Immutep Data From EFTISARC-NEO Study Evaluating Eftilagimod Alfa With Radiotherapy Plus KEYTRUDA Exceeds Prespecified Level Of Pathologic Response Rates, Reaches Median 51.5% Tumor Hyalinization/Fibrosis

Immutep Limited (ASX: IMM; NASDAQ: IMMP) ("Immutep" or "the Company"), a late-stage immunotherapy company targeting cancer and autoimmune diseases, today announces positive data from the EFTISARC-NEO trial that 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.

The investigator-initiated Phase II study evaluating eftilagimod alfa (efti) with radiotherapy plus KEYTRUDA® (pembrolizumab) in the neoadjuvant setting for resectable soft tissue sarcoma (STS) significantly exceeded the study's prespecified level of pathologic response rates. In the evaluable patient population (N=38), the novel combination with efti reached a median 51.5% tumour hyalinization/fibrosis (p<0.001), meeting the study's primary endpoint.1

These promising results were achieved in patients with ten different STS subtypes including rare and/or highly aggressive tumours with poor prognosis such as myxofibrosarcoma (N=16), undifferentiated pleomorphic sarcoma (N=10) and malignant peripheral nerve sheath tumor (N=2).