Immutep Intends to Focus Efti on HNSCC and Sarcoma

Immutep (ASX:IMM) said it currently intends to focus future registration-directed clinical development of eftilagimod alfa, or efti, on head and neck squamous cell carcinoma in patients with negative PD-L1 expression, defined as a Combined Positive Score below 1, and on the neoadjuvant setting of soft tissue sarcoma. The company said the focus reflects clinical data generated to date, its interactions with the U.S. Food and Drug Administration, Fast Track designation for head and neck squamous cell carcinoma and Orphan Drug Designation granted for soft tissue sarcoma in April 2026. Its ongoing root cause analysis following the early discontinuation of the TACTI-004 study has identified structural differences, such as a subtle difference in N-glycan structure, between the efti used in TACTI-004 and the efti used in earlier successful clinical studies, which Immutep considers potentially relevant given the markedly different immune activation profile observed and the unexpected clinical outcome.

Immutep said that on the data available so far it believes the TACTI-004 outcome cannot be explained by clinical factors or trial execution factors, and that it will provide a further update on completion of the analysis. The company has contracted a new manufacturing run of efti at 200 L scale, noting that ten GMP batches previously manufactured at that scale were used in Phase I and Phase II studies including TACTI-mel, TACTI-002 and INSIGHT-003, while TACTI-004 was conducted exclusively with efti manufactured at 2,000 L scale. Preparations for the next clinical trials have commenced, with study start targeted during the second half of calendar 2027, subject to final decisions on strategy and trial design, regulatory interactions, manufacturing timelines, partnering and resources. Licensing partner Dr. Reddy's Laboratories has been consulted and is supportive of the approach, and Immutep said development of IMP761, its agonist anti-LAG-3 antibody for autoimmune disease, continues in line with previously disclosed plans.