Two New Antibiotics Expand the Complicated UTI Treatment Landscape

In "Two New Antibiotics Expand the Complicated UTI Treatment Landscape," the panel unpacks two recent approvals that are reshaping how clinicians think about treating this condition.

Dr. Gupta introduces two recent approvals, starting with an intravenous formulation of a decades-old drug approved in October 2025. Dr. Kaye explains that intravenous fosfomycin has long been available in Europe, supported by older trials and extensive observational data. A pivotal phase three trial, called Zeus, found it non-inferior to piperacillin-tazobactam for complicated UTI and pyelonephritis, including strong performance against resistant Escherichia coli. Manufacturing problems delayed its United States availability after publication, stalling early momentum. Dr. Kaye does not see it as a primary workhorse, but values it for limiting carbapenem use against resistant or extended-spectrum beta-lactamase-producing Escherichia coli. He also sees it as an alternative to linezolid or daptomycin for vancomycin-resistant enterococcus. Dr. Pogue flags an important caveat: the approved intravenous dose delivers eighteen grams of the drug daily for seven days, carrying roughly six grams of sodium. That raises hypernatremia and hypokalemia risks that Dr. Kaye says concern him most in patients with compromised cardiac function or heart failure history. Dr. Gupta then turns to the first oral carbapenem, approved in June 2026 for pyelonephritis and for patients with limited alternative oral options. Dr. Pogue, noting the pivotal trial remains unpublished, walks through its history. A 2022 trial found the drug non-inferior to ertapenem at three-times-daily dosing, but signals of weaker performance in elderly and extended-spectrum beta-lactamase-positive patients prompted a dose increase to four times daily. The newer trial compared the higher, all-oral dose against seven days of intravenous imipenem. Patients averaged sixty-five years old, with a two-to-one ratio of complicated UTI to pyelonephritis. The trial showed non-inferiority without notable safety signals, giving Dr. Pogue confidence in the data despite the pending publication.

The next episode in this series, "Weighing the Benefits and Risks of an Oral Carbapenem Option," has Dr. Kaye weighing exactly who should receive this new oral option.