Immutep Limited announced positive data from the EFTISARC-NEO Phase II trial, evaluating eftilagimod alpha (efti) in combination with radiotherapy and KEYTRUDA® (pembrolizumab) for patients with resectable soft tissue sarcoma (STS). The results, presented at the Connective Tissue Oncology Society (CTOS) 2024 Annual Meeting, indicate significant efficacy of the triple combination in the neoadjuvant setting.
The EFTISARC-NEO trial's principal investigators, Katarzyna Kozak, M.D., Ph.D., and Paweł Sobczuk, M.D., Ph.D., highlighted the synergistic effects of the therapeutic approach. They noted that the high level of hyalinization/fibrosis achieved with the novel combination therapy was three times above historical results from standard radiotherapy, demonstrating remarkable efficacy in patients with resectable soft tissue sarcomas.
Significant Increase in Tumor Hyalinization
The study revealed a greater than three-fold increase in tumor hyalinization/fibrosis (median 50%) at the time of surgical resection, compared to a historical median of 15% from standard radiotherapy alone. Tumor hyalinization/fibrosis rate has been identified as an important predictor of overall survival for STS patients.
Pathologic Response and Safety Profile
The EFTISARC-NEO trial, with data cut-off on October 20, 2024, demonstrated that 71.4% of patients achieved a pathologic response, defined as ≥35% of hyalinization/fibrosis, and 9.5% of patients achieved a complete pathologic response. The triple combination therapy exhibited a favorable safety profile, with no grade ≥3 toxicities related to efti and pembrolizumab.
Immutep's Perspective
Dr. Frédéric Triebel, CSO of Immutep, expressed satisfaction with the preliminary results, particularly the 71.4% pathologic response rate and low viable tumor cells observed across different STS subtypes. He emphasized the potential of efti as a neoadjuvant immunotherapy to drive improved clinical outcomes.
Trial Details
The ongoing open-label EFTISARC-NEO Phase II study, conducted by the Maria Skłodowska-Curie National Research Institute of Oncology (MSCNRIO) in Warsaw, is expected to reach its planned enrollment of 40 patients in Q1 CY2025. The trial is primarily funded by a grant from the Polish Medical Research Agency program. Further details are available at clinicaltrials.gov (NCT06128863).
