ImmunoGenesis has dosed the first subject in a multicenter Phase I/II clinical trial investigating IMGS-101 (evofosfamide) in combination with checkpoint inhibitors balstilimab and zalifrelimab. The dosing took place at the University of Texas MD Anderson Cancer Center in Houston, marking a significant step forward in the company's innovative approach to cancer immunotherapy.
Novel Approach Targets Hypoxic Tumor Microenvironment
The open-label trial focuses on adult patients with locally advanced or metastatic castration-resistant prostate cancer, human papillomavirus (HPV)-negative squamous cell carcinoma of the head and neck (SCCHN), and pancreatic cancer—three cancer types that have historically shown limited response to immunotherapy approaches.
Dr. Charles Schweizer, Senior Vice President of Clinical Development at ImmunoGenesis, emphasized the significance of this trial: "This trial marks an exciting step forward in addressing one of the key challenges in cancer immunotherapy. Hypoxia limits T-cell infiltration and suppresses immune responses, especially in prostate, pancreatic, and head and neck cancers."
He added, "By reversing hypoxia, IMGS-101 may restore T-cell access to tumors, enhancing the effectiveness of checkpoint inhibitors and potentially transforming outcomes in these hard-to-treat cancers."
Mechanism of Action and Scientific Rationale
IMGS-101, also known as evofosfamide, is a 2-nitroimidazole prodrug of the cytotoxin bromo-isophosphoramide mustard (Br-IPM). While initially developed as a hypoxia-activated prodrug, research from Dr. Michael Curran's laboratory at MD Anderson Cancer Center revealed its unique ability to reverse tumor hypoxia—a condition characterized by low oxygen levels that creates an immunosuppressive environment.
Preclinical models and early Phase I studies have shown that IMGS-101 can restore T-cell function, with preliminary evidence suggesting synergy when combined with immune checkpoint inhibitors. This mechanism directly addresses one of the fundamental barriers to effective immunotherapy in solid tumors.
The combination therapy pairs IMGS-101 with balstilimab and zalifrelimab, both developed by immuno-oncology company Agenus. Balstilimab is a fully human monoclonal immunoglobulin G1 targeting programmed cell death protein 1 (PD-1), while zalifrelimab targets cytotoxic T-lymphocyte associated antigen 4 (CTLA-4)—two critical immune checkpoint pathways.
Trial Design and Objectives
The clinical trial consists of two parts: a dose escalation phase followed by an expansion phase. These components will assess the pharmacokinetics, efficacy, anti-tumor activity, and safety profile of the three-drug combination.
The study specifically targets cancer types characterized by hypoxic tumor microenvironments that typically limit the effectiveness of immunotherapy. By conditioning these tumors to respond to checkpoint inhibition through hypoxia reversal, ImmunoGenesis aims to overcome a significant obstacle in cancer treatment.
Addressing Unmet Medical Needs
The selected cancer types represent significant unmet medical needs. Castration-resistant prostate cancer, HPV-negative head and neck cancer, and pancreatic cancer are known for their poor responses to current immunotherapies, limited treatment options, and generally poor prognoses in advanced stages.
If successful, this approach could provide a new treatment paradigm for patients with these difficult-to-treat malignancies. The strategy of modifying the tumor microenvironment to enhance immunotherapy efficacy represents an emerging direction in cancer research that could potentially extend beyond the cancer types included in this initial trial.
Company Background and Collaboration
ImmunoGenesis, founded based on research from Dr. Michael Curran's laboratory, focuses on developing novel approaches to overcome resistance mechanisms in cancer immunotherapy. This trial represents a significant milestone in the company's clinical development program.
The collaboration with Agenus, which provided the checkpoint inhibitors balstilimab and zalifrelimab, highlights the increasing trend of partnership in developing combination immunotherapy approaches that target multiple aspects of tumor immune evasion simultaneously.
As the trial progresses, it will provide valuable insights into whether hypoxia reversal can indeed transform cold, immunotherapy-resistant tumors into ones that respond to checkpoint inhibition—potentially opening new treatment avenues for patients with limited options.
