• Immutep sinks 35pc despite positive TACTI-003 Phase IIb trial results
  • Investors may have had higher expectations, leading to the market reaction
  • The trial evaluated efti with KEYTRUDA for first-line head and neck cancer


Immutep (ASX:IMM) plunged 35% this morning after releasing its topline results from the TACTI-003 Phase IIb Trial in First Line Head and Neck Cancer.

The overall results were positive so there was no clear reason for the selloff. One reason could be that investors may have had higher expectations for the trial results.

The TACTI-003 Phase IIb trial evaluated the effectiveness of eftilagimod alfa (efti), in combination with KEYTRUDA (pembrolizumab) for treating first-line head and neck squamous cell carcinoma (HNSCC).

This clinical trial represents a pivotal step forward in cancer treatment, particularly for recurrent or metastatic forms of HNSCC.

The primary focus of the trial was to assess how efti, Immutep’s proprietary soluble LAG-3 protein and MHC Class II agonist, performs alongside KEYTRUDA, a well-established anti-PD-1 therapy from Merck & Co.

The results revealed that the combination therapy significantly outperformed KEYTRUDA monotherapy across various levels of PD-L1 expression.

Notably, patients with high PD-L1 expression (CPS >20) exhibited an overall response rate (ORR) of 31.0%, compared to 18.5% with KEYTRUDA alone in the randomised Cohort A of the trial.

In Cohort B, which focused on patients with negative PD-L1 expression (CPS <1), the response rate saw an improvement from earlier assessments, reaching levels that have been accepted for presentation at an upcoming ESMO Virtual Plenary session.

This underscores the potential of the efti and KEYTRUDA combination to offer viable treatment options for patient groups who currently lack effective chemotherapy-free alternatives.

Dr. Martin Forster, an investigator involved in the trial, noted efti’s consistent efficacy across varying PD-L1 expression levels and HPV (human papillomavirus) status.

“The strong, consistent response rates, 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 patients’ clinical responses and expand patient populations that benefit from anti-PD-1 therapy.”

Building on these positive findings, Immutep now plans to engage with regulatory agencies to discuss potential pathways forward for treating metastatic first-line HNSCC patients.

Efti is a special protein developed by Immutep to help the immune system fight cancer better.

It works by activating certain immune cells called antigen presenting cells (APCs), which then boost the activity of other immune cells like cytotoxic T cells, helper T cells, dendritic cells, NK cells, and monocytes.

This activation helps the immune system produce important molecules like IFN-γ and CXCL10, which are crucial in fighting cancer.