Colistin

證據等級: L5

預測適應症: 10 個

Colistin: From Multidrug-Resistant Gram-Negative Infections to Post-Infectious Syndrome

One-Sentence Summary

Colistin (polymyxin E, DB00803) is a last-resort cyclic polypeptide antibiotic used to treat multidrug-resistant (MDR) Gram-negative bacterial infections, currently not marketed in Canada. The TxGNN model predicts it may be effective for post-infectious syndrome — particularly in preventing infection-related complications in critically ill patients — with this being the highest-evidenced indication among the 10 predictions assessed (TxGNN score 99.91%), supported by 13 clinical trials including the landmark SuDDICU Phase 3 cluster-crossover RCT (n = 20,010). Of all predicted indications evaluated, only post-infectious syndrome reaches the “Proceed with Guardrails” threshold; seven of ten predictions are recommended Hold.

Quick Overview

Item	Content
Original Indication	MDR Gram-negative bacterial infections (last-resort antibiotic)
Predicted New Indication	Post-Infectious Syndrome
TxGNN Prediction Score	99.91%
Evidence Level	L2
Canada Market Status	Not marketed
Number of DINs	0
Recommended Decision	Proceed with Guardrails

Why is This Prediction Reasonable?

Currently, detailed mechanism of action data is not available in this evidence pack (listed as Data Gap). Based on known pharmacology, colistin is a cyclic polypeptide of the polymyxin class. It exerts bactericidal activity by competitively displacing divalent cations (Ca²⁺, Mg²⁺) from lipid A within lipopolysaccharide (LPS) on the outer membrane of Gram-negative bacteria, causing membrane destabilisation, increased permeability, and cell death. This unique mechanism retains activity against pan-drug-resistant strains — carbapenem-resistant Acinetobacter baumannii (CRAB), Klebsiella pneumoniae (CRKP), and Carbapenem-resistant Enterobacteriaceae (CRE) — that have exhausted all other antibiotic options.

Post-infectious syndrome encompasses persistent complications arising after the acute phase of a bacterial infection — prolonged organ dysfunction, systemic inflammatory sequelae, and ICU-acquired morbidity. Colistin connects to this indication through two mechanistic pathways: (1) direct bacterial eradication of the MDR Gram-negative pathogens that initiate the infectious cascade, thereby curtailing downstream syndrome development; and (2) its established role in Selective Decontamination of the Digestive Tract (SDD), where oral/enteral colistin systematically suppresses gut colonisation by potentially pathogenic Gram-negative organisms in ICU patients — a strategy designed to prevent the bacteraemia-to-organ-failure pathway before post-infectious syndrome can establish itself.

The completed SuDDICU Phase 3 cluster-crossover RCT (NCT02389036, n = 20,010) — in which colistin is a core component of the SDD regimen — provides the single strongest evidence anchor, elevating this indication to L2. This is not a narrow drug repurposing in the traditional sense; rather, it is an evidence-grounded extension of colistin’s established antibacterial mechanism into a preventive ICU context. Multiple additional Phase 3/4 trials further characterise colistin’s efficacy and safety profile against the MDR Gram-negative pathogens underlying post-infectious syndrome.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT02389036	Phase 3	Completed	20,010	SuDDICU: SDD (colistin as core component) vs. standard oral care in ICU patients — crossover cluster RCT measuring 90-day mortality and infection rates. The largest single trial supporting colistin’s preventive role in critically ill patients.
NCT06051513	N/A	Recruiting	404	Colistimethate sodium injection vs. standard care for carbapenem-resistant Enterobacteriaceae (CRE) HAP and BSI; head-to-head RCT directly evaluating colistin prodrug efficacy and safety.
NCT04882085	Phase 4	Completed	60	CAZ-AVI vs. best available treatment (colistin-containing) for carbapenem-resistant Gram-negative HAP/VAP/cUTI/cIAI/BSI in Chinese adults; completed, providing comparative efficacy and safety data.
NCT07004049	Phase 4	Recruiting	600	TREAT-GNB adaptive platform trial evaluating antibiotic strategies for severe MDR Gram-negative BSI and lower respiratory tract infections; colistin as a principal treatment arm.
NCT01023087	N/A	Completed	70	Prospective study of renal impairment incidence and impact of drug level monitoring in colistin-treated patients; essential nephrotoxicity safety data for guardrails design.
NCT03894046	Phase 3	Completed	207	Sulbactam-ETX2514 vs. colistin (active comparator) for Acinetobacter baumannii HABP/VABP/bacteremia; provides indirect comparative efficacy and safety benchmarking.
NCT01970371	Phase 3	Completed	69	Plazomicin vs. colistin (+ meropenem or tigecycline) for CRE infections (BSI/HABP/VABP/cUTI); randomised superiority design with colistin as active comparator.
NCT01732250	Phase 4	Completed	406	Colistin alone vs. colistin + meropenem for clinically significant MDR Gram-negative infections; largest head-to-head colistin monotherapy vs. combination trial.
NCT06827756	Phase 4	Completed	90	Norfloxacin vs. nitazoxanide vs. colistin as secondary prophylaxis for spontaneous bacterial peritonitis (SBP) in cirrhotic patients with ascites; directly tests colistin in a post-infection prevention context.
NCT03597841	N/A	Completed	278	Turkish national multicenter prospective cohort of carbapenem-resistant Klebsiella pneumoniae bacteraemia (OXA-48 endemic setting); colistin as one of the few remaining treatment options, characterising outcomes.

Literature Evidence

Currently no directly relevant published literature is available for post-infectious syndrome in the evidence pack.

Canada Market Information

Colistin (DB00803) is not currently marketed in Canada. No Drug Identification Numbers (DINs) are registered with Health Canada.

Safety Considerations

Nephrotoxicity: The most clinically significant safety concern for colistin is acute kidney injury (AKI). NCT01023087 was specifically designed to characterise the incidence of renal impairment, reflecting the high clinical importance of this risk. Close renal function monitoring (serum creatinine, eGFR, urine output) is essential.
Neurotoxicity: Peripheral neuropathy and neuromuscular blockade have been reported with systemic colistin use, requiring neurological monitoring particularly in prolonged treatment courses.

For complete warnings, contraindications, and drug interaction data, please refer to the full package insert. Safety data from Canadian/Taiwan regulatory sources is not currently available for this report.

Conclusion and Next Steps

Decision: Proceed with Guardrails

Rationale: Colistin’s role as a core SDD component in critically ill patients is anchored by the completed SuDDICU Phase 3 trial (n = 20,010) and corroborated by multiple Phase 3/4 MDR GNB treatment trials. The mechanistic link between Gram-negative bacterial eradication and prevention of post-infectious syndrome is biologically sound, and the evidence level (L2) is sufficient to justify structured clinical evaluation — provided rigorous safety monitoring is implemented given the known nephrotoxicity and neurotoxicity profile.

To proceed, the following is needed:

Mechanism of action data from DrugBank (currently Data Gap; required for mechanistic rationale refinement)
Complete safety data including Health Canada package insert warnings and contraindications (currently unavailable — Blocking data gap)
Precise target population definition (SDD-eligible ICU patients vs. acute MDR GNB infection management vs. post-infection prophylaxis)
Renal function monitoring protocol addressing AKI risk, particularly in patients with pre-existing kidney disease or concurrent nephrotoxic agents
Health Canada Special Access Programme (SAP) pathway assessment, as no DIN currently exists for colistin in Canada
Assessment of whether colistin or its prodrug colistimethate sodium (CMS) is the preferred formulation for the intended clinical application

YMYL Disclaimer: This report is for research reference only and does not constitute medical advice. All drug repurposing candidates require clinical validation before any therapeutic application.

Disclaimer

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