Immutep Refocuses Eftilagimod Alfa Development on HNSCC With CPS <1 and Neoadjuvant Soft Tissue Sarcoma
核心洞察
Immutep will narrow registration-directed development of eftilagimod alfa to head and neck squamous cell carcinoma (搜索) with CPS below one and neoadjuvant soft tissue sarcoma (搜索).
The pivot follows early discontinuation of TACTI-004 and a root cause analysis identifying subtle N-glycan structural differences between 200-litre and 2,000-litre efti batches.
Immutep has contracted a new 200-litre manufacturing run, the scale used for ten GMP batches in earlier successful Phase I and Phase II studies.
Immutep Ltd (ASX: IMM) has outlined a more focused development strategy for its immunotherapy eftilagimod alfa (efti), concentrating future registration-directed work on head and neck squamous cell carcinoma (搜索) (HNSCC) and soft tissue sarcoma (搜索) (STS). The company plans to target HNSCC patients with negative programmed death-ligand 1 expression, defined by a Combined Positive Score (CPS) below one, alongside the neoadjuvant treatment setting for STS.
The decision follows the early discontinuation of the TACTI-004 study and an ongoing root cause analysis that has identified subtle structural differences between efti manufactured at 200-litre and 2,000-litre scales. Preparations for the next clinical studies have begun, with Immutep targeting a start during the second half of calendar 2027, subject to final trial design, regulatory interactions, manufacturing timelines, partnering and available resources.
Manufacturing Differences Under Investigation
Immutep's investigation identified differences between efti manufactured at the 200-litre scale for earlier clinical studies and product manufactured at the 2,000-litre scale for TACTI-004, including a subtle variation in N-glycan structure. The company considers those differences potentially relevant because TACTI-004 produced a markedly different immune activation profile from previous trials alongside an unexpected clinical outcome, although the root cause analysis remains incomplete.
Based on the data available so far, Immutep does not believe the TACTI-004 result can be explained by clinical factors such as protocol design, treatment-arm imbalances or safety findings, nor by trial execution factors including randomisation or general clinical conduct.
Immutep has consequently contracted a new 200-litre manufacturing run of efti. Ten GMP batches produced at that scale were previously used in successful Phase I and Phase II studies including TACTI-mel, TACTI-002 and INSIGHT-003, while TACTI-004 exclusively used material manufactured at the 2,000-litre scale.
Clinical Development Narrows to Two Indications
For HNSCC, Immutep intends to focus on patients with a CPS below one, drawing on clinical efficacy and mature overall survival data in a population it considers to have high unmet need and limited approved treatment options. Efti holds US Food and Drug Administration Fast Track designation for first-line HNSCC, and Immutep described previous FDA feedback on the proposed pathway as constructive.
The second focus is efti in the neoadjuvant setting for STS, supported by positive Phase II data in which the primary endpoint was achieved. The FDA granted efti Orphan Drug Designation for STS in April 2026.
Licensing partner Dr. Reddy's Laboratories has been consulted and supports the proposed strategy, while Immutep has begun preliminary discussions with other parties about the development pathway.
"Based on the totality of evidence generated with efti, we believe there is a scientifically and clinically justified path to continue its development. This includes clinical and translational data across multiple tumour types, consistent evidence of immune activation, encouraging results in soft tissue sarcoma (搜索) and head and neck cancer with CPS < 1, and constructive regulatory interactions," Immutep CEO Marc Voigt said.
"At the same time, we fully recognise the significance of the TACTI-004 outcome. Our root cause analysis remains ongoing, including further investigation of smaller differences identified between product batches. We intend to apply these learnings rigorously and focus future potential development on settings where the clinical evidence, biological rationale, time-to-market and unmet medical need are most compelling."
Efti Mechanism and Broader Pipeline
Efti is an immunotherapy designed to activate antigen-presenting cells through the MHC Class II (搜索) pathway, stimulating both adaptive and innate immune responses against cancer. Its safety profile has supported combinations with anti-PD-[L]1 immunotherapy, radiotherapy and chemotherapy.
Beyond efti, Immutep continues development of IMP761, its agonist anti-LAG-3 (搜索) antibody for autoimmune disease, in line with previously disclosed plans as it narrows the near-term clinical strategy around efti.