8-K

UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 20, 2025

Alector, Inc.

(Exact name of Registrant as Specified in Its Charter)

Delaware	001-38792	82-2933343
(State or Other Jurisdiction<br>of Incorporation)	(Commission File Number)	(IRS Employer<br>Identification No.)
131 Oyster Point Blvd.<br><br>Suite 600
South San Francisco, California		94080
(Address of Principal Executive Offices)		(Zip Code)
Registrant’s Telephone Number, Including Area Code: (415) 231-5660
---

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading<br>Symbol(s)	Name of each exchange on which registered
Common Stock	ALEC	The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 Results of Operations and Financial Condition.

On October 21, 2025, the Company issued a press release announcing data results from the Company’s Phase 3 INFRONT-3 clinical trial that included its preliminary estimate of cash, cash equivalents, and short-term investments as of September 30, 2025. A copy of the press release is attached as Exhibit 99.1 and incorporated herein by reference.

The information contained under Item 2.02 of this Current Report on Form 8-K (including Exhibit 99.1) shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that Section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Exchange Act, except as shall be expressly stated by specific reference in such filing.

Item 2.05 Costs Associated with Exit or Disposal Activities.

On October 21, 2025, the Company committed to a plan to reduce its workforce (the “Plan”) by approximately 49% in order to align resources with the Company’s strategic priorities. Based upon the results of the Company’s 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), the Company is discontinuing the open-label extension portion of the INFRONT-3 trial and the continuation study for latozinemab. The Company initiated a reduction in force impacting approximately 75 employees across the organization.

Total incremental restructuring charges associated with the reduction in force are expected to be approximately $7.7 million. The Plan includes severance and related termination benefits for affected employees. Cash payments related to these expenses will be paid out and the reduction in force is expected to be completed during the first half of 2026. The estimated costs that the Company expects to incur in connection with the reduction are subject to a number of assumptions, and actual results may differ significantly from these estimates. The Company may also incur additional costs not currently contemplated due to events that may occur as a result of, or that are associated with, the reduction.

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On October 20, 2025, Sara Kenkare-Mitra, Ph.D., President and Head of Research and Development of the Company, informed the Company of her resignation from her position effective December 22, 2025, to pursue other professional opportunities. Dr. Kenkare-Mitra’s resignation is not the result of any disagreement with the Company related to its operations, policies, or practices. The Company thanks Dr. Kenkare-Mitra for her dedication over her years of service to the Company.

In connection with Dr. Kenkare-Mitra’s resignation, Dr. Kenkare-Mitra and the Company have agreed to enter into a separation agreement. Under the separation agreement, Dr. Kenkare-Mitra will be paid a lump-sum cash payment equal to nine months of her annual base salary and a payment equal to 50% of her annual bonus target, and she will receive nine months of Company-paid premiums for COBRA coverage. In consideration for such compensation, Dr. Kenkare-Mitra will agree to a customary general release of claims for the benefit of the Company. The foregoing description of the separation agreement does not purport to be complete and is qualified by reference to the separation agreement, which the Company intends to file with the Securities and Exchange Commission as an exhibit to a subsequent periodic report.

Item 7.01 Regulation FD Disclosure.

On October 21, 2025, the Company issued a press release announcing data results from the Company’s Phase 3 INFRONT-3 clinical trial evaluating the Company’s latozinemab (AL001) product candidate and the Plan described above. A copy of the press release is attached as Exhibit 99.1 and incorporated herein by reference.

The information contained under Item 7.01 of this Current Report on Form 8-K (including Exhibit 99.1) shall not be deemed “filed” for purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act or the Exchange Act except as may be expressly set forth by specific reference in such filing.

Note Regarding Forward-Looking Statements

This Current Report on Form 8-K contains forward-looking statements as that term is defined in Section 27A of the Securities Act and Section 21E of the Exchange Act. Such forward-looking statements involve substantial risks and uncertainties. All statements other than statements of historical fact contained in this Form 8-K are forward-looking statements, including statements relating to the Company’s plans, expectations, forecasts and future events. Such forward-looking statements include, but are not limited to, statements relating to the potential of, and expectations regarding, the Company’s business strategy, and statements relating to the anticipated timing and details of the Plan and the expected impacts, charges and costs associated with the Plan that the Company expects to incur. In some cases, you can identify forward-looking statements by terminology such as “believe,” “estimate,” “intend,” “may,” “plan,” “potentially,” “will,” “expect,” “enable,” “likely” or the negative of these terms or other similar expressions. We have based these forward-looking statements largely on our current expectations and projections about future events and trends that we believe may affect our financial condition, results of operations, business strategy and financial needs. Actual events, trends or results could differ materially from the plans, intentions and expectations disclosed in these forward-looking statements based on various factors. Information regarding the foregoing and additional risks may be found in the section entitled “Risk Factors” in the Company’s Annual and Quarterly Reports on

Form 10-K and 10-Q filed with the Securities and Exchange Commission (the “SEC”), and the Company’s future reports to be filed with the SEC. These forward-looking statements are made as of the date of this Form 8-K, and the Company assumes no obligation to update the forward-looking statements, or to update the reasons why actual results could differ from those projected in the forward-looking statements, except as required by law.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No.	Description
99.1	Press Release, dated October 21, 2025
104	Cover Page Interactive Data File (embedded with the inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

			ALECTOR, INC.
Date:	October 21, 2025	By:	/s/ Arnon Rosenthal
			Arnon Rosenthal, Ph.D.<br>Co-founder and Chief Executive Officer

EX-99.1

Exhibit 99.1

Alector Announces Topline Results from Latozinemab Phase 3 Trial in Individuals with Frontotemporal Dementia Due to a GRN Mutation and Provides Business Update

SOUTH SAN FRANCISCO, Calif., October 21, 2025 – Alector, Inc. (Nasdaq: ALEC), a clinical-stage biotechnology company focused on developing therapies to counteract the devastating progression of neurodegeneration, today announced results from the Phase 3 INFRONT-3 clinical trial evaluating latozinemab (AL001) in individuals with frontotemporal dementia due to a progranulin gene mutation (FTD-GRN).

In the 96-week, double-blind INFRONT-3 trial, latozinemab, developed in collaboration with GSK, did not meet the clinical co-primary endpoint of slowing FTD-GRN progression, as measured by the Clinical Dementia Rating® plus National Alzheimer’s Coordinating Center Frontotemporal Lobar Degeneration Sum of Boxes (CDR® plus NACC FTLD-SB). Although treatment resulted in a statistically significant effect on the biomarker co-primary endpoint of plasma progranulin (PGRN) concentrations, the secondary and exploratory endpoints, such as fluid biomarkers and volumetric magnetic resonance imaging (vMRI), demonstrated no treatment-related effects on FTD-GRN. Preliminary safety data have not highlighted any major safety concerns at present. More in-depth analysis of the data is ongoing.

“While latozinemab did not demonstrate a clinical benefit in INFRONT-3, the insights gained are invaluable for understanding progranulin-related neurodegeneration," said Giacomo Salvadore, M.D., Chief Medical Officer of Alector. "We extend our deepest gratitude to the patients, caregivers, and investigators who made this trial possible, and we plan to share the results with the scientific community to support continued progress in understanding progranulin biology and FTD pathophysiology.”

Based on these results, the open-label extension portion of the INFRONT-3 trial and the continuation study for latozinemab will be discontinued.

The INFRONT-3 trial results will be presented at an upcoming medical congress.

Alector Pipeline Outlook

Alector remains focused on advancing a pipeline of programs designed to treat neurodegenerative diseases through mechanisms that remove toxic proteins, replace deficient proteins, and restore immune and neuronal function.

In the ongoing collaboration with GSK, nivisnebart (AL101/GSK4527226) is being evaluated in PROGRESS-AD, a global, 76-week Phase 2 clinical trial in individuals with early Alzheimer’s disease (AD). Enrollment was completed in April 2025, and trial completion is expected in 2026. An independent interim analysis is planned for the first half of 2026.

A key pillar of Alector’s focus is its proprietary blood-brain barrier (BBB) 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 at lower doses. 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.

Alector is progressing multiple preclinical programs enabled by ABC and has selected lead candidate AL137 for its ABC-enabled anti-amyloid beta (Aβ) antibody program in AD, and AL050 for its ABC-enabled glucocerebrosidase (GCase) enzyme replacement therapy program in Parkinson’s disease (PD). The company is targeting submission of investigational new drug (IND) applications for AL137 in 2026 and for AL050 in 2027.

Alector is also continuing to advance its ABC-enabled siRNA platform. The platform is being designed for peripheral dosing, offering the potential for more convenient administration compared with traditional intrathecal or intracerebroventricular delivery. The most advanced siRNA program is ADP064-ABC, targeting tau for the potential treatment of AD and FTD.

Collectively, these programs reflect Alector’s continued commitment to advancing innovative approaches to treat neurodegenerative diseases.

Alector Executive Leadership and Business Update

To align resources with these strategic priorities, Alector is reducing its workforce by approximately 49%. This is intended to focus the company’s resources on its highest-priority programs and to ensure continued progress across its portfolio. Alector thanks all employees affected by these measures for their dedication and contributions to the company’s mission.

In parallel, Sara Kenkare-Mitra, Ph.D., President and Head of Research and Development (R&D), has resigned from her role, effective December 22, 2025, to pursue new leadership opportunities. She will remain with Alector until then to ensure a smooth transition and continuity across the R&D organization. The company is deeply appreciative of Dr. Kenkare-Mitra for her leadership and impactful contributions to Alector.

“Sara has been an extraordinary builder and operator who transformed Alector into a mature, fully integrated R&D organization,” said Arnon Rosenthal, Ph.D., Chief Executive Officer of Alector. “Her sage leadership has been critical for the successful execution of our preclinical and clinical pipeline programs. Sara’s integrity and vision have left a lasting mark on the science, culture, and people at Alector, and we wish her continued success in her next chapter.”

Alector estimates that it had approximately $291.1 million in cash, cash equivalents, and short-term investments as of September 30, 2025, which the company expects will provide runway

through 2027. Alector plans to issue guidance for 2026 when it reports fourth quarter and full year 2025 financial results.

About INFRONT-3

INFRONT-3 (ClinicalTrials.gov identifier NCT04374136) was a pivotal, randomized, double-blind, placebo-controlled Phase 3 clinical trial evaluating the safety and efficacy of latozinemab (AL001) in slowing disease progression in individuals with frontotemporal dementia due to a progranulin gene mutation (FTD-GRN). The trial enrolled symptomatic and at-risk FTD-GRN participants at multiple sites across North America, Europe, Argentina, and the Asia-Pacific region. The primary analysis was conducted in symptomatic participants only, in alignment with regulatory guidance from the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA).

Based on the FDA’s recommendation, Alector and GSK amended the statistical analysis plan in the U.S. to include plasma progranulin (PGRN) concentration as a co-primary endpoint along with the Clinical Dementia Rating® plus National Alzheimer’s Coordinating Center Frontotemporal Lobar Degeneration Sum of Boxes (CDR® plus NACC FTLD-SB). This designation of plasma PGRN as a co-primary endpoint does not apply outside the United States.

Participants were randomized to receive 60 mg/kg of latozinemab or placebo intravenously every four weeks over the 96-week treatment period (Part 1, the double-blind period). Following completion of Part 1, participants could either enter a 10-week safety follow-up or roll over into a 96-week open-label extension (OLE) study. Those who completed the OLE had the option to roll over into a continuation study (ClinicalTrials.gov identifier NCT06111014).

About Alector Alector is a clinical-stage biotechnology company focused on developing therapies to counteract the devastating progression of neurodegenerative diseases. Leveraging the principles of genetics, immunology, and neuroscience, the company is advancing a portfolio of programs that aim to remove toxic proteins, replace missing proteins, and restore immune and nerve cell function. Supported by biomarkers, Alector’s product candidates seek to treat a range of indications, such as Alzheimer’s disease, Parkinson's disease, and frontotemporal dementia. The company is also developing Alector Brain Carrier (ABC), a proprietary blood-brain barrier platform, which is being selectively applied to its preclinical and research pipeline. ABC aims to enhance the delivery of therapeutics, achieve deeper brain penetration and efficacy at lower doses, and ultimately improve patient outcomes while reducing costs. Alector is headquartered in South San Francisco, California. For more information, please visit www.alector.com.

Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements in this press release include, but are not limited to, statements regarding our business plans, business strategy,

workforce reduction, product candidates, research and preclinical pipeline, blood-brain barrier technology platform, planned and ongoing preclinical studies and clinical trials, anticipated timing of and detail regarding release of data for PROGRESS-AD, expected milestones, expectations of our collaborations and financial and cash guidance. Such statements are subject to numerous risks and uncertainties, including but not limited to risks and uncertainties as set forth in Alector’s Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q, with the Securities and Exchange Commission (“SEC”), as well as the other documents Alector files from time to time with the SEC. These documents contain and identify important factors that could cause the actual results for Alector to differ materially from those contained in Alector’s forward-looking statements. Any forward-looking statements contained in this press release speak only as of the date hereof, and Alector specifically disclaims any obligation to update any forward-looking statement, except as required by law.

Alector Contacts:

Alector

Katie Hogan

202-549-0557

katie.hogan@alector.com

Argot Partners (media)

David Rosen

646-461-6387

alector@argotpartners.com

Argot Partners (investors)

Laura Perry

212-600-1902

alector@argotpartners.com