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FOSFOMYCIN CALCIUM

Fosfomycin calcium is an antibiotic being studied in different clinical trials for preventing or treating infections. These studies include people with a high risk of infection after cancer treatments, adults with urinary tract infections, and critically ill patients in intensive care. This article explains, in simple language, what these trials are testing, how fosfomycin calcium is given (by mouth or through a vein), and what outcomes researchers measure, such as infection control, side effects, and antibiotic resistance.

Table of Contents

What Fosfomycin Calcium Is (Based on These Trials)

Fosfomycin calcium is an antibiotic that is being tested in multiple clinical trial settings. In the provided trials, it appears as a chemical active substance (“FOSFOMYCIN CALCIUM”) and is used in different ways depending on the disease setting.

Across the trials, fosfomycin calcium is studied for:

  • Infection prevention (prophylaxis) in very high-risk patients with blood cancers, especially during periods of very low white blood cells.

  • Treatment of uncomplicated urinary tract infection (uUTI) in adult women, measured by symptom relief and urine culture results.

  • Drug level monitoring in intensive care settings to see if typical dosing reaches target blood levels linked with best antibiotic activity.

[1][2][3]

How Fosfomycin Calcium Is Given in Studies (Oral vs IV)

How a medicine is given (the “route”) can matter because it changes where the drug goes in the body and how quickly it works.

  • Oral (by mouth): In a phase III prevention trial, participants receive oral capsules containing 700 mg calcium fosfomycin (equivalent to 500 mg active drug) and take it three times daily during the neutropenia-risk period. In a uUTI phase IV trial, oral fosfomycin calcium capsules are also used and compared to another fosfomycin formulation.

  • Intravenous (IV) (into a vein): In an ICU cohort study, fosfomycin calcium is one of the IV antibiotics measured to determine whether current dosing reaches planned PK/PD targets. Blood samples are taken via existing lines (catheters) to measure antibiotic concentrations.

[1][3][2]

Trial Focus: Preventing Febrile Neutropenia in Acute Leukemia or Stem Cell Transplant

Two provided records describe a multicenter randomized phase III study comparing oral fosfomycin to oral ciprofloxacin for prevention of febrile neutropenia in people with acute leukemia receiving intensive chemotherapy and/or those receiving a hematopoietic stem cell transplant (HSCT).

Febrile neutropenia means:

  • Fever (which can be a sign of infection), and

  • Neutropenia (very low neutrophils, a key infection-fighting white blood cell).

Important details from the trial descriptions include:

  • Design: multicenter, prospective, randomized, open-label, non-inferiority.

  • Population: adults with acute leukemia getting induction chemotherapy and/or HSCT recipients; expected neutropenia for at least 7 days; other risk factors for infection may be considered.

  • Intervention timing: prophylaxis starts from the first day of induction chemotherapy or conditioning and continues until absolute neutrophil count (ANC) is above 0.5 × 109/L (or up to a maximum follow-up window described in the protocol).

The main outcome focuses on whether participants develop febrile neutropenia of infectious origin that requires antibacterial treatment. Secondary outcomes include documented infections, use of broad-spectrum antibiotics (tracked as days of antibiotics per hospitalization days), overall survival, drug-related adverse events, and multiple microbiology-focused outcomes such as resistome and microbiome changes and colonization by multidrug-resistant bacteria.

[1][4]

Trial Focus: Treating Uncomplicated Urinary Tract Infection (uUTI) in Adult Women

A phase IV randomized, multicenter, double-blind, double-dummy trial evaluates oral fosfomycin calcium in adult women with uncomplicated urinary tract infection (uUTI).

uUTI in this trial is identified using symptoms such as urinary frequency, urgency, dysuria (burning or pain when urinating), and/or suprapubic pain (pain above the pubic bone). The trial also uses a urine dipstick positive for leukocyte esterase, which suggests pyuria (white blood cells in urine, often seen with infection).

The trial’s main goal is to show that fosfomycin calcium is non-inferior to fosfomycin trometamol for both:

  • Clinical resolution (symptoms get better), and

  • Microbiological response (urine culture bacteria reduced to <1000 CFU/mL at the test-of-cure visit).

The study also monitors safety and tolerability of the oral capsule regimen in this population.

[2]

Trial Focus: Measuring Fosfomycin Levels in ICU Patients (PK/PD Study)

A separate multinational prospective cohort study (DALI-2) includes critically ill ICU patients receiving IV antibiotics (including fosfomycin calcium). This study does not change routine care; instead, it measures antibiotic blood levels to see if contemporary dosing achieves pre-defined PK/PD targets associated with maximal activity.

Key ideas explained simply:

  • Pharmacokinetics (PK) means “what the body does to the drug,” such as how drug levels rise and fall over time.

  • Pharmacodynamics (PD) means “what the drug does to the bacteria/body,” often linked to what drug level is needed to work well.

The study collects up to three blood samples per antibiotic (using existing catheters) and then checks whether the measured antibiotic concentrations meet the target levels. Secondary outcomes include relationships between target achievement and outcomes such as clinical success/failure, mortality at day 14 and day 30, ICU-free days, emergence of resistance, and whether concentrations exceed levels associated with toxicity.

[3]

Antibiotic Resistance, Resistome, and the Microbiome in These Trials

Several trials include outcomes that look beyond short-term symptom control and focus on how antibiotics may affect bacteria carried in the body.

  • Colonization by multidrug-resistant bacteria: Some studies measure how often patients become “colonized,” meaning resistant bacteria are present (for example, in the gut) even if there is no active infection. This can be tracked with surveillance cultures or with metagenomic sequencing.

  • Resistome evolution: This refers to changes over time in antibiotic resistance genes in the microbial community.

  • Microbiome evolution: This means changes in the normal gut bacteria during different prophylactic strategies.

[1][4]

Safety Outcomes and Side Effects Tracked in Trials

Clinical trials routinely track safety. In the fosfomycin vs ciprofloxacin febrile neutropenia prevention trial, safety outcomes include drug related adverse events (how often side effects happen, and their severity and type). The uUTI trial also includes safety and tolerability monitoring for the oral capsule regimen.

In the ICU PK/PD cohort study, safety-related endpoints include the proportion of patients whose antibiotic concentrations exceed pre-defined values associated with toxicity, and the frequency of suspected adverse drug events and how they relate to measured drug levels.

[1][2][3]

How to Understand the Trial Designs (Randomized, Non-Inferiority, Blinding)

The provided trials use different designs, each answering a different type of question.

  • Randomized: assignment by chance to different groups (for example, fosfomycin vs ciprofloxacin). This helps reduce bias.

  • Non-inferiority: designed to show a treatment is not worse than the comparison treatment by more than a pre-set margin. This is used in the febrile neutropenia prevention trial and the uUTI efficacy comparison.

  • Open-label: both patient and study team know the assigned treatment (used in the febrile neutropenia prophylaxis trial).

  • Double-blind, double-dummy: used to keep participants and researchers unaware of which active treatment is taken, even when the treatments look different.

  • Cohort PK/PD study: observes patients receiving standard care antibiotics and measures drug levels to see if dosing targets are achieved (used in the ICU study).

[1][2][3]
Topic What the trials study
Drug Fosfomycin calcium (oral capsules; intravenous use in ICU dosing study)
Main clinical settings Prevention of febrile neutropenia infections in acute leukemia/HSCT; treatment of uncomplicated UTI in adult women; antibiotic level monitoring in critically ill ICU patients
Key comparators Ciprofloxacin (febrile neutropenia prevention trial); fosfomycin trometamol (uUTI trial)
Common trial designs Randomized non-inferiority studies; open-label designs; double-blind/double-dummy design for uUTI trial; PK/PD cohort study in ICU
What “success” can mean No febrile neutropenia needing antibiotics; symptom resolution in uUTI; bacteria reduced/cleared in urine culture; reaching target antibiotic blood levels in ICU patients
Safety and resistance monitoring Adverse events; need for broad-spectrum antibiotics; monitoring colonization with multidrug-resistant bacteria; resistome and gut microbiome changes

FAQ

  • What is fosfomycin calcium in these clinical trials? Fosfomycin calcium is an antibiotic studied as either oral capsules/tablets (taken by mouth) or as an intravenous medicine (given into a vein). Trials test how well it prevents or treats infections and how safe it is in different patient groups.
  • Which infections or infection-related problems are being studied with fosfomycin calcium? Trials include preventing febrile neutropenia (fever with very low white blood cells) in people with acute leukemia or after stem cell transplant, and treating uncomplicated urinary tract infections (uUTI) in adult women. Fosfomycin calcium is also included in an ICU study that measures antibiotic levels in critically ill patients with serious infections.
  • How do researchers compare fosfomycin calcium to other treatments? Some studies compare fosfomycin calcium to another antibiotic such as ciprofloxacin, and one study compares fosfomycin calcium to a different form of fosfomycin called fosfomycin trometamol. These comparisons often use a “non-inferiority” design, meaning the goal is to show the study drug works not worse than the comparison treatment within a set margin.
  • What outcomes do these trials measure? Depending on the trial, outcomes include whether febrile neutropenia develops and needs antibiotic treatment, rates and types of documented infections, overall survival, drug-related side effects (adverse events), and changes in bacteria in the gut such as antibiotic-resistant bacteria. Some studies also measure microbiome (normal bacteria) changes and antibiotic blood levels.
  • How long might participants be followed in these studies? Follow-up depends on the condition being studied. For febrile neutropenia prevention, outcomes may be tracked until neutrophil counts recover or up to about 60 days, with survival followed up to about 12 weeks. In bloodstream infection studies, mortality can be assessed at 30 days and up to 90 days. In urinary tract infection studies, symptom and culture checks can occur around 7 days after treatment ends, with additional follow-up around 28 days in some designs.

Ongoing Clinical Trials on FOSFOMYCIN CALCIUM

  • Study of pivmecillinam compared to standard antibiotics for treating Escherichia coli urinary tract infection with fever

    Recruiting

    1 1 1
    Investigated drugs:
    Norway Sweden

  • MV140 for Women with Recurrent Uncomplicated Urinary Tract Infections

    Not yet recruiting

    1 1 1
    Investigated drugs:
    Portugal

  • Study of antibiotic treatment effectiveness in critically ill patients receiving drug combination therapy

    Not yet recruiting

    1 1 1 1
    Investigated drugs:
    France

  • Study Comparing Fosfomycin and Ciprofloxacin for Preventing Fever in Patients with Acute Leukemia After Chemotherapy or Stem Cell Transplant

    Not yet recruiting

    1 1 1 1
    Investigated diseases:
    Investigated drugs:
    Spain

  • Study on Antibiotic Treatment Before Surgery for Benign Prostate Hyperplasia: Fosfomycin Calcium, Bromhexine Hydrochloride, Sulfamethoxazole, and Trimethoprim

    Not yet recruiting

    1 1 1 1
    Investigated drugs:
    France

  • Study on the Safety and Effectiveness of Fosfomycin Calcium for Treating Uncomplicated Urinary Tract Infections in Adult Women

    Not yet recruiting

    1 1 1 1
    Investigated drugs:
    Spain

  • Study Comparing Oral Fluoroquinolones or Trimethoprim-Sulfamethoxazole to IV Therapy in Stable Patients with Gram-Negative Blood Infections

    Not recruiting

    1 1 1 1
    Investigated drugs:
    Greece Italy Spain

Glossary

  • Antibiotic: A medicine that kills bacteria or stops them from growing. Antibiotics do not treat viruses.
  • Fosfomycin calcium: A chemical form of fosfomycin used as an antibiotic in these trials. It is studied as oral capsules and as an intravenous (IV) medicine.
  • Fosfomycin trometamol: Another form of fosfomycin used for comparison in a urinary tract infection trial. Different forms can affect how the drug is taken and absorbed.
  • Oral capsules / oral therapy: Medicine taken by mouth (swallowed). In one trial, fosfomycin calcium is given as oral capsules multiple times per day.
  • Intravenous (IV) / infusion: Medicine given directly into a vein, often through a drip (infusion). One ICU study measures fosfomycin calcium levels when given this way.
  • Febrile neutropenia: A medical emergency risk state where a person has a fever and very low neutrophils (a type of white blood cell). It can happen after intensive chemotherapy or stem cell transplant.
  • Neutrophils: White blood cells that help fight bacterial infections. When neutrophils are low, infection risk rises.
  • Absolute neutrophil count (ANC): A lab number showing how many neutrophils are in the blood. Trials may continue prevention until ANC rises above 0.5 × 10^9/L.
  • Prophylaxis / prophylactic strategy: Treatment given to prevent an infection before it happens. Fosfomycin calcium is tested as prophylaxis against febrile neutropenia-related infections.
  • Randomized trial: A study where participants are assigned by chance to different treatments. This helps make groups similar and results more reliable.
  • Open-label: A study where participants and researchers know which treatment is being given.
  • Double-blind: A study where participants and researchers do not know which treatment a participant is receiving, to reduce bias.
  • Double-dummy: A technique used when two treatments look different (for example, different pills). Participants may receive placebo versions so that blinding is maintained.
  • Phase III trial: A larger clinical trial phase that tests how well a treatment works and how safe it is, often compared to standard treatment.
  • Phase IV trial: A study phase performed after a drug is already in use, often to compare strategies or confirm effectiveness and safety in real-world settings.
  • Non-inferiority trial: A study designed to show that a new treatment is not unacceptably worse than a comparison treatment by more than a pre-set amount.
  • Comparator: The treatment used for comparison in a clinical trial (for example, ciprofloxacin or fosfomycin trometamol).
  • Documented infection: An infection confirmed with medical evidence, such as lab tests or cultures, rather than only symptoms.
  • Broad-spectrum antibiotics: Antibiotics that work against many types of bacteria. Some trials track how often these are needed.
  • Adverse event (AE): Any unwanted medical problem that happens during a trial, whether or not it is clearly caused by the study drug.
  • Overall survival: The length of time participants are alive after a defined starting point in a study (such as randomization).
  • Resistome: A collection of antibiotic resistance genes in bacteria living in or on the body. Trials may study how antibiotics affect this over time.
  • Multidrug-resistant bacteria: Bacteria that are resistant to several antibiotics, making infections harder to treat.
  • Surveillance cultures: Regular lab tests (cultures) used to check whether resistant bacteria are present (colonization), even if there is no active infection.
  • Metagenomic sequencing: A lab method that reads genetic material from many microbes at once to detect bacteria and resistance patterns.
  • Microbiome (gut microbiome): The community of normal bacteria living in the intestines. Trials may measure how antibiotics change this community.
  • Uncomplicated urinary tract infection (uUTI): A bladder infection in an otherwise healthy person without signs of more serious kidney infection or complicating conditions. One trial studies fosfomycin calcium in adult women with uUTI.
  • Clinical response: Improvement in symptoms (how the person feels), such as less pain or fewer urinary symptoms.
  • Microbiological response: Improvement shown on lab testing, such as reduced or cleared bacteria in a urine culture.
  • Test of cure (TOC): A planned follow-up visit after treatment ends to check symptoms and lab tests (for example, urine culture) to see if the infection is resolved.
  • Intensive care unit (ICU): A hospital unit for very sick patients needing close monitoring and advanced support. One study measures whether antibiotic dosing reaches target blood levels in ICU patients.
  • Pharmacokinetics (PK): How the body handles a drug over time—how it is absorbed, distributed, and removed. ICU trials may take blood samples to measure this.
  • Pharmacodynamics (PD): How the drug affects bacteria and the body, often linked to the drug level needed for best effect.
  • PK/PD target exposure: A goal range for drug concentrations in the blood that is linked to the best chance of killing bacteria while limiting toxicity.
  • Gram-negative bacteraemia: A bloodstream infection caused by Gram-negative bacteria. One trial studies early switch from IV antibiotics to oral antibiotics; fosfomycin calcium is listed among trial antibiotics.

References