Immutep Receives Positive Feedback from FDA on Late-Stage Clinical Development of Eftilagimod Alfa in Head and Neck Cancer with CPS 1 SYDNEY, AUSTRALIA August 5th, 2025 Immutep Limited (ASX: IMM; NASDAQ: IMMP) ( Immutep

Positive Feedback from FDA on Late-Stage Clinical Development of Eftilagimod Alfa in Head and

Neck Cancer with CPS <1

SYDNEY, AUSTRALIA August 5th, 2025 Immutep Limited (ASX: IMM; NASDAQ: IMMP) ( Immutep or the

Company ), a late-stage immunotherapy company targeting cancer and autoimmune diseases, today announces it has received positive and constructive feedback from the US Food and Drug Administration (FDA), regarding future clinical development of

its first-in-class MHC Class II agonist, eftilagimod alfa ( efti ), for first line treatment of recurrent/metastatic head and neck squamous cell carcinoma

(1L HNSCC) patients who have PD-L1 expression below 1 (Combined Positive Score [CPS] <1).

of the encouraging data in 1L HNSCC with CPS <1 from the TACTI-003 (KEYNOTE-C34) Phase IIb trial evaluating efti in combination with MSD s (Merck & Co.,

Inc., Rahway, NJ, USA) anti-PD-1 KEYTRUDA (pembrolizumab), the FDA agreed on the potential of efti in

combination with KEYTRUDA to address the high unmet need in this CPS <1 patient segment and is supportive of the combination s further development.

Paths for future clinical development and potential accelerated approval in light of the FDA s Project FrontRunner include a randomised registrational

trial evaluating efti in combination with KEYTRUDA against standard-of-care therapy or alternatively a smaller single-arm study

(e.g. 70 - 90 patients) with safety, response rate, and duration of response as key endpoints, followed by a confirmatory randomised study that builds on the existing data.

We are pleased with the FDA s feedback and guidance that underscores the high unmet need of head and neck cancer patients whose PD-L1 expression level is below one. The FDA feedback positions Immutep to evaluate options for future collaborative clinical development paths to bring a new, effective and safe treatment option to this underserved

patient population, said Marc Voigt, CEO of Immutep.

Our primary focus clearly remains the pivotal

TACTI-004 Phase III evaluating efti as first line therapy for non-small cell lung cancer and we are excited with its progress to date and the consistent, encouraging

feedback we hear from physicians. This focus and additional considerations will be reviewed internally and discussed with stakeholders and potential strategic partners in regards to forward paths in head and neck cancer, added Mr Voigt.

Project FrontRunner is an FDA Oncology Center of Excellence (OCE) initiative to encourage drug sponsors to consider when it may be appropriate to

develop and seek approval of cancer drugs for advanced/metastatic disease, in an earlier clinical setting rather than the usual approach to develop and seek approval of a drug for treatment of patients who have received numerous prior lines of

therapies or have exhausted available treatment options. In this setting, advancing new effective therapies has the greatest potential to significantly improve quantity and quality of patients lives.

Patients with CPS <1 in 1L HNSCC represent a treatment population with high unmet medical need. Up to 20% of 1L HNSCC patients have CPS <1 and despite

immunotherapy s progress in fighting cancer, anti-PD-1 therapy alone (without chemotherapy) is only approved for patients who express

PD-L1 (CPS >1). All currently available treatment options for patients with PD-L1 CPS <1 include chemotherapy.

Immutep is a late-stage biotechnology company developing novel immunotherapies for cancer and autoimmune disease. 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.

KEYTRUDA is a registered trademark

of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

Australian Investors/Media:

Eleanor Pearson, Sodali & Co.

U.S. Investors/Media:

Chris Basta, VP, Investor Relations and Corporate Communications

+1 (631) 318 4000; chris.basta@immutep.com

announcement was authorised for release by the Board of Immutep Limited.