FDA

Fosfomycin injection OK’d for complicated UTIs

October 30, 2025

Brand name: Contepo

Generic name: fosfomycin injection

Manufacturer: Meitheal Pharmaceuticals

Approval date: October 22, 2025

FDA approved Contepo (fosfomycin for injection), an epoxide antibacterial, for the treatment of complicated urinary tract infections (cUTI) including acute pyelonephritis caused by susceptible isolates of Escherichia coli and Klebsiella pneumoniae.

Efficacy

In the multinational, double-blind ZEUS trial (NCT02753946), 464 adults hospitalized with cUTI (including acute pyelonephritis) were randomized to either Contepo 6 g IV every 8 hours or piperacillin/tazobactam 4.5 g IV every 8 hours for 7 days of therapy. Treatment was allowed for up to 14 days in bacteremic patients. The study didn’t include a switch to oral antibacterial drugs.

The microbiological modified intent-to-treat (mMITT) population included all patients who received study medication and had at least 1 baseline uropathogen, excluding patients with organisms resistant to study drugs at baseline. This population consisted of 339 patients with cUTI, including 184 patients (54%) with acute pyelonephritis. Median age was 53 years and 64% were female. Concomitant bacteremia was identified in 9% of patients at baseline, and 32% of patients met 2 or more systemic inflammatory response syndrome (SIRS) criteria at baseline.

Overall success was defined as clinical cure plus microbiological eradication (baseline uropathogens with growth in urine ≥10⁵ CFU/mL were reduced to <10⁴ CFU/mL) at the test-of-cure (TOC) visit, 19 (+2) days after randomization. Overall success rate at the TOC visit was 63.5% in the Contepo group vs. 55.6% in the piperacillin/tazobactam group.

In the mMITT population, the overall success rates at TOC in patients with concurrent bacteremia were 9/19 (47.4%) for Contepo-treated patients and 5/13 (38.5%) in piperacillin/tazobactam-treated patients

Safety

Most common adverse reactions (≥2%) in the trial were transaminase elevations, hypokalemia, neutropenia, nausea, vomiting, diarrhea, hypocalcemia, hypernatremia, headache, and hypophosphatemia.

Sources:

Contepo (fosfomycin) [package insert]. Food and Drug Administration. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/212271s000lbl.pdf Revised October 2025. Accessed October 29, 2025.