Spero Therapeutics Inc. is laying the groundwork to move its lead candidate, the carbapenem SPR-994, into a phase III trial for people with complicated urinary tract infections (cUTI) around year-end, encouraged by interim phase I data suggesting the candidate can be just as safe and effective as its progenitor, Meiji Seika Pharma Co. Ltd.'s Asia-marketed Orapenem (tebipenem pivoxil). Spero's phase III trial, subject to FDA review, would be a noninferiority study pitting oral SPR-994 against I.V. Merck & Co. Inc.-marketed Invanz (ertapenem), the most commonly prescribed carbapenem for cUTI.