Oral V₂ receptor antagonist (RWJ-351647) in patients with cirrhosis and ascites: A randomized, double-blind, placebo-controlled, single ascending dose study

Background: RWJ-351647 is a selective V2 receptor antagonist that inhibits vasopressin-induced water reabsorption in the kidney. Aim: To investigate the safety and tolerability of RWJ-351647 compared with placebo after single oral dose administration to patients with cirrhosis and ascites, on a stable treatment with furosemide and spironolactone. Methods: Single oral doses of 1, 2 and 5 mg of RWJ-351647 were administered to 24 patients with ascites on stable concomitant diuretic treatment. Results: RWJ-351647 had a tmax of 1 to 1.1 h and mean half-life of 10.4-17.4 h. There was no affect on the pharmacokinetics of concomitant diuretics. Increases in cumulative urine volume and free water excretion, and a decrease in urine osmolality were noted in a dose-dependent manner reaching the statistical significance at the 5-mg dose. Four patients exhibited a decrease of >2 kg in weight in the 24 h after dosing. RWJ-351647 was well tolerated, with no evidence of a dose-related increase in adverse events when compared with placebo. No changes in either serum chemistry or plasma AVP (arginine vasopressin) and renin levels were observed despite the observed aquaresis. Conclusion: RWJ-351647 is an effective aquaretic causing dose-dependent increases in urine output and free water clearance, when co-administered with conventional diuretics in patients with cirrhosis and ascites.