ProstatitisPhase 4FOS-PROSTNCT07902427

Oral Fosfomycin as Sequential Oral Treatment for Multidrug-Resistant Escherichia Coli in Acute Bacterial Prostatitis

A Phase 4 study testing Fosfomycin Trometamol Salt in people with Prostatitis and Escherichia Coli Infection, run by Hospital Mutua de Terrassa at 7 sites in Spain.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

FOS-PROST was a prospective, non-randomized, controlled phase IV clinical trial designed to evaluate the clinical and microbiological efficacy of oral fosfomycin trometamol as sequential antibiotic therapy in patients with acute bacterial prostatitis caused by multidrug-resistant *Escherichia coli*. Read more about this study

Who is it for?: Ages 18 years and older, men only
Conditions the study is for: Prostatitis, Escherichia Coli Infection
What is being tested?: Fosfomycin Trometamol Salt
Type of treatment: Pill or oral medicine, Injection or infusion
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 88 participants
Where: 7 sitesSpain
Study dates: 25 Jan 2022to 30 Jun 2026
Phase: Phase 4
Are there results?: None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 years and older
Men only
No healthy volunteers
Adult, Older adult

Who may be able to join

Male patients aged 18 years or older with febrile acute bacterial prostatitis (temperature >37.5°C) caused by Escherichia coli.
Diagnosis required a prostate-specific antigen (PSA) level >4 μg/L, at least one microbiological criterion, and at least two clinical criteria as specified below.
Microbiological Criteria (at least one required):
Urine culture yielding >100,000 CFU/mL of multidrug-resistant (MDR) Escherichia coli for the experimental group or non-MDR E. coli for the control group, with a fosfomycin minimum inhibitory concentration (MIC) ≤32 mg/L in both groups.
Positive blood culture for MDR E. coli in the experimental group or non-MDR E. coli in the control group, with a fosfomycin MIC ≤32 mg/L in both groups, accompanied by clinical signs of sepsis without another evident or probable source of bacteremia and pyuria (≥10 leukocytes/mm³ or positive leukocyte esterase on urine dipstick).
Clinical criteria (at least two required):

Show all 16Show fewer

Lower urinary tract symptoms:
Irritative symptoms: urinary urgency, increased urinary frequency, dysuria, or tenesmus.
Obstructive symptoms: difficulty initiating urination, decreased urinary stream, postvoid residual urine, or acute urinary retention.
Perineal pain, spontaneous or associated with urination:
Pain involving the suprapubic, perineal, lumbosacral, scrotal, penile, or inner thigh regions.
Enlarged, warm, or tender prostate on digital rectal examination.
History of prostatic disease (prostate cancer or benign prostatic hyperplasia) associated with:
Recent urinary tract instrumentation.
Recent transrectal prostate biopsy (<7 days).
Altered level of consciousness in patients older than 70 years without another apparent cause.

Who cannot join

Known allergy or intolerance to fosfomycin.
Polymicrobial bacteremia or polymicrobial urine culture.
Clinical evidence of acute pyelonephritis, including costovertebral angle tenderness, urinary tract obstruction, or renal abscess.
Anatomical abnormalities of the urinary tract.
Catheter-associated urinary tract infection.
Undrained prostatic abscess.

Show all 17Show fewer

Another concomitant infection.
Failure to achieve clinical stability after five days of parenteral antibiotic treatment.
Septic shock at the time of treatment allocation.
Polycystic kidney disease.
History of chronic prostatitis.
Recurrent acute bacterial prostatitis, defined as two or more episodes during the preceding year or one episode during the preceding six months.
Immunosuppression, including kidney transplantation, liver cirrhosis, renal replacement therapy, chronic corticosteroid treatment, active chemotherapy, or anti-TNF therapy.
Terminal illness, estimated life expectancy of less than 90 days, or exclusive palliative care.
Participation in another clinical trial involving active treatment.
Fosfomycin MIC exceeding the susceptibility threshold specified in the study inclusion criteria.
Refusal to provide informed consent.

Trial locations and contacts

7 sites in 1 country.

City, postcode or hospital

7 sites in 1 country

Spain7 sites

Hospital del Mar
Barcelona, Barcelona, 08003
Clínica Universidad de Navarra
Pamplona, Navarre, 31008
Hospital Universitari Parc Taulí
Sabadell, Barcelona, 08208
Hospital de Sant Joan Despí Moisès Broggi
Sant Joan Despí, Barcelona, 08970
Hospital Universitari Mutua Terrassa
Terrassa, Barcelona, 08221
Hospital de Terrassa
Terrassa, Catalonia, 08227
Hospital Álvaro Cunqueiro
Vigo, Pontevedra, 36312

Other trials in Spain

About this study

Official title: Oral Fosfomycin as Sequential Oral Treatment for Multidrug-Resistant Escherichia Coli in Acute Bacterial Prostatitis: The FOS-PROST Study

According to the study protocol, patients with multidrug-resistant *E. coli* were assigned to receive oral fosfomycin trometamol, whereas patients with non-multidrug-resistant *E. coli* were assigned to receive conventional oral antibiotic treatment with ciprofloxacin or trimethoprim-sulfamethoxazole, according to antimicrobial susceptibility testing.

All patients received 1 to 5 days of appropriate intravenous antibiotic therapy before switching to oral treatment. Fosfomycin trometamol was administered at a standard dose of 3 g once daily. The planned total duration of antibiotic treatment was 21 days in both groups, including intravenous and oral therapy.

During study conduct, some patients with non-multidrug-resistant *E. coli* also received fosfomycin. All patients with multidrug-resistant *E. coli* received fosfomycin.

Clinical and microbiological outcomes were compared between treatment groups. Secondary objectives included evaluating carbapenem consumption, hospital length of stay, safety, recurrence, and fosfomycin pharmacokinetics.

Read the detailed description

Acute bacterial prostatitis caused by multidrug-resistant *Escherichia coli* represents a therapeutic challenge because resistance to commonly used oral antibiotics limits treatment options and may increase the need for prolonged intravenous antibiotic therapy.

FOS-PROST was a multicenter, prospective, non-randomized, controlled phase IV clinical trial investigating oral fosfomycin trometamol as sequential antibiotic treatment for acute bacterial prostatitis caused by multidrug-resistant *E. coli*.

Eligible adult male patients with microbiologically confirmed acute bacterial prostatitis caused by *E. coli* were enrolled. All participants received 1 to 5 days of appropriate intravenous antibiotic therapy before switching to oral treatment, once clinical stability and the conditions for oral sequential therapy had been achieved.

According to the study protocol, patients with multidrug-resistant *E. coli* were assigned to receive oral fosfomycin trometamol at a standard dose of 3 g every 24 hours. Patients with non-multidrug-resistant *E. coli* were assigned to receive conventional oral antibiotic therapy with ciprofloxacin or trimethoprim-sulfamethoxazole, according to antimicrobial susceptibility testing.

The planned total duration of antibiotic treatment was 21 days in both groups, including intravenous and oral therapy.

During study conduct, some patients with non-multidrug-resistant *E. coli* received oral fosfomycin rather than conventional oral antibiotic therapy. All patients with multidrug-resistant *E. coli* received fosfomycin.

The study evaluated clinical cure and microbiological cure as separate efficacy outcomes. Secondary outcomes included recurrence, adverse events, carbapenem consumption, hospital length of stay, and fosfomycin pharmacokinetics.

The statistical analysis included a comparison according to the treatment actually received (as-treated analysis) and a per-protocol analysis excluding patients who did not meet the protocol-defined treatment allocation criteria.

Conditions: Prostatitis, Escherichia Coli Infection
Being tested: Fosfomycin Trometamol Salt, control group
Keywords: Multi-drug resistance, Sequential oral treatment, Fosfomycin, Acute bacterial prostatitis, Escherichia coli
Medical subject headings: Prostatitis, Escherichia coli Infections

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Fosfomycin Trometamol SaltDrug
Also called J01XX01 - FOSFOMICINA
Oral fosfomycin trometamol, 3 g every 24 hours, administered as sequential antibiotic therapy after 1 to 5 days of appropriate intravenous antibiotic treatment, once clinical stability and oral tolerance were achieved. The planned total duration of antibiotic treatment, including intravenous and oral therapy, was 21 days. Dose adjustments for renal impairment were specified in the protocol.
control groupDrug
Oral ciprofloxacin, 500 mg every 12 hours, administered as sequential antibiotic therapy according to antimicrobial susceptibility testing, following 1 to 5 days of appropriate intravenous antibiotic treatment. The planned total duration of antibiotic therapy was 21 days.
control groupDrug
Oral trimethoprim-sulfamethoxazole, 160 mg/800 mg every 12 hours, administered as sequential antibiotic therapy according to antimicrobial susceptibility testing, following 1 to 5 days of appropriate intravenous antibiotic treatment. The planned total duration of antibiotic therapy was 21 days.

Study groups in NCT07902427
Study group	Role	What they receive
Experimental Group	Experimental	Adult male patients with acute bacterial prostatitis caused by multidrug-resistant Escherichia coli, according to the Magiorakos criteria, assigned to receive sequential oral fosfomycin trometamol at a standard dose of 3 g every 24 hours after 1 to 5 days of appropriate intravenous antibiotic therapy. Receives: Drug: Fosfomycin Trometamol Salt
Control group	Active comparator	Adult male patients with acute bacterial prostatitis caused by non-multidrug-resistant Escherichia coli, assigned to receive sequential oral antibiotic treatment with ciprofloxacin or trimethoprim-sulfamethoxazole, according to antimicrobial susceptibility testing, after 1 to 5 days of appropriate intravenous antibiotic therapy. Receives: Drug: control group

What is being measured

The primary outcome is the main question the study is designed to answer.

Percentage of Participants With Clinical Cure
Clinical cure was defined as the resolution of all symptoms present at baseline without the need for additional antibiotic treatment. Clinical cure required the absence of fever (axillary temperature greater than 38°C), urinary symptoms (dysuria, urinary frequency, urgency, or suprapubic pain), and altered level of consciousness if present at baseline.
Measured: Day 21 ± 3 days from treatment initiation (end of treatment)
Percentage of Participants With Microbiological Cure
Microbiological cure was defined as a negative urine culture at the end of antibiotic treatment. Only participants with an available urine culture at the end-of-treatment assessment were included in the analysis of this outcome. Participants without an available urine culture were excluded from the microbiological cure analysis.
Measured: Day 21 ± 3 days from treatment initiation (end of treatment).

Secondary outcomes (8)

Estimated Carbapenem Defined Daily Doses (DDDs) Avoided per Patient
The potential carbapenem-sparing effect of sequential oral fosfomycin trometamol was estimated in patients with acute bacterial prostatitis caused by multidrug-resistant Escherichia coli. Assuming that these patients would otherwise have received intravenous ertapenem until completion of the planned 21-day antibiotic course, the number of potentially avoided ertapenem Defined Daily Doses (DDDs) was calculated based on the remaining treatment duration after switching to oral fosfomycin. Results were expressed as estimated DDDs avoided per patient.
Measured: During the 21-day antibiotic treatment period.
Hospital Length of Stay in Days
Hospital length of stay was assessed as the number of days of actual hospital admission during the acute bacterial prostatitis episode and compared between the fosfomycin and control group. In accordance with the study protocol, patients with hospital-acquired multidrug-resistant Escherichia coli infection were excluded from this analysis
Measured: During the hospital admission for the acute bacterial prostatitis episode.
Estimated Hospitalization Days Avoided per Patient
The potential reduction in hospital or hospital-at-home admission days associated with sequential oral fosfomycin trometamol was estimated among patients receiving oral fosfomycin. Assuming that these patients would otherwise have required continued parenteral antibiotic therapy during hospital or hospital-at-home admission, the number of potentially avoided admission days was estimated from the remaining days of the planned 21-day antibiotic treatment course after switching to oral fosfomycin. Results were expressed as estimated admission days avoided per patient.
Measured: During the 21-day antibiotic treatment period
Plasma Fosfomycin Concentration
Plasma fosfomycin concentrations (mg/L) were planned to be measured using blood samples collected at predefined time points after oral fosfomycin trometamol administration in selected participants at the coordinating center. The planned pharmacokinetic assessment was not performed, and no plasma fosfomycin concentration data were collected.
Measured: At 1, 2, 4, 12, and 24 hours after the first oral fosfomycin dose; additional trough concentrations during hospitalization or at Visit 4, as applicable.
Percentage of Participants Experiencing Adverse Events
The incidence and severity of adverse events were assessed in patients receiving sequential oral fosfomycin trometamol or conventional oral antibiotic therapy. Adverse events were recorded during antibiotic treatment and subsequent follow-up through Day 51 (± 7 days) from treatment initiation. Results were expressed as the number and percentage of participants experiencing adverse events in each treatment group, with assessment of their severity.
Measured: From treatment initiation through Day 51 (± 7 days).
Acute Bacterial Prostatitis-Related Mortality
Mortality related to the acute bacterial prostatitis episode was assessed in both treatment groups. The outcome was measured as the number and percentage of participants who died from causes attributable to the acute bacterial prostatitis episode during the study observation period.
Measured: From treatment initiation through Day 51 (± 7 days).
Incidence of Acute Bacterial Prostatitis Recurrence
The incidence of acute bacterial prostatitis relapse or reinfection was assessed prospectively during the protocol-defined follow-up period. Relapse was defined as recurrence of urinary tract infection symptoms with isolation of the same microorganism, whereas reinfection was defined as recurrence of symptoms with isolation of a different bacterial strain. Results were expressed as the number and percentage of participants experiencing relapse or reinfection in each treatment group.
Measured: From completion of antibiotic treatment through Day 51 (± 7 days) from treatment initiation.
Incidence of Emergent Fosfomycin Resistance
The emergence of fosfomycin resistance was planned to be assessed through microbiological susceptibility testing during treatment and follow-up in participants receiving oral fosfomycin trometamol. This assessment was not performed, and no data on emergent fosfomycin resistance were collected.
Measured: From treatment initiation through Day 51 (± 7 days).

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

25 Jan 202230 Jun 2026

First posted28 Oct 2026
Study start25 Jan 2022
Primary completion18 Mar 2026
Study completion30 Jun 2026

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Publications (19)Papers the sponsor has linked to this study.
Other trials for ProstatitisStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 4
Primary purpose: Treatment
Allocation: Non-randomised
Intervention model: Parallel groups
Model description: Prospective, non-randomized, open-label, parallel-group phase IV clinical trial. According to the protocol, patients with acute bacterial prostatitis caused by multidrug-resistant Escherichia coli were assigned to receive sequential oral fosfomycin trometamol, whereas patients with non-multidrug-resistant E. coli constituted the prospective comparator group and were assigned to receive conventional oral antibiotic treatment with ciprofloxacin or trimethoprim-sulfamethoxazole. Treatment allocation was based on the antimicrobial susceptibility profile rather than randomization.
Masking: None (open label)
Enrolment: 88 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT07902427
Sponsor's protocol ID: FOS-PROST-001
Other IDs: 2019-003792-19, 2019
Acronym: FOS-PROST
Status last verified: Oct 2026
First submitted: 27 Jan 2020
Last updated: 28 Oct 2026
Results posted: No
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: No

Publications

Rodriguez-Bano J, Pascual A. Clinical significance of extended-spectrum beta-lactamases. Expert Rev Anti Infect Ther. 2008 Oct;6(5):671-83. doi: 10.1586/14787210.6.5.671.
PubMed 18847405
Hernandez JR, Martinez-Martinez L, Canton R, Coque TM, Pascual A; Spanish Group for Nosocomial Infections (GEIH). Nationwide study of Escherichia coli and Klebsiella pneumoniae producing extended-spectrum beta-lactamases in Spain. Antimicrob Agents Chemother. 2005 May;49(5):2122-5. doi: 10.1128/AAC.49.5.2122-2125.2005.
PubMed 15855544
Boix-Palop L, Xercavins M, Badia C, Obradors M, Riera M, Freixas N, Perez J, Rodriguez-Carballeira M, Garau J, Calbo E. Emerging extended-spectrum beta-lactamase-producing Klebsiella pneumoniae causing community-onset urinary tract infections: a case-control-control study. Int J Antimicrob Agents. 2017 Aug;50(2):197-202. doi: 10.1016/j.ijantimicag.2017.03.009. Epub 2017 May 24.
PubMed 28552471
Tzouvelekis LS, Markogiannakis A, Psichogiou M, Tassios PT, Daikos GL. Carbapenemases in Klebsiella pneumoniae and other Enterobacteriaceae: an evolving crisis of global dimensions. Clin Microbiol Rev. 2012 Oct;25(4):682-707. doi: 10.1128/CMR.05035-11.
PubMed 23034326
Falagas ME, Maraki S, Karageorgopoulos DE, Kastoris AC, Mavromanolakis E, Samonis G. Antimicrobial susceptibility of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Enterobacteriaceae isolates to fosfomycin. Int J Antimicrob Agents. 2010 Mar;35(3):240-3. doi: 10.1016/j.ijantimicag.2009.10.019.
PubMed 20034765
de Cueto M, Lopez L, Hernandez JR, Morillo C, Pascual A. In vitro activity of fosfomycin against extended-spectrum-beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae: comparison of susceptibility testing procedures. Antimicrob Agents Chemother. 2006 Jan;50(1):368-70. doi: 10.1128/AAC.50.1.368-370.2006.
PubMed 16377714
Falagas ME, Kastoris AC, Kapaskelis AM, Karageorgopoulos DE. Fosfomycin for the treatment of multidrug-resistant, including extended-spectrum beta-lactamase producing, Enterobacteriaceae infections: a systematic review. Lancet Infect Dis. 2010 Jan;10(1):43-50. doi: 10.1016/S1473-3099(09)70325-1.
PubMed 20129148
Michalopoulos AS, Livaditis IG, Gougoutas V. The revival of fosfomycin. Int J Infect Dis. 2011 Nov;15(11):e732-9. doi: 10.1016/j.ijid.2011.07.007. Epub 2011 Sep 25.
PubMed 21945848
Raz R. Fosfomycin: an old--new antibiotic. Clin Microbiol Infect. 2012 Jan;18(1):4-7. doi: 10.1111/j.1469-0691.2011.03636.x. Epub 2011 Sep 13.
PubMed 21914036
Roussos N, Karageorgopoulos DE, Samonis G, Falagas ME. Clinical significance of the pharmacokinetic and pharmacodynamic characteristics of fosfomycin for the treatment of patients with systemic infections. Int J Antimicrob Agents. 2009 Dec;34(6):506-15. doi: 10.1016/j.ijantimicag.2009.08.013. Epub 2009 Oct 13.
PubMed 19828298
Parker SL, Frantzeskaki F, Wallis SC, Diakaki C, Giamarellou H, Koulenti D, Karaiskos I, Lipman J, Dimopoulos G, Roberts JA. Population Pharmacokinetics of Fosfomycin in Critically Ill Patients. Antimicrob Agents Chemother. 2015 Oct;59(10):6471-6. doi: 10.1128/AAC.01321-15. Epub 2015 Aug 3.
PubMed 26239990
Gardiner BJ, Mahony AA, Ellis AG, Lawrentschuk N, Bolton DM, Zeglinski PT, Frauman AG, Grayson ML. Is fosfomycin a potential treatment alternative for multidrug-resistant gram-negative prostatitis? Clin Infect Dis. 2014 Feb;58(4):e101-5. doi: 10.1093/cid/cit704. Epub 2013 Oct 28.
PubMed 24170195
Rosso-Fernandez C, Sojo-Dorado J, Barriga A, Lavin-Alconero L, Palacios Z, Lopez-Hernandez I, Merino V, Camean M, Pascual A, Rodriguez-Bano J; FOREST Study Group. Fosfomycin versus meropenem in bacteraemic urinary tract infections caused by extended-spectrum beta-lactamase-producing Escherichia coli (FOREST): study protocol for an investigator-driven randomised controlled trial. BMJ Open. 2015 Mar 31;5(3):e007363. doi: 10.1136/bmjopen-2014-007363.
PubMed 25829373
Grayson ML, Macesic N, Trevillyan J, Ellis AG, Zeglinski PT, Hewitt NH, Gardiner BJ, Frauman AG. Fosfomycin for Treatment of Prostatitis: New Tricks for Old Dogs. Clin Infect Dis. 2015 Oct 1;61(7):1141-3. doi: 10.1093/cid/civ436. Epub 2015 Jun 10.
PubMed 26063723
Los-Arcos I, Pigrau C, Rodriguez-Pardo D, Fernandez-Hidalgo N, Andreu A, Larrosa N, Almirante B. Long-Term Fosfomycin-Tromethamine Oral Therapy for Difficult-To-Treat Chronic Bacterial Prostatitis. Antimicrob Agents Chemother. 2015 Dec 14;60(3):1854-8. doi: 10.1128/AAC.02611-15.
PubMed 26666924

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 28 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Oral Fosfomycin as Sequential Oral Treatment for Multidrug-Resistant Escherichia Coli in Acute Bacterial Prostatitis: The FOS-PROST Study
ClinicalTrials.gov ID: NCT07902427
Acronym / sponsor ID: FOS-PROST / FOS-PROST-001
Conditions: Prostatitis, Escherichia Coli Infection
Keywords: Multi-drug resistance, Sequential oral treatment, Fosfomycin, Acute bacterial prostatitis, Escherichia coli
Phase: Phase 4
Study type: Interventional
Recruitment status: Completed
Enrolment: 88 participants (actual)
Lead sponsor: Hospital Mutua de TerrassaUniversity, hospital or other
Collaborators: Parc Taulí Hospital Universitari, Consorci Sanitari de Terrassa, Hospital del Mar, Clinica Universidad de Navarra, Universidad de Navarra, Hospital Álvaro Cunqueiro, Hospital de Sant Joan Despí Moisès Broggi
Study start: 25 Jan 2022 (actual)
Primary completion: 18 Mar 2026 (actual)
Study completion: 30 Jun 2026 (actual)
First posted: 28 Oct 2026 (actual)
Results: Not posted in the source record

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

During study conduct, some patients with non-multidrug-resistant *E. coli* also received fosfomycin. All patients with multidrug-resistant *E. coli* received fosfomycin.

Detailed description

The planned total duration of antibiotic treatment was 21 days in both groups, including intravenous and oral therapy.

Study design

Primary purpose: Treatment
Allocation: Non-randomised
Intervention model: Parallel groups
Masking: None (open label)
Number of arms: 2
Model description: Prospective, non-randomized, open-label, parallel-group phase IV clinical trial. According to the protocol, patients with acute bacterial prostatitis caused by multidrug-resistant Escherichia coli were assigned to receive sequential oral fosfomycin trometamol, whereas patients with non-multidrug-resistant E. coli constituted the prospective comparator group and were assigned to receive conventional oral antibiotic treatment with ciprofloxacin or trimethoprim-sulfamethoxazole. Treatment allocation was based on the antimicrobial susceptibility profile rather than randomization.

Arm	Type	Receives
Experimental Group	Experimental	Drug: Fosfomycin Trometamol SaltAdult male patients with acute bacterial prostatitis caused by multidrug-resistant Escherichia coli, according to the Magiorakos criteria, assigned to receive sequential oral fosfomycin trometamol at a standard dose of 3 g every 24 hours after 1 to 5 days of appropriate intravenous antibiotic therapy.
Control group	Active comparator	Drug: control groupAdult male patients with acute bacterial prostatitis caused by non-multidrug-resistant Escherichia coli, assigned to receive sequential oral antibiotic treatment with ciprofloxacin or trimethoprim-sulfamethoxazole, according to antimicrobial susceptibility testing, after 1 to 5 days of appropriate intravenous antibiotic therapy.

Who may qualify

Ages: 18 years and older
Sex: Male only
Healthy volunteers: Not accepted
Age groups: Adult, Older adult

Key inclusion criteria (16 listed)

Male patients aged 18 years or older with febrile acute bacterial prostatitis (temperature >37.5°C) caused by Escherichia coli.
Diagnosis required a prostate-specific antigen (PSA) level >4 μg/L, at least one microbiological criterion, and at least two clinical criteria as specified below.
Microbiological Criteria (at least one required):
Urine culture yielding >100,000 CFU/mL of multidrug-resistant (MDR) Escherichia coli for the experimental group or non-MDR E. coli for the control group, with a fosfomycin minimum inhibitory concentration (MIC) ≤32 mg/L in both groups.
Positive blood culture for MDR E. coli in the experimental group or non-MDR E. coli in the control group, with a fosfomycin MIC ≤32 mg/L in both groups, accompanied by clinical signs of sepsis without another evident or probable source of bacteremia and pyuria (≥10 leukocytes/mm³ or positive leukocyte esterase on urine dipstick).

Key exclusion criteria (17 listed)

Known allergy or intolerance to fosfomycin.
Polymicrobial bacteremia or polymicrobial urine culture.
Clinical evidence of acute pyelonephritis, including costovertebral angle tenderness, urinary tract obstruction, or renal abscess.
Anatomical abnormalities of the urinary tract.
Catheter-associated urinary tract infection.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Fosfomycin Trometamol SaltAlso: J01XX01 - FOSFOMICINAOral fosfomycin trometamol, 3 g every 24 hours, administered as sequential antibiotic therapy after 1 to 5 days of appropriate intravenous antibiotic treatment, once clinical stability and oral tolerance were achieved. The planned total duration of antibiotic treatment, including intravenous and oral therapy, was 21 days. Dose adjustments for renal impairment were specified in the protocol.	Drug	Experimental Group
control groupOral ciprofloxacin, 500 mg every 12 hours, administered as sequential antibiotic therapy according to antimicrobial susceptibility testing, following 1 to 5 days of appropriate intravenous antibiotic treatment. The planned total duration of antibiotic therapy was 21 days.	Drug	Control group
control groupOral trimethoprim-sulfamethoxazole, 160 mg/800 mg every 12 hours, administered as sequential antibiotic therapy according to antimicrobial susceptibility testing, following 1 to 5 days of appropriate intravenous antibiotic treatment. The planned total duration of antibiotic therapy was 21 days.	Drug	Control group

Primary outcome

Percentage of Participants With Clinical Cure
Time frame: Day 21 ± 3 days from treatment initiation (end of treatment)
Clinical cure was defined as the resolution of all symptoms present at baseline without the need for additional antibiotic treatment. Clinical cure required the absence of fever (axillary temperature greater than 38°C), urinary symptoms (dysuria, urinary frequency, urgency, or suprapubic pain), and altered level of consciousness if present at baseline.
Percentage of Participants With Microbiological Cure
Time frame: Day 21 ± 3 days from treatment initiation (end of treatment).
Microbiological cure was defined as a negative urine culture at the end of antibiotic treatment. Only participants with an available urine culture at the end-of-treatment assessment were included in the analysis of this outcome. Participants without an available urine culture were excluded from the microbiological cure analysis.

8 secondary outcomes

Estimated Carbapenem Defined Daily Doses (DDDs) Avoided per Patient
Time frame: During the 21-day antibiotic treatment period.
Hospital Length of Stay in Days
Time frame: During the hospital admission for the acute bacterial prostatitis episode.
Estimated Hospitalization Days Avoided per Patient
Time frame: During the 21-day antibiotic treatment period
Plasma Fosfomycin Concentration
Time frame: At 1, 2, 4, 12, and 24 hours after the first oral fosfomycin dose; additional trough concentrations during hospitalization or at Visit 4, as applicable.
Percentage of Participants Experiencing Adverse Events
Time frame: From treatment initiation through Day 51 (± 7 days).
Acute Bacterial Prostatitis-Related Mortality
Time frame: From treatment initiation through Day 51 (± 7 days).
Incidence of Acute Bacterial Prostatitis Recurrence
Time frame: From completion of antibiotic treatment through Day 51 (± 7 days) from treatment initiation.
Incidence of Emergent Fosfomycin Resistance
Time frame: From treatment initiation through Day 51 (± 7 days).

Results and safety

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 28 Oct 2026.
Background: PubMed 18847405Rodriguez-Bano J, Pascual A. Clinical significance of extended-spectrum beta-lactamases. Expert Rev Anti Infect Ther. 2008 Oct;6(5):671-83. doi: 10.1586/14787210.6.5.671.
Background: PubMed 15855544Hernandez JR, Martinez-Martinez L, Canton R, Coque TM, Pascual A; Spanish Group for Nosocomial Infections (GEIH). Nationwide study of Escherichia coli and Klebsiella pneumoniae producing extended-spectrum beta-lactamases in Spain. Antimicrob Agents Chemother. 2005 May;49(5):2122-5. doi: 10.1128/AAC.49.5.2122-2125.2005.
Background: PubMed 28552471Boix-Palop L, Xercavins M, Badia C, Obradors M, Riera M, Freixas N, Perez J, Rodriguez-Carballeira M, Garau J, Calbo E. Emerging extended-spectrum beta-lactamase-producing Klebsiella pneumoniae causing community-onset urinary tract infections: a case-control-control study. Int J Antimicrob Agents. 2017 Aug;50(2):197-202. doi: 10.1016/j.ijantimicag.2017.03.009. Epub 2017 May 24.
Background: PubMed 23034326Tzouvelekis LS, Markogiannakis A, Psichogiou M, Tassios PT, Daikos GL. Carbapenemases in Klebsiella pneumoniae and other Enterobacteriaceae: an evolving crisis of global dimensions. Clin Microbiol Rev. 2012 Oct;25(4):682-707. doi: 10.1128/CMR.05035-11.
Background: PubMed 20034765Falagas ME, Maraki S, Karageorgopoulos DE, Kastoris AC, Mavromanolakis E, Samonis G. Antimicrobial susceptibility of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Enterobacteriaceae isolates to fosfomycin. Int J Antimicrob Agents. 2010 Mar;35(3):240-3. doi: 10.1016/j.ijantimicag.2009.10.019.
Background: PubMed 16377714de Cueto M, Lopez L, Hernandez JR, Morillo C, Pascual A. In vitro activity of fosfomycin against extended-spectrum-beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae: comparison of susceptibility testing procedures. Antimicrob Agents Chemother. 2006 Jan;50(1):368-70. doi: 10.1128/AAC.50.1.368-370.2006.
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Background: PubMed 19828298Roussos N, Karageorgopoulos DE, Samonis G, Falagas ME. Clinical significance of the pharmacokinetic and pharmacodynamic characteristics of fosfomycin for the treatment of patients with systemic infections. Int J Antimicrob Agents. 2009 Dec;34(6):506-15. doi: 10.1016/j.ijantimicag.2009.08.013. Epub 2009 Oct 13.
Background: PubMed 26239990Parker SL, Frantzeskaki F, Wallis SC, Diakaki C, Giamarellou H, Koulenti D, Karaiskos I, Lipman J, Dimopoulos G, Roberts JA. Population Pharmacokinetics of Fosfomycin in Critically Ill Patients. Antimicrob Agents Chemother. 2015 Oct;59(10):6471-6. doi: 10.1128/AAC.01321-15. Epub 2015 Aug 3.
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Individual participant dataSharing planned: No

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

The record lists no contact. Use the official record to reach the sponsor.

7 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 4 study testing Fosfomycin Trometamol Salt in people with Prostatitis and Escherichia Coli Infection, run by Hospital Mutua de Terrassa at 7 sites in Spain.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 16 inclusion and 17 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 28 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 7 sites in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Percentage of Participants With Clinical Cure (time frame: Day 21 ± 3 days from treatment initiation (end of treatment)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07902427, which also lists 19 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Oct 2026.