March 14 (Reuters) - The U.S. FDA has approved Madrigal

Pharmaceuticals' ( MDGL ) drug for a fatty liver disease known

as non-alcoholic steatohepatitis (NASH), the first treatment to

get the nod for the condition and opening up a multi-billion

opportunity.

The company's oral drug, called Rezdiffra, has been approved

for patients who have NASH with fibrosis, or scarring, that has

progressed to stage 2 or 3 in severity, according to an FDA

label released on Thursday.

NASH, which was recently renamed metabolic

dysfunction-associated steatohepatitis (MASH), affects about 1.5

million people in the United States, according to the company's

estimates, but there was no approved treatment for it until now.