How Immutep’s Efti Combo Is Changing the Soft Tissue Sarcoma Landscape
Immutep’s novel immunotherapy combination with radiotherapy and KEYTRUDA® has met its primary endpoint in a Phase II trial for resectable soft tissue sarcoma, showing promising early signs of improved patient outcomes.
- Efti with radiotherapy and KEYTRUDA® exceeded primary endpoint of tumor hyalinization/fibrosis
- Median tumor hyalinization/fibrosis reached 50%, surpassing historical radiotherapy data
- Trial enrolled 40 patients with resectable soft tissue sarcoma in Poland
- Results support efti’s role in activating immune response against sarcoma tumors
- Detailed data to be presented at upcoming medical meeting
A Breakthrough in Soft Tissue Sarcoma Treatment
Immutep Limited (ASX: IMM; NASDAQ: IMMP) has announced a significant milestone in its ongoing effort to improve outcomes for patients with soft tissue sarcoma (STS), a rare and aggressive form of cancer. The company’s Phase II EFTISARC-NEO trial, which combines its proprietary immunotherapy eftilagimod alpha (efti) with radiotherapy and the checkpoint inhibitor KEYTRUDA® (pembrolizumab), has met its primary endpoint. This achievement marks a promising advance in the neoadjuvant treatment setting for patients with resectable STS.
The primary endpoint focused on tumor hyalinization and fibrosis, an early surrogate marker observed at surgical resection that correlates with better overall and recurrence-free survival. Impressively, the trial reported a median tumor hyalinization/fibrosis rate of 50%, significantly exceeding the prespecified target of 35% and historical data of 15% seen with radiotherapy alone. This suggests the combination therapy may substantially enhance the immune system’s ability to attack the tumor.
Clinical and Scientific Context
The trial was conducted at the Maria Skłodowska-Curie National Research Institute of Oncology in Warsaw, Poland, a leading center for STS treatment. Principal investigators Dr. Katarzyna Kozak and Dr. Paweł Sobczuk highlighted the encouraging nature of these results, emphasizing the chemotherapy-free regimen’s potential to transform the immunosuppressive tumor microenvironment typical of soft tissue sarcomas. By activating antigen-presenting cells, efti stimulates a broad immune response involving cytotoxic T cells, helper T cells, natural killer cells, and others, which may explain the observed anti-cancer efficacy.
Soft tissue sarcoma remains an orphan disease with limited treatment options and poor prognosis. According to the American Cancer Society, approximately 13,520 new STS cases are expected in the United States in 2025, with around 5,420 deaths. The high unmet medical need underscores the importance of innovative therapies like efti.
Looking Ahead
The EFTISARC-NEO study, primarily funded by a Polish government grant, completed enrollment of 40 patients earlier this year. While detailed efficacy and safety data are still forthcoming, the company plans to present comprehensive results at a future medical meeting later in 2025. These findings will be critical for assessing the full clinical potential of the combination and guiding next steps in development and regulatory strategy.
Immutep’s efti is also being evaluated across multiple solid tumors, including non-small cell lung cancer and head and neck squamous cell carcinoma, benefiting from a favorable safety profile and FDA Fast Track designations. The success in STS adds to the growing body of evidence supporting efti’s role as a versatile immunotherapy agent.
Bottom Line?
With primary endpoint success in a challenging cancer, Immutep’s next data release could reshape soft tissue sarcoma treatment prospects.
Questions in the middle?
- What detailed efficacy and safety data will the full trial results reveal?
- How might these results influence regulatory approval timelines and commercial partnerships?
- Can efti’s immune activation translate into long-term survival benefits for STS patients?
