TLDR
- Immutep stock jumped over 101% on Wednesday after receiving FDA Orphan Drug Designation for eftilagimod alfa (efti).
- The designation covers soft tissue sarcoma, a rare cancer affecting fewer than 200,000 people in the US.
- Benefits include seven years of market exclusivity, tax credits, fee exemptions, and regulatory support.
- The FDA decision is backed by Phase II EFTISARC-NEO trial data, which met its primary endpoint in 38 patients.
- This follows the recent halt of the TACTI-004 Phase III trial, which is expected to extend the company’s cash runway beyond Q2 2027.
Immutep’s stock more than doubled on Wednesday after the Australian biotech received Orphan Drug Designation (ODD) from the U.S. Food and Drug Administration for its lead cancer drug, eftilagimod alfa.
The ASX-listed company saw its stock climb 101.3% to A$0.079 during Wednesday trade.
The FDA designation covers efti’s use in soft tissue sarcoma (STS), a rare cancer with an unmet medical need in the United States.
ODD comes with a valuable set of perks: regulatory guidance, potential tax credits, fee exemptions, and seven years of market exclusivity if the drug is eventually approved.
The FDA’s decision was supported by data from the Phase II EFTISARC-NEO trial. That study tested efti in combination with radiotherapy and Merck’s KEYTRUDA (pembrolizumab) in patients with resectable soft tissue sarcoma ahead of surgery.
In 38 evaluable patients, the trial met its primary endpoint. It recorded a median tumour hyalinization/fibrosis rate of 51.5%, well above the pre-set target of 35% and the historical benchmark of around 15% seen with radiotherapy alone.
Results held across multiple sarcoma subtypes. The safety profile was described as favourable, with no delays to planned surgery reported.
TACTI-004 Wind-Down
The positive FDA news comes shortly after Immutep halted its TACTI-004 Phase III trial in early March. That trial was testing efti in first-line non-small cell lung cancer.
An Independent Data Monitoring Committee recommended the trial be stopped due to futility. The company is now winding down TACTI-004 in an orderly fashion.
Immutep said the trial closure is expected to stretch its cash runway well beyond its previous guidance of Q2 2027.
Pipeline and Financials
Beyond STS and lung cancer, Immutep is running five LAG-3 programs. One of these, IMP761, is currently in a Phase I study targeting autoimmune diseases.
The company posted a net loss of A$61.4 million for the 2025 financial year, up from A$42.7 million in 2024.
As a pre-commercial company, Immutep still requires additional funding to sustain its research and development work.
It maintains partnerships with major pharma players, including Merck (MSD), to help advance its pipeline.
The EFTISARC-NEO trial data, which directly supported Wednesday’s FDA designation, included translational findings consistent with efti’s mechanism of action — immune activation via LAG-3.
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