Avibactam
| 證據等級: L5 | 預測適應症: 10 個 |
目錄
Avibactam: From Resistant Gram-negative Infections to Streptococcal Pneumonia
One-Sentence Summary
Avibactam is a non-β-lactam β-lactamase inhibitor, approved globally (as ceftazidime-avibactam) for serious multi-drug resistant gram-negative bacterial infections, but not currently registered in Singapore. The TxGNN model predicts it may be effective for Streptococcal Pneumonia, yet 0 clinical trials and 0 publications currently support this direction. Mechanistic review classifies this as a biologically implausible false positive: Streptococcus pneumoniae confers β-lactam resistance through PBP mutations — not serine β-lactamase production, which is avibactam's sole target.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not registered in Singapore; globally used as ceftazidime-avibactam combination for resistant Gram-negative infections |
| Predicted New Indication | Streptococcal Pneumonia |
| TxGNN Prediction Score | 99.70% |
| Evidence Level | L5 |
| Singapore Market Status | ✗ Not Marketed |
| Number of Registrations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Avibactam is a diazabicyclooctane (DBO)-class, non-β-lactam β-lactamase inhibitor that forms a covalent yet reversible bond with the active-site serine residue of class A, C, and selected class D serine β-lactamases (including KPC, CTX-M, AmpC, and OXA-48). When paired with a β-lactam partner — most notably ceftazidime (Avycaz) — it restores antibacterial potency against carbapenem-resistant Enterobacteriaceae (Klebsiella pneumoniae, Escherichia coli) and certain non-fermenters (Pseudomonas aeruginosa). Avibactam itself carries no intrinsic antibacterial activity.
This prediction does not hold up under mechanistic scrutiny. Streptococcus pneumoniae is a Gram-positive organism. Its resistance to β-lactam antibiotics is mediated exclusively by mutations in penicillin-binding proteins (PBPs), not by serine β-lactamase hydrolysis. Because avibactam acts only on serine β-lactamases, it has no mechanistic pathway to overcome PBP-mediated resistance and cannot potentiate antibiotic activity against S. pneumoniae. No published evidence of avibactam activity-enhancement against any Gram-positive pathogen currently exists.
The TxGNN score of 99.70% most likely reflects graph traversal noise: the knowledge graph may link avibactam → β-lactam antibiotic → respiratory infection → pneumococcal pneumonia through shared edge weights without capturing organism-level mechanistic constraints. This is a recognised limitation of graph-embedding models, where topological proximity in a knowledge graph does not always reflect biological plausibility. Notably, this prediction ranks 4,629th among all disease nodes in the model's global output — indicating it is far from a high-confidence prediction even within the model's own hierarchy.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available.
Safety Considerations
Please refer to the package insert for safety information.
Conclusion and Next Steps
Decision: Hold
Rationale: Avibactam targets serine β-lactamases expressed by Gram-negative bacteria and has no known mechanism of action against Streptococcus pneumoniae, whose β-lactam resistance is driven by PBP mutations. With zero supporting clinical or pre-clinical evidence, this prediction is an L5 model-only hypothesis that fails mechanistic plausibility screening at the earliest stage.
To proceed, the following would be needed:
- Demonstration of serine β-lactamase expression in clinically relevant S. pneumoniae strains (not currently documented in the literature)
- Pre-clinical in vitro data showing any avibactam-mediated potentiation of β-lactam activity against S. pneumoniae
- Complete MOA data from DrugBank or package insert to identify any secondary mechanisms not currently captured
- Singapore regulatory pathway assessment, as avibactam is not registered locally
Appendix: All Predicted Indications Summary
This is a multi-candidate evaluation report (TW-DB09060-multi). The table below summarises all 10 TxGNN-ranked predictions.
| Rank | Disease | TxGNN Score | Evidence Level | Trials | Publications | Decision | Mechanistic Assessment |
|---|---|---|---|---|---|---|---|
| 1 | Streptococcal Pneumonia | 99.70% | L5 | 0 | 0 | Hold | ❌ False positive — PBP-mediated resistance, not β-lactamase |
| 2 | Influenza, Severe | 99.28% | L5 | 0 | 0 | Hold | ❌ False positive — viral target; no bacterial β-lactamase pathway |
| 3 | Ureter Tuberculosis | 99.11% | L5 | 0 | 0 | Hold | ⚠️ Theoretical basis via M. tuberculosis BlaC inhibition; no evidence for this anatomical site |
| 4 | Urinary Schistosomiasis | 99.06% | L5 | 0 | 0 | Hold | ❌ False positive — helminthic parasite; no cell wall or β-lactamase target |
| 5 | Hyperamylasemia | 99.01% | L5 | 0 | 0 | Hold | ❌ False positive — metabolic marker; graph embedding confuses "enzyme inhibitor" semantic nodes |
| 6 | Polyclonal Hyperviscosity Syndrome | 99.01% | L5 | 0 | 0 | Hold | ❌ False positive — haematological/immunological disease; no mechanistic link |
| 7 | Staphylococcus aureus Infection | 98.97% | L4 | 2 | 20 | Hold | ⚠️ Limited mechanistic basis (PC1 β-lactamase inhibition); in vitro ceftaroline-avibactam data exist, but no direct clinical outcome evidence |
| 8 | Renal Tuberculosis | 98.93% | L5 | 0 | 1 | Hold | ⚠️ Theoretical BlaC basis; sole matched publication is on CRE infections — a false-match |
| 9 | Squamous Cell Lung Carcinoma | 98.86% | L5 | 0 | 0 | Hold | ❌ False positive — oncological disease; no antineoplastic mechanism |
| 10 | Congenital Analbuminemia | 98.84% | L5 | 0 | 0 | Hold | ❌ False positive — PK protein-binding parameter misinterpreted as therapeutic relationship |
Key Findings
- All 10 predictions are rated "Hold" — none meet the threshold for advancing to structured clinical exploration.
- 8 of 10 predictions are mechanistically implausible false positives, spanning viral, parasitic, oncological, haematological, and metabolic conditions for which avibactam has no conceivable mechanism.
- Rank 7 (Staphylococcus aureus infection) is the most evidence-supported candidate (L4, 2 observational trials, 20 publications) and carries the most plausible theoretical rationale (ceftaroline-avibactam vs. MRSA/MSSA via PC1 β-lactamase), yet remains "Hold" because existing evidence does not directly test avibactam's clinical contribution to S. aureus infection outcomes.
- Ranks 3 and 8 (Ureter/Renal Tuberculosis) share a theoretical mechanistic foundation via M. tuberculosis BlaC inhibition (supported by Soroka et al. 2015), but lack any evidence specific to genitourinary TB, and the single matched publication for renal TB is a mismatch about CRE infections.
- Singapore regulatory barrier: Avibactam is not registered in Singapore. Any repurposing programme would require a full regulatory submission prior to clinical use.
⚠️ Disclaimer: This report is for research reference only and does not constitute medical advice. All drug repurposing candidates require prospective clinical validation before any clinical application.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.