The drug Tolvaptan, which is already approved by the U.S. Food and Drug Administration (FDA) to treat low blood sodium levels, has been voted down by a panel of specialists at the FDA. The drug, sold by Otsuka Pharmaceuticals of Japan, has been put through clinical trials to treat autosomal dominant polycystic kidney disease (ADPKD), a rare disease in which the kidneys essentially grow hundreds of cysts, resulting in kidney failure.

ADPKD is rare, affecting between one in 400 and one in 1,000 people, and can be inherited from just one parent, presenting symptoms between the age of 40 and 60. The disease is caused by a mutation in the PKD1 gene in 85 percent of cases and in the PKD2 gene in the remaining 15 percent of cases. Tolvaptan had received FDA fast track status because it helped the kidneys to function better in clinical trials. The drug was also given priority review by the FDA, which means a decision must be made by September 1.

"While we are disappointed in the Committee's recommendation, we remain committed to providing patients and physicians with a novel treatment for ADPKD, a rare genetic disease. We are looking forward to continuing discussions with the FDA to address the panel's concerns," said Robert McQuade, Ph.D., executive vice president and chief strategic officer at Otsuka Pharmaceutical Development & Commercialization, Inc.

The company hopes to eventually gain FDA approval for its drug by working closely with the FDA in order to determine why the drug has not garnered favor from the advisory panel.