Tetraphase's shares drop 80 percent on late-stage study failure for antibiotic eravacycline

Shares in Tetraphase Pharmaceuticals plummeted as much as 80 percent after the company announced that a Phase III study of the experimental antibiotic eravacycline for the treatment of complicated urinary tract infections (cUTI) failed to hit its main endpoint of statistical non-inferiority versus Johnson & Johnson's Levaquin (levofloxacin).

The pivotal portion of the IGNITE2 trial randomised 908 patients with cUTI to receive eravacycline or Levaquin, with each subject administered a minimum of three days of intravenous dosing, before transitioning to oral therapy for a total treatment period of seven days. Tetraphase noted that for the FDA, the primary analysis evaluated the responder outcome in the microbiological intent-to-treat (ITT) population at the post-treatment visit using a 10 percent non-inferiority margin. Meanwhile, for the European Medicines Agency, the primary analysis evaluated the microbiological response in the microbiologically modified ITT population and microbiologically evaluable populations.

According to the company, eravacycline did not achieve the primary endpoint under either analysis. CEO Guy Macdonald said "we plan to further analyse the data and provide an update after we have discussed the data and our plans for a path forward with the regulatory agencies."

Last year, Tetraphase announced that the Phase III IGNITE 1 study of eravacycline for the treatment of complicated intra-abdominal infection met its main goal of statistical non-inferiority versus Merck & Co.'s Invanz (ertapenem).

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