Randomized, Double‐Blind, Controlled Study to Evaluate Safety and Pharmacokinetics of Single Ascending Doses of ASP5354, an Investigational Imaging Product, in Healthy Adult Volunteers

Intraoperative ureter identification helps reduce the risk of ureteral injury. Currently, no suitable agents for real‐time ureter visualization are approved. ASP5354 (TK‐1) is a novel indocyanine green derivative. In this first‐in‐human phase 1, double‐blind, sequential ascending‐dose study, urethral catheters were placed in 6 healthy volunteers who were randomized to single‐dose, intravenous ASP5354 0.1 mg (n = 4) or placebo (n = 2). Sequential dose escalations to 0.5‐, 2‐, 8‐, and 24‐mg ASP5354 in new cohorts were contingent upon Dose‐Escalation Committee approval after review of pharmacokinetic (PK) and safety data. Blood and urine samples were collected over 24 hours following dose administration. Objectives were to assess the safety/tolerability and PK of ASP5354. Treatment‐emergent adverse events (TEAEs) were reported in 3 (15%) and 2 (20%) participants in the ASP5354 and placebo groups, respectively. In the former, there were 6 TEAEs (5/6 grade 1‐2). One ASP5354 participant experienced grade 3 pyelonephritis, attributed to the catheter. No TEAEs were related to ASP5354. Mean plasma terminal elimination half‐life ranged from 2.1 to 3.6 hours, with near complete urinary excretion of unchanged ASP5354 within 24 hours after administration. Linear and dose‐proportional PK were observed. These results support further evaluation of ASP5354 at doses up to 24 mg for intraoperative near‐infrared fluorescence ureter visualization.