ASP1951 + PTZ-522

ASP1951 + PTZ-522 is a combination designation referring to the same investigational immuno-oncology antibody program, in which ASP1951 (also known as PTZ-522) is a novel-format, human, high‑affinity, tetravalent agonistic monoclonal antibody targeting glucocorticoid-induced tumor necrosis factor receptor (GITR, TNFRSF18) for the treatment of advanced solid tumors.[2][7][9][10][12][13] Developed originally by Potenza Therapeutics and subsequently by Astellas after its acquisition of Potenza, this GITR agonist is designed to provide T‑cell priming and costimulation, enhancing proliferation and function of tumor‑infiltrating lymphocytes and potentially overcoming resistance to existing immune checkpoint inhibitors; it has been evaluated intravenously as monotherapy and in combination with pembrolizumab in Phase 1 studies in advanced solid malignancies including squamous cell carcinoma of the head and neck, non‑small cell lung cancer, cervical cancer, colorectal cancer, and metastatic castration‑resistant prostate cancer.[1][3][9][10][12][13]