Immutep completes enrollment in TACTI-003 Phase IIb trial

Immutep announces the completion of patient enrollment in the TACTI-003 Phase IIb trial evaluating eftilagimod alpha, its proprietary soluble LAG-3 protein and MHC Class II agonist, in combination with MSD’s anti-PD-1 therapy KEYTRUDA as first-line treatment of recurrent or metastatic head and neck squamous cell carcinoma. 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 tumors and in patients with PD-L1 negative tumors. A total of 138 patients with recurrent or metastatic HNSCC whose tumours express PD-L1 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 are also stratified by CPS 1-19 and CPS greater than20, 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. 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 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. The primary endpoint of the study is Overall Response Rate of evaluable patients according to RECIST 1.1. Secondary endpoints include Overall Survival, Overall Response Rate according to iRECIST, Progression Free Survival, and Duration of Response. The primary analysis according to the trial protocol will be performed after all subjects have completed at least three cycles of treatment or discontinued the trial, and all relevant data for the primary endpoint has been collected, cleaned, and analysed. The Company expects to report data from the trial in H1 CY2024.