Immutep Announces Late-Breaking Abstract on IMP761 Accepted for Poster Presentation at ACR Convergence 2026

• Late-breaking poster will present data from the first-in-human Phase I study of IMP761, a first-in-class LAG-3 agonist antibody, in healthy volunteers

SYDNEY, AUSTRALIA, Oct. 19, 2026 (GLOBE NEWSWIRE) -- Immutep Limited (ASX: IMM; NASDAQ: IMMP) (“Immutep” or “the Company”), a clinical-stage biotechnology company targeting cancer and autoimmune diseases, today announces that a late-breaking abstract has been accepted for poster presentation at the American College of Rheumatology (ACR) Convergence 2026, taking place from 6 to 11 November 2026 in Orlando, Florida, USA.

The poster will present data from the randomised, placebo-controlled, double-blind first-in-human Phase I study (NCT06637865) of IMP761, Immutep’s first-in-class immunosuppressive LAG-3 agonist antibody. The study is being conducted by the Centre for Human Drug Research (CHDR) in Leiden, the Netherlands, in healthy volunteers using CHDR’s keyhole limpet haemocyanin (KLH) challenge model. First interim data from the study were presented at the EULAR 2026 Congress in June 2026.

Details of the presentation are as follows:

The poster will be made available on the Posters & Publications page of Immutep’s website following the presentation.

IMP761 is a first-in-class immunosuppressive LAG-3 agonist antibody and the only LAG-3 agonist currently in clinical development. It is designed to selectively target activated T cells at sites of inflammation, with the aim of reducing pathological immune responses while preserving systemic immune function. Preclinical data supporting IMP761’s mechanism have been published in the Journal of Immunology,¹ with additional supporting data in oligoarticular juvenile idiopathic arthritis (o-JIA) published in Pediatric Research.² The program builds on Immutep’s expertise in the LAG-3 pathway and is being developed as a potential mechanism-based therapy across multiple autoimmune indications driven by T-cell-mediated inflammation.

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.

This press release contains forward-looking statements, including statements regarding anticipated clinical development, regulatory progress and potential benefits of IMP761. These forward-looking statements are based on current expectations, estimates and projections, and involve known and unknown risks, uncertainties and other important factors that could cause actual results to differ materially from those expressed or implied in such statements.

Factors that could cause actual results to differ materially include risks associated with clinical trial outcomes, regulatory developments, and the Company’s ability to advance its product candidates.

Readers are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date of this release. Immutep undertakes no obligation to update or revise such statements, except as required by applicable law.

This announcement has been prepared for informational purposes only and does not constitute an offer to sell, or a solicitation of an offer to buy, securities in any jurisdiction.

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

¹ Angin M, Brignone C, Triebel F. A LAG-3-Specific Agonist Antibody for the Treatment of T Cell-Induced Autoimmune Diseases. J Immunol. 2020;204:810-818. ² Sag E, Demir S, Aspari M, et al. Juvenile idiopathic arthritis: lymphocyte activation gene-3 is a central immune receptor in children with oligoarticular subtypes. Pediatr Res. 2021;90:744-751.