CStone Pharmaceuticals, an innovation-driven biopharmaceutical company focused on the research and development of anti-cancer therapies, announced that the first patient has been successfully dosed in the global multicenter Phase I clinical trial of its novel PD-1/VEGF/CTLA-4 trispecific antibody, CS2009, with no infusion reactions or other adverse events observed.

This trial aims to evaluate the clinical potential of CS2009 in a wide range of advanced solid tumors including, but not limited to, non-small cell lung cancer, hepatocellular carcinoma, gastric adenocarcinoma, endometrial cancer, ovarian cancer, renal cell carcinoma, and cervical cancer, in efforts to advance the development of innovative tumor immunotherapies.

CS2009, an innovative trispecific antibody designed and developed by CStone, combines three clinically validated targets—PD-1, VEGFA, and CTLA-4—and exerts multidimensional anti-tumor effects through synergistic actions. Specifically, anti-PD-1 activity that reverses T cell exhaustion, anti-CTLA-4 activity that promotes T cell activation and proliferation, while anti-VEGFA activity blocks tumor angiogenesis and improves the tumor micro-environment (TME). In the TME, anti-PD-1 and anti-CTLA-4 activities are significantly enhanced by crosslinking with VEGFA. Meanwhile, CS2009 preferentially blocks PD-1 and CTLA-4 on double-positive tumor-infiltrating T cells while minimizing interference with CTLA-4 regulation in peripheral T cells, thus potentially offering enhanced efficacy with lower systemic toxicity.

In preclinical studies, CS2009 demonstrated superior anti-tumor activity compared to potential competitors. By combining CTLA-4 inhibition with PD-1 and VEGFA blockade, CS2009 may further enhance benefits for patients with low or negative PD-L1 expression, who respond poorly to PD-(L)1 therapies. This well positions CS2009 as a next-generation, first- or best-in-class immunotherapy backbone, with the potential to replace current anti-PD-(L)1-based therapies.