and licensing arrangements. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed on acceptable terms, or at all. In addition, global economic conditions may impact our ability to raise additional funds, and we may be impacted by disruptions to, and volatility in, the credit and financial markets in the United States and worldwide, tariff policy and geopolitical tensions between the United States and foreign countries, rising inflation and supply disruptions, the ongoing conflicts between Russia and Ukraine and Israel and Hamas and related sanctions, and otherwise. If these conditions persist and deepen, we could experience an inability to access additional capital, or our liquidity could otherwise be impacted. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs and/or future commercialization efforts. Our failure to raise capital or enter into such agreements as and when needed could have a material adverse effect on our business, results of operations and financial condition.

Current wording

As a result, we will need substantial additional funding to support our continuing operations and pursue our growth strategy. Until we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of public or private equity offerings and debt financings or other sources, such as potential collaboration agreements, strategic alliances and licensing arrangements. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed on acceptable terms, or at all. In addition, global economic conditions may impact our ability to raise additional funds, and we may be impacted by disruptions to, and volatility in, the credit and financial markets in the United States and worldwide, tariff policy and geopolitical tensions between the United States and foreign countries, rising inflation and supply disruptions, the ongoing conflicts between Russia and Ukraine, the recent military actions involving Iran, and the Israel-Hamas war and related sanctions, and otherwise. If these conditions persist and deepen, we could experience an inability to access additional capital, or our liquidity could otherwise be impacted. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs and/or future commercialization efforts. Our failure to raise capital or enter into such agreements as and when needed could have a material adverse effect on our business, results of operations and financial condition.

Previous wording

As we currently only have one product candidate, sabirnetug, in clinical development, we do not separately track expenses by program. Further, we have historically relied primarily on consultants for research and development activities; our internal research and development personnel costs currently represent approximately 15% of our total research and development expenses. Our research and development expenses increased substantially since initiating the clinical trial program for sabirnetug in 2021. We expect that our research and development expenses will continue to increase substantially in connection with our continued clinical development activities for sabirnetug.

Current wording

As we currently only have one product candidate, sabirnetug, in clinical development, we do not separately track expenses by program. Further, we have historically relied primarily on consultants for research and development activities; our internal research and development personnel costs currently represent approximately 28% of our total research and development expenses. Our research and development expenses increased substantially since initiating the clinical trial program for sabirnetug in 2021. We expect that our research and development expenses will continue to increase substantially in connection with our continued clinical development activities for sabirnetug.

Previous wording

Research and development expenses were $22.0 million and $27.2 million for the three months ended September 30, 2025 and 2024, respectively. The $5.2 million decrease was primarily due to a reduction of $4.4 million for CRO costs associated with the ALTITUDE-AD clinical trial, for which we completed enrollment in March 2025 following dosing of the first patient in May 2024. Additionally, we incurred reduced expenses of $2.5 million for license agreements and $0.6 million related to services provided by research and development consultants and contractors. Partially offsetting these decreased expenses were increases of $1.0 million for manufacturing and materials costs associated with our ALTITUDE-AD clinical trial, $0.7 million for other clinical trial expenses and $0.6 million for personnel-related costs.

Current wording

Research and development expenses were $16.5 million and $25.3 million for the three months ended March 31, 2026 and 2025, respectively. The $8.8 million decrease was primarily due to reductions of $6.7 million for manufacturing and materials costs and $3.4 million for CRO costs, which are both associated with our ALTITUDE-AD clinical trial. Partially offsetting these decreased expenses were increases of $1.0 million for other clinical trial expenses and $0.3 million for personnel-related costs.

Previous wording

General and administrative expenses were $14.3 million and $15.2 million for the nine months ended September 30, 2025 and 2024, respectively. The $0.9 million decrease was primarily due to reductions in recruiting expenses of $0.3 million, insurance expenses of $0.3 million, audit and other accounting services expenses of $0.2 million and $0.1 million for legal fees.

Current wording

General and administrative expenses were $4.7 million and $5.1 million for the three months ended March 31, 2026 and 2025, respectively. The $0.4 million decrease was primarily due to reductions in legal fees of $0.3 million, audit and other accounting services expenses of $0.1 million, consulting expenses of $0.1 million and insurance expenses of $0.1 million, partially offset by an increase for personnel-related costs of $0.2 million.

Previous wording

Other income was $0.1 million and $2.5 million for the three months ended September 30, 2025 and 2024, respectively. The $2.4 million decrease was primarily attributable to a $1.9 million decrease in interest income on our portfolio of marketable securities due primarily to a lower average investment balance during the three months ended September 30, 2025 with the utilization of cash from investment maturities supporting our ongoing operating cash needs. Additionally, there were increased expenses associated with the change in fair value of our embedded derivatives related to our Loan Agreement of $0.4 million and other expense, net of $0.1 million.

Current wording

Other income was $0.4 million and $1.6 million for the three months ended March 31, 2026 and 2025, respectively. The $1.2 million decrease was primarily attributable to a $1.4 million decrease in interest income on our portfolio of marketable securities due primarily to a lower average investment balance during the three months ended March 31, 2026, with the utilization of cash from investment maturities supporting our ongoing operating cash needs. Additionally, there was a $0.1 million increase in interest expense. Offsetting these items was the increased income recognized with the change in fair value of our embedded derivatives related to our Loan Agreement of $0.3 million.

Previous wording

Our operations have been financed primarily by net proceeds from the sale and issuance of our common stock and convertible preferred stock, net proceeds from our initial and subsequent public offering and from sales of shares of our common stock under our ATM, borrowings under the Loan Agreement, the issuance of notes, grant revenue and, during our collaboration with Merck, which was in place from 2003 to 2011, certain payments received under our collaboration agreement.

Current wording

Our operations have been financed primarily by net proceeds from the sale and issuance of our common stock and convertible preferred stock, net proceeds from our initial and subsequent public offering, the Private Placement and from sales of shares of our common stock under our ATM, borrowings under the Loan Agreement, the issuance of notes, grant revenue and, during our collaboration with Merck, which was in place from 2003 to 2011, certain payments received under our collaboration agreement.

Previous wording

On March 27, 2024, we filed a shelf registration statement on Form S-3, or the 2024 Registration Statement. Pursuant to the 2024 Registration Statement, we may offer and sell securities having an aggregate public offering price of up to $200.0 million.

Current wording

On March 27, 2024, we filed a shelf registration statement on Form S-3, or the 2024 Registration Statement. Pursuant to the 2024 Registration Statement, we may offer and sell securities having an aggregate public offering price of up to $200.0 million. On November 13, 2025, we filed a prospectus supplement to the 2024 Registration Statement with respect to our ATM, designating up to $50.0 million of the $200.0 million of securities that may be offered pursuant to the 2024 Registration Statement for issuance under the ATM.

Previous wording

During the nine months ended September 30, 2025, no shares of common stock were issued under our ATM. In January 2024, we issued 2,068,246 shares of common stock under the ATM for net proceeds of $7.9 million, or $3.84 per share.

Current wording

During the three months ended March 31, 2026 and 2025, no shares of common stock were issued under our ATM. We have issued shares of common stock for aggregate gross proceeds of $12.2 million under the ATM since the program’s inception.

Previous wording

Net cash used in operating activities increased by $37.4 million to $96.4 million for the nine months ended September 30, 2025 from $59.0 million for the nine months ended September 30, 2024. The $31.0 million increase in net loss for the nine months ended September 30, 2025, adjusted for a decrease in noncash income for amortization and accretion on marketable securities of $3.7 million and a decrease in the change in fair value of embedded derivatives of $1.3 million accounted for a $26.0 million increase in cash used in operating activities as compared to the nine months ended September 30, 2024. Working capital changes contributed $11.5 million of additional cash used in operations, including increases in cash used for accounts payable and accrued clinical trial expenses of $5.9 million and $13.6 million, respectively, which were partially offset by cash provided from prepaid expenses and other current assets of $5.4 million and $2.6 million from accrued expenses and other liabilities.

Current wording

Thedecrease in net cash used in operations of $10.0 million to $24.1 million for the three months ended March 31, 2026, from $34.1 million for the three months ended March 31, 2025, is primarily attributable to a decrease in net loss for the three months ended March 31, 2026 of$8.1 million, an increase in noncash adjustments of $0.3 million and working capital changes of $1.6 million. Significant noncash items consisted of a decrease in noncash income for amortization and accretion on marketable securities of $0.6 million and the change in fair value of embedded derivatives of $0.3 million. Working capital changes contributed $1.6 million to the reduction in cash used in operations, including decreases in cash used for accounts payable and accrued clinical trial expenses of $5.6 million and $1.4 million, respectively, which were partially offset by an increase in cash used for accrued expenses and other liabilities of $5.1 million and a decrease in cash provided by prepaid expenses and other current assets of $0.3 million.

Previous wording

Cash provided by investing activities during the nine months ended September 30, 2025 of $107.7 million increasedby $89.3 million from cash provided by investing activities of $18.4 million during the nine months ended September 30, 2024, primarily due to a decrease in purchases of marketable securities of $117.6 million, which was partially offset by a decrease in proceeds from maturities and sales of marketable securities of $28.2 million and a $0.1 million increase in purchases of property and equipment.

Current wording

Net cash used in investing activities increased by $42.5 million to$13.8 million for thethree months ended March 31, 2026 from cash provided by investing activities of $28.7 million for the three months ended March 31, 2025. This increase was primarily due to a decrease in proceeds from maturities and sales of marketable securities of $36.8 million, and an increase in purchases of marketable securities of $5.8 million, partially offset by a $0.1 million decrease in purchases of property and equipment.

Previous wording

Based on our current operating plan, we believe that our existing cash and cash equivalents and marketable securities will be sufficient to enable us to fund our operating expenses and capital expenditure requirements into early 2027. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect, including based on our decision to initiate other clinical trials or programs. In addition, changing circumstances may cause us to increase our spending significantly faster than we currently anticipate, and we may need to spend more money than currently expected because of circumstances beyond our control. We may need to raise additional funds sooner than anticipated if we choose to expand more rapidly than we presently anticipate.

Current wording

Based on our current operating plan, we believe there is substantial doubt about our ability to continue as a going concern for at least 12 months following the date of issuance of our unaudited condensed financial statements included in this Quarterly Report on Form 10-Q. We could exhaust our available capital resources sooner than we expect, including if we decide to initiate other clinical trials or programs. In addition, changing circumstances may cause us to increase our spending significantly faster than we currently anticipate, and we may need to spend more money than currently expected because of circumstances beyond our control. We may need to raise additional funds sooner than anticipated if we choose to expand more rapidly than we presently anticipate.

Previous wording

•our progress and success in investigating Enhanced Brain Delivery, or EBDTM, therapy for AD;

Current wording

•our progress and success in investigating EBD therapy for AD;

Previous wording

We are also a “smaller reporting company,” meaning that the market value of our shares held by non-affiliates is less than $700 million and our annual revenue was less than $100 million during the most recently completed fiscal year. We may continue to be a smaller reporting company if either (i) the market value of our shares held by non-affiliates is less than $250 million or (ii) our annual revenue was less than $100 million during the most recently completed fiscal year and the market value of our shares held by non-affiliates is less than $700 million. If we are a smaller reporting company at the time we cease to be an emerging growth company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company, we may choose to present only the two most recent fiscal years of audited financial statements in our Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation.

Current wording

We are also a “smaller reporting company,” meaning that the market value of our shares held by non-affiliates is less than $700 million and our annual revenue was less than $100 million during the most recently completed fiscal year. We may continue to be a smaller reporting company if either (i) the market value of our shares held by non-affiliates is less than $250 million or (ii) our annual revenue is less than $100 million during the most recently completed fiscal year and the market value of our shares held by non-affiliates is less than $700 million. If we are a smaller reporting company at the time we cease to be an emerging growth company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company, we may choose to present only the two most recent fiscal years of audited financial statements in our Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation.