New data presented at the Connective Tissue Oncology Society (CTOS) 2024 Annual Meeting reveals promising results from a Phase II trial of Immutep's eftilagimod alpha (efti) in combination with radiotherapy and pembrolizumab (KEYTRUDA®) for patients with soft tissue sarcoma (STS). The EFTISARC-NEO trial indicates significant efficacy in the neoadjuvant setting for resectable STS.
The trial, led by Katarzyna Kozak, M.D., Ph.D., and Paweł Sobczuk, M.D., Ph.D., at MSCNRIO (Warsaw), showed 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 is an important predictor of overall survival for STS patients.
Pathologic Response and Safety
The EFTISARC-NEO trial, with data cutoff 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 was well-tolerated, with no grade ≥3 toxicities related to efti and pembrolizumab.
Expert Commentary
"Our belief in efti’s unique mechanism of action to complement radiotherapy and pembrolizumab in order drive better outcomes for patients with this rare aggressive disease was the foundation of the EFTISARC-NEO trial," stated Drs. Kozak and Sobczuk. "These very encouraging results we are presenting today build our confidence in the synergistic effects of this new therapeutic approach and its potential to treat these patients in dire need of more effective therapies."
Ongoing 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, anticipates reaching its planned enrollment of 40 patients in Q1 CY2025. The trial is primarily funded by a grant from the Polish Medical Research Agency program. More information is available at clinicaltrials.gov (NCT06128863).
Immutep's Perspective
Dr. Frédéric Triebel, CSO of Immutep, commented, "We are pleased with the strength of these preliminary results in this difficult-to-treat cancer. To see 71.4% of soft tissue sarcoma patients achieving a pathologic response defined as ≥35% of hyalinization/fibrosis combined with low viable tumour cells at 8% is very promising, especially as strong efficacy has been observed in different STS subtypes."
