IMT-009 Data at AACR Hints at Precision Attack on Tough Tumors

SAN DIEGO, CA – April 17, 2026 – Immunitas Therapeutics today unveiled encouraging early-stage clinical data for its novel immunotherapy, IMT-009, offering a potential new strategy against some of the most difficult-to-treat cancers. The results, presented at the American Association for Cancer Research (AACR) Annual Meeting 2026, demonstrate that the first-in-class antibody was not only well-tolerated but also showed preliminary signs of anti-tumor activity in heavily pretreated patients, a population with few remaining treatment avenues.

The Phase 1/2a data provides the first clinical look at IMT-009's unique mechanism and supports its continued development as both a standalone therapy and in combination with other agents. The findings also point toward a precision-medicine approach, with emerging biomarkers that could help identify which patients are most likely to respond to the treatment.

A Novel Pathway to Unleash the Immune System

At the heart of Immunitas's strategy is a novel immunological target: the CD161-CLEC2D pathway. IMT-009 is a highly specialized monoclonal antibody engineered to block this pathway, which is implicated in suppressing the body's natural anti-cancer immune response and promoting treatment resistance.

CD161 is a receptor found on the surface of critical immune cells, including Natural Killer (NK) cells and subsets of T cells, which are the primary soldiers in the body's fight against cancer. When its ligand, CLEC2D, which is often expressed on tumor cells, binds to CD161, it acts as a brake, dampening the activity of these immune fighters. Preclinical research has shown that by physically blocking this interaction, IMT-009 effectively releases this brake, reinvigorating T and NK cells to recognize and attack malignant cells.

As a 'first-in-class' therapy, IMT-009 is the first drug candidate to target this specific checkpoint. Its design is further refined with an 'Fc-attenuated' structure, a sophisticated engineering choice that prevents the antibody from inadvertently destroying the very CD161-positive immune cells it is designed to activate. This focus on a previously undrugged pathway represents a fresh approach in the crowded immuno-oncology landscape, moving beyond more established targets to open up new possibilities for patients.

Early Signs of Efficacy in Resistant Tumors

The most significant results from the study, which enrolled patients with advanced solid tumors and hematologic malignancies, came from a cohort with microsatellite stable colorectal cancer (MSS CRC). This form of colorectal cancer accounts for the vast majority of cases and is notoriously resistant to conventional immunotherapies, often referred to as immunologically 'cold' tumors.

Among heavily pretreated MSS CRC patients receiving IMT-009 as a monotherapy, the trial reported one confirmed partial response—a significant shrinkage of the tumor. Another patient in this group experienced stable disease for 14 months, a noteworthy duration of disease control in this advanced setting. The data was presented by Dr. Susanna V. Ulahannan of the University of Oklahoma's Stephenson Cancer Center.

Further promise was seen in the combination arm of the study, where IMT-009 was administered with fruquintinib (Fruzaqla), an oral VEGFR inhibitor approved for metastatic colorectal cancer. This combination also yielded one confirmed partial response, with three additional patients remaining on treatment for over six months. The scientific rationale for this pairing is compelling; anti-angiogenic drugs like fruquintinib can help remodel the tumor microenvironment, potentially making 'cold' tumors more visible and accessible to the immune system, thereby creating a synergistic effect with an immunotherapy like IMT-009.

The Promise of Precision: Finding the Right Patients

Beyond the initial efficacy signals, the data presented by Immunitas included translational findings that could be crucial for the drug's future success. The research suggests that specific biological clues, or biomarkers, within a patient's tumor may predict their likelihood of benefiting from IMT-009.

Investigators identified that the presence of tertiary lymphoid structures (TLS)—organized hubs of immune activity that can form inside tumors—may be associated with clinical benefit. Specifically, the analysis pointed to TLS containing the CD161 and CLEC2D pathway components, alongside high expression of a chemokine called CXCL13, which is vital for recruiting immune cells. The presence of these features suggests a pre-existing but suppressed immune response that IMT-009 could effectively unleash.

"We are particularly encouraged by the early signals of clinical activity and the emerging biomarker insights, which may help guide patient selection and inform future development strategies, both as a monotherapy and in combination," said Amanda Wagner, Chief Executive Officer at Immunitas, in the company's official announcement.

This biomarker-driven strategy aligns with a major trend in modern oncology: moving away from a one-size-fits-all approach and toward precision therapies tailored to the unique biology of each patient's cancer. If validated, these biomarkers could allow doctors to select patients who have the highest chance of responding, maximizing efficacy while sparing others from a potentially ineffective treatment.

A Favorable Safety Profile and Path Forward

For any new cancer therapy, especially one being tested for the first time in humans, safety is paramount. The Phase 1/2a data showed that IMT-009 was generally well tolerated. In the monotherapy arm, the highest treatment-related adverse event was Grade 2, considered mild to moderate. In the combination arm, only one serious (Grade 4) adverse event was observed, which was deemed unrelated to IMT-009 by the investigator. This favorable safety profile is critical as the drug advances into later-stage trials and more complex combinations.

The positive results mark a significant milestone for Immunitas Therapeutics. Founded in 2019 with backing from a strong syndicate of investors including Bayer and Novartis venture funds, the company has raised over $120 million to advance its platform. The company's deep focus on the CD161 pathway also extends beyond cancer, with a second candidate, IMT-380, being developed for autoimmune diseases.

With these encouraging first-in-human results in hand, Immunitas plans to continue its clinical trial to establish the recommended dose for Phase 2 studies. The combination of early efficacy in a tough-to-treat cancer, a clean safety profile, and a clear biomarker strategy provides a solid foundation for IMT-009's path forward. For patients and clinicians awaiting new options, the continued development of IMT-009 represents a tangible source of optimism in the ongoing fight against cancer.