MitoGel is a novel investigational product composed of RTGel, a unique hydrogel polymer which exists as liquid at cold temperatures and a viscous gel at body temperatures, and Mitomycin C, a clinically proven safe and effective treatment for urothelial carcinoma in the bladder. MitoGel can be instilled into the upper urinary tract as a cold liquid, where it solidifies to a gel upon warming to body temperature. The agent remains in the upper tract for a period of 4-6 hours, resulting in sustained contact between the tissues and Mitomycin C. Preclinical studies of MitoGel in the Yorkshire swine have demonstrated that both single and serial instillations into the pelvicalyceal system via both retrograde and antegrade approaches are safe, with no observable adverse clinical, laboratory, or histological effects. For these reasons, MitoGel has generated interest as a treatment for UTUC.