Immutep Announces Abstract Accepted for Presentation at the American Society of Clinical Oncology (ASCO) 2026 Annual Meeting

Immutep Limited (ASX: IMM; NASDAQ: IMMP) (“Immutep” or “the Company”), a clinical-stage immunotherapy company targeting cancer and autoimmune diseases, today announces an abstract has been selected for poster presentation at the upcoming 2026 American Society of Clinical Oncology’s (ASCO) Annual Meeting, taking place in-person and online from 29 May-2 June 2026 in Chicago, Illinois (United States).

The accepted abstract, titled “Impact of eftilagimod alfa, an APC activator via MHC class II, on lymphocyte activation and survival outcomes in metastatic cancer patients,” will be presented within the Developmental Therapeutics—Immunotherapy sessions by Professor Martin Forster from the UCL Cancer Institute, UK.

The poster will present cumulative clinical and translational data demonstrating that eftilagimod alfa (efti), an antigen-presenting cell (APC) activator targeting MHC Class II, induces rapid and sustained lymphocyte activation. Across multiple late-stage cancer studies 1 , immune activation markers were associated with improved overall survival outcomes in patients with metastatic disease, supporting the clinical relevance of eftilagimod alfa’s mechanism of action.

ASCO 2026 Poster Presentation Details

Title : Impact of eftilagimod alfa, an APC activator via MHC class II, on lymphocyte activation and survival outcomes in metastatic cancer patients Poster Session : Developmental Therapeutics—Immunotherapy Date and Time : 30 May 2026, 1:30 PM-4:30 PM CDT Poster Board : 359 Abstract # : 2569

About ASCO 2026

The ASCO Annual Meeting represents the world’s largest gathering of oncology physicians, industry representatives, researchers, patient advocates and investment analysts to discuss cutting-edge clinical research and emerging therapeutics in oncology, and to gain insights to improve cancer care. More than 40,000 attendees from around the world are expected to participate in person and online to stay up to date on the latest advances across all areas of cancer research and to hear real-time insights from world-renowned experts. For additional information on the ASCO Annual Meeting, please visit www.asco.org .

About Immutep

Immutep is a clinical-stage biotechnology company developing novel immunotherapies for cancer and autoimmune diseases . The Company is a pioneer in the understanding and advancement of therapeutics related to Lymphocyte Activation Gene-3 (LAG-3), and its diversified product portfolio harnesses LAG-3’s ability to stimulate or suppress the immune response. Immutep is dedicated to leveraging its expertise to bring innovative treatment options to patients in need and to maximise value for shareholders. For more information, please visit www.immutep.com .

Australian Investors/Media: Eleanor Pearson, Sodali & Co. +61 2 9066 4071; [email protected]

U.S. Investors/Media: Matthew Beck, astr partners +1 (917) 415-1750; [email protected]

This announcement was authorised for release by the CEO of Immutep Limited.

1 Please note that the abstract does not include data from the TACTI-004 study, as immune data collection for that trial has not yet been completed. All data presented were collected from earlier clinical trials, initiated prior to TACTI-004.