Inadequately concentrated drug may have caused Tetraphase Pharmaceuticals Inc.'s topline phase III blowup with intravenous (I.V.) eravacycline in complicated urinary tract infections (cUTI), and the company said the results bear no read-through to the same compound's value in complicated intra-abdominal infections (cIAI), for which it's under review in the U.S. and Europe.