Mid-FDA Review, Tetraphase Stumbles Again on Latest Phase 3 Setback

Xconomy Boston — 

Tetraphase Pharmaceuticals’ ups and downs have continued, as new data have clouded the future of the Watertown, MA, company’s experimental antibiotic, eravacycline, once again.

Tetraphase (NASDAQ: TTPH) reported that eravacycline failed a 1,200-patient Phase 3 study called Ignite3, one of four late-stage trials the company ran to test the antibiotic against either complicated urinary tract infections (cUTI) or complicated intra-abdominal infections (cIAI). In Ignite3, a daily intravenous infusion of eravacycline performed worse than the antibiotic ertapenem at wiping out cUTI infections. Eravacycline just had to be comparable to ertapenem to succeed.

Shares of Tetraphase shares were down more than 54 percent, to $2.49 apiece, in pre-market trading Wednesday morning.

Tetraphase’s antibiotic has now succeeded in two Phase 3 trials in cIAI and failed in two others in cUTI, causing a variety of big stock swings over the past few years and an uncertain commercial future. The antibiotic is currently under review in the U.S. and Europe for cIAI infections, for which the results of two studies, Ignite1 and Ignite4, were positive.

Tetraphase’s eravacycline is a broad-spectrum antibiotic, meaning it is being developed to handle multiple types of bacterial infections. New antibiotics are sorely needed due to the rise of deadly drug-resistant bugs. According to the Centers for Disease Control and Prevention, 2 million Americans each year suffer from drug-resistant bacterial infections, and more than 23,000 of them die. Tetraphase and another Boston-area company, Paratek Pharmaceuticals (NASDAQ: PRTK), both have a chance to bring new weapons to the fight in the near-term. Paratek just filed for approval of a broad-spectrum antibiotic, omadacycline, for bacterial pneumonia and skin infections, last week.  It’s also being developed for cUTI and cIAI infections.

Here’s more on Tetraphase, eravacycline, and some of the other antibiotics in clinical development.