Randomized, dose-finding, Phase II study of the selective relaxant binding drug, sugammadex, capable of safely reversing profound rocuronium-induced neuromuscular block

BACKGROUND: The reversal of a deep neuromuscular blockade remains a significant clinical problem. Sugammadex, a modified gamma-cyclodextrin, encapsulates steroidal neuromuscular blocking drugs, promoting their rapid dissociation from nicotinic receptors. Sugammadex is the first drug that acts as a selective relaxant binding agent. METHODS: We enrolled 50 patients into a Phase H dose-finding study of the efficacy and safety of sugammadex. Subjects, anesthetized with nitrous oxide and propofol, were randomized to one of two doses of rocuronium (0.6 or 1.2 mg/kg) and to one of five doses of sugammadex (0.5, 1.0, 2.0, 4.0, or 8.0 mg/kg). Neuromuscular monitoring was performed using the TOF Watch SX (R) acceleromyograph. Recovery was defined as a train-of-four ratio >= 0.9. Sugammadex was administered during profound block when neuromuscular monitoring demonstrated a posttetanic count of one or two. RESULTS: Reversal of neuromuscular block was obtained after administration of sugammadex in all but the lowest dose groups (0.5-1.0 mg/kg) where several subjects could not be adequately reversed. At the 2 mg/kg dose all patients were reversed with sugammadex, but there was significant variability (1.8-15.2 min). Patient variability decreased and speed of recovery increased in a dose-dependent manner. At the highest dose (8 mg/kg), mean recovery time was 1.2 min (range 0.8-2.1 min). No serious adverse events were reported during this trial. CONCLUSIONS: Sugammadex was well tolerated and effective in rapidly reversing profound rocuronium-induced neuromuscular block. The mean time to recovery decreased with increasing doses. Profound rocuronium-induced neuromuscular block can be reversed successfully with sugammadex at doses >= 2 mg/kg.