Immutep Receives FDA Orphan Drug Designation for Sarcoma Treatment

Eftilagimod alfa granted rare disease status for soft tissue sarcoma, a difficult-to-treat cancer.

Apr. 16, 2026 at 2:03am

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A translucent, ghostly X-ray image revealing the intricate internal structure of a soft tissue sarcoma tumor, conveying the clinical challenge and the potential of a new treatment to address this rare and difficult-to-treat cancer.An X-ray view of a soft tissue sarcoma tumor, highlighting the complex internal structures that eftilagimod alfa aims to target with its novel immunotherapy approach.Rahway Today

Immutep Limited, a clinical-stage biotechnology company, announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) for eftilagimod alfa ('efti') for the treatment of soft tissue sarcoma (STS), a rare and challenging cancer. The ODD program is designed to encourage the development of therapies for diseases affecting fewer than 200,000 people in the U.S. and provides regulatory support, potential tax credits, fee exemptions, and market exclusivity upon approval.

Why it matters

Soft tissue sarcomas are a rare and aggressive form of cancer with limited treatment options, making the FDA's ODD for efti an important milestone. This designation recognizes the potential of efti to address the significant unmet medical need for STS patients and could accelerate the development and approval of this novel immunotherapy.

The details

The FDA's ODD for efti is based on encouraging clinical data from the investigator-initiated Phase II EFTISARC-NEO trial, which evaluated efti in combination with radiotherapy and pembrolizumab (KEYTRUDA) in patients with resectable soft tissue sarcoma. The study met its primary endpoint, demonstrating a median tumor hyalinization/fibrosis of 51.5%, exceeding the pre-specified target of 35% and historical benchmarks of ~15% with radiotherapy alone. These results were observed across multiple sarcoma subtypes and were supported by translational data showing immune activation consistent with efti's mechanism of action, with a favorable safety profile and no delays to planned surgery.

  • The FDA granted the Orphan Drug Designation for eftilagimod alfa on April 15, 2026.
  • The EFTISARC-NEO trial results were presented at the ESMO Congress 2025 and the CTOS 2025 Annual Meeting.

The players

Immutep Limited

A clinical-stage biotechnology company targeting cancer and autoimmune diseases, and the developer of eftilagimod alfa.

United States Food and Drug Administration (FDA)

The U.S. government agency responsible for regulating and supervising the safety of food, drugs, and other products, including granting Orphan Drug Designation for eftilagimod alfa.

Marc Voigt

The CEO of Immutep Limited.

KEYTRUDA

A registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., a pharmaceutical company.

EFTISARC-NEO

An investigator-initiated Phase II clinical trial evaluating eftilagimod alfa in combination with radiotherapy and pembrolizumab (KEYTRUDA) in patients with resectable soft tissue sarcoma.

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What they’re saying

“We are pleased that the FDA has recognised the potential of efti for patients with soft tissue sarcoma, a rare and difficult to treat cancer.”

— Marc Voigt, CEO of Immutep

What’s next

Immutep is currently undertaking a comprehensive review and analysis following the discontinuation of its Phase III TACTI-004 trial, and the outcome will influence the decision regarding any potential future clinical trial with efti in soft tissue sarcoma.

The takeaway

The FDA's Orphan Drug Designation for eftilagimod alfa in soft tissue sarcoma highlights the significant unmet medical need for new treatment options and the potential of this novel immunotherapy to address this rare and aggressive form of cancer.