Phase Ib/Ii Study Of An Il-2/T-Cell Receptor Fusion Protein In Combination With Gemcitabine And Cisplatin In Advanced Or Metastatic Chemo-Refractory Urothelial Cancer (Uc)

4515 Background: Although UC is sensitive to platinum-based chemotherapy such as gemcitabine (G) + cisplatin (C), patients who are refractory to GC have limited therapeutic options. ALT-801 is an IL-2/single-chain T-cell receptor fusion protein previously tested in various murine models. ALT-801 demonstrated potent activity against syngeneic and xenograft UC, suggesting sensitivity of this disease to IL-2 based immunotherapy. Methods: We report efficacy and safety results of co-administration of G (1000 mg/m2/dose, d 1 u0026 8) + C (70 mg/m2/dose, d 1) with ALT-801 (0.06 mg/kg/dose, d3, 5, 8, 12) on a 21 day schedule for 3 cycles in patients with advanced/metastatic chemo-refractory UC. The initial ALT-801 dose escalation and expansion study included chemo-naive or refractory subjects of group 1. Group 2 are patients in a 2-armed Phase II dose expansion study of only chemo-refractory subjects receiving either 0.06 mg/kg ALT-801 + GC or 0.06 mg/kg ALT-801 + G based on the renal function. Those with at least st...