What Spooked Conatus Pharmaceuticals (CNAT) Investors This Evening

Some investors might love biotech stocks for their lottery ticket-like returns when a company strikes medical gold. A lottery ticket, however, costs only a buck or two, while getting a biotech company wrong can hurt a lot more than that. Case in point: Conatus Pharmaceuticals (NASDAQ: CNAT ) shares are diving over 25% in after-hours trading Wednesday, after the drug maker announced that POLT-HCV-SVR, the company’s exploratory Phase 2b POLT-HCV-SVR proof-of-concept clinical trial, did not meet its primary endpoint.