• Novel combination of efti with radiotherapy and pembrolizumab met primary endpoint of tumour hyalinization/fibrosis
• Results support efti's ability to transform immunosuppressed tumour microenvironment in soft tissue sarcoma
• Detailed results planned for future medical meeting presentation

Immutep Limited (ASX: IMM; NASDAQ: IMMP) has announced that the investigator-initiated EFTISARC-NEO Phase II trial evaluating eftilaginod alpha (efti) with radiotherapy plus KEYTRUDA® (pembrolizumab) in the neoadjuvant setting for resectable soft tissue sarcoma (STS) has met its primary endpoint. The novel combination significantly exceeded the study's prespecified median of 35% tumour hyalinization/fibrosis versus 15% for historical data from radiotherapy alone in patients with resectable STS. Tumour hyalinization/fibrosis is an early surrogate endpoint at the time of surgical resection that has been associated with improved overall survival and recurrence-free survival for STS patients. The trial's investigators plan to present detailed results from the study at a future medical meeting. The EFTISARC-NEO study, which is primarily funded with a grant from the Polish government, subsequently completed enrolment of 40 patients in January 2025. STS is an orphan disease with high unmet medical need and a poor prognosis for patients. Efti is Immutep's proprietary soluble LAG-3 protein and MHC Class II agonist that stimulates both innate and adaptive immunity for the treatment of cancer.

The results support Immutep's belief that efti's activation of antigen-presenting cells and subsequent broad adaptive and innate immune response helps transform the immunosuppressed tumour microenvironment of soft tissue sarcomas, leading to strong anti-cancer efficacy. Detailed results from the trial are planned for presentation at a future medical meeting.