Promising Early Results from Phase II Soft Tissue Sarcoma Trial with Efti, Radiotherapy, and Checkpoint Inhibitor

A recent Phase II clinical trial has yielded promising results for a new therapeutic approach to treating soft tissue sarcoma (STS), a rare and challenging cancer. The EFTISARC-NEO study, initiated by investigators, combines eftilagimod alpha (efti) with radiotherapy and pembrolizumab (KEYTRUDA®), a standard treatment for STS. This is the first time efti has been used in a neoadjuvant setting, allowing for the assessment of its impact on the tumor microenvironment before surgery.

The trial, conducted by the Maria Skłodowska-Curie National Research Institute of Oncology in Warsaw, has shown that the triple combination is well-tolerated and has not introduced any new safety concerns. Out of the first six patients who completed the treatment and underwent surgery, four (67%) exhibited near-complete responses, a significant improvement compared to standard therapies.

The principal investigators, Dr. Katarzyna Kozak and Dr. Paweł Sobczuk, highlighted the encouraging initial pathologic responses and the potential synergistic effects of this novel treatment. They observed a high degree of hyalinization/fibrosis in the surgical samples, a rare occurrence with conventional treatments.

Immutep's Chief Scientific Officer, Dr. Frédéric Triebel, expressed satisfaction with the early findings, noting that the study is the first to evaluate efti in a non-metastatic cancer setting. He emphasized the role of efti in driving a significant anti-cancer immune response by activating antigen-presenting cells.

Efti's unique activation of dendritic cells, as an MHC Class II agonist, leads to a broad immune response against cancer, including the proliferation of CD8+ cytotoxic T cells. The combination with radiotherapy and anti-PD-1 therapy is expected to generate a robust anti-tumour immune response, even in the immunosuppressed tumor microenvironment of STS.

The EFTISARC-NEO study is an open-label trial that plans to treat up to 40 patients. It is primarily funded by a grant from the Polish government and is registered on clinicaltrials.gov (NCT06128863). The primary endpoint of the study is the pathologic response rate, which will be assessed at the time of surgical resection. The study is ongoing, with 14 patients enrolled to date, and further clinical data is expected to be presented at a medical conference later this year.

Soft tissue sarcoma is a rare disease with a poor prognosis and a significant unmet medical need. The incidence varies globally, with approximately 23,400 cases annually in Europe and 13,400 new cases estimated in the United States each year.

Immutep is a clinical-stage biotechnology company specializing in the development of LAG-3 immunotherapies for cancer and autoimmune diseases. The company is committed to bringing innovative treatment options to patients and maximizing value for shareholders.