Study of Fosfomycin-containing Antibiotic Regimens for the Treatment of Infective Endocarditis in Clinical Practice (FOSFO-IE)

November 4, 2026 updated by: Ente Ospedaliero Ospedali Galliera

A Prospective, Multicenter, Non-interventional, Observational Pharmacological Study on the Clinical Outcomes and Safety Profile of Fosfomycin-containing Antibiotic Regimens for the Treatment of Infective Endocarditis in Clinical Practice

A prospective, multicenter, non-interventional, observational cohort study on the use of a pharmacological agent, conducted within Infectious Diseases units-and, where available, as part of multidisciplinary teams for infective endocarditis-selected according to predefined feasibility criteria. Enrollment will be consecutive and will include all eligible patients for whom fosfomycin has already been initiated, or is initiated by the treating clinician, as part of routine clinical practice.

The decision to prescribe fosfomycin, the dosage, antibiotic combinations, duration of treatment, diagnostic tests, and any potential cardiac surgery strategy will remain entirely independent of the study and subject to local clinical judgment.

The study population will consist of adult patients with a diagnosis of definite or probable infective endocarditis, according to the 2023 Duke-ISCVID criteria, who have received at least one dose of intravenous (IV) fosfomycin as part of the antibiotic regimen for the clinical episode under observation. The availability of the minimum set of clinical, therapeutic, and microbiological data required by the protocol is a necessary requirement for inclusion.

Primary objective To describe the overall clinical outcomes and safety profile of fosfomycin-containing antibiotic regimens used in clinical practice for the treatment of infective endocarditis, assessed by the proportion of overall therapeutic success at a predefined 90-day follow-up and the incidence of adverse events of interest.

Secondary objectives To describe the methods of fosfomycin use in this setting, including clinical indication, timing of initiation, dosage, duration, combination agents, and the rationale behind the therapeutic choice.

To describe the clinical, microbiological, echocardiographic, and imaging characteristics of the enrolled patients.

To evaluate early and late microbiological outcomes, including blood culture clearance, persistence of bacteremia, microbiological recurrence, emergence of resistance, and relapse.

To describe the safety profile of fosfomycin, with particular attention to sodium overload, hypokalemia, electrolyte imbalances, renal toxicity, and adverse events leading to modification or discontinuation of treatment.

To explore the association between patterns of fosfomycin use and clinical or microbiological outcomes, without the intent of establishing causal inference.

To describe microbiological data related to fosfomycin in a standardized manner, specifying the raw MIC value, the antimicrobial susceptibility testing (AST) method, the interpretive criteria applied, and whether or not categorization according to applicable clinical breakpoints is possible.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
120

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Patients affected by infective endocarditis

Description

Inclusion Criteria:

  • Age ≥18 years.
  • Diagnosis of definite or possible infective endocarditis according to the 2023 Duke-ISCVID criteria.
  • Administration of at least one dose of intravenous (IV) fosfomycin as part of the antibiotic regimen for the episode of infective endocarditis under study.
  • Decision to initiate fosfomycin based solely on clinical grounds, independent of participation in the study.
  • Availability of the minimum set of clinical, therapeutic, and microbiological data required by the protocol.

Exclusion Criteria:

  • Case that cannot be classified as definite or probable infective endocarditis according to the 2023 Duke-ISCVID criteria.
  • Use of fosfomycin for indications unrelated to the episode of infective endocarditis under study.
  • Substantial inability to collect essential baseline or outcome data.
  • Refusal of consent, where required by applicable regulations.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: COHORT
  • Time Perspectives: PROSPECTIVE

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
To describe the overall clinical outcomes and safety profile of fosfomycin-containing antibiotic regimens used for the treatment of infective endocarditis, assessed by the proportion of overall therapeutic success at a predefined 90-days follow up+safety
Time Frame: From enrollment to the end of treatment and for the following 90 days
From enrollment to the end of treatment and for the following 90 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Ente Ospedaliero Ospedali Galliera

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Azienda Ospedaliera SS. Antonio e Biagio e Cesare Arrigo di Alessandria
Azienda Ospedaliera Universitaria Ferrara
Azienda USL Reggio Emilia - IRCCS
Osp. di Sanremo - ATS Liguria
ASST Lecco, Lecco

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 10, 2027

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2029

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 30, 2030

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 4, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 4, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 10, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 10, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 4, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • FOSFO-IE

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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