and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

Termination of a Material Definitive Agreement. Alector, Inc. (the “Company”) was developing the investigational progranulin-elevating monoclonal antibodies, latozinemab and nivisnebart, in collaboration with Glaxo Wellcome UK Limited (“GSK”), under the Collaboration and License Agreement between the parties, dated as of July 1, 2021, and as amended on May 19, 2023 (the “GSK Agreement”). On October 21, 2025, the Company announced that the Phase 3 INFRONT-3 clinical trial evaluating latozinema…

and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

Entry into a Material Definitive Agreement. On May 7, 2026, Alector, Inc. (the “ Company ”) entered into a Sales Agreement (the “ Sales Agreement ”) with TD Securities (USA) LLC (“ TD Cowen ”), pursuant to which the Company may offer and sell from time to time through TD Cowen up to $125,000,000 of shares (the “ Shares ”) of the Company’s common stock, par value $0.0001 per share (the “ Common Stock ”), in such share amounts as the Company may specify by notice to TD Cowen, in accordance with…

and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

Chief Financial Officer — Neil Berkley: Neil Berkley was promoted from Interim Chief Financial Officer to the permanent role of Chief Financial Officer.

and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

President and Head of Research and Development — Sara Kenkare-Mitra, Ph.D.: Dr. Sara Kenkare-Mitra resigned to pursue other professional opportunities.

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.

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 po…

and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

Chief Financial Officer — Dr. Marc Grasso: Dr. Marc Grasso resigned as Chief Financial Officer to pursue other opportunities.

and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

Chief Medical Officer — Dr. Gary Romano: Dr. Gary Romano resigned to pursue other opportunities.

Costs Associated with Exit or Disposal Activities. On March 7, 2025, Alector, Inc. (“Alector” or “the Company”) committed to a plan to reduce its workforce (the “Plan”) by approximately 13% as part of its cost reduction initiatives in order to align resources with the Company’s strategic priorities, including advancing its preclinical and research pipeline. The Company initiated a reduction in force impacting approximately 25 employees across the organization. The Company continues to expect…

and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

Other Events. Alector, Inc. (the “Company”) was developing AL002, its TREM2 program asset, to treat patients with early Alzheimer’s disease (AD) in collaboration with AbbVie Biotechnology, Ltd. (“AbbVie”) under the Co-Development and Option Agreement, dated as of October 16, 2017, between the parties, as amended on February 13, 2023 (the “AbbVie Agreement”). As announced on November 25, 2024, the INVOKE-2 Phase 2 clinical trial evaluating the safety and efficacy of AL002 in slowing disease pr…

Costs Associated with Exit or Disposal Activities. On November 25, 2024, Alector, Inc. (“Alector” or “the Company”) committed to a plan to reduce its workforce (the “Plan”) by approximately 17% in order to align resources with the Company's strategic priorities. Based upon the results of the Company's INVOKE-2 Phase 2 clinical trial evaluating the safety and efficacy of AL002 in early Alzheimer’s disease, the Company is stopping the long term extension of the INVOKE-2 study. The Company initi…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information related to the Loan Agreement set forth in

Entry into a Material Definitive Agreement. On November 14, 2024 (the “Closing Date”), Alector, Inc., a Delaware corporation (the “Company”), and Alector LLC, a Delaware limited liability company, as co-borrower (together with the Company, the “Borrowers”), entered into a loan and security agreement (the “Loan Agreement”) by and among the Borrowers, the several banks and other financial institutions from time to time party thereto (the “Lenders”) and Hercules Capital, Inc., as administrative…

and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.

Director — Terry McGuire: Mr. McGuire retired from the Board for personal reasons, and two new directors were appointed.

and Item 9.01 (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, and shall not be incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, except as shall be expressly set forth by specific reference in such a filing.