Received January 13, 2006
Accepted on August 21, 2006

ORIGINAL ARTICLES

Successful Long-Term Treatment of Hyponatremia in Syndrome of Inappropriate Antidiuretic Hormone Secretion with Satavaptan (SR121463B), an Orally Active Nonpeptide Vasopressin V₂-Receptor Antagonist

Alain Soupart ^*1, Peter Gross , Jean-Jacques Legros , Sándor Alföldi ^||, Djillali Annane ^¶, Hassan M. Heshmati , and Guy Decaux ^**

*Department of Internal Medicine, Jolimont/Tubize-Nivelles Hospital, Tubize, Research Unit for the Study of Hydromineral Metabolism and **Department of General Internal Medicine, Erasmus University Hospital, Free University of Brussels, Brussels, and Department of Internal Medicine, Regional Hospital Center of Citadelle, Liege, Belgium; Nephrology, Department of Medicine, University Medical Center Care Gustav Carus, Dresden, Germany; ||Szent Imre Kórház és Rendelöintézet I, Belgyógyászati Osztály, Budapest, Hungary; ¶Department of Intensive Care Unit, Raymond Poincare Hospital, Garches, France; and Clinical Development, Sanofi-Aventis, Malvern, Pennsylvania

¹ To whom correspondence should be addressed. E-mail: alainsoupart{at}swing.be.

	Abstract

The effects of satavaptan (SR121463B), a novel long-acting orally active vasopressin V₂-receptor antagonist, were investigated in patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH). In the first part of this randomized, double-blind study, 34 patients first were treated with satavaptan (versus placebo) for up to 5 d and then during 23 d of open-label dosage-adjustment period. In the second part of the study, long-term efficacy and safety of satavaptan was assessed in an open-label trial during at least 12 mo. Mean (±SD) serum sodium (SNa) levels before treatment were 127 ± 2 mmol/L (placebo, n = 8), 125 ± 6 mmol/L (25 mg, n = 14), and 127 ± 5 mmol/L (50 mg, n = 12). Responders (patients SNa levels normalized or increased by at least 5 mmol/L from baseline during the double-blind period) were 79% in the 25-mg group (SNa 136 ± 3 mmol/L; P = 0.006), 83% in the 50-mg group (SNa 140 ± 6 mmol/L; P = 0.005), and 13% in the placebo group (SNa 130 ± 5 mmol/L). No drug-related serious adverse events were recorded. During the long-term treatment, 15 of 18 enrolled patients achieved 6 mo and 10 achieved 12 mo of treatment. The SNa response was maintained during this time with a good tolerance. The new oral vasopressin V₂-receptor antagonist satavaptan adequately corrects mild or moderate hyponatremia in patients with SIADH and has a good safety profile.