Immutep’s Efti in Combination with KEYTRUDA® (pembrolizumab) Drives Strong Overall Survival in Head and Neck Cancer with CPS <1

Rhea-AI Summary

Immutep (NASDAQ: IMMP) has announced exceptional results from its TACTI-003 Phase IIb trial, showing a median Overall Survival (OS) of 17.6 months for head and neck cancer patients with PD-L1 CPS <1. The trial evaluated eftilagimod alfa (efti) combined with KEYTRUDA® in first-line therapy for recurrent/metastatic head and neck squamous cell carcinoma.

The results significantly outperform current standard-of-care treatments, which show OS of 10.7 months for cetuximab + chemotherapy and 11.3 months for anti-PD-1 therapy + chemotherapy. The combination therapy was well-tolerated with no new safety concerns. Notably, this represents a potential breakthrough for the 20% of patients with CPS <1, who currently have no chemotherapy-free treatment options.

The company has requested an FDA meeting to discuss potential paths to approval, leveraging its Fast Track designation in 1L HNSCC.

Positive

• Achieved exceptional 17.6-month median Overall Survival, significantly higher than current treatment options
• Treatment shows 7-fold increase in response rates compared to anti-PD-1 monotherapy
• Well-tolerated safety profile with no new safety signals
• Addresses high unmet medical need for 20% of 1L HNSCC patients
• Fast Track designation from FDA already secured

Negative

• Still requires FDA approval for commercialization
• Limited patient sample size (N=31) in the trial

News Market Reaction

+45.61%

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+45.61% News Effect

On the day this news was published, IMMP gained 45.61%, reflecting a significant positive market reaction.

Data tracked by StockTitan Argus on the day of publication.

• Complementary nature of these two immunotherapies leads to excellent 17.6-month median Overall Survival in head and neck cancer patients with PD-L1 CPS <1
• Mature overall survival data builds on encouraging high response rates with multiple complete responses
• Patients with CPS <1 represent a high unmet medical need and have no available treatment options without chemotherapy
• Meeting with FDA has now been requested to discuss next steps including potential paths to approval

SYDNEY, AUSTRALIA, May 05, 2025 (GLOBE NEWSWIRE) --  Immutep Limited (ASX: IMM; NASDAQ: IMMP) (“Immutep” or “the Company”), a late-stage immunotherapy company targeting cancer and autoimmune diseases, today announces an excellent median Overall Survival (OS) of 17.6 months has been achieved in Cohort B of the TACTI-003 (KEYNOTE-C34) Phase IIb trial. This part of the Phase II study evaluates eftilagimod alfa (efti) in combination with MSD’s (Merck & Co., Inc., Rahway, NJ, USA) anti-PD-1 therapy KEYTRUDA® (pembrolizumab) as first line therapy in recurrent/metastatic head and neck squamous cell carcinoma (1L HNSCC) patients with PD-L1 expression below 1 (Combined Positive Score [CPS] <1).

The mature 17.6-months median OS in evaluable patients (N=31) with a data cut-off of 31 March 2025 compares favourably to historical results from the two current standard-of-care approaches for 1L HNSCC patients with CPS <1 including 10.7-months from cetuximab + chemotherapy and 11.3-months from anti-PD-1 therapy + chemotherapy, as well as 7.9-months from anti-PD-1 monotherapy.^1,2

Patients with CPS <1 in 1L HNSCC represent a treatment population with high unmet medical need. Up to 20% of 1L HNSCC patients have CPS <1 and despite immunotherapy’s progress in fighting cancer, anti-PD-1 therapy alone (without chemotherapy) is only approved for patients who express PD-L1 (CPS >1). Additionally, all available treatment options for patients with PD-L1 CPS <1 include chemotherapy.

Importantly, efti in combination with pembrolizumab continues to be well-tolerated with no new safety signals. This safety and mature OS data build on the encouraging high overall response rate with multiple complete responses achieved through combining these powerful immunotherapies in 1L HNSCC patients with CPS <1.³

“We are excited to see this strong survival benefit for head and neck cancer patients with such cold tumors. Combining these two complementary immunotherapies has led to a 7-fold increase in response rates and a more than doubling of median overall survival as compared to historical results from anti-PD-1 monotherapy. Driving durable responses that translate into clinically meaningful survival holds tremendous promise for these patients in need of more tolerable and efficacious therapies,” said Marc Voigt, CEO of Immutep.

“There is a high unmet need in 1L HNSCC patients with cold tumors and PD-L1 CPS <1, due to the lack of an approved immunotherapy-only treatment regimen and a lack of competitor trials with chemotherapy-free approaches targeting this patient population. Given the strength of the efficacy and safety results generated to date with efti in combination with pembrolizumab, we will meet with regulators to discuss next steps and potential paths to approval,” added Mr. Voigt.

Next Steps
Efti has Fast Track designation in 1L HNSCC and Immutep has requested a meeting with the U.S. Food and Drug Administration (FDA) to discuss next steps including potential paths to approval for 1L HNSCC with PD-L1 CPS <1. Patient follow up, data collection, cleaning and analysis continue for TACTI-003, and the Company plans to provide a further update later this year.

About Eftilagimod Alfa (efti)
Efti is Immutep’s proprietary soluble LAG-3 protein and MHC Class II agonist that stimulates both innate and adaptive immunity for the treatment of cancer. As a first-in-class antigen presenting cell (APC) activator, efti binds to MHC (major histocompatibility complex) Class II molecules on APC leading to activation and proliferation of CD8+ cytotoxic T cells, CD4+ helper T cells, dendritic cells, NK cells, and monocytes. It also upregulates the expression of key biological molecules like IFN-ƴ and CXCL10 that further boost the immune system’s ability to fight cancer.

Efti is under evaluation for a variety of solid tumours including non-small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC), and metastatic breast cancer. Its favourable safety profile enables various combinations, including with anti-PD-[L]1 immunotherapy and/or chemotherapy. Efti has received Fast Track designation in first line HNSCC and in first line NSCLC from the United States Food and Drug Administration (FDA).

About Immutep
Immutep is a late-stage biotechnology company developing novel immunotherapies for cancer and autoimmune disease. The Company is a pioneer in the understanding and advancement of therapeutics related to Lymphocyte Activation Gene-3 (LAG-3), and its diversified product portfolio harnesses LAG-3’s ability to stimulate or suppress the immune response. Immutep is dedicated to leveraging its expertise to bring innovative treatment options to patients in need and to maximise value for shareholders. For more information, please visit www.immutep.com.

1. Burtness, B. et al. Pembrolizumab Alone or With Chemotherapy for Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma in KEYNOTE-048: Subgroup Analysis by Programmed Death Ligand-1 Combined Positive Score. Journal of Clinical Oncology 2022 40:21, 2321-2332.
2. Burtness B. et al. Abstract LB-258: Efficacy of first-line (1L) pembrolizumab by PD-L1 combined positive score <1, 1-19, and ≥20 in recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC): KEYNOTE-048 subgroup analysis. Cancer Res 15 August 2020; 80 (16_Supplement): LB–258. https://doi.org/10.1158/1538-7445.AM2020-LB-258
3. Forster M. et al., ESMO Immuno-Oncology 2024 - December 2024, TACTI-003 Cohort B: Eftilagimod Alpha (Soluble LAG-3) and Pembrolizumab in First-Line Recurrent or Metastatic Head & Neck Squamous Cell Carcinoma with CPS <1
   
   

Australian Investors/Media:
Catherine Strong, Sodali & Co.
+61 (0)406 759 268; catherine.strong@sodali.com

U.S. Media:
Chris Basta, VP, Investor Relations and Corporate Communications
+1 (631) 318 4000; chris.basta@immutep.com

FAQ

What are the survival results for IMMP's efti and KEYTRUDA combination in head and neck cancer?

The combination achieved a median Overall Survival of 17.6 months in head and neck cancer patients with PD-L1 CPS <1, significantly higher than current standard-of-care treatments which show 10.7-11.3 months survival.

How does IMMP's treatment compare to existing therapies for head and neck cancer?

The treatment showed a 7-fold increase in response rates compared to anti-PD-1 monotherapy, with 17.6 months median survival versus 10.7 months for cetuximab + chemotherapy and 11.3 months for anti-PD-1 therapy + chemotherapy.

What is the market potential for IMMP's head and neck cancer treatment?

The treatment addresses a high unmet medical need, targeting approximately 20% of first-line head and neck cancer patients who have PD-L1 CPS <1 and currently have no available chemotherapy-free treatment options.

What is the regulatory status of IMMP's efti treatment?

Efti has received Fast Track designation for 1L HNSCC, and Immutep has requested a meeting with the FDA to discuss potential paths to approval for patients with PD-L1 CPS <1.

Is IMMP's efti and KEYTRUDA combination safe for patients?

Yes, the combination therapy continues to be well-tolerated with no new safety signals reported in the trial.