Acumen Pharmaceuticals, Inc.

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 following Phase 1 results in “early AD” patients (patients with mild cognitive impairment or mild dementia due to AD) that were reported in July 2023. Sabirnetug is a recombinant humanized immunoglobulin gamma 2, or IgG2, monoclonal antibody, or mAb, that was designed to selectively target AßOs.

Current 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 following Phase 1 results in “early AD” patients (patients with mild cognitive impairment or mild dementia due to AD) that were reported in July 2023. Sabirnetug is a recombinant humanized immunoglobulin gamma 2, or IgG2, monoclonal antibody, or mAb, that was designed to selectively target AßOs. In addition, we are investigating a subcutaneous dosing option of sabirnetug, as well as a blood-brain barrier-penetrating, oligomer-targeted Enhanced Brain Delivery (EBDTM) therapy for AD.

Previous wording

We announced the results of a Phase 1 clinical trial investigating a subcutaneous dosing option of sabirnetug in March 2025. This study in healthy volunteers enrolled 16 subjects who received four weekly subcutaneous doses of 1,200 mg of sabirnetug and 12 subjects who received single intravenous doses of 2,800 mg of sabirnetug. The most frequently reported adverse events included injection site reactions (62.5%), all of which were mild (Grade 1) in severity and resolved. No other safety issues were identified. Additionally, subcutaneous administration of sabirnetug was shown to produce sufficient systemic exposure to support further development of this formulation as a more convenient administration option for patients.

Current wording

We announced the results of a Phase 1 clinical trial investigating a subcutaneous dosing option of sabirnetug in March 2025. This study in healthy volunteers enrolled 16 subjects who received four weekly subcutaneous doses of 1,200 mg of sabirnetug and 12 subjects who received a single intravenous dose of 2,800 mg of sabirnetug. The most frequently reported adverse events included injection site reactions (62.5%), all of which were mild (Grade 1) in severity and resolved. No other safety issues were identified. Additionally, subcutaneous administration of sabirnetug was shown to produce sufficient systemic exposure to support further development of this formulation as a more convenient administration option for patients.

Previous wording

During the three months ended March 31, 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 six months ended June 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.

Previous wording

We have incurred net losses and negative cash flows from operations since our inception. Our net losses were $28.8 million and $14.9 million for the three months ended March 31, 2025 and 2024, respectively. Approximately $25.3 million, or 88%, of the net loss for the three months ended March 31, 2025 was due to research and development spending. As of March 31, 2025, we had an accumulated deficit of $353.9 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 $69.7 million and $35.4 million for the six months ended June 30, 2025 and 2024, respectively. Approximately $62.4 million, or 89%, of the net loss for the six months ended June 30, 2025 was due to research and development spending. As of June 30, 2025, we had an accumulated deficit of $394.9 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.

Previous wording

As of March 31, 2025, we had cash and cash equivalents andmarketable securities of $197.9 million; included in this amount is the first tranche of $30.0 million that we received under our Loan Agreement, which was received on November 10, 2023. Based on our current operating plan, we expect that our existing cash and cash equivalents and marketable securities will be sufficient to enable us to fund our oper ating 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. See “Liquidity and Capital Resources.”

Current wording

As of June 30, 2025, we had cash and cash equivalents andmarketable securities of $166.2 million; included in this amount is the first tranche of $30.0 million that we received under our Loan Agreement, which was received on November 10, 2023. Based on our current operating plan, we expect that our existing cash and cash equivalents and marketable securities will be sufficient to enable us to fund our oper ating 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. See “Liquidity and Capital Resources.”

Previous wording

Research and development costs primarily consist of direct costs associated with consultants and materials, biologic shipping and storage, third-party contract research organizations, or CROs, and contract manufacturing organizations, or

Current wording

Research and development costs primarily consist of direct costs associated with consultants and materials, biologic shipping and storage, third-party contract research organizations, or CROs, and contract manufacturing organizations, or CMOs, license agreements, salaries and other personnel-related expenses. Research and development costs are expensed as incurred. More specifically, these costs include:

Previous wording

As we currently only have one product candidate, sabirnetug, in 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 17% 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 14% 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

General and administrative expenses were $5.1 million and $5.3 million for the three months ended March 31, 2025 and 2024, respectively. The$0.2 million decrease was primarily due to immaterial decreases in personnel costs, insurance and recruiting costs, which were partially offset by a small increase in legal expenses.

Current wording

General and administrative expenses were $4.6 million and $4.8 million for the three months ended June 30, 2025 and 2024, respectively. The$0.2 million decrease was primarily due to decreases in insurance and recruiting costs.

Previous wording

Research and development expenses were $25.3 million and $12.4 million for the three months ended March 31, 2025 and 2024, respectively. The $12.9 million increase was prim arily due to $7.0 million for CRO costs associated with the ALTITUDE-AD clinical trial, for which we announced the dosing of the first patient in May 2024. Additionally, we incurred a $4.7 million increase for manufacturing and materials, a $0.9 million increase for personnel costs, a $0.4 million increase for other research projects and a $0.3 million increase for storage, shipping and packaging costs. These increases were partially offset by a decrease of $0.4 million related to services provided by research and development consultants and contractors.

Current wording

Research and development expenses were $62.4 million and $32.0 million for the six months ended June 30, 2025 and 2024, respectively. The $30.4 million increase was prim arily due to a $19.4 million increase for manufacturing and materials and an $11.5 million increase for CRO costs mainly related to investigator grant expenses 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 a $1.7 million increase for personnel-related costs, a $0.7 million increase for other research expenses and a $0.4 million increase for shipping, packaging and storage costs. These increases were partially offset by decreases in the following: $1.7 million for license agreement expenses, $0.9 million related to services provided by research and development consultants and contractors, and $0.7 million for other clinical trial expenses.

Previous wording

Other income decreased by$1.3 million to $1.6 million for the three months ended March 31, 2025 from $2.9 million for the three months ended March 31, 2024. The$1.3 million decrease was attributable to a $1.5 million decrease in interest income on our portfolio of marketable securities due to both lower interest rates and a lower average investment balance during the three months ended March 31, 2025 with the utilization of cash from investment maturities supporting our ongoing operating cash needs.

Current wording

Other income was $2.4 million and $6.7 million for the six months ended June 30, 2025 and 2024, respectively. The$4.3 million decrease was primarily attributable to a $3.3 million decrease in interest income on our portfolio of marketable securities due to both lower interest rates and a lower average investment balance during the six months ended June 30, 2025 with the utilization of cash from investment maturities supporting our ongoing operating cash needs. Additionally, there were decreases in change in fair value of our embedded derivatives related to our Loan Agreement of$0.9 million and other expense, net of $0.1 million.

Previous wording

During the three months ended March 31, 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 six months ended June 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.

Previous wording

As of March 31, 2025, we had cash and cash equivalents andmarketable securities totaling $197.9 million. Ouravailable-for-sale marketable securities mature within two years. Based on our current operating plan, we expect 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.

Current wording

As of June 30, 2025, we had cash and cash equivalents andmarketable securities totaling $166.2 million. Ouravailable-for-sale marketable securities mature within two years. Based on our current operating plan, we expect 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.

Previous wording

Net cash used in operating activities increased by $16.2 million to $34.1 million for the three months ended March 31, 2025 from $17.9 million for the three months ended March 31, 2024. The$13.9 million increase in our net loss for the three months ended March 31, 2025, adjusted for a decrease in non-cash income for amortization and accretion on marketable securities of $1.2 million partially offset by an increase in the change in fair value of embedded derivatives of $0.2 million, accounted for a $12.9 million increase in cash used in operating activities as compared to the three months ended March 31, 2024. Working capital changes contributed $3.3 million of additional cash used in operations, including cash used for accounts payable and accrued clinical trial expenses of $6.3 million and $1.8 million, respectively, which were partially offset by cash provided from accrued expenses and other liabilities of $3.6 million and $1.2 million from prepaid expenses and other current assets.

Current wording

Net cash used in operating activities increased by $31.6 million to $66.0 million for the six months ended June 30, 2025 from $34.4 million for the six months ended June 30, 2024. The$34.3 million increase in net loss for the six months ended June 30, 2025, adjusted for a decrease in non-cash income for amortization and accretion on marketable securities of $2.6 million and a decrease in the change in fair value of embedded derivatives of $0.9 million accounted for a $30.8 million increase in cash used in operating activities as compared to the six months ended June 30, 2024. Working capital changes contributed $0.8 million of additional cash used in operations, including increases in cash used for accounts payable and accrued clinical trial expenses of $6.4 million and $6.9 million, respectively, which were mostly offset by cash provided from accrued expenses and other liabilities of $7.4 million and $5.1 million from prepaid expenses and other current assets.

Previous wording

Cash provided by investing activities during the three months ended March 31, 2025 of $28.7 million increased by $37.9 million from cash used in investing activities of $9.2 million during the three months ended March 31, 2024, primarily due to increases in proceeds from maturities of marketable securities of $27.7 million, and decreases in purchases of marketable securities of $10.2 million.

Current wording

Cash provided by investing activities during the six months ended June 30, 2025 of $67.2 million increasedby $38.7 million from cash used in investing activities of $28.5 million during the six months ended June 30, 2024, primarily due to an increase in proceeds from maturities of marketable securities of $19.7 million, as well as a decrease in purchases of marketable securities of $19.0 million.

Previous wording

Cash provided by financing activities during the three months ended March 31, 2025 was immaterial and decreased by $7.1 million from cash provided by financing activities of $7.1 million during the three months ended March 31, 2024. Cash provided by financing activities during the three months ended March 31, 2024 was primarilydue to net proceeds of $7.9 million from the issuance of common stock under our ATM, partially offset by $0.7 million for payment under a finance lease agreement for certain computer equipment for our Phase 2 ALTITUDE-AD clinical trial.

Current wording

Cash provided by financing activities during the six months ended June 30, 2025 was immaterial and decreased by $7.0 million from cash provided by financing activities of $7.0 million during the six months ended June 30, 2024. Cash provided by financing activities during the six months ended June 30, 2024 was primarilydue to net proceeds of $7.9 million from the issuance of common stock under our ATM, partially offset by $0.7 million for payment under a finance lease agreement for certain computer equipment for our Phase 2 ALTITUDE-AD clinical trial.

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 the first half of 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 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.