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Highlights
- Immutep (IMM) shares data from its Phase IIb TACTI-003 trial.
- Promising results in treating head and neck squamous cell carcinoma (HNSCC).
- Combination therapy shows significant improvement in survival rates.
Immutep (ASX:IMM) has revealed groundbreaking results from its Phase IIb TACTI-003 trial, targeting head and neck squamous cell carcinoma (HNSCC). The findings, presented at the ESMO Immuno-Oncology Congress 2024, highlight the efficacy of combining the company’s lead drug candidate eftilagimod alpha (efti) with KEYTRUDA, a PD-1 inhibitor from Merck & Co. This collaboration addresses a critical gap in treating patients with low PD-L1 protein expression.
Cancer Cells and Immune Evasion
Cancer cells often evade detection by the immune system through proteins like PD-L1, which bind to T-cells' PD-1 receptors, deactivating the immune response. While PD-1 inhibitors like KEYTRUDA block this pathway, their effectiveness diminishes in patients with low PD-L1 levels, measured by the PD-L1 Combined Positive Score (CPS). These patients, who represent about 20% of HNSCC cases, typically see limited success with standard PD-1 therapies.
Immutep’s efti works differently, stimulating a broader immune response by activating and proliferating T-cells. When paired with PD-1 inhibitors, efti enhances the immune system's ability to target cancer cells, overcoming the limitations seen in low PD-L1 cases.
Significant Results in Survival and Response
The trial results showcase remarkable improvements in outcomes for HNSCC patients with CPS below one. Immutep’s combination therapy achieved a 12-month overall survival rate of 67%, a significant increase from the historical 39% seen with PD-1 inhibitors alone. Progression-free survival rose to 5.8 months from the typical 2.1 months, while the duration of response extended to 9.3 months, compared to 2.6 months with standard PD-1 therapy.
Moreover, the objective response rate—indicating tumor shrinkage or disappearance—reached 35.5% with efti, far surpassing the 5.4% seen with standalone PD-1 inhibitors. Notably, the complete response rate, where cancer becomes undetectable, stood at 12.9%-16.1% depending on assessment criteria, a significant milestone compared to zero responses in the control group.
A Potential New Hope for HNSCC Patients
Immutep CEO Marc Voigt emphasized the importance of this advancement, particularly for patients with few existing treatment options. The data suggests a promising alternative for those reliant on chemotherapy, offering hope to a group often facing limited prospects.
Immutep’s findings mark a pivotal step in enhancing cancer immunotherapy and addressing unmet needs in oncology. As these results continue to generate interest, they pave the way for potential advancements in the treatment of difficult-to-treat cancers.
