New Vaprisol indication ushers in age of aquaresis

Astellas Pharma US, a subsidiary of Japan's Astellas, says that the Food and Drug Administration has approved its drug Vaprisol (conivaptan HCl injection) for the treatment of the electrolyte disorder hypervolemic hyponatremia, in hopitalized patients. The firm added that hyponatremia is thought to affect up to 4% of hospitalized patients in the USA each year and, in severe cases, can result in brain swelling, respiratory arrest and death.

The approval is based on the results of a randomized, double-blind, placebo-controlled study that examined the effect of a daily 40mg dose of Vaprisol on patients suffering from the condition. The trial showed that the drug brought about clinically meaningful aquaresis (excretion of electrolyte-free water) resulting in an average increase in serum sodium levels of 6.4 mEq/l 24 hours after administration. The firm added that the most commonly-observed adverse events where infusion site reactions which, in some cases, lead to a discontinuation of treatment.

Steven Goldsmith, a professor of medicine at the University of Minnesota Medical School, said that Vaprisol represents a novel treatment option for the illness as it effectively increases serum sodium concentrations in a predictable manner, thereby allowing effective therapy. The firm added that the approval decision follows the FDA's clearance of the drug as a treatment for euvolemic hyponatremia in 2005 (Marketletters passim).