Immutep Surges 10% on Breakthrough Survival Data in Head & Neck Cancer Trial

Key Highlights:

• Efti + KEYTRUDA® combo shows 17.6-month median survival in CPS <1 patients
• Outperforms historical standards of care by a wide margin
• FDA meeting requested to explore regulatory path for approval
• Shares gain over 10% as market applauds clinical progress

Immutep Ltd (ASX: IMM) delivered a jolt of optimism to investors on Monday, with its shares climbing over 10% to A$0.298, after announcing compelling new survival data from its TACTI-003 Phase IIb trial. The study evaluates Immutep’s flagship immunotherapy candidate, eftilagimod alfa (efti), in combination with Merck’s KEYTRUDA® (pembrolizumab), for first-line treatment of recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) patients with PD-L1 CPS <1.

The latest readout reveals a median overall survival (OS) of 17.6 months—a striking result for a patient population that traditionally lacks effective, chemotherapy-free options. Historical benchmarks for CPS <1 patients show a median OS of just 7.9 months with anti-PD-1 monotherapy and around 10.7 to 11.3 months with chemotherapy-based regimens. By comparison, Immutep’s combination approach more than doubles survival outcomes without the toxicity burden of chemotherapy.

“This is a transformative result for a very hard-to-treat group,” said Immutep CEO Marc Voigt. “Patients with PD-L1 CPS <1 currently have no approved immunotherapy-only options. Efti plus pembrolizumab is showing not just durable responses, but meaningful survival improvement with excellent tolerability.”

The market responded in kind. Trading volume surged past 7.5 million shares—well above the 4-week average of 4.5 million—pushing IMM stock up 10.19% at last check. Despite a year-to-date decline of 18.5%, this rally underscores renewed investor confidence in the company's late-stage clinical pipeline.

Immutep Stock Price Chart - 5th May 2025, Source: stocknessmonster

Immutep now plans to meet with the U.S. Food and Drug Administration to explore regulatory approval pathways. Efti already holds Fast Track designation in both first-line HNSCC and non-small cell lung cancer (NSCLC), positioning it as a frontrunner in next-generation immunotherapy.

With a market cap of approximately A$434 million and a diversified LAG-3-focused immunotherapy pipeline, Immutep is advancing on multiple fronts. Beyond HNSCC, efti is also being tested in NSCLC and metastatic breast cancer, often in combination with checkpoint inhibitors or chemotherapy, thanks to its favorable safety profile.

For now, however, all eyes remain on the FDA and the potential for efti to become a first-in-class, chemotherapy-free immunotherapy option for patients with limited alternatives.