GT Biopharma is exploring the potential of combining its investigational natural killer (NK) cell engager GTB-5550 with KRAS inhibitors following encouraging preclinical findings in pancreatic cancer models. The clinical-stage immuno-oncology company presented the new data at the Society for Immunotherapy of Cancer (SITC) 2026 Annual Meeting, held November 4-8 in Phoenix, AZ.
The research evaluated whether GTB-5550, developed using the company’s proprietary TriKE® platform, could enhance the antitumor activity of KRAS inhibitors. In preclinical orthotopic patient-derived pancreatic ductal adenocarcinoma (PDAC) xenograft models, treatment with GTB-5550 alongside a KRAS inhibitor produced stronger tumor control than KRAS inhibition alone. Researchers reported complete tumor clearance in several animals, along with reductions in local tumor invasion and prevention of metastatic spread.
The combination also resulted in approximately twice the level of tumor infiltration compared with KRAS inhibitor monotherapy. Additional findings included greater persistence of adoptively transferred NK cells and increased expression of CXCR3, a receptor associated with immune cell trafficking. Researchers observed elevated markers of apoptosis in tumor cells, suggesting greater tumor cell death with the combination treatment.
GT Biopharma said the results support further investigation of GTB-5550 as a potential partner for targeted therapies in pancreatic cancer. The company is evaluating options for a future Phase 1b study combining GTB-5550 with a KRAS inhibitor in patients with pancreatic cancer.
Source: drug-dev.com · Image: Pathology department at the central cancer research laboratories by Unknown photographer, Public domain, via Wikimedia Commons
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