Shares of Vital Therapies Inc. plunged 93 percent Wednesday after the San Diego-based firm reported another phase III miss with its ELAD cell-based therapy in acute forms of liver failure. Despite showing a numerical improvement in survival, the study, dubbed VTL-308, fell short of the primary endpoint seeking an improvement in overall survival in patients with severe alcoholic hepatitis through at least 91 days, as assessed using the Kaplan Meier statistical method.