Emtricitabine
| 證據等級: L5 | 預測適應症: 3 個 |
目錄
Emtricitabine: From HIV-1 Infection to Simian Immunodeficiency Virus Infection
One-Sentence Summary
Emtricitabine (DrugBank DB00879) is a nucleoside reverse transcriptase inhibitor (NRTI) antiretroviral, known publicly for its role in treating HIV-1 infection. The TxGNN model predicts high relevance for Simian Immunodeficiency Virus (SIV) Infection, an analogous lentivirus infection studied in non-human primates, supported by 2 clinical trials and 20 publications — though the supporting evidence is almost entirely preclinical/animal-model research rather than human clinical data for this specific indication.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | HIV-1 infection (based on known drug classification; no formal license record present in this evidence pack) |
| Predicted New Indication | Simian Immunodeficiency Virus Infection |
| TxGNN Prediction Score | 99.92% |
| Evidence Level | L4 |
| US Market Status | Not Marketed |
| Number of NDAs | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data was not available in this evidence pack. Based on known information, emtricitabine is a cytidine analogue nucleoside reverse transcriptase inhibitor (NRTI), most widely known as a component of combination antiretroviral regimens (e.g., Truvada, Atripla) for HIV-1 infection. Its efficacy against HIV-1 is well established mechanistically through inhibition of viral reverse transcriptase.
Simian Immunodeficiency Virus (SIV) is the lentivirus most closely related to HIV-1 and is the standard non-human primate model used to study HIV pathogenesis, prevention, and treatment. Because SIV and HIV-1 share reverse transcriptase machinery and infection biology, it is mechanistically plausible that emtricitabine — and combinations containing it — would show activity against SIV, which is exactly what the underlying literature reflects.
Importantly, SIV infection is not a human disease; it occurs naturally only in non-human primates and is used experimentally to model HIV. The evidence base for this prediction therefore consists almost entirely of macaque/primate preclinical studies (pre-exposure prophylaxis, chemoprophylaxis, viral dynamics), not human trials of emtricitabine “for SIV.” This should be read as strong translational/mechanistic support for emtricitabine’s antiretroviral class effect rather than a directly actionable new human indication.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT00863668 | N/A | Withdrawn | 0 | Studied HIV RNA decay kinetics under ART (raltegravir-based); references comparable first-phase decay estimates in SIV-infected rhesus macaques as background rationale, not an emtricitabine-SIV treatment trial. |
| NCT03577782 | Phase 1/2 | Unknown | 12 | Evaluated vedolizumab + antiretroviral therapy for HIV virological remission in treatment-naive subjects; SIV not directly studied. |
Note: Neither trial directly tests emtricitabine as a treatment for SIV infection; both are HIV-1 human trials that reference SIV models contextually.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 31362305 | 2019 | Animal study | J Infect Dis | Oral tenofovir alafenamide/emtricitabine combination protects macaques against vaginal SHIV infection. |
| 29788316 | 2018 | Animal study | J Infect Dis | Vaginal gel containing emtricitabine/tenofovir protects against repeated rectal SHIV exposure in macaques. |
| 27465645 | 2016 | Animal study | J Infect Dis | Oral emtricitabine + tenofovir alafenamide chemoprophylaxis protects macaques from rectal SHIV infection. |
| 26743846 | 2016 | Animal study | J Infect Dis | Emtricitabine/tenofovir disoproxil fumarate prevents vaginal SHIV infection in macaques even with concurrent STI coinfection. |
| 23633402 | 2013 | Animal study | J Infect Dis | Oral emtricitabine/tenofovir disoproxil fumarate prevents transmission of tenofovir-resistant (K65R) SHIV in macaques. |
| 22814162 | 2012 | Animal study | Jpn J Infect Dis | Double oral emtricitabine/tenofovir dosing protects macaques against highly pathogenic SHIV infection. |
| 32128569 | 2020 | Animal study | J Infect Dis | Long-acting cabotegravir compared with oral emtricitabine/tenofovir disoproxil fumarate for penile SHIV exposure protection in macaques. |
| 19656878 | 2009 | Animal study | J Virol | Topical gel with tenofovir alone or combined with emtricitabine gives complete protection from repeated vaginal SHIV exposure in macaques. |
| 21632769 | 2011 | Animal study | J Virol | Intermittent Truvada (emtricitabine/tenofovir disoproxil fumarate) prophylaxis protects against rectal transmission of an emtricitabine-resistant (M184V) SHIV mutant. |
| 20874040 | 2010 | Review | Pharmacotherapy | Reviews systemic pre-exposure prophylaxis strategies (including emtricitabine-based regimens) for HIV prevention. |
10 most relevant of 20 total publications shown; remaining 10 cover related SIV viral dynamics, reservoir, and resistance studies without direct emtricitabine efficacy data.
US Market Information
Emtricitabine currently has no marketing authorization records in this evidence pack (US market status: Not Marketed, 0 licenses on file). Publicly, emtricitabine is known to be marketed in the US as a component of combination products (e.g., Truvada, Atripla), but no such license data was returned by the source query for this evidence pack.
Safety Considerations
Please refer to the package insert for safety information.
Conclusion and Next Steps
Decision: Hold
Rationale: The predicted indication, Simian Immunodeficiency Virus infection, is a non-human primate disease rather than a human clinical indication, so the supporting evidence — while mechanistically coherent (L4, preclinical/mechanism-level) — cannot translate directly into a human repurposing pathway. Combined with the absence of US license records and a blocking data gap on TFDA labeling/safety information, there is insufficient basis to advance to guardrailed development at this time.
To proceed, the following is needed:
- TFDA product label (warnings/contraindications) — currently a blocking data gap
- Confirmed original indication and license data (US or Taiwan) for emtricitabine
- Reframing of the target indication toward a human-relevant correlate (e.g., HIV-1 pre-exposure prophylaxis) if the intent is human repurposing, since SIV itself is not a treatable human condition
- Detailed mechanism of action documentation from DrugBank
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.