Ceftazidime (±avibactam) with IV fosfomycin versus ceftazidime alone for hospitalized adults with severe suspected Gram‑negative infection

Ceftazidime Plus Fosfomycin Versus Ceftazidime Alone for Severe Gram-negative Infections: a Triple-blind, Placebo-controlled Point-of-care Randomized Clinical Trial

Phase 3 Interventional University of Geneva, Switzerland · NCT07063095

This trial will test whether adding intravenous fosfomycin to ceftazidime (or ceftazidime‑avibactam) helps hospitalized adults with suspected severe Gram‑negative infections recover faster than ceftazidime alone.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment100 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity of Geneva, Switzerland Academic / other
Locations1 site (Geneva, Canton of Geneva)
Trial IDNCT07063095 on ClinicalTrials.gov

What this trial studies

This Phase 3, randomized, placebo‑controlled trial enrolls hospitalized adults with suspected severe Gram‑negative bacterial infection to receive either ceftazidime (with or without avibactam) plus intravenous fosfomycin or ceftazidime plus placebo. The primary clinical aims are to see if the combination shortens the time to normalization of qSOFA parameters and lowers C‑reactive protein compared with standard therapy, while further characterizing safety. Patients must be adults able to provide consent (or have a legal representative) and have not received Gram‑negative directed antibiotics for more than 24 hours prior to inclusion. The trial is conducted at Hôpitaux Universitaires de Genève with inpatient IV antibiotic administration and blinded placebo control.

Who should consider this trial

Good fit: Hospitalized adults (≥18 years) with suspected severe Gram‑negative bacterial infection who can consent (or have a legal representative) and who have received ≤24 hours of Gram‑negative directed antibiotics are ideal candidates.

Not a fit: Pregnant or breastfeeding patients, those with known contraindications to ceftazidime/avibactam or fosfomycin, or those already on targeted Gram‑negative therapy for more than 24 hours are unlikely to benefit or be eligible.

Why it matters

Potential benefit: If successful, adding fosfomycin could shorten time to clinical improvement, reduce inflammation, and potentially lower complications and length of hospital stay.

How similar studies have performed: Preclinical data and small clinical reports suggest synergy between ceftazidime (±avibactam) and fosfomycin against some resistant Gram‑negative bacteria, but large randomized Phase 3 evidence is limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Adult (≥18 years)
2. Hospitalized with suspected severe Gram-negative bacterial infection
3. Signed informed consent from the patient (or oral consent from a patient with capacity but with physical inability to sign, with signed witness testimony from a person independent of the study team) of from the legal representative if the patient lacks capacity to provide informed consent

Exclusion Criteria:

1. Pregnancy or lactation
2. Known contra-indication to CAZ±AVI or FOS
3. Gram-negative directed antibiotic treatment begun \>24 hours before inclusion

Where this trial is running

Geneva, Canton of Geneva

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Gram Negative InfectionsSepsis and Septic Shockceftazidimecavifosgram-negative bacteriaintravenous fosfomycin
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.