Investors sorting through NGM Biopharmaceuticals Inc.'s interim results from the fourth and final cohort of the adaptive phase II trial with aldafermin in nonalcoholic steatohepatitis (NASH) may have felt let down when comparing the data to previous cohorts' outcomes. Shares of the South San Francisco-based firm (NASDAQ:NGM) closed Monday at $10.78, having sunk $2.77 or 20.4%.