An advisory panel to the U.S. Food and Drug Administration on Thursday unanimously backed the accelerated approval of Intercept Pharmaceuticals Inc's drug to treat a rare liver condition.

The drug, obeticholic acid (OCA), is being reviewed for use in patients with primary biliary cholangitis, a condition in which the body mistakes the bile ducts in the liver as foreign objects and tries to destroy their lining.

"If approved, we project launch in July and gross peak annual worldwide sales could reach about $2.2 billion," Wedbush Securities analyst Liana Moussatos said in a note this week.

Accelerated approval is given to drugs based on a surrogate endpoint such as a radiographic image or laboratory measure that points to a clinical benefit.

Surrogate endpoints are used when clinical trials may require too many patients and the outcome may take too long.

Companies are required to conduct studies to confirm the anticipated benefit. If a confirmatory trial does not prove such a benefit, the FDA can revoke the approval.