Tetraphase Pharmaceuticals Inc.'s stock plunged 79% in premarket trade Wednesday, in the wake of disappointing late-stage trial results of its treatment for urinary tract infections. The stock is on track to open at the lowest level since May 2014, as a number of Wall Street analysts followed the trial news with downgraded and price target cuts. Late Tuesday, Tetraphase said a phase 3 clinical trial of eravacycline failed to achieve its primary endpoint. "We plan to further analyze the data and provide an update after we have discussed the data and our plans for a path forward with the regulatory agencies," said Chief Executive Guy Macdonald. No less than four of the 11 analysts covering Tetraphase, and tracked by FactSet, have downgraded the stock following the trial news. Tetraphase's stock is trading at $9.28 ahead of the open, which is 82% below its July 16 record close of $51.89. The stock went public on March 20, 2013 at an initial-public-offering price of $7.
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