A groundbreaking Phase II clinical trial is investigating a novel triple immunotherapy combination for patients with PD-1 refractory gastroesophageal cancer, addressing a critical unmet need in second-line treatment options.
The study, conducted at Memorial Sloan Kettering Cancer Center, combines AgenT-797, an allogeneic invariant natural killer T (iNKT) cell therapy, with botensilimab, an Fc-enhanced CTLA-4 inhibitor, and balstilimab, an anti-PD-1 antibody. The treatment regimen also includes standard second-line therapy components ramucirumab and paclitaxel.
Patient Population and Trial Design
The trial enrolled 37 patients with advanced gastroesophageal adenocarcinoma who had progressed on first-line treatment. Initial data from 15 patients shows a predominantly male cohort (73%) with a median age of 63 years. The majority of patients (67%) presented with two or more metastatic sites, with liver metastases being most common (60%).
The study implemented three treatment arms:
- AgenT-797 cells alone induction (13% of patients)
- AgenT-797/botensilimab/balstilimab combination induction (33% of patients)
- No induction followed by full combination therapy (53% of patients)
Significant Biomarker Findings
Biomarker analysis revealed compelling evidence of enhanced immune response:
- Increased tumor infiltration by immune cells, particularly CD3+ and CD8+ T cells
- Significant upregulation of granzyme B and Ki67 expression in CD8+ T cells, indicating improved cytotoxic activity
- Enhanced antigen-presenting cell activity, marked by increased CD11c+ and CD86+ HLA-DR+ cell populations
Immune System Activation
The treatment combination demonstrated robust immune system activation:
- Significant increases in both central and effector memory T cells
- Marked elevation in proinflammatory biomarkers, including IFN-γ, TNF-α, IL-15, and Granzyme B
- Sustained interferon-gamma response, particularly notable in the AgenT-797/botensilimab/balstilimab combination arm
Clinical Context
This innovative approach addresses a significant therapeutic challenge in gastroesophageal cancer treatment. While PD-1 inhibitors combined with chemotherapy are approved for frontline treatment, most patients eventually develop resistance, and current second-line options show limited efficacy.
The trial builds on previous promising results from separate Phase I studies of AgenT-797 and the botensilimab/balstilimab combination in various refractory solid tumors. The current study (NCT06251973) aims to evaluate whether combining these novel immunotherapy approaches can overcome resistance mechanisms and improve patient outcomes.
