Dec 19 (Reuters) - Madrigal Pharmaceuticals' experimental drug met the main goals in a eagerly anticipated late-stage study, propelling it to the forefront in the race for the first approved treatment for patients with advanced liver scarring.

Shares of the drugmaker surged more than three-fold on Monday after the positive data on resmetirom - a potential treatment for NASH, or nonalcoholic steatohepatitis, the fastest-growing cause of liver transplants.

At least one analyst hailed the data as the "best case scenario", after the drug helped reduce liver scarring or fibrosis in patients.

The drug also met the main goal of helping patients reach "NASH resolution" as measured by the lack of liver ballooning and low inflammation.

"This significantly exceeds consensus expectations, which were for success on the NASH resolution endpoint with only a small probability of hitting on fibrosis improvement," said SVB Securities analyst Thomas Smith.

Shares of Madrigal more than tripled to $209. The results also tripped the shares of rival NASH drug developers such as Akero Therapeutics and 89bio, which were down more than 15% each.

NASH is a form of nonalcoholic fatty liver disease, characterized by the organ developing fibrosis or scarring, which can progress to cirrhosis and liver failure.

Approved treatments for the disease are expected to be a multibillion dollar market in the United States, with Novo Nordisk as well as other smaller companies racing to develop the drugs.

Madrigal plans to file a marketing application with the regulators seeking accelerated approval in the first half of 2023.

In the trial, an 80 milligram dose helped 26% of patients reach NASH resolution, compared to 30% for a higher 100 milligram dose, and 10% for placebo.

The drug resmetirom also showed improvement in fibrosis or scarring with no worsening of fatty liver disease in 24% of patients, compared to 26% for the 100 milligram dose, and 14% for placebo. (Reporting by Leroy Leo and Raghav Mahobe and Sriparna Roy in Bengaluru; Additional reporting by Manas Mishra; Editing by Krishna Chandra Eluri and Shailesh Kuber)