Immutep Quarterly Activities Report Q2 FY26

Media Release

Entered into strategic collaboration with Dr. Reddy’s for commercialisation of eftilagimod alfa (efti) in all countries outside North America, Europe, Japan, and Greater China

In January 2026, Immutep received ~A$30 million upfront payment from Dr. Reddy’s and is eligible to receive up to ~A$528 million in potential milestones, plus royalties on commercial sales of efti

Strong operational progress reported for TACTI-004 (KEYNOTE-F91) Phase III trial evaluating efti in first line non-small cell lung cancer (1L NSCLC), with completion of the futility analysis on track for the first quarter of CY2026

Data from INSIGHT-003 at ESMO Congress 2025 show combination of efti with KEYTRUDA ® and chemotherapy generates strong response rates across all PD-L1 expression levels in 1L NSCLC, including 61.7% ORR in low & no PD-L1 (TPS 50%). This is particularly important for patients with low and no PD-L1 (TPS <50%), who represent over two-thirds of the 1L NSCLC patient population and for whom PD-(L)1 inhibitors typically perform suboptimally. In patients with TPS <50% (N=47), the combination with efti has achieved a strong and improved 61.7% ORR compared to historical control of 40.8%. 1,2

Further to the strong efficacy data from INSIGHT-003, the combination with efti continues to have a favourable safety profile.

SOFT TISSUE SARCOMA

EFTISARC-NEO – Phase II Trial in Soft Tissue Sarcoma

In October, Immutep announced that positive data from the EFTISARC-NEO Phase II investigator-initiated trial evaluating efti with radiotherapy plus KEYTRUDA in the neoadjuvant setting for resectable soft tissue sarcoma (STS) was shared in a Proffered Paper oral presentation by Katarzyna Kozak, M.D., Ph.D., Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland at the ESMO Congress 2025 in Berlin, Germany.

The EFTISARC-NEO trial met the primary endpoint and significantly exceeded the study’s prespecified 35% tumour hyalinization/fibrosis with a median 51.5% tumour hyalinization/fibrosis (p<0.001) in the evaluable patient population (N=38). 3 This may hold significance in terms of future outcomes as tumour hyalinization/fibrosis serves as an early surrogate endpoint correlated with improved survival in STS patients. 4 Disease-free survival and overall survival data are immature at this stage and will be presented in the future.

In November, early translational data from the EFTISARC-NEO trial were detailed in an oral presentation by Paweł Sobczuk, M.D., Ph.D., Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland, at the Connective Tissue Oncology Society (CTOS) 2025 Annual Meeting held in Boca Raton, Florida. Results from the initial twenty patients who underwent surgery in the trial show a strong immune system activation in line with efti’s mode of action, with statistically significant increases in the expression of key cytokines and chemokines in peripheral blood — specifically CXCL9, CXCL10, IL-23, and IFN-γ.

The increase on treatment of immune response biomarkers like IFN-γ correlated with pathologic responses in this study, meaning patients with a biomarker increase during treatment also had a higher probability of a good clinical response at surgery.

Additionally, during the quarter, the EFTISARC NEO trial was awarded second place in the distinguished Golden Scalpel Award competition in Poland. This competition recognises the most innovative solutions in Polish medicine and is presented by independent experts to initiatives that set new standards in advancing healthcare. EFTISARC-NEO was the only oncology project to receive this accolade, underscoring its leadership and breakthrough potential in cancer treatment.

BREAST CANCER

AIPAC-003 – Phase II/III Trial in Metastatic Breast Cancer

Immutep continues to execute the AIPAC-003 trial, which has enrolled 71 metastatic hormone receptor positive (HR+), HER2-negative/low patients resistant to endocrine therapy including cyclin-dependent kinase 4/6 (CDK4/6) inhibitors or triple-negative breast cancer patients.

Immutep completed patient enrolment in the randomised Phase II portion of the AIPAC-003 trial in late 2024. Patients across 22 clinical sites in Europe and the United States have been randomised 1:1 to receive either 30 mg or 90 mg dosing of efti in combination with paclitaxel to determine the optimal biological dose consistent with the FDA’s Project Optimus initiative and prior regulatory interaction with FDA.

In October, Immutep announced that positive feedback had been received from the US Food and Drug Administration (“FDA”) regarding the successful completion of Project Optimus requirements and agreement on 30 mg as the optimal biological dose for efti. The agreement with the FDA on efti’s optimal biological dosing carries strategic importance in the ongoing and future clinical development of efti, including the global TACTI-004 (KEYNOTE-F91) Phase III trial.

In December, Immutep announced that new data from the AIPAC-003 trial was presented by Dr. Nuhad Ibrahim, Professor, Department of Breast Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center at the 2025 San Antonio Breast Cancer Symposium (SABCS) taking place in San Antonio, Texas.

The data presented shows that both efti dosing levels on top of weekly paclitaxel in heavily pretreated metastatic breast cancer patients, who received a median of three prior lines of systemic therapy, led to strong objective response rates (ORR) and disease control rates (DCR) of 41.9% and 87.1% (30 mg efti) and 48.5% and 78.8% (90 mg efti), respectively, in the evaluable population (N=64).

New Investigator-Initiated Phase II Trial for Neoadjuvant Efti in HR+/HER2-negative Breast Cancer

Immutep continues to progress with a new investigator-initiated Phase II trial evaluating neoadjuvant efti as monotherapy and in combination with chemotherapy prior to surgery in early-stage HR+/HER2-negative breast cancer patients. The trial aims to assess pathological complete response (pCR) after neoadjuvant efti treatment and neoadjuvant chemotherapy (NAC).

The study will treat up to 50 evaluable patients in a two-stage design and will be primarily funded by grants and The GW University Cancer Center. Immutep will provide efti at no cost, technical support, and limited funding that falls within its existing budget.

UROTHELIAL CANCER

INSIGHT-005

The investigator-initiated INSIGHT-005 Phase I study, conducted by the Institute of Clinical Cancer Research, Krankenhaus Nordwest (IKF) to evaluate the safety and efficacy of efti in combination with avelumab in up to 30 patients with metastatic urothelial cancer, was discontinued by IKF after the end of the quarter. This decision was made, as significant changes in the treatment landscape created challenges with patient recruitment. Only 3 patients were recruited in total.

IMP761 DEVELOPMENT PROGRAM FOR AUTOIMMUNE DISEASE

IMP761 – Phase I Trial

In December, Immutep announced a positive update from the placebo-controlled, double-blind first-in-human Phase I study in healthy participants evaluating IMP761, a first-in-class LAG-3 agonist antibody for autoimmune diseases.

The single-ascending dose escalation portion of the trial successfully completed the 2.5 and 7 mg / kg dosing levels of IMP761 with continued positive safety and efficacy data. IMP761 was tolerated well with no treatment-related adverse reactions beyond mild intensity. Additionally, evidence of dose dependent immunosuppressive effects with IMP761 was observed with significant, long-lasting inhibition of the three T-cell-mediated intradermal reactions to a strong foreign antigen on day 2, 9 and 23.

Given the encouraging efficacy and safety to date, the trial will continue as planned and additional updates are anticipated in the first half of CY2026 including a planned presentation of data at a major medical conference.

INTELLECTUAL PROPERTY

During the quarter, Immutep was granted four patents.

The New Zealand Patent Office granted a new patent protecting Immutep’s intellectual property for a binding assay for determining MHC Class II binding activity of LAG-3 protein. The assay is used in the characterisation of efti in GMP-grade manufacturing.

Three new patents directed to IMP761 were also granted. Two were granted in Brazil and one in Japan.

CORPORATE & FINANCIAL SUMMARY

Annual General Meeting Immutep successfully held its Annual General Meeting (AGM) during the quarter, with all resolutions put forward to shareholders strongly approved. The Company appreciates the continued support and engagement of its shareholders as it advances its strategic and operational objectives.

Cash Flow Summary

During the quarter, Immutep continued to exercise prudent cash management as it advanced its clinical trial programs for efti and for IMP761.

The Company is well funded with a strong cash and cash equivalent, and term deposit balance as at 31 December 2025 of approximately A$99.1 million, which is in line with budget as at the beginning of FY2026, while progressing our clinical programs within announced timeframes. The total balance consists of 1) a cash and cash equivalent balance of A$72.7 million and 2) bank term deposits totaling A$26.4 million, which have been recognised as short-term investments due to having maturities of more than 3 months and less than 12 months. This amount is topped up by the upfront payment (~A$30.2 million) from Dr. Reddy’s received in January 2026, leading to a pro-forma balance of A$129.3 million at the time of preparing this report.

In Q2 FY26, cash receipts from customers were A$4k. The net cash used in G&A activities in the quarter was A$1.3 million, compared to A$578k in Q1 FY26. During the quarter, Immutep received EUR2.59 million (~ A$4.6 million) R&D tax incentive payment in cash from the French Government under its Crédit d’Impôt Recherche scheme (CIR) to support the ongoing and planned global clinical development of efti and IMP761.

The cash used in R&D activities during the quarter was A$9.9 million, compared to A$15.8 million in Q1 FY26. The higher figure in the prior quarter was primarily due to the large prepaid clinical trial expenses and higher milestone‑based manufacturing payments made in Q1 FY26.

Payment for staff costs was A$2.6 million in the quarter, compared to A$3.4 million in Q1 FY26. Total net cash outflows used in operating activities in the quarter were A$9.4 million compared to A$19.0 million in Q1 FY26.

Payments to Related Parties comprises Non-Executive Directors’ fees and Executive Directors’ remuneration of A$474k.

Total cash outflow used in investing activities for the quarter was A$144k, which is mainly for the acquisition of office and lab equipment.

Furthermore, during the quarter, a long-term vendor * agreed to defer payment of ~A$30 million which would be payable by Immutep for future services related to Biologics License Application (BLA) readiness by up to 30 months. This provides strong external validation of Immutep’s development strategy and long-term value creation potential.

The current funds available to the Company at the time of this report provide an expected cash reach well into Q2 CY2027, not including receipt of any future potential milestone payments to be received.

About Immutep 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 .

Shirish Gadgeel et al. Updated Analysis From KEYNOTE-189: Pembrolizumab or Placebo Plus Pemetrexed and Platinum for Previously Untreated Metastatic Nonsquamous Non–Small-Cell Lung Cancer. JCO 38, 1505-1517 (2020). DOI:10.1200/JCO.19.03136

Immutep’s Efti with KEYTRUDA® (pembrolizumab) & Chemotherapy Achieves High Response Rates in First-Line Non-Small Cell Lung Cancer - May 2025 press release

ESMO Congress 2025 Proffered Paper presentation, “EFTISARC-NEO: A phase II study of neoadjuvant eftilagimod alpha, pembrolizumab and radiotherapy in patients with resectable soft tissue sarcoma”

Rao SR et al. Extent of tumor fibrosis/hyalinization and infarction following neoadjuvant radiation therapy is associated with improved survival in patients with soft-tissue sarcoma. Cancer Med. 2022 Jan;11(1):194-206. doi: 10.1002/cam4.4428. Epub 2021 Nov 27. PMID: 34837341; PMCID: PMC8704179.

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

U.S. Investors/Media: Chris Basta, VP, Investor Relations and Corporate Communications +1 (631) 318 4000; [email protected]

------------------------------------

*Immutep does not consider the arrangement with or the identity of the vendor to be information that a reasonable person would expect to have a material effect on the price or value of the entity’s securities and considers that this disclosure contains all materially relevant and accurate information in assessing the impact on the value of Immutep’s securities. The long-term vendor is recognised internationally as one of the leaders in its sector, supporting a broad portfolio of biotechnology and pharmaceutical companies across multiple regions. The vendor operates multiple state-of-the-art facilities across Asia, North America, and Europe and is recognised for its strong financial position, robust global infrastructure, and industry-leading quality systems. It is publicly listed on a major international exchange.