Immutep reports strong results from efti-KEYTRUDA combination in carcinoma treatment

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By Imelda Cotton - 
Imutep ASX IMM squamous cell carcinoma TACTI003 results

Clinical-stage biotechnology company Immutep (ASX: IMM) has released top-line results from a Phase IIb trial evaluating eftilagimod alfa (efti) in combination with anti-PD-1 therapy KEYTRUDA (pembrolizumab) as a first-line treatment for recurrent and metastatic head and neck squamous cell carcinoma.

The results showed that a combination of both drugs can lead to overall response rates that exceed those of KEYTRUDA monotherapy across all levels of PD-L1 expression.

Programmed cell death ligand 1 (PD-L1) is defined as a protein that can bind to the PD-1 protein to help block the immune system from killing cancer cells.

Improved response rate

The Phase IIb trial enrolled 171 patients with positive and negative PD-L1 expression at over 30 sites across the US, Europe and Australia.

In the randomised and controlled cohort A, the combination of efti and KEYTRUDA showed a 31% response rate in patients with high PD-L1 expression compared to 18.5% for KEYTRUDA alone.

Cohort B comprised patients with negative PD-L1 expression — for which there is currently no effective chemotherapy-free treatment option — and showed an improved response rate from the preliminary 26.9% reported in April.

The response rate across both cohorts for efti in combination with KEYTRUDA was approximately 34%, regardless of human papillomavirus status and PD-L1 expression.

Promising results

Trial investigator and associate professor at London’s University College Hospital Dr Martin Forster said the results had been promising for squamous cell cancer patients.

“The strong, consistent response irrespective of whether patients have high, low or negative PD-L1 expression is intriguing and offers a glimpse into this novel combination’s ability to improve clinical responses and expand the number of patients that benefit from anti-PD-1 therapy.”

Complementary nature

Immutep chief scientific officer Dr Frédéric Triebel said the company was pleased with the quality of the trial responses.

“Durability is tracking well, driven by the complementary nature of these two unique immunotherapies in fighting cancer,” he said.

“From a statistical point of view, we are excited to see a 68% differential in the largest patient segment of this trial in a randomised setting as well as the strength of clinical results in patients with negative PD-L1 expression.”