Immutep's Efti in Combination with MSD's KEYTRUDA® Leads to Positive Efficacy with Favourable Safety in First Line Head and Neck Cancer

Core Insights - Immutep Limited announced positive efficacy and safety results from the TACTI-003 Phase IIb trial, evaluating eftilagimod alpha (efti) in combination with KEYTRUDA for treating recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) [1][3][9] Efficacy Results - Efti combined with KEYTRUDA achieved an overall response rate (ORR) of 32.8% (34.5% including one partial response after data cut-off) in patients with any PD-L1 expression (CPS ≥1), compared to 26.7% for KEYTRUDA alone [4][5] - The combination showed the highest efficacy in patients with high PD-L1 expression (CPS ≥20), with an ORR of 31.0% versus 18.5% for KEYTRUDA alone, and a complete response rate of 6.9% compared to 3.7% [4][5] Duration of Response - The median duration of response (DOR) for the Efti and KEYTRUDA combination was 17.5 months, slightly higher than the 17.1 months for KEYTRUDA alone, indicating favorable durability compared to historical data of ~6 to ~7 months for other anti-PD-1 combinations [5][6] Biological Activity - A statistically significant increase in absolute lymphocyte count (ALC) was observed in the Efti and KEYTRUDA arm, indicating efti's biological activity and effective immune response [5][6][7] Safety Profile - The combination therapy maintained a favorable safety profile, with a discontinuation rate from treatment-emergent adverse events of 4.3% for Efti and KEYTRUDA, similar to 4.4% for KEYTRUDA alone [6][7] - No new safety signals were observed, and the safety profile remained comparable to KEYTRUDA monotherapy, aside from expected injection site reactions [6][7] Future Directions - Immutep plans to continue monitoring the TACTI-003 trial data, with overall survival results expected in 2025, and will engage with regulatory authorities regarding potential paths forward [1][8][9]