Shares of 89bio Inc. /zigman2/quotes/214906549/composite ETNB +4.35% were up 4.2% in premarket trading on Tuesday, the day after the company shared encouraging, early-stage data from a clinical trial assessing an experimental therapy called pegozafermin as a treatment for non-alcoholic steatohepatitis. "We continue to view the FGF21 analogs as one of the most compelling classes of drugs being developed in NASH," SVB Leerink analyst Thomas Smith told investors on Tuesday. Brian Abrahams, an analyst at RBC Capital Markets, wrote Monday that the new data reinforced the "broad potential benefits of pegozafermin." The data came from a 20-patient, open-label study; a larger Phase 2b trial with more than 200 patients is currently underway. So far this year 89bio's stock has declined 26.5%, while the broader S&P 500 /zigman2/quotes/210599714/realtime SPX +0.01% is down 7.4%.