Immunitas Presents Phase 1/2a Data Highlighting Anti-Tumor Activity of Novel Immunotherapy IMT-009 at AACR 2026 Annual Meeting

IMT-009 was generally well tolerated as monotherapy and in combination with fruquintinib, demonstrating early signs of anti-tumor activity in heavily pretreated patients

Translational findings suggest biomarkers associated with tertiary lymphoid structures may help identify patients most likely to benefit from IMT-009 treatment

WALTHAM, Mass., April 17, 2026 /PRNewswire/ -- Immunitas Therapeutics ("Immunitas"), a clinical stage precision immunotherapy company committed to discovering and developing novel, antibody-based therapeutics for patients with autoimmune diseases and cancer, today presented Phase 1/2a clinical data for IMT-009, its first-in-class anti-CD161 antibody, at the American Association for Cancer Research (AACR) Annual Meeting 2026, taking place April 17-22 in San Diego, California.

The presentation, titled "A first-in-human, dose escalation (DE) and biomarker cohort expansion (BCE) of IMT-009 (IMT) in advanced cancer and Phase 1b (Ph1b) combination with fruquintinib (F) in microsatellite stable colorectal cancer (MSS CRC)," highlights Phase 1/2a results supporting continued evaluation of IMT-009 as both a monotherapy and combination treatment for patients with solid tumors and hematologic malignancies.

"These data highlight IMT-009's potential as a novel immunotherapy with a differentiated mechanism designed to address significant unmet needs across difficult-to-treat cancers," said Amanda Wagner, Chief Executive Officer at Immunitas. "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."

As of January 30, 2026, 22 patients were treated with IMT-009 monotherapy in the dose-escalation portion of the trial, and 26 patients were enrolled in the biomarker cohort expansion across selected tumor types. IMT-009 is a fully human, Fc-attenuated IgG1 monoclonal antibody that targets CD161, a receptor associated with immune suppression and treatment resistance in cancer. By blocking the CD161-CLEC2D pathway, IMT-009 is designed to enhance anti-tumor immune activity. In the Phase 1b combination arm, 19 patients with second- to fourth-line MSS colorectal cancer received IMT-009 in combination with fruquintinib.

Key findings from the presentation include:

• Preliminary anti-tumor activity in heavily pretreated patients: Among patients with MSS colorectal cancer treated with IMT-009 monotherapy at 240 mg or higher, one confirmed partial response was observed, and one additional patient remained on treatment for 14 months with stable disease. In the combination arm, one confirmed partial response was observed, with three additional patients remaining on treatment for more than six months.
• Favorable tolerability profile: IMT-009 was generally well tolerated as monotherapy and in combination with fruquintinib. In the monotherapy dose-escalation study, the highest treatment-related adverse event observed was Grade 2. In the combination arm, there was one Grade 4 treatment-emergent adverse event that was not considered related to IMT-009 by the investigator.
• Biomarker findings supporting patient selection strategies: Translational analyses suggest that the presence and number of CLEC2D-positive/CD161-positive tertiary lymphoid structures (TLS), as well as CXCL13 expression, may be associated with clinical benefit and could help inform future patient selection approaches.

Presentation Details
Title: A first-in-human, dose escalation (DE) and biomarker cohort expansion (BCE) of IMT-009 (IMT) in advanced cancer and Phase 1b (Ph1b) combination with fruquintinib (F) in microsatellite stable colorectal cancer (MSS CRC)
Presenting Author: Susanna V. Ulahannan, M.D., The University of Oklahoma, Stephenson Cancer Center/SCRI
Abstract Number: CT048
Session: First-in-Human Phase I Clinical Trials
Location: Poster Section 50
Date & Time: Monday, April 20, 2026, 9:00 a.m. - 12:00 p.m. PT

About IMT-009
IMT-009 is a fully human, Fc-attenuated IgG1 monoclonal antibody that binds to CD161 and blocks its interaction with its ligand, CLEC2D. Preclinical data confirm that CD161 blockade with IMT-009 results in enhanced anti-tumor activity. IMT-009 is under evaluation in a Phase 1/2a clinical trial for use as a monotherapy and combination treatment for solid tumor and hematological malignancies. The Phase 1 study is designed to evaluate the safety, tolerability, pharmacodynamic biomarkers, and preliminary efficacy of IMT-009 as well as identify the Recommended Phase 2 Dose (RP2D).

About Immunitas Therapeutics
Immunitas is a clinical stage precision immunotherapy company committed to discovering and developing novel treatments for patients with cancer and autoimmune disease. Our specialized knowledge of the CD161 pathway has yielded multiple differentiated antibody therapeutics, including IMT-009, which is currently in clinical studies for the treatment of solid tumors and hematologic malignancies, and IMT-380 for the treatment of autoimmune conditions. The company was founded by Longwood Fund with leading scientists from Dana-Farber, MGH, the Broad, and MIT. Since being founded in 2019, Immunitas has raised over $120 million from a strong syndicate of investors including Agent Capital, Alexandria Venture Investments, Evotec, Leaps by Bayer, Longwood Fund, M Ventures, Medical Excellence Capital, and Novartis Venture Fund. To learn more, visit www.immunitastx.com.

Media Contact:
Peg Rusconi, Deerfield Group
[email protected]

SOURCE Immunitas Therapeutics, Inc.