NEW YORK (AP) -- Shares of Intercept Pharmaceuticals nearly quadrupled in value Thursday after the company stopped a clinical trial of a liver disease drug early, saying there was clear evidence the treatment worked.

Intercept said a data monitoring board recommended it stop the trial because patients who were being treated with its experimental drug, obeticholic acid, were faring better than patients who took a placebo. Intercept is studying the drug as a treatment for nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis is a type of chronic liver disease caused by excessive fat accumulation in the liver. It causes inflammation that can cause scarring. The scarring can lead to cirrhosis, liver failure, and death.

Shares of Intercept Pharmaceuticals Inc. surged $203.48 to close at $275.87. During the day they reached a high of $305. The stock closed at $72.39 on Wednesday.

"This is a very rare event, and a significant positive for the prospects for the drug," wrote Janney Capital Markets analyst Jim Molloy.

Nonalcoholic steatohepatitis is the leading cause of liver transplants in the U.S., Molloy said. As about 22 million Americans have the condition and about 8 million suffer from its advanced stages. He said there are no approved drugs for the illness.

The New York drugmaker went public in October 2012. Its initial public offering priced at $15 per share.

The study compared a daily 25-millligram oral dose of obeticholic acid with a placebo. Patients who were treated with the drug for 72 weeks were more likely to have a significant reduction in disease.