Agenus Unveils Promising Biomarker Data for Immuno-Oncology Treatments

Agenus Inc. (Nasdaq: AGEN), a trailblazer in the field of immuno-oncology, has recently presented compelling new data regarding its innovative therapies at the American Association for Cancer Research Immuno-Oncology (AACR-IO) Conference held in Los Angeles. On February 19, 2026, the company unveiled findings from its Phase 1b C-800-01 trial that highlight the potential of their dual treatment regimen combining botensilimab (BOT) and balstilimab (BAL) for patients with microsatellite-stable metastatic colorectal cancer (MSS mCRC) and other immunologically “cold” tumors.

The Phase 1b C-800-01 trial, which evaluates the efficacy of BOT, an Fc-enhanced anti–CTLA-4 antibody, in conjunction with BAL, an anti–PD-1 antibody, has offered groundbreaking insights into patient stratification through biomarker analysis. Traditional biomarkers have often faltered in predicting treatment responses in MSS mCRC, a tumor type historically resistant to conventional immunotherapies. However, the latest findings suggest a more nuanced approach that integrates both blood-based inflammatory markers and tumor microenvironment (TME) features.

The retrospective analyses revealed an association between survival rates and the interplay of two opposing biological factors: systemic inflammation and tumor immune activity. Notably, the combination therapy of BOT+BAL demonstrated clinical benefits even at levels of immune infiltration typically deemed inadequate for standard checkpoint inhibitors. This suggests that the Fc-enhanced mechanism of action in BOT lowers the baseline immunity threshold required for therapeutic effectiveness.

In a cohort of 341 efficacy-evaluable patients with advanced, treatment-refractory cancers, the trial reported the following outcomes:

These statistics indicate a durable clinical activity across various tumor types commonly classified as immunologically “cold,” including MSS mCRC, ovarian cancer, sarcoma, and non-small cell lung cancer that has relapsed or is refractory to PD-1 therapies.

Agenus's research has revealed critical insights into how systemic inflammation and immune activity within the tumor can inform patient stratification:

Dhan Chand, PhD, Vice President of Research and Development at Agenus, emphasized the significance of these findings: “These data show that outcomes with BOT+BAL are shaped by the interplay between systemic inflammation and tumor immune biology. By integrating blood- and tumor-based features, we are establishing a biologically grounded approach to patient stratification in immunologically ‘cold’ cancers such as MSS colorectal cancer, where conventional biomarkers provide limited guidance.”

The recent data presented by Agenus marks a significant advancement in the landscape of immuno-oncology, particularly for patients with tumors that have proven resistant to traditional therapies. As the company continues to explore the potential of BOT and BAL, the integration of comprehensive biomarker analysis may open new avenues for effective patient management and treatment strategies. Investors and stakeholders will be closely watching these developments as Agenus strives to redefine immunotherapy applications for a broader range of cancer patients.