TACTI-004 Update & Positive Mature Data from INSIGHT-003

• INSIGHT-003 shows mature mOS of 30.9 months in 1L non-squamous NSCLC
• Outcomes compare favourably with historical benchmarks
• TACTI-004 root cause analysis ongoing, results expected in Q3 CY2026

Immutep Limited announced a significant update from its INSIGHT-003 Phase I trial, evaluating eftilagimod alfa (efti) in combination with MSD's anti-PD-1 therapy KEYTRUDA and chemotherapy for 1st line therapy in advanced/metastatic non-small cell lung cancer (NSCLC). The mature results showed a median Overall Survival (mOS) of 30.9 months in the overall population, with the same mOS observed in patients with low PD-L1 expression. The results compare favourably with historical benchmarks. The company is also conducting a root cause analysis of its TACTI-004 Phase III trial, which was discontinued in March 2026. Preliminary immune monitoring data indicate a different immune activation profile in TACTI-004 compared with previous studies. Additional results from the root cause analysis are expected in Q3 CY2026.