Immutep Reveals Positive Early Results from TACTI-003 Cohort B

Data from a Phase IIb trial shows promising early results for the combination of eftilagimod alpha (efti) and KEYTRUDA® (pembrolizumab) in treating head and neck squamous cell carcinoma (HNSCC) patients who do not express PD-L1. Conducted by Immutep Limited, a biotechnology company dedicated to developing novel LAG-3 immunotherapies, this study targets patients facing high unmet medical needs.

The trial, named TACTI-003 (KEYNOTE-PNC-34), evaluates the effectiveness of Immutep’s MHC Class II agonist efti in combination with MSD’s anti-PD-1 therapy, KEYTRUDA®. In the cohort of patients whose tumors do not express PD-L1 (Combined Positive Score <1), the combination therapy achieved an overall response rate (ORR) of 26.9% and a disease control rate (DCR) of 57.7%. These results were derived from 26 out of 33 patients who had sufficient follow-up data as of February 2024.

Dr. Martin Forster from the UCL Cancer Institute and University College London Hospital NHS Foundation commented that these results are particularly encouraging for this subset of HNSCC patients. Traditionally, HNSCC poses significant treatment challenges and is noted for its genetic complexity and aggressive nature. As such, the ability to show efficacy without the use of chemotherapy marks a significant shift in treatment strategy.

Efti’s mode of action involves the activation of antigen-presenting cells, which in turn boosts the immune system. This action is thought to significantly enhance the efficacy of immune checkpoint inhibitors like KEYTRUDA®. Efti is currently the only MHC Class II agonist in clinical development, and it appears to generate a robust anti-cancer immune response across varying levels of PD-L1 expression, even in tumors with negative PD-L1 expression.

The data collection and analysis are ongoing, with additional information from the trial expected in the first half of 2024. This follows the initial data release from Cohort B where all subjects underwent thorough follow-up and data cleaning.

Cohort A of the TACTI-003 trial involves 138 patients with PD-L1 positive tumors and is being conducted across over 30 global centers. Patients are categorized based on their Combined Positive Scores, and the primary endpoint assessment will occur once all participants have completed at least three treatment cycles or have discontinued the treatment.

The worldwide incidence of HNSCC, as highlighted by various global cancer studies, underscores the critical need for new treatment options. HNSCC is not only one of the most common forms of cancer but also brings significant psychological distress and reduced quality of life.

Efti has been granted FDA Fast Track designation for first-line treatment of HNSCC, regardless of PD-L1 expression. This designation accelerates the review process, reflecting the potential of efti in combination with other therapies for significantly benefiting patients.

Immutep remains committed to advancing its diversified product portfolio, which is heavily focused on Lymphocyte Activation Gene-3 (LAG-3) related therapeutics. Through their pioneering efforts, the company seeks to deliver novel treatments that can improve patient outcomes and maximize shareholder value.