Exhibit 99.1 APTEVO THERAPEUTICS REPORTS 2023 FINANCIAL RESULTS AND PROVIDES A BUSINESS UPDATE Announces 1H24 Plan for Development of Lead Candidate APVO436 for the Treatment of Frontline Acute Myeloid Leukemia, Interim Results Expected Late 2H24 ALG.APV-527 Phase 1 Trial for the Treatment of Multiple Solid Tumors Continues Enrollment, Interim Results Expected 1H24 SEATTLE, WA – March 5, 2024 – Aptevo Therapeutics Inc. (Nasdaq: APVO), a clinical-stage biotechnology company focused on developing novel immune ...

th | --- | --- | --- | |------------------------------------------------------|------------------|-----------------------------------------------------------------------| | Title of Each Class | Trading Symbol | Name of Exchange on Which Registered | | Common Stock, $0.001 par value per share | APVO | The Nasdaq Stock Market LLC (The Nasdaq Capital Market) | UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SEC ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37746 | --- | --- | --- | |-----------------------------------------------------------------------------|-------------------- ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37746 | --- | --- | --- | |------------------------------------------------------------------------------------------------------- ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-37746 | --- | --- | --- | |------------------------------------------------------------------------------------------------------ ...

th | --- | --- | --- | |-----------------------------------------------------------------------------|------------------|-----------------------------------------------------------------------| | | | | | Securities registered pursuant to Section 12(b) of the Act: | | | | Title of Each Class | Trading Symbol | Name of Exchange on Which Registered | | Common Stock, $0.001 par value per share | APVO | The Nasdaq Stock Market LLC (The Nasdaq Capital Market) | UNITED STATES SECURITIES AND EXCHANGE COMMISSION Was ...