Altimmune set for worst day ever after underwhelming data for liver disease drug

Shares of drug developer Altimmune ALT.O fall as much as 62.4% to a near two-year low of $2.90

Stock set for its biggest one-day pct. drop ever, if losses hold

Co says its experimental obesity drug, pemvidutide, helped patients with a type of fatty liver disease achieve disease resolution without worsening of liver scarring in a mid-stage study

However, the drug does not show statistically significant improvement in liver scarring or fibrosis in patients with the condition, metabolic dysfunction-associated steatohepatitis (MASH) - ALT

While the overall data looks good, "missing on statistical significance for fibrosis will be hard for investors to look past" says Citzensbank analyst Jonathan Wolleben

*"We believe the results are underwhelming...view the weight-loss magnitude at 24 weeks as non-differentiating" - William Blair analyst Andy Hsieh

There's a limited ability to demonstrate stringent scarring improvement at the 48-week time point - Hsieh

Including session's move, stock down 51.8% YTD