** Shares of drugmaker Madrigal Pharmaceuticals MDGL.O rise 13.8% to $352.3

** Co reports Q4 sales of $103.3 mln from its fatty liver disease drug Rezdiffra, beating analysts' estimate of $71.95 mln as per data compiled by LSEG

** Two-year data from a late-stage study evaluating Rezdiffra shows it helped significantly reduce liver stiffness in patients with metabolic dysfunction-associated steatohepatitis (MASH)

** Says 51% of patients enrolled in the trial achieved 25% or greater reduction in liver stiffness -MDGL

** Significant reduction of liver stiffness has been associated with reduced progression to end-stage liver disease -MDGL

** MASH is a serious condition that causes excess build up of fat in the liver and causes inflammation and fibrosis, or scarring, of the organ

** Stock has risen 33% in the past 12 months

(Reporting by Padmanabhan Ananthan)

((Padmanabhan.Ananthan@thomsonreuters.com;))