Immutep's Lung Cancer Trial Hits 50% Mark, Aiming for New Standard of Care

SYDNEY, AUSTRALIA – February 06, 2026 – Australian biotechnology firm Immutep Limited has reached a significant milestone in its quest to redefine the treatment landscape for the world's deadliest cancer. The company announced it has enrolled 378 patients, exactly half of its target, in a pivotal global Phase III trial for its novel immunotherapy, eftilagimod alfa (efti), in first-line non-small cell lung cancer (1L NSCLC).

This achievement keeps the registrational TACTI-004 trial on a brisk timeline, with crucial upcoming events, including a futility analysis expected in the first quarter of this year and the completion of patient enrollment anticipated by the third quarter. The trial evaluates a powerful combination therapy: efti, plus MSD’s blockbuster anti-PD-1 drug KEYTRUDA® (pembrolizumab) and standard chemotherapy. The ultimate goal is to establish a new, more effective standard of care for a disease where significant unmet needs persist despite recent advances.

“The excellent pace of enrolment globally in the TACTI-004 trial speaks to the promise of efti and the need for more efficacious therapies in the first line setting for patients with advanced/metastatic non-small cell lung cancer,” said Immutep Chief Executive Officer, Marc Voigt, in a statement. “Our team continues to work hard to bring this innovative cancer immunotherapy to market and looks forward to delivering on additional important upcoming milestones ahead.”

A Novel Mechanism to Boost the Immune Army

At the heart of Immutep's strategy is efti’s unique scientific foundation. Unlike many immunotherapies that work by blocking inhibitory signals on immune cells—effectively “releasing the brakes”—efti is designed to “push the accelerator.” It is a first-in-class soluble LAG-3 protein that acts as an MHC Class II agonist. In simpler terms, it directly activates a critical group of immune cells known as antigen-presenting cells (APCs), such as dendritic cells and monocytes.

This activation triggers a broad, systemic immune response. Activated APCs become more effective at presenting tumor antigens to the immune system’s foot soldiers, the T cells, essentially training them to recognize and attack cancer. This process leads to the activation and proliferation of CD8+ cytotoxic T cells, the primary killers of cancerous cells, and generates a cascade of signaling molecules like IFN-gamma that further amplify the anti-tumor assault. This mechanism differentiates it from LAG-3 antagonists, which block an inhibitory receptor on T cells.

Data from earlier, smaller studies like the Phase II TACTI-002 trial have provided a strong rationale for this large-scale Phase III investigation. In that study, the combination of efti and pembrolizumab (without chemotherapy) demonstrated an objective response rate of 35.1% and a median overall survival of 20.2 months in 1L NSCLC patients. Crucially, this anti-tumor activity was observed across all levels of PD-L1 expression, a biomarker that often dictates treatment choice. This suggests efti could broaden the benefit of immunotherapy to a much larger patient population, including those who currently show limited response to existing treatments. The potential of this approach has been recognized by regulators, with the U.S. Food and Drug Administration (FDA) granting Fast Track designation for efti in this indication.

Navigating a High-Stakes Market

Success in the TACTI-004 trial would position Immutep to challenge a highly competitive and lucrative market. The 1L NSCLC space is currently dominated by pharmaceutical giants like Merck (MSD), Bristol Myers Squibb, and Roche, with KEYTRUDA-based combinations representing the established standard of care. The global lung cancer therapeutics market is valued in the tens of billions of dollars, making any new entrant with a superior efficacy or safety profile a significant disruptor.

Immutep, a comparatively smaller late-stage biotech, is navigating this landscape through strategic collaborations. Its partnership with MSD provides access to KEYTRUDA for the trial, a critical component for testing the combination. Furthermore, the company has bolstered its financial standing and future commercialization plans through a recent deal with Dr. Reddy's for the rights to market efti in numerous territories outside of the major markets. This agreement not only provided an upfront payment of AUD 30.2 million but also includes potential milestone payments and royalties, significantly extending Immutep’s cash runway into mid-2027 and de-risking its path to market.

This financial stability is crucial as the company shepherds its lead candidate through the expensive and lengthy Phase III process. With a strong cash position of A$99.1 million as of late 2025, Immutep is well-capitalized to see the TACTI-004 trial through its next major inflection points.

The Road Ahead: A Trial for All Comers

The TACTI-004 study (NCT05481108) is a robustly designed, randomized, and double-blind trial involving approximately 756 patients across more than 140 clinical sites in 27 countries. Its design is notable for enrolling patients regardless of their PD-L1 expression level. If successful, the combination could offer a one-size-fits-all approach that simplifies treatment decisions for oncologists and expands options for patients whose tumors don't express high levels of the PD-L1 biomarker.

The trial's dual primary endpoints are progression-free survival (PFS) and overall survival (OS), the gold standards for demonstrating clinical benefit in oncology. The upcoming futility analysis in the coming weeks will be the first major test, providing an early look at whether the treatment is performing as expected. While not a definitive measure of success, passing this hurdle would provide significant validation for the trial's continuation.

For the thousands of patients diagnosed with advanced lung cancer each year, the progress of trials like TACTI-004 represents a source of hope. By combining a novel immune activator with the established power of a checkpoint inhibitor and chemotherapy, Immutep and its partners are betting they can create a new triplet therapy that meaningfully extends and improves lives, potentially setting a new benchmark in the ongoing war against lung cancer.