Shares of Tenax Therapeutics Inc. (NASDAQ:TENX) fell 76.4 percent to 46 cents by Tuesday's close on news that its lead candidate, levosimendan, failed to meet the co-primary endpoints of a phase III study evaluating its potential for the reduction of morbidity and mortality in cardiac surgery patients at risk for developing low cardiac output syndrome (LCOS), an indication for which it had been granted FDA fast track status.