Cefaclor

證據等級: L5

預測適應症: 10 個

Cefaclor: From Bacterial Infections to Gonococcal Urethritis

One-Sentence Summary

Cefaclor is a second-generation oral cephalosporin antibiotic, widely used to treat bacterial infections of the respiratory tract, urinary tract, and skin. The TxGNN model's highest-evidence prediction is Gonococcal Urethritis (model rank #3), supported by 0 registered clinical trials and 6 published studies spanning 1979–1997. The majority of the top-10 TxGNN predictions (ranks 1, 2, 4–10) lack biological plausibility and are assessed as likely knowledge-graph noise; only the gonococcal urethritis prediction carries actionable clinical evidence.

Quick Overview

Item	Content
Original Indication	Broad-spectrum bacterial infections (respiratory, urinary tract, skin)
Predicted New Indication (Best Evidence)	Gonococcal Urethritis
TxGNN Prediction Score	97.48%
Evidence Level	L3
Singapore Market Status	✗ Not Marketed
Number of Registrations	0
Recommended Decision	Proceed with Guardrails

Why is This Prediction Reasonable?

Cefaclor belongs to the second-generation cephalosporin class of β-lactam antibiotics. Its core mechanism is inhibition of bacterial cell wall synthesis through covalent binding to penicillin-binding proteins (PBPs). Because Neisseria gonorrhoeae possesses a cell wall and expresses susceptible PBP variants, Cefaclor's antibacterial mechanism applies directly — making this a biologically plausible repurposing candidate, not a graph-generated artefact.

The connection between Cefaclor's established role in treating bacterial infections and its potential use in gonococcal urethritis is straightforward: both involve susceptible gram-negative bacteria requiring cell wall disruption. Between 1979 and 1997, multiple controlled and comparative clinical trials demonstrated clinical cure rates above 89% when Cefaclor was used in single or multi-dose regimens, including head-to-head comparisons against spectinomycin. The evidence base is older but methodologically direct.

The critical caveat is that the antibiotic landscape has shifted significantly. Current WHO and CDC guidelines deprioritise second-generation cephalosporins for gonococcal infections due to the global emergence of cephalosporin-resistant N. gonorrhoeae strains (including ESBL and high-level cephalosporin resistance). Any consideration of Cefaclor for this indication would require local antibiogram data to confirm strain susceptibility before clinical use.

Note on MOA data gap: Formal DrugBank mechanism-of-action data was not retrieved for this report. The pharmacological rationale above is derived from the class-level knowledge of second-generation cephalosporins and from the mechanistic link documented in the Evidence Pack's repurposing_rationale field.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
121455	1979	Clinical Trial (open-label)	Postgraduate Medical Journal	Controlled trial in 40 men with uncomplicated gonococcal urethritis; 1 g loading dose of Cefaclor showed activity against N. gonorrhoeae in vitro and clinically
116373	1979	Clinical Trial (open-label)	Sexually Transmitted Diseases	Randomised trial in men; regimens of 2–4 g Cefaclor ± probenecid evaluated; therapeutic outcomes confirmed by Day 7 follow-up cultures of 66 participants
6225482	1983	Comparative Clinical Trial	British Journal of Venereal Diseases	400 men randomised to spectinomycin, cefamandole, or Cefaclor ± probenecid; Cefaclor 3 g + probenecid achieved 95.8% cure rate vs. 98.9% for spectinomycin
6400040	1984	Clinical Trial (interventional)	Medical Journal of Malaysia	Single-dose oral Cefaclor evaluated in men with uncomplicated gonococcal urethritis
9582471	1997	Comparative Study	Genitourinary Medicine	Reassessment of in vivo and in vitro efficacy of Cefaclor for uncomplicated gonococcal infection; evaluated as potential alternative to third-generation cephalosporins in resource-limited settings
2673664	1989	Large Case Series	Current Medical Research and Opinion	1,505-patient multi-national study comparing cefetamet pivoxil against standard antibiotics including Cefaclor; single doses of comparator cephalosporins shown effective for gonorrhoea

Singapore Market Information

Cefaclor has no registered products in Singapore at this time (HSA market status: Not Marketed; total licences: 0). This means any clinical development pathway would need to proceed via new product registration with the Health Sciences Authority (HSA) under the relevant therapeutic indication.

Safety Considerations

Please refer to the package insert for safety information. Full prescribing data — including warnings, contraindications, and drug interactions — was not available in this Evidence Pack.

Pharmacokinetic alert (from repurposing rationale): Patients with hypoalbuminaemia may exhibit significantly altered Cefaclor pharmacokinetics due to reduced protein binding, leading to elevated free-drug concentrations. This should be considered when dosing in patients with hepatic disease, malnutrition, or albumin-related disorders.

Conclusion and Next Steps

Decision: Proceed with Guardrails

Rationale: Multiple controlled clinical trials from 1979–1997 confirmed Cefaclor's direct antibacterial activity against N. gonorrhoeae with cure rates exceeding 89–95%, and the β-lactam cell-wall inhibition mechanism is directly applicable. However, the evidence predates the emergence of cephalosporin-resistant gonorrhoea strains, which substantially limits direct clinical translation without contemporary susceptibility data.

To proceed, the following is needed:

Local antibiogram data: Current N. gonorrhoeae susceptibility profiles in Singapore (or target market) must confirm Cefaclor MIC values are within therapeutic range — this is the single most critical gate
Formal MOA documentation: Retrieve DrugBank API entry (DB00833) to complete the mechanistic dossier
Regulatory safety package: Obtain and parse the Singapore HSA package insert (or equivalent market authorisation in an approved jurisdiction) to fill the blocking data gap (DG001) on warnings and contraindications
Resistance review: Systematic literature review of post-2000 cephalosporin resistance rates in gonorrhoea to quantify the gap between 1979–1997 trial populations and current epidemiology
HSA registration pathway: Initiate pre-submission consultation with HSA given zero current Singapore registrations

This report is generated for research purposes only and does not constitute medical advice. All drug repurposing candidates require clinical validation before therapeutic application.

Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.