CYP19A1 and metabolic dysfunction-associated steatohepatitis: This discovery then led to the development of ARO-HSD, a RNAi therapeutic that selectively targets HSD17B13 mRNA in hepatocytes, which has demonstrated improvements in NASH outcomes, as assessed by ALT, AST, and MRI-PDFF, in a Phase 1/2 clinical trial (106, 107).