Ertapenem

證據等級: L5

預測適應症: 2 個

Ertapenem: From Gram-Negative Bacterial Infections to Bacterial Arthritis

One-Sentence Summary

Ertapenem is a once-daily carbapenem antibiotic used internationally for serious gram-negative bacterial infections, including complicated intra-abdominal infections, community-acquired pneumonia, and complicated urinary tract infections. The TxGNN model predicts it may be effective for Bacterial Arthritis — leveraging its broad gram-negative spectrum, excellent bone/synovial tissue penetration, and OPAT-friendly once-daily dosing — with 0 clinical trials and 10 publications currently supporting this specific direction.

Quick Overview

Item	Content
Original Indication	Not found in database; ertapenem (INVANZ) is known internationally for serious gram-negative infections — likely a data gap
Predicted New Indication	Bacterial Arthritis
TxGNN Prediction Score	99.72%
Evidence Level	L3
US Market Status	Not found in database (data gap — ertapenem/INVANZ has known FDA approval)
Number of NDAs	0 (database; see note in US Market section)
Recommended Decision	Hold

Why is This Prediction Reasonable?

Ertapenem is a 1-β-methyl carbapenem that inhibits bacterial cell wall synthesis by binding preferentially to penicillin-binding proteins PBP-2 and PBP-3. It has a broad antimicrobial spectrum covering gram-negative Enterobacteriaceae (including ESBL-producing strains), anaerobes, and some gram-positive organisms including methicillin-susceptible Staphylococcus aureus. Notably, it lacks activity against Pseudomonas aeruginosa and Acinetobacter — a key pharmacological distinction from meropenem and imipenem. Its extended half-life (~4 hours) and high protein binding enable once-daily IV dosing, a property that makes it uniquely suited to outpatient parenteral antimicrobial therapy (OPAT). Detailed mechanism of action data was not available in the database for this query; the above reflects established pharmacology from the primary literature.

Bacterial arthritis (septic arthritis) is a serious joint infection requiring prompt and often prolonged antibiotic therapy. Gram-negative organisms — including Klebsiella pneumoniae, Citrobacter spp., Prevotella spp., and anaerobes — account for a meaningful proportion of cases, particularly in elderly, immunocompromised, diabetic, or post-surgical patients. This pathogen profile aligns directly with ertapenem’s antimicrobial spectrum. Ertapenem achieves adequate concentrations in synovial fluid and bone tissue, supporting its mechanistic applicability to musculoskeletal infections. Its role as a salvage agent for multidrug-resistant gram-negative septic arthritis is supported by the repurposing rationale in the Evidence Pack.

Case-level evidence demonstrates real-world use: ertapenem successfully treated Klebsiella pneumoniae septic wrist arthritis (PMID 22233826) and Citrobacter koseri septic arthritis with osteomyelitis in a diabetic patient (PMID 31352398). A large OPAT retrospective cohort (n=306, PMID 24709258) documented bone and joint infections as among the most common long-term ertapenem indications, with acceptable safety outcomes. A prospective cohort (PMID 31220276) further validated subcutaneous ertapenem as suppressive therapy for prosthetic joint infections when surgery was not feasible. Together, these data provide mechanistic and observational support for the TxGNN prediction — though no dedicated RCT exists for this indication.

Clinical Trial Evidence

Currently no related clinical trials registered for ertapenem specifically in bacterial arthritis.

Note: The second-ranked TxGNN prediction — Staphylococcus aureus infection (score: 99.28%) — is supported by 8 clinical trials including an actively recruiting Phase 2 RCT (NCT04886284) directly evaluating cefazolin + ertapenem for MSSA bacteremia, and carries an L2 evidence grade with a “Proceed with Guardrails” recommendation. This may represent a stronger and more actionable near-term repurposing opportunity.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
24709258	2014	Retrospective Cohort	Antimicrob Agents Chemother	In 306 patients receiving long-term outpatient ertapenem, intra-abdominal infections were most common (38%), followed by pneumonia (12%); bone and joint infections were a key indication — long-term use was safe and effective
31220276	2019	Prospective Cohort	J Antimicrob Chemother	Off-label subcutaneous ertapenem as prolonged suppressive therapy in 10 patients with prosthetic joint infection or chronic osteomyelitis where optimal surgery was not feasible; supports use in musculoskeletal infections
39193962	2024	Retrospective Analysis	Clinical Laboratory	Pathogen distribution and antimicrobial resistance in bone and joint infections (BJIs) among children under 4 years; provides epidemiological context for empiric carbapenem selection
41878879	2026	Cohort / Comparative	J Antimicrob Chemother	Evaluated temocillin as an alternative to carbapenems (including ertapenem) for 3GC-resistant Enterobacterales BJIs; underlines carbapenems as current standard of care for resistant organisms in joints
22233826	2011	Case Report	J Chemotherapy	Klebsiella pneumoniae septic wrist arthritis successfully treated with ertapenem + levofloxacin; direct clinical evidence for ertapenem efficacy in gram-negative septic arthritis
31352398	2019	Case Report	BMJ Case Reports	Citrobacter koseri septic arthritis with osteomyelitis in a diabetic patient successfully treated with ertapenem; demonstrates salvage role for opportunistic gram-negative joint infections
31585203	2020	Case Report	Anaerobe	First reported Clostridium paraputrificum native shoulder septic arthritis and osteomyelitis; anaerobic etiology within ertapenem’s spectrum; treated with arthroscopic debridement plus antibiotics
37578166	2023	Case Report + Review	J Investig Med High Impact Case Rep	Prevotella bivia septic arthritis in an immunocompetent adult; anaerobic gram-negative etiology directly covered by ertapenem; initially misdiagnosed, highlighting diagnostic challenges
38924836	2024	In vitro / Translational	Diagn Microbiol Infect Dis	Auranofin (FDA-approved for rheumatoid arthritis) restored ertapenem susceptibility in carbapenem-resistant E. coli through synergy; potential combination strategy for refractory gram-negative joint infections
29183082	2017	Review	JAMA	Review of hidradenitis suppurativa diagnosis and treatment; limited direct relevance to bacterial arthritis — included for completeness

US Market Information

No US market records were returned by the database query for ertapenem (0 licenses found). This is most likely a data gap rather than a true absence of approval.

Ertapenem is marketed internationally as INVANZ (Merck & Co.) and holds FDA approval for multiple serious gram-negative infection indications. Please verify current US status and label language directly via:

FDA Orange Book: search “ertapenem” at https://www.accessdata.fda.gov/scripts/cder/ob/
DailyMed: full prescribing information at https://dailymed.nlm.nih.gov

Known approved indications internationally include: complicated intra-abdominal infections, complicated skin/skin-structure infections, community-acquired pneumonia, complicated urinary tract infections, acute pelvic infections, and prophylaxis for colorectal surgery.

Safety Considerations

Detailed safety data (warnings, contraindications, drug interactions) was not returned by the database for this query.

Please refer to the INVANZ package insert for complete safety information. Key safety signals known from the published literature and clinical practice include:

Seizure risk: Carbapenem class effect; risk is elevated in patients with central nervous system disorders, renal impairment, or those receiving high doses
Valproic acid interaction: Carbapenems are known to significantly reduce serum valproate concentrations — this is a clinically important drug interaction that may precipitate seizures in patients on valproic acid for epilepsy
β-Lactam cross-sensitivity: Patients with serious allergy to other β-lactams require careful risk-benefit assessment
Hypoalbuminemia: Ertapenem is highly protein-bound; patients with serum albumin <2.5 g/dL may have suboptimal drug exposures (see PMID 40448546 in the MSSA bacteremia literature)

Conclusion and Next Steps

Decision: Hold

Rationale: Evidence for ertapenem specifically in bacterial arthritis is currently limited to retrospective cohort studies, case reports, and observational data (L3), with no registered clinical trials targeting this indication. Mechanistic plausibility is strong and individual case reports are encouraging, but the evidence base does not yet support progression to formal development without additional structured investigation.

To proceed, the following is needed:

Resolve data gaps first: Obtain the INVANZ package insert (FDA DailyMed or Merck label) to complete the safety profile — this is a blocking item (DG001)
Confirm US approval status: Verify via FDA Orange Book; populate the US market information section with actual NDA data
Retrieve DrugBank MOA data: Query DrugBank API for DB00303 to formally document mechanism of action (DG002 remediation)
Prospective registry or feasibility study: Design a structured observational study of ertapenem OPAT in gram-negative septic arthritis, particularly in ESBL-producing organism cases
Define target population: Focus on patients where gram-negative or anaerobic etiology is likely (elderly, diabetic, immunocompromised, post-surgical) and where OPAT is clinically advantageous
Prioritize the MSSA bacteremia indication in parallel: Rank-2 prediction (Staphylococcus aureus infection, score 99.28%) has an actively recruiting Phase 2 RCT (NCT04886284: Cefazolin + Ertapenem for MSSA bacteremia), L2 evidence, and a “Proceed with Guardrails” recommendation — this represents a substantially stronger and more immediately actionable repurposing opportunity
Disclaimer

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