Fosfomycin
| Evidence Level: L2 | Predicted Indications: 10 |
Table of Contents
Fosfomycin: From Urinary Tract Infection to Gonococcal Urethritis
One-Sentence Summary
Fosfomycin is a long-established antibacterial agent whose principal use is the treatment of urinary tract infections (cystitis, complicated UTI, pyelonephritis) via inhibition of an early step in bacterial cell wall synthesis. The TxGNN model predicts it may also be effective for Gonococcal Urethritis (Neisseria gonorrhoeae infection), a prediction that is currently supported by 0 registered clinical trials and 6 publications, including one randomized controlled trial.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Urinary tract infection / cystitis (established antibacterial use; not derived from an India regulatory license — see note below) |
| Predicted New Indication | Gonococcal Urethritis |
| TxGNN Prediction Score | 99.99% |
| Evidence Level | L2 |
| India Market Status | ✗ Not marketed |
| Number of Registrations | 0 |
| Recommended Decision | Research Question |
Note on Original Indication: Fosfomycin has no current India (CDSCO) marketing license in this Evidence Pack (
market_status: Not marketed, 0 licenses), so the original indication above is drawn from the drug’s globally established antibacterial use referenced in the supporting literature (e.g., PMID 23958364, PMID 30861061), not from a local regulatory record.
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data from DrugBank is not available in this Evidence Pack (flagged as data gap DG002). Based on information embedded in the supporting literature, fosfomycin is described as “an epoxide antibiotic with a differentiated mechanism of action inhibiting an early step in bacterial cell wall synthesis” (PMID 30861061), consistent with its known action as an inhibitor of the bacterial enzyme MurA, blocking peptidoglycan synthesis.
Fosfomycin’s original and best-established use is in urinary tract infections, where it achieves high, sustained concentrations in urine and urogenital mucosal secretions after systemic or intramuscular administration. Gonococcal urethritis is anatomically and physiologically related — it is a urethral/mucosal infection reachable by the same route of drug concentration. In vitro, fosfomycin has demonstrated bactericidal activity against Neisseria gonorrhoeae, and this was clinically exploited historically (intramuscular fosfomycin regimens in the 1970s) and revisited more recently with oral fosfomycin trometamol.
That said, gonorrhea treatment today is governed by antimicrobial resistance surveillance and current guidelines generally favor other first-line agents (e.g., ceftriaxone-based regimens); fosfomycin’s role would need to be positioned as an alternative/salvage option rather than a first-line replacement, and resistance monitoring would be essential before any repositioning claim.
Clinical Trial Evidence
Currently no related clinical trials registered
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 27064136 | 2016 | RCT | Clin Microbiol Infect | Open randomized controlled trial in 126 men with uncomplicated gonococcal urethritis; fosfomycin trometamol 3g given on days 1, 3, 5 evaluated for efficacy |
| 832528 | 1977 | Cohort | Chemotherapy | 70 patients with acute/subacute gonococcal urethritis treated with intramuscular fosfomycin; bacteriological/clinical cure rates of 86–92% depending on dosing regimen |
| 832523 | 1977 | Cohort | Chemotherapy | Multicenter Spanish study of 959 patients treated for various infections including gonococcal urethritis, evaluating fosfomycin’s broad-spectrum activity |
| 35820778 | 2023 | Cohort | Sex Transm Infect | Secondary analysis of the NABOGO trial assessing spontaneous clearance of asymptomatic anogenital/pharyngeal N. gonorrhoeae and its determinants |
| 19593988 | 2009 | Review | Natl J Androl | Review of diagnosis and treatment approaches for genitourinary infection with non-gonococcal Neisseria in men |
| 17878816 | 2007 | Case Report | J Fr Ophtalmol | Case of gonococcal conjunctivitis with corneal perforation from a penicillin/tetracycline/fluoroquinolone-resistant N. gonorrhoeae strain, resolved with 15 days of high-dose parenteral antibiotic therapy |
Safety Considerations
Drug Interactions: 3 documented interactions —
- Balsalazide — Moderate (source: DDInter)
- Picosulfuric acid — Moderate (source: DDInter)
- Metoclopramide — Minor (source: DDInter)
Detailed package insert warnings and contraindications are not currently available in this Evidence Pack (flagged as blocking data gap DG001 — India/CDSCO label data pending); please refer to the official package insert for full safety information once available.
Conclusion and Next Steps
Decision: Research Question
Rationale: Evidence is limited to L2 (one RCT plus older cohort data from the 1970s, with no currently registered clinical trials); the drug is also not currently marketed in India, and current gonorrhea treatment guidelines favor other first-line agents amid resistance concerns, so this remains a research question rather than an actionable repositioning candidate.
To proceed, the following is needed:
- Official package insert / label warnings and contraindications for fosfomycin (Blocking gap, DG001) — required before any S1 safety screening can proceed
- DrugBank mechanism-of-action data (High priority gap, DG002) to properly assess mechanistic plausibility
- Current antimicrobial resistance data for N. gonorrhoeae against fosfomycin in the relevant population
- Assessment of regulatory pathway given fosfomycin’s current unmarketed status in India
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.