UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

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

APTEVO THERAPEUTICS INC.

(Exact name of Registrant as Specified in Its Charter)

(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:

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

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 5.07 Submission of Matters to a Vote of Security Holders.

On September 22, 2026, Aptevo Therapeutics Inc. (the “Company”) held its Special Meeting of Stockholders (the “Special Meeting”), at which a quorum was present. Stockholders considered four proposals outlined below, each of which is described in more detail in the Company’s definitive proxy statement for the Special Meeting filed with the Securities and Exchange Commission on August 31, 2026 (the “Proxy Statement”). The final voting results with respect to each of the proposals acted upon at the 2026 Special Meeting are set forth below.

Proposal 1: Approval of the Company's Amended and Restated Certificate of Incorporation

An amendment to the Company’s Amended and Restated Certificate of Incorporation, as amended, to make certain technical and administrative changes was not approved based on the following:

Proposal 2: Approval of the issuance of common stock

The issuance of more than 20% of the Company's issued and outstanding common stock as of August 12, 2026 pursuant to the warrant reload and private placement transactions with certain holders, pursuant to Nasdaq Listing Rules 5635(d) was approved based on the following:

Proposal 3: Approval of the Company's Fifth Amended and Restated 2018 Stock Incentive Plan

The Aptevo Therapeutics Inc. Fifth Amended and Restated 2018 Stock Incentive Plan was approved based on the following votes:

Proposal 4: Authorization to adjourn the Special Meeting

The authorization to adjourn the Special Meeting to a later date, if necessary or appropriate, was approved based on the following votes:

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.