Immutep Completes Enrollment in TACTI-003 Phase IIb Trial of Efti and KEYTRUDA in First Line Metastatic or Recurrent Head and Neck Squamous Cell Carcinoma

Media Release

• A total of 171 head and neck squamous cell carcinoma (HNSCC) patients enrolled in randomised, multicentre Phase IIb trial evaluating efti in combination with pembrolizumab
• Efti has FDA Fast Track designation for first-line treatment of HNSCC

SYDNEY, AUSTRALIA, Nov. 09, 2023 (GLOBE NEWSWIRE) -- Immutep Limited (ASX: IMM; NASDAQ: IMMP) ("Immutep” or “the Company”), a clinical-stage biotechnology company developing novel LAG-3 immunotherapies for cancer and autoimmune disease, today announces the completion of patient enrollment in the TACTI-003 (KEYNOTE-PNC-34) Phase IIb trial evaluating eftilagimod alpha (efti), its proprietary soluble LAG-3 protein and MHC Class II agonist, in combination with MSD’s anti-PD-1 therapy KEYTRUDA (pembrolizumab) as first-line treatment of recurrent or metastatic head and neck squamous cell carcinoma (HNSCC).

The Phase IIb trial enrolled 171 patients at over 30 centres across the United States, Europe, and Australia to evaluate the safety and efficacy of efti in combination with pembrolizumab in patients with PD-L1 positive (Combined Positive Score [CPS] ≥1) tumors (Cohort A) and in patients with PD-L1 negative tumors (Cohort B).

A total of 138 patients with recurrent or metastatic HNSCC whose tumours express PD-L1 (CPS ≥1) have been enrolled into the 1:1 randomized Cohort A of the trial evaluating the safety and efficacy of 30mg of efti in combination with 400mg of KEYTRUDA given every six weeks compared to 400mg of KEYTRUDA alone. Patients in Cohort A whose tumors express PD-L1 (CPS >1) are also stratified by CPS 1-19 and CPS >20, and the clinical results for these three CPS groups will be evaluated.

Additionally, 33 patients with recurrent or metastatic HNSCC were enrolled into Cohort B to determine the efficacy and safety of the same combination therapy in patients with PD-L1 negative tumours (CPS <1). These patients are not expected to respond to KEYTRUDA monotherapy, with a typical Overall Response Rate of up to 5%, and therefore were not randomized.¹ Due to a higher number of patients with negative PD-L1 expression (CPS <1) who were eligible for and allocated to Cohort B and the number of patients in screening at the time of achieving the trial's enrollment goal, the trial enrolled 171 patients.