Alector, Inc.

Previous wording

We are a late-stage clinical biotechnology company with a mission to make degenerative brain disorders history. Our robust portfolio of therapies is focused on counteracting the devastating progression of neurodegenerative diseases, particularly in areas of high unmet need where therapeutic options are limited. We are at the forefront of a scientific and clinical revolution, committed to understanding the complex mechanisms that drive neurodegenerative diseases, including the roles of toxic misfolded proteins, deficient proteins, and lysosomal, immune system, and neuronal dysfunction.

Current wording

We are a clinical stage biotechnology company with a mission to make degenerative brain disorders history. Our robust portfolio of therapies is focused on counteracting the devastating progression of neurodegenerative diseases, particularly in areas of high unmet need where therapeutic options are limited. We are at the forefront of a scientific and clinical revolution, committed to understanding the complex mechanisms that drive neurodegenerative diseases, including the roles of toxic misfolded proteins, deficient proteins, and lysosomal, immune system, and neuronal dysfunction.

Previous wording

Our clinical development portfolio includes latozinemab (AL001) and AL101/GSK4527226. We continue to pursue our brain-penetrant anti-amyloid beta antibody in Alzheimer’s disease (AD) and our GCase enzyme replacement therapy in Parkinson’s disease (PD).

Current wording

Nivisnebart (formerly AL101/GSK4527226) is currently in clinical development. We are pursuing our brain-penetrant anti-amyloid beta antibody in Alzheimer’s disease (AD) and our GCase enzyme replacement therapy in Parkinson’s disease (PD).

Previous wording

In July 2021, we entered into a Collaboration and License Agreement with Glaxo Wellcome UK Limited, a subsidiary of GlaxoSmithKline plc (GSK Agreement), to collaborate on the global development and commercialization of progranulin (PGRN)-elevating monoclonal antibodies, including latozinemab and AL101/GSK4527226.

Current wording

In July 2021, we entered into a Collaboration and License Agreement with Glaxo Wellcome UK Limited, a subsidiary of GlaxoSmithKline plc (GSK Agreement), to collaborate on the global development and commercialization of progranulin (PGRN)-elevating monoclonal antibodies, including latozinemab and nivisnebart.

Previous wording

AL101/GSK4527226, the second product candidate in our PGRN portfolio, is an investigational human recombinant monoclonal antibody designed to elevate PGRN levels in the brain, similar to latozinemab, but with distinct pharmacokinetic and pharmacodynamic properties that may be more suitable for treating prevalent neurodegenerative diseases. Alector and GSK are co-developing AL101/GSK4527226 for the potential treatment of early AD, and it may also be evaluated for other indications, including PD. LOF mutations in the GRN gene, which moderately reduce PGRN levels, have been shown to increase the risk of developing AD and PD. Conversely, increased PGRN levels have been demonstrated to be protective for those diseases in animal models. Given the strong link between GRNLOF mutations and neurodegeneration, elevating PGRN levels may provide a potential therapeutic approach that offers broad neuroprotection in both AD and PD.

Current wording

Nivisnebart is an investigational human recombinant monoclonal antibody designed to elevate PGRN levels in the brain. Its pharmacokinetic and pharmacodynamic properties may be suitable for treating prevalent neurodegenerative diseases. We and GSK are co-developing nivisnebart for the potential treatment of early AD, and it may also be evaluated for other indications, including PD. LOF mutations in the GRN gene, which moderately reduce PGRN levels, have been shown to increase the risk of developing AD and PD. Conversely, increased PGRN levels have been demonstrated to be protective for those diseases in animal models. Given the strong link between GRNLOF mutations and neurodegeneration, elevating PGRN levels may provide a potential therapeutic approach that offers broad neuroprotection in both AD and PD.

Previous wording

In April 2025, enrollment was completed in PROGRESS-AD, a randomized, double-blind, placebo-controlled, 76-week Phase 2 global clinical trial evaluating the safety and efficacy of AL101/GSK4527226 in slowing disease progression in early AD. Trial completion is expected in 2026. In May 2023, we and GSK amended the GSK Agreement (the GSK Amendment). Under the terms of the GSK Amendment, we are responsible for funding GSK’s and our development costs up to $140.5 million for the conduct of the initial Phase 2 trial of AL101 in early AD.

Current wording

In April 2025, enrollment was completed in PROGRESS-AD, a randomized, double-blind, placebo-controlled, 76-week Phase 2 global clinical trial evaluating the safety and efficacy of nivisnebart in slowing disease progression in early AD. Trial completion is expected in 2026. An independent interim analysis is planned for the first half of 2026. In August 2025, the first patient from PROGRESS-AD was enrolled and dosed in the optional open-label extension (OLE) study, and enrollment in the OLE is ongoing. In May 2023, we and GSK amended the GSK Agreement (the GSK Amendment). Under the terms of the GSK Amendment, we are responsible for funding and sharing GSK’s and our development costs up to $140.5 million for the conduct of the initial Phase 2 trial of nivisnebart in early AD.

Previous wording

In a randomized, double-blind, placebo-controlled Phase 1 study in 88 healthy volunteers who received either single or multiple doses of AL101/GSK4527226 administered intravenously or subcutaneously, AL101/GSK4527226 was generally well tolerated and elevated PGRN levels in cerebrospinal fluid.

Current wording

In a randomized, double-blind, placebo-controlled Phase 1 study in 88 healthy volunteers who received either single or multiple doses of nivisnebart administered intravenously or subcutaneously, nivisnebart was generally well tolerated and elevated PGRN levels in cerebrospinal fluid.

Previous wording

We have expanded and continue to advance our preclinical and research pipeline by leveraging our expertise in neuroscience and selectively applying our proprietary blood-brain barrier technology platform, Alector Brain Carrier (ABC). Our strategic approach positions us to develop therapeutic candidates for a range of neurodegenerative diseases.

Current wording

We have expanded and continue to advance our preclinical and research pipeline by leveraging our expertise in neuroscience and selectively applying our proprietary blood-brain barrier technology platform, Alector Brain Carrier (ABC). Built on the core design principles of versatility, tunability, and differentiated binding to a distinct region of the transferrin receptor (TfR), ABC is intended to support the targeted delivery of therapeutics to the brain and to optimize safety and efficacy. The platform’s tunable TfR binding affinities allow adjustment of binding strength to align with the needs of diverse therapeutic cargos, including antibodies, enzymes, proteins, and siRNA, aiming to achieve efficient transport across the BBB with the goal of balancing brain uptake, potency, and safety. Our ABC platform that has been applied to our product candidates thus far targets a distinct epitope of TfR. Our strategic approach positions us to develop therapeutic candidates for a range of neurodegenerative diseases.

Previous wording

ADP037-ABC is our proprietary anti-amyloid beta (Aβ) antibody paired with our proprietary ABC for the treatment of AD. It is designed to remove brain Aβ plaques, with the potential to reduce the incidence and/or severity of amyloid-related imaging abnormalities (ARIA) and enable subcutaneous delivery. It targets a validated epitope, specific to brain Aβ plaques, combined with an optimal antibody constant region to enhance phagocytosis of Aβ plaques. By leveraging ABC technology, ADP037-ABC aims to clear Aβ efficiently, thereby reducing plaque accumulation and potentially slowing disease progression while minimizing ARIA.

Current wording

AL137 is our proprietary anti-amyloid beta (Aβ) antibody paired with our proprietary ABC in preclinical development for the potential treatment of AD. It is designed to remove brain Aβ plaques, with the potential to reduce the incidence and/or severity of amyloid-related imaging abnormalities (ARIA) and the potential to enable subcutaneous delivery. AL137 features a high-affinity, humanized antibody that selectively binds PyroGlu3, a validated epitope on the toxic form of Aβ found in plaques, a fully active effector function that enables maximal recruitment of myeloid cells to remove plaques, and Alector’s proprietary ABC with tuned affinity and binding epitope designed to facilitate brain penetration and plaque removal while minimizing hematologic adverse effects. In preclinical studies to date, AL137 has demonstrated robust brain penetration in non-human primates, and an AL137 surrogate has demonstrated amyloid beta 42 reduction in murine studies.

Previous wording

ADP064-ABC targets tau pathology in AD using anti-tau siRNA combined with ABC, which aims to prevent the synthesis of the tau mRNA and protein, with the goal of removing toxic tau, suppressing tau protein expression, and slowing cognitive decline in AD.

Current wording

We continue to advance our ABC-enabled siRNA platform. The platform is designed for peripheral dosing, offering the potential for more convenient administration compared with traditional intrathecal or intracerebroventricular delivery, as well as the potential for homogeneous drug distribution throughout the brain. Current programs include our lead siRNA program, ADP064-ABC, an anti-tau siRNA for AD and other tauopathies, which aims to prevent the synthesis of the tau mRNA and protein, with the goal of removing toxic tau, suppressing tau protein expression, and slowing cognitive decline in

Previous wording

To date, we have not had any products approved for sale and have not generated any revenue from product sales. Further, we do not expect to generate revenue from product sales until such time, if ever, that we are able to successfully complete the development and obtain marketing approval for one of our product candidates. We will continue to require additional capital to develop our product candidates and fund operations for the foreseeable future. We have incurred net losses in each year since inception, and we expect to continue to incur net losses for the foreseeable future. Our ability to generate product revenue will depend on the successful development and eventual commercialization of one or more of our product candidates. Our net losses were $30.5 million and $71.0 million for the three and six months ended June 30, 2025, respectively. Our net losses were $38.7 million and $74.8 million for the three and six months ended June 30, 2024, respectively. As of June 30, 2025, we had an accumulated deficit of $900.1 million. Substantially all of our net losses have resulted from costs incurred in connection with our research and development programs and from general and administrative costs associated with our operations. We expect our expenses will increase substantially in connection with our ongoing activities, as we:

Current wording

To date, we have not had any products approved for sale and have not generated any product or royalty revenue from product sales. Further, we do not expect to generate revenue from product sales until such time, if ever, that we are able to successfully complete the development and obtain marketing approval for one of our product candidates. We will continue to require additional capital to develop our product candidates, advance our research and preclinical programs, and fund operations for the foreseeable future. We have incurred net losses in each year since inception, and we expect to continue to incur net losses for the foreseeable future. Our ability to generate product revenue will depend on the successful development and eventual commercialization of one or more of our product candidates. Our net losses were $34.7 million and $105.7 million for the three and nine months ended September 30, 2025, respectively. Our net losses were $42.2 million and $117.0 million for the three and nine months ended September 30, 2024, respectively. As of September 30, 2025, we had an accumulated deficit of $934.8 million. Substantially all of our net losses have resulted from costs incurred in connection with our research and development programs and from general and administrative costs associated with our operations. We expect our expenses will increase substantially in connection with our ongoing activities, as we:

Previous wording

obtain, maintain, expand, and protect our intellectual property portfolio.

Current wording

obtain, maintain, and protect our intellectual property portfolio.

Previous wording

On March 7, 2025, we committed to a plan to reduce our workforce by approximately 13% to better align our resources with our strategic priorities including advancing our preclinical and research pipeline. We initiated such reduction in force impacting approximately 25 employees across the organization. Our cash, cash equivalents, and marketable securities as of June 30, 2025, totaled $307.3 million, which we anticipate provides runway into the second half of 2027.

Current wording

On March 7, 2025, we committed to a plan to reduce our workforce by approximately 13% to better align our resources with our strategic priorities including advancing our preclinical and research pipeline. We initiated such reduction in force impacting approximately 25 employees across the organization. On October 21, 2025, we committed to a plan to reduce our workforce by approximately 47% in order to align resources with the Company’s strategic priorities following the results of the Phase 3 INFRONT-3 clinical trial evaluating the safety and efficacy of latozinemab (AL001) in individuals with frontotemporal dementia due to a GRN mutation (FTD-GRN). Our cash, cash equivalents, and marketable securities as of September 30, 2025, totaled $291.1 million, which we anticipate provides runway through 2027.

Previous wording

We have not generated any revenue from product sales and do not expect to do so in the near future. Our revenue to date has been primarily related to the AbbVie Agreement and GSK Agreement for the license and co-development of product candidates with those parties. We recognized revenue from the upfront payments and the milestone payment received from AbbVie over time as services were provided. We recognize revenue from the upfront payments from GSK at a point in time for a development license and over time for research and development services. Revenues for research and development services are recognized as the program costs are incurred by measuring actual costs incurred to date compared to the overall total expected costs to satisfy the performance obligation.

Current wording

We have not generated any product or royalty revenue from product sales and do not expect to do so in the near future. Our revenue to date has been primarily related to the AbbVie Agreement and GSK Agreement for the license and co-development of product candidates with those parties. We recognized revenue from the upfront payments and the milestone payment received from AbbVie over time as services were provided. We recognize revenue from the upfront payments from GSK at a point in time for a development license and over time for research and development services. Revenues for research and development services are recognized as the program costs are incurred by measuring actual costs incurred to date compared to the overall total expected costs to satisfy the performance obligation.

Previous wording

Under the terms of the GSK Agreement, we received $700 million in upfront payments, of which $500 million was received in August 2021 and $200 million was received in January 2022. In addition, we will be eligible to receive up to an additional $1.5 billion in clinical development, regulatory, and commercial launch-related milestone payments for latozinemab and AL101. Alector and GSK are jointly developing latozinemab and AL101. In May 2023, we and GSK amended the GSK Agreement. Under the terms of the GSK Amendment, we are responsible for funding GSK’s and our development costs up to $140.5 million for the conduct of the initial Phase 2 clinical trial of AL101 in AD.

Current wording

Under the terms of the GSK Agreement, we received $700 million in upfront payments, of which $500 million was received in August 2021 and $200 million was received in January 2022. In addition, we may be eligible to receive up to an additional $1.5 billion in clinical development, regulatory, and commercial launch-related milestone payments, subject to successful advancement and commercialization of product candidates in multiple indications under the agreement. Alector and GSK are conducting development jointly. In May 2023, we and GSK amended the GSK Agreement. Under the terms of the GSK Amendment, we are responsible for funding GSK’s and our development costs up to $140.5 million for the conduct of the initial Phase 2 clinical trial of nivisnebart in AD.

Previous wording

In the United States, Alector and GSK will equally share profits and losses from commercialization of latozinemab and AL101. We may opt out of the sharing of development costs and of profit and losses from commercialization in the United States on a product-by-product basis. In such case, we will no longer conduct development or commercialization of that product, and we will receive royalties on net sales of the product in the United States instead of a share of profits. Outside of the United States, GSK will be responsible for commercialization of latozinemab and AL101 for all indications, and we will be eligible for double-digit tiered royalties.

Current wording

In the United States, Alector and GSK will equally share profits and losses from commercialization of product candidates under the agreement. We may opt out of the sharing of development costs and of profit and losses from commercialization in the United States on a product-by-product basis. In such case, we will no longer conduct development or commercialization of that product, and we will receive royalties on net sales of the product in the United States instead of a share of profits. Outside of the United States, GSK will be responsible for commercialization of latozinemab and nivisnebart for all indications, and we will be eligible for double-digit tiered royalties.

Previous wording

We expect that our revenue for the next several years will be derived primarily from the GSK Agreement. The balance of deferred revenue was $182.3 million as of June 30, 2025, related to the GSK Agreement. The deferred revenue is expected to be recognized over the research and development period of the programs through the completion of the initial Phase 2 clinical trials for specified indications for latozinemab and AL101.

Current wording

We expect that our revenue for the next several years will be derived primarily from the GSK Agreement. The balance of deferred revenue was $179.0 million as of September 30, 2025, related to the GSK Agreement. The deferred revenue is expected to be recognized over the research and development period of the programs through the completion of the initial Phase 2 clinical trials for specified indications for latozinemab and nivisnebart.

Previous wording

Specific program expenses include expenses associated with the development of our most advanced product candidates: latozinemab, which is being studied in a pivotal Phase 3 clinical trial, INFRONT-3; and AL101, which is being studied in the PROGRESS-AD Phase 2 clinical trial. We also have expenses related to the discovery and development of future product candidates and separately tracked expenses related to programs that we expect to move out of preclinical studies and into Phase 1 clinical trials. These expenses primarily relate to salaries and benefits, stock-based compensation, facility expenses, including depreciation, and lab consumables.

Current wording

Specific program expenses include expenses associated with the development of our most advanced product candidate: nivisnebart, which is being studied in the PROGRESS-AD Phase 2 clinical trial. We also have expenses related to the research and development of future product candidates and separately tracked expenses related to programs that we expect to move out of preclinical studies and into Phase 1 clinical trials. These expenses primarily relate to salaries and benefits, stock-based compensation, facility expenses, including depreciation, and lab consumables.

Previous wording

Where we share costs with our collaboration partners, such as in our GSK Agreement, research and development expenses may include cost sharing reimbursements from, or payments to, our partner.

Current wording

Where we share costs with our collaboration partners, such as in our GSK Agreement, research and development expenses may include reimbursements from, or payments to, our partner.

Previous wording

At this time, we cannot reasonably estimate or know the nature, timing, and estimated costs of the efforts that will be necessary to complete the development of, and obtain regulatory approval for, any of our product candidates. We expect our research and development expenses to increase substantially for the foreseeable future as we continue to invest in research and development activities related to developing our product candidates, as our product candidates advance into later stages of development, as we begin to conduct larger clinical trials, and as we seek regulatory approvals for any product candidates that successfully complete clinical trials. The process of conducting the necessary clinical research to obtain regulatory approval is costly and time-consuming, and the successful development of our product candidates is highly uncertain.

Current wording

At this time, we cannot reasonably estimate or know the nature, timing, and estimated costs of the efforts that will be necessary to complete the development of, and obtain regulatory approval for, any of our product candidates. We expect our research and development expenses relating to latozinemab and AL002 to decrease in the foreseeable future as a result of the discontinuation and wind-down of clinical trials for latozinemab and AL002. However, we continue to invest in research and development activities related to programs in our research and preclinical pipeline and to the advancement of those programs into clinical trials.

Previous wording

Collaboration revenue was $7.9 million for the three months ended June 30, 2025, compared to $15.1 million for the three months ended June 30, 2024. The $7.2 million decrease was mainly due to the satisfaction of the performance obligation associated with the AL002 program and the latozinemab FTD-C9orf72 Phase 2 trial in the fourth quarter of 2024. Revenues are recognized as the program costs are incurred by measuring actual costs incurred to date compared to the overall total expected costs to satisfy each performance obligation.

Current wording

Collaboration revenue was $3.3 million for the three months ended September 30, 2025, compared to $15.3 million for the three months ended September 30, 2024. The $12.0 million decrease was mainly due to the satisfaction of the performance obligation associated with the AL002 program and the latozinemab FTD-C9orf72 Phase 2 trial in the fourth quarter of 2024. Revenues are recognized as the program costs are incurred by measuring actual costs incurred to date compared to the overall total expected costs to satisfy each performance obligation.

Previous wording

Research and development expenses were $27.6 million for the three months ended June 30, 2025, compared to $46.3 million for the three months ended June 30, 2024. The decrease of $18.7 million was mainly due to a decrease in research and development expenses for the AL002 program and latozinemab program as well as a decrease in personnel related costs as a result of the reductions in force.

Current wording

Research and development expenses were $29.4 million for the three months ended September 30, 2025, compared to $48.0 million for the three months ended September 30, 2024. The decrease of $18.6 million was mainly due to a decrease in research and development expenses for the AL002 program as well as a decrease in personnel related costs as a result of the reductions in force.

Previous wording

Other income, net was $3.6 million for the three months ended June 30, 2025, compared to $7.0 million for the three months ended June 30, 2024. The decrease of $3.4 million was due to lower interest income from a reduction in marketable securities used to fund our operations and interest rate cuts.

Current wording

Other income, net was $2.9 million for the three months ended September 30, 2025, compared to $6.2 million for the three months ended September 30, 2024. The decrease of $3.3 million was due to lower interest income from a reduction in marketable securities used to fund our operations and interest rate cuts.

Previous wording

There was no income tax expense for the three months ended June 30, 2025 and income tax expense was less than $0.1 million for the three months ended June 30, 2024.

Current wording

There was no income tax expense for the three months ended September 30, 2025 and the three months ended September 30, 2024.

Previous wording

Comparison of the Six Months Ended June 30, 2025 and 2024

Current wording

Comparison of the Nine Months Ended September 30, 2025 and 2024

Previous wording

Collaboration revenue was $11.5 million for the six months ended June 30, 2025, compared to $31.0 million for the six months ended June 30, 2024. The $19.4 million decrease was mainly due to the satisfaction of the performance obligation associated with the AL002 program and the latozinemab FTD-C9orf72 Phase 2 trial in the fourth quarter of 2024. Revenues are recognized as the program costs are incurred by measuring actual costs incurred to date compared to the overall total expected costs to satisfy the performance obligation.

Current wording

Collaboration revenue was $14.8 million for the nine months ended September 30, 2025, compared to $46.3 million for the nine months ended September 30, 2024. The $31.5 million decrease was mainly due to the satisfaction of the performance obligation associated with the AL002 program and the latozinemab FTD-C9orf72 Phase 2 trial in the fourth quarter of 2024. Revenues are recognized as the program costs are incurred by measuring actual costs incurred to date compared to the overall total expected costs to satisfy the performance obligation.

Previous wording

Research and development expenses were $61.3 million for the six months ended June 30, 2025 compared to $91.5 million for the six months ended June 30, 2024. The decrease of $30.2 million was mainly due to a decrease in research and development expenses for the AL002 program and latozinemab program as well as a decrease in personnel related costs as a result of the reductions in force.

Current wording

Research and development expenses were $90.6 million for the nine months ended September 30, 2025 compared to $139.5 million for the nine months ended September 30, 2024. The decrease of $48.9 million was mainly due to a decrease in research and development expenses for the AL002 program and latozinemab program as well as a decrease in personnel related costs as a result of the reductions in force.

Previous wording

Other income, net was $7.8 million for the six months ended June 30, 2025 compared to $14.6 million for the six months ended June 30, 2024. The decrease of $6.8 million was due to lower interest income from a reduction in marketable securities used to fund our operations and interest rate cuts.

Current wording

Other income, net was $10.8 million for the nine months ended September 30, 2025 compared to $20.9 million for the nine months ended September 30, 2024. The decrease of $10.1 million was due to lower interest income from a reduction in marketable securities used to fund our operations and interest rate cuts.

Previous wording

There was no income tax expense for the six months ended June 30, 2025 compared to less than $0.1 million for the six months ended June 30, 2024.

Current wording

There was no income tax expense for the nine months ended September 30, 2025 compared to less than $0.1 million for the nine months ended September 30, 2024.

Previous wording

As of June 30, 2025, we had $307.3 million of cash, cash equivalents, and marketable securities. As of June 30, 2025, we had an accumulated deficit of $900.1 million.

Current wording

As of September 30, 2025, we had $291.1 million of cash, cash equivalents, and marketable securities. As of September 30, 2025, we had an accumulated deficit of $934.8 million.

Previous wording

Our primary uses of cash are to fund our operations, which consist primarily of research and development expenditures related to our programs, and to a lesser extent, general and administrative expenditures. We expect our expenses to continue to increase in connection with our ongoing activities, in particular as we continue to advance our product candidates and our discovery programs. In addition, we expect to incur additional costs associated with operating as a public company.

Current wording

Our primary uses of cash are to fund our operations, which consist primarily of research and development expenditures related to our programs, and to a lesser extent, general and administrative expenditures. We expect our expenses to continue to increase in connection with our ongoing activities, in particular as we continue to advance our product candidates and our discovery and research programs. In addition, we expect to incur additional costs associated with operating as a public company.

Previous wording

Based on our current operating plan, we believe that our existing cash, cash equivalents, and marketable securities will enable us to fund our operations and capital expenditure requirements into the second half of 2027. We reduced our workforce to better align our resources with our current strategic priorities and maintain our expectations with respect to our ability to fund our operations. We have based this estimate on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we currently expect. We may also choose to seek additional financing opportunistically. We may seek to raise capital through public equity or debt financings, license agreements, collaborative agreements or other arrangements with other companies, asset sales, or through other sources of financing. We have an omnibus shelf registration statement on Form S-3 with the SEC, which became effective on May 1, 2023, which permits us to issue up to $400 million in common stock, other equity securities and/or debt securities. We will need to obtain substantial additional funding in the future for our research and development activities and continuing operations. If we are unable to raise capital when needed or on favorable terms, we would be forced to delay, reduce, or eliminate our research and development programs or future commercialization efforts. On November 7, 2023, we entered into an at-the-market sales agreement with Cowen and Company, LLC (TD Cowen) pursuant to which we may offer and sell from time to time through TD Cowen up to $125,000,000 of shares of our common stock, in such share amounts as we may specify by notice to TD Cowen. On January 17, 2024, we entered into an underwriting agreement with Cantor Fitzgerald & Co. (Cantor), pursuant to which we offered and sold 10,869,566 shares of the Company’s common stock at a price per share of $6.57 paid by Cantor. Additionally, on November 14, 2024, we entered into a loan agreement with our subsidiary, Alector LLC, as a co-borrower, the Lenders, and Hercules Capital, Inc., in its capacity as administrative agent and collateral agent for itself and the Lenders (the “Loan Agreement”), pursuant to which we may access up to two tranches of Term Loans in an aggregate principal amount of up to $50,000,000. The initial tranche of Term Loans provides for an aggregate principal amount of up to $25,000,000 through June 30, 2026, subject to the satisfaction of certain conditions. The second tranche of Term Loans provides for up to $25,000,000 and is available at the sole discretion of the Lenders. We borrowed $10,000,000 principal amount of the initial tranche of Term Loans on the closing date of the Loan Agreement.

Current wording

On November 7, 2023, we entered into an at-the-market sales agreement with TD Securities (USA) LLC (TD Securities, formerly known as Cowen and Company, LLC) pursuant to which we may offer and sell from time to time through TD Securities up to $125,000,000 of shares of our common stock, in such share amounts as we may specify by notice to TD Securities (the Sales Agreement). As of September 30, 2025, we have issued 5,415,162 shares and received approximately $14.7 million in net proceeds from the sale of securities pursuant to the Sales Agreement. In October 2025, we issued an additional 1,695,000 shares and received approximately $5.3 million in net proceeds from the sale of securities pursuant to the Sales Agreement. On January 17, 2024, we entered into an underwriting agreement with Cantor Fitzgerald & Co. (Cantor), pursuant to which we offered and sold 10,869,566 shares of the Company’s common stock at a price per share of $6.57 paid by Cantor. Additionally, on November 14, 2024, we entered into a loan agreement with our subsidiary, Alector LLC, as a co-borrower, the Lenders, and Hercules Capital, Inc., in its capacity as administrative agent and collateral agent for itself and the Lenders (the Loan Agreement), pursuant to which we may access up to two tranches of Term Loans in an aggregate principal amount of up to $50,000,000. The initial tranche of Term Loans provides for an aggregate principal amount of up to $25,000,000 through June 30, 2026, subject to the satisfaction of certain conditions. The second tranche of Term Loans provides for up to $25,000,000 and is available at the sole discretion of the Lenders. We borrowed $10,000,000 principal amount of the initial tranche of Term Loans on the closing date of the Loan Agreement.

Previous wording

We expect to obtain substantial additional funding in the future for our research and development activities and continuing operations. If we are unable to raise capital when needed or on favorable terms, we would be forced to delay, reduce, or eliminate our research and development programs or future commercialization efforts.

Current wording

We will need to obtain substantial additional funding in the future for our research and development activities and continuing operations. If we are unable to raise capital when needed or on favorable terms, we would be forced to delay, reduce, or eliminate our research and development programs or future commercialization efforts.

Previous wording

our ability to maintain our current research and development programs and establish new research and development programs;

Current wording

the timing and progress of our current research and development programs and our ability to establish new research and development programs;

Previous wording

our efforts to enhance operational, financial, and information management systems, and hire or retain personnel, including personnel to support development of our product candidates;

Current wording

our efforts to maintain or enhance operational, financial, and information management systems, and hire or retain personnel, including personnel to support development of our product candidates;

Previous wording

For the six months ended June 30, 2025, cash used in operating activities was $109.8 million. This was mainly due to the net loss of $71.0 million. We also had a decrease in refund liability to collaboration partner of $26.1 million, a decrease in deferred revenue of $11.5 million, a decrease in accrued liabilities and accrued clinical supply costs of $16.5 million. This was offset by a non-cash charge of $15.4 million for stock-based compensation.

Current wording

For the nine months ended September 30, 2025, cash used in operating activities was $142.3 million. This was mainly due to the net loss of $105.7 million. We also had a decrease in refund liability to collaboration partner of $38.1 million, a decrease in deferred revenue of $14.8 million, a decrease in accrued liabilities and accrued clinical supply costs of $14.0 million. This was offset by a non-cash charge of $21.8 million for stock-based compensation.

Previous wording

For the six months ended June 30, 2024, cash used in operating activities was $124.1 million. This was mainly due to the net loss of $74.8 million. We also had a decrease in deferred revenue of $31.0 million, a decrease in refund liability to collaboration partner of $22.5 million, and a decrease in accrued liabilities and accrued clinical supply costs of $9.8 million. This was offset by a non-cash charge of $20.2 million for stock-based compensation.

Current wording

For the nine months ended September 30, 2024, cash used in operating activities was $174.9 million. This was mainly due to the net loss of $117.0 million. We also had a decrease in deferred revenue of $46.3 million, a decrease in refund liability to collaboration partner of $33.6 million, and a decrease in accrued liabilities and accrued clinical supply costs of $6.5 million. This was offset by a non-cash charge of $29.3 million for stock-based compensation.

Previous wording

For the six months ended June 30, 2025, cash provided by investing activities of $121.5 million was primarily related to the maturities of marketable securities of $250.4 million offset by purchases of marketable securities of $131.9 million.

Current wording

For the nine months ended September 30, 2025, cash provided by investing activities of $171.0 million was primarily related to the maturities of marketable securities of $359.0 million offset by purchases of marketable securities of $190.8 million.

Previous wording

For the six months ended June 30, 2024, cash provided by investing activities of $25.4 million was primarily related to the maturities of marketable securities of $322.2 million offset by purchases of marketable securities of $297.8 million.

Current wording

For the nine months ended September 30, 2024, cash provided by investing activities of $65.7 million was primarily related to the maturities of marketable securities of $446.1 million offset by purchases of marketable securities of $381.1 million.

Previous wording

For the six months ended June 30, 2025, cash provided by financing activities of $0.1 million was primarily from the proceeds from the purchase of common stock under the employee stock purchase plan.

Current wording

For the nine months ended September 30, 2025, cash provided by financing activities of $14.8 million was primarily from the proceeds from the sale of securities pursuant to the sales agreement with TD Securities.

Previous wording

For the six months ended June 30, 2024, cash provided by financing activities of $71.8 million was primarily from the issuance of common stock upon a public offering.

Current wording

For the nine months ended September 30, 2024, cash provided by financing activities of $71.8 million was primarily from the issuance of common stock upon a public offering.