Acumen Pharmaceuticals, Inc.

Previous 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.

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 AβOs, which are globular assemblies of the amyloid-beta, or Aβ, peptide that are distinct from Aβ monomers and amyloid plaques. Based on decades of research and supporting evidence, AβOs 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 compared to placebo 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 AβOs. 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 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.

Current wording

In addition, we are investigating a blood-brain barrier-penetrating, Aβ 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. Following this robust preclinical data from bothin vitro andin vivo studies, in June 2026 we announced the nomination of two EBD development candidates, ACU301 and ACU401. Based on these developments, an investigational new drug, or IND, application for the lead candidate is targeted for mid-2027. This stems from our July 2025 entry into a collaboration, option and license agreement with JCR Pharmaceuticals Co. Ltd., or JCR, to develop an Aβ oligomer-targeted EBD therapy for the treatment of AD. Under the terms of the agreement, during the year ended December 31, 2025, we made an upfront license payment to JCR and, in June 2026, we exercised our exclusive option to develop two EBD development candidates, which required an option exercise payment of $9.25 million that was paid to JCR in July 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

On March 13, 2026, we entered into a securities purchase agreement with certain institutional and accredited investors for a private placement, or the Private Placement, of 10,833,331 shares of our common stock, at an offering price of $3.30 per share. The Private Placement closed on March 16, 2026, for aggregate gross proceeds of approximately $35.7 million, before deducting offering costs of approximately $0.3 million. We intend to use the net proceeds from the Private Placement to primarily support our EBD program, including ongoing preclinical development work to support the nomination of a lead clinical candidate molecule, and for working capital and other general corporate purposes.

Current wording

On March 13, 2026, we entered into a securities purchase agreement with certain institutional and accredited investors for a private placement, or the Private Placement, of 10,833,331 shares of our common stock, at an offering price of $3.30 per share. The Private Placement closed on March 16, 2026, for aggregate gross proceeds of approximately $35.7 million, before deducting offering costs of approximately $0.3 million. We intend to continue to use the net proceeds from the Private Placement to primarily support our EBD program, including ongoing preclinical development work to support the nomination of a lead clinical candidate molecule, and for working capital and other general corporate purposes.

Previous 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.

Current wording

During the six months ended June 30, 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 $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.

Current wording

We have incurred net losses and negative cash flows from operations since our inception. Our net losses were $53.5 million and $69.7 million for the six months ended June 30, 2026 and 2025, respectively. Approximately $44.3 million, or 83%, of the net loss for the six months ended June 30, 2026 was due to research and development spending. As of June 30, 2026, we had an accumulated deficit of $499.9 million and cash and cash equivalents and marketable securities of $110.2 million. We expect our expenses and operating losses will increase substantially for the foreseeable future as we continue clinical development activities for sabirnetug, advance our EBD program, seek to expand our product candidate portfolio through developing additional product candidates, and incur ongoing 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 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.

Current wording

We do not separately track expenses by program as we currently have only one clinical-stage product candidate, sabirnetug, and our pre-clinical EBD development candidates, all of which are focused on the research and development of treatments for AD. Further, we have historically relied primarily on consultants for research and development activities; our internal research and development personnel costs currently represent approximately 21% 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 increase substantially in connection with our continued clinical development activities for sabirnetug and the advancement of our EBD program.

Previous 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.

Current wording

Research and development expenses were $27.8 million and $37.1 million for the three months ended June 30, 2026 and 2025, respectively. The $9.3 million decrease was primarily due to reductions of $15.2 million for manufacturing and materials costs and $3.3 million for CRO costs, which are both associated with our ALTITUDE-AD clinical trial. Additionally, we realized a decrease of $0.4 million for other research and development expenses. Partially offsetting the decreased expenses were increases of $9.3 million for license agreement expenses related to the option exercise payment owed to JCR for our exclusive option to license and develop two EBD development candidates and $0.3 million for other clinical trial expenses.

Previous 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.

Current wording

General and administrative expenses were $9.4 million and $9.7 million for the six months ended June 30, 2026 and 2025, respectively. The $0.3 million decrease was primarily due to reductions in consulting expenses of $0.2 million, insurance expenses of $0.2 million, audit and other accounting services expenses of $0.1 million, and $0.1 million for legal fees, partially offset by an increase in personnel costs of approximately $0.3 million.

Previous 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.

Current wording

Other income was $0.3 million and $2.4 million for the six months ended June 30, 2026 and 2025, respectively. The $2.1 million decrease was primarily attributable to a $2.3 million decrease in interest income on our portfolio of marketable securities due primarily to a lower average investment balance during the six months ended June 30, 2026 with the utilization of cash from investment maturities supporting our ongoing operating cash needs. This decrease was partially offset by increased income of $0.2 million associated with the change in fair value of our embedded derivatives related to the Loan Agreement.

Previous 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.

Current wording

During the six months ended June 30, 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

As of March 31, 2026, we had cash and cash equivalents andmarketable securities totaling $128.4 million. Ouravailable-for-sale marketable securities mature in less than one year. We could exhaust our available capital resources sooner than we expect, including if we decide to initiate other clinical trials or programs. We evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern. Based on our current operating plan, we do not expect the current balance of our cash and cash equivalents and marketable securities will be sufficient to fund our operations for at least 12 months from the date of issuance of our unaudited condensed financial statements included in this Quarterly Report on Form 10-Q. The current balance of our cash and cash equivalents and marketable securities is expected to fund our operations into early 2027. Accordingly, management has concluded that substantial doubt exists regarding our ability to continue as a going concern.

Current wording

As of June 30, 2026, we had cash and cash equivalents andmarketable securities totaling $110.2 million. Ouravailable-for-sale marketable securities mature in less than one year. We could exhaust our available capital resources sooner than we expect, including if we decide to initiate other clinical trials or programs. We evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern. Based on our current operating plan, we do not expect the current balance of our cash and cash equivalents and marketable securities will be sufficient to fund our operations for at least 12 months from the date of issuance of our unaudited condensed financial statements included in this Quarterly Report on Form 10-Q. The current balance of our cash and cash equivalents and marketable securities is expected to fund our operations into early 2027. Accordingly, management has concluded that substantial doubt exists regarding our ability to continue as a going concern.

Previous 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.

Current wording

Thedecrease in net cash used in operations of $23.8 million to $42.2 million for the six months ended June 30, 2026, from $66.0 million for the six months ended June 30, 2025, is primarily attributable to a decrease in net loss for the six months ended June 30, 2026 of $16.3 million, an increase in noncash adjustments of $0.4 million and working capital changes of $7.1 million. Significant noncash items consisted of a decrease in noncash income for amortization and accretion on marketable securities of $0.5 million and the change in fair value of embedded derivatives of $0.2 million. Working capital changes contributed $7.1 million to the reduction in cash used in operations, including a decrease in cash used for accounts payable of $16.4 million, which was partially offset by an increase in cash used for accrued expenses and other liabilities of $7.5 million, a decrease in cash provided by prepaid expenses and other current assets of $1.6 million and an increase in cash used for accrued clinical trial expenses of $0.1 million.

Previous 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.

Current wording

Net cash provided by investing activities decreasedby $55.0 million to$12.2 million for thesix months ended June 30, 2026 from $67.2 million for the six months ended June 30, 2025. This decrease was primarily due to a decrease in proceeds from maturities and sales of marketable securities of $52.3 million and an increase in purchases of marketable securities of $2.8 million, partially offset by a $0.1 million decrease in purchases of property and equipment.

Previous wording

Net cash provided by financing activities during the three months ended March 31, 2026 increased by $35.8 million from net cash used in financing activities of less than $0.1 million during the three months ended March 31, 2025. Cash provided by financing activities during the three months ended March 31, 2026 was primarily due to net proceeds of $35.7 million from the issuance of common stock in connection with the Private Placement and $0.1 million from the exercise of stock options, which was partially offset by $0.1 million paid for employee withholding taxes resulting from the repurchase of common shares following the vesting of RSUs.

Current wording

Net cash provided by financing activities during the six months ended June 30, 2026 increased to $35.5 million from net cash used in financing activities of less than $0.1 million during the six months ended June 30, 2025. Cash provided by financing activities during the six months ended June 30, 2026 was primarily due to net proceeds of $35.4 million from the issuance of common stock in connection with the Private Placement and an increase of $0.1 million from the exercise of stock options, which were partially offset by an increase of $0.1 million paid for employee withholding taxes resulting from the repurchase of common shares following the vesting of RSUs.

Previous wording

Additional funding may not be available to us on acceptable terms or at all. Any such funding may result in dilution to stockholders, imposition of debt covenants and repayment obligations or other restrictions that may affect our business. We also could be required to seek funds through arrangements with collaborative partners or otherwise that may require us to relinquish rights to some of our technologies or product candidates or otherwise agree to terms unfavorable to us. Any funds we raise may not be sufficient to enable us to continue to implement our long-term business strategy. Further, our ability to raise additional capital may be adversely impacted by global economic conditions and the recent disruptions to and volatility in the credit and financial markets in the United States and worldwide, as well as tariff policy and geopolitical tensions between the United States and foreign countries. Additionally, escalation in interest rates, in conjunction with banking failures, may lead to financial institutions being more prudent with capital deployment and tightening lending. If we are unable to raise sufficient additional capital on a timely basis, we could be forced to curtail our planned operations and the pursuit of our business strategy, which would have a material adverse effect on the value of our common stock.

Current wording

Additional funding may not be available to us on acceptable terms or at all. Any such funding may result in dilution to stockholders, imposition of debt covenants and repayment obligations or other restrictions that may affect our business. We also could be required to seek funds through arrangements with collaborative partners or otherwise that may require us to relinquish rights to some of our technologies or product candidates or otherwise agree to terms unfavorable to us. Any funds we raise may not be sufficient to enable us to continue to implement our long-term business strategy. Further, our ability to raise additional capital may be adversely impacted by global economic conditions and the recent disruptions to and volatility in the credit and financial markets in the United States and worldwide, as well as tariff policy and geopolitical tensions between the United States and foreign countries. Additionally, escalation in interest rates may lead financial institutions to become more selective with capital deployment and to tighten lending practices. If we are unable to raise sufficient additional capital on a timely basis, we could be forced to curtail our planned operations and the pursuit of our business strategy, which would have a material adverse effect on the value of our common stock.