Two companies developing drugs to treat complicated urinary tract infections say it is feasible to conduct trials according to recommendations in FDA's new draft guidance. But clinicians are concerned the results of such studies won't be applicable to real-world clinical practice in the U.S.

A complicated urinary tract infection (cUTI) is characterized by pyuria and pathogen on culture of urine or blood, plus a functional or anatomical abnormality of the urinary tract, and is accompanied by symptoms such as fever, chills and back pain. For a minority of patients, cUTIs can be life threatening due to the risk of septic shock.