89bio is a clinical-stage biopharmaceutical company with no approved products or commercial revenue. Its entire focus is developing FASN (fatty acid synthase) inhibitors — drugs that block an enzyme overactive in certain diseases, driving excess fat production. The lead candidate is denifanstat, an oral, once-daily pill targeting MASH (metabolic dysfunction-associated steatohepatitis), a progressive liver disease where excess fat accumulates in the liver, driving inflammation and scarring that can progress to cirrhosis and liver failure. Denifanstat attacks MASH at three root causes simultaneously: reducing fat synthesis, suppressing inflammation, and blocking fibrosis — a broader mechanism than most competing therapies. Denifanstat completed a Phase 2b trial in MASH, meeting both primary endpoints, and received FDA Breakthrough Therapy designation in October 2024. The next major step is a combination trial pairing denifanstat with resmetirom (already FDA-approved for MASH), where preclinical data showed histological improvement of 80% for the combination versus 33% and 25% for each drug alone. A Phase 2 trial of this combination in cirrhotic MASH is planned for the second half of 2026. Beyond MASH, 89bio licenses denifanstat rights in Greater China to Ascletis, which filed an NDA in China for acne in December 2025. 89bio is also developing a second FASN inhibitor, TVB-3567, for acne outside China. 89bio funds operations through equity markets and has no sales infrastructure, intending to commercialize independently or via a partner if denifanstat is approved.