Immutep Reports Positive Results in First Line Head and Neck Squamous Cell Carcinoma Patients with Negative PD-L1 Expression

Media Release

• Efti in combination with KEYTRUDA (pembrolizumab) achieved a 35.5% response rate in evaluable patients (N=31), according to RECIST 1.1, among the highest recorded for a treatment approach not containing chemotherapy in patients with CPS <1
• High complete response rate of 9.7% with three patients showing a disappearance of cancer lesions post treatment
• Durability of responses tracks well and over 50% of patients received treatment for at least six months
• Combination continues to have a favourable safety profile with no new safety signals observed
• Based on encouraging results and high unmet medical need, the path forward will be discussed with regulatory agencies
• Company to host webcast today at 9am AEST (7pm ET, 11 July), details below

SYDNEY, AUSTRALIA, July 12, 2024 (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 positive results from Cohort B of the TACTI-003 (KEYNOTE-PNC-34) Phase IIb trial evaluating eftilagimod alfa (efti) in combination with MSD’s (Merck & Co., Inc., Rahway, NJ, USA) anti-PD-1 therapy KEYTRUDA (pembrolizumab) as first-line treatment of recurrent or metastatic head and neck squamous cell carcinoma patients (1L HNSCC) with negative PD-L1 expression. The updated efficacy and safety data was presented by Dr. Robert Metcalf during an oral presentation at the ESMO Virtual Plenary session at 18:30-19:30 CEST on 11 July 2024.

Results
The investigational immuno-oncology (IO) combination utilising efti and KEYTRUDA achieved an objective response rate (ORR) of 35.5% (11 of 31 evaluable patients) and a disease control rate (DCR) of 58.1%, according to RECIST 1.1, in 1L HNSCC patients whose tumours do not express PD-L1 (Combined Positive Score [CPS] <1). These results are among the highest recorded for a chemotherapy-free approach in negative PD-L1 patients and compare favourably to a historical control of 5.4% ORR and 32.4% DCR from anti-PD-1 monotherapy.¹

Additionally, the IO combination attained a high complete response rate of 9.7% (3 of 31 patients), which compares favourably to a historical control of 0% from anti-PD-1 monotherapy in 1L HNSCC patients with a CPS <1.² Notably, one patient with early progressive disease according to RECIST 1.1 has evolved into a confirmed partial responder who remains on therapy after 14 months, resulting in a 38.7% ORR for the IO-combination, according to iRECIST.