Zidovudine
| Evidence Level: L5 | Predicted Indications: 6 |
Table of Contents
Zidovudine: From HIV/AIDS to Simian Immunodeficiency Virus Infection
One-Sentence Summary
Zidovudine (AZT) is a nucleoside reverse transcriptase inhibitor (NRTI) originally developed and approved for HIV/AIDS treatment. The TxGNN model’s top-ranked prediction is Simian Immunodeficiency Virus (SIV) infection — a lentiviral disease that only occurs in non-human primates — with 0 clinical trials and 20 publications (all preclinical animal-model studies) supporting this specific direction. Because SIV is not a human disease, this is not a translatable repurposing candidate; it reflects a mechanistic analogy (same NRTI target, same viral genus) rather than a new clinical indication.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | HIV/AIDS (Human Immunodeficiency Virus infection) — established international indication; no India regulatory license text is present in this evidence pack |
| Predicted New Indication | Simian Immunodeficiency Virus Infection (non-human primate lentiviral disease) |
| TxGNN Prediction Score | 99.96% |
| Evidence Level | L4 (preclinical/mechanistic studies only) |
| India Market Status | Not Marketed |
| Number of Registrations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism-of-action data is flagged as a data gap in this evidence pack (DG002). Based on the available literature, zidovudine is an NRTI: it is phosphorylated intracellularly and, as the triphosphate, competitively inhibits reverse transcriptase and causes viral DNA chain termination — the mechanism that made it the first approved antiretroviral for HIV/AIDS.
SIV and HIV are both members of the Lentivirus genus and share highly homologous reverse transcriptase enzymes, which is why AZT shows measurable antiviral activity against SIV in vitro and in rhesus/cynomolgus macaque models. This explains why TxGNN’s knowledge graph places these two diseases close together and assigns a very high similarity score.
However, this mechanistic overlap does not make SIV infection a viable human repurposing target: SIV does not infect humans, and all 20 supporting publications are animal-model or in vitro studies (prophylaxis, viral-load kinetics, resistance mutations) rather than human clinical evidence. This is best understood as TxGNN correctly identifying a biologically real drug-target relationship that happens to fall on a non-human disease node — useful for validating the model, but not actionable as a new human indication.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 1489181 | 1992 | Animal model | Antimicrob Agents Chemother | Oral AZT prevented SIV infection in infant rhesus macaques given pre/post-exposure prophylaxis |
| 19240457 | 2009 | Animal model | AIDS | AZT+3TC+indinavir postexposure prophylaxis prevented vaginal SIV transmission in macaques |
| 7848683 | 1994 | Animal model | AIDS Res Hum Retroviruses | AZT reduced viral load kinetics during acute SIV infection in cynomolgus macaques |
| 7695293 | 1995 | Animal model | Antimicrob Agents Chemother | Immediate AZT treatment protected SIV-infected newborn macaques from rapid-onset AIDS |
| 7797947 | 1995 | Animal model | J Infect Dis | AZT prolonged survival and lowered CNS/CSF virus load in perinatally SIV-infected macaques |
| 9021180 | 1997 | Animal model (resistance) | Antimicrob Agents Chemother | Identified AZT-resistant SIV mutant (Q151M in reverse transcriptase) causing AIDS in newborn macaques |
| 16973590 | 2006 | Animal model | J Virol | Quadruple antiretroviral therapy (incl. AZT) produced rapid viral decay in SIV-infected macaques |
| 2016686 | 1991 | Animal model | J Acquir Immune Defic Syndr | Compared antiviral effects of AZT vs. 3’-fluorothymidine in SIV-infected cynomolgus monkeys |
| 22713337 | 2012 | In vitro/animal model | Antimicrob Agents Chemother | SIV response to a novel NRTI benchmarked in vitro and in vivo against existing NRTIs including AZT |
| 8452370 | 1993 | In vitro | Antimicrob Agents Chemother | AZT vs. neutralizing antibodies on SIV-infected macaque macrophages |
India Market Information
Zidovudine currently has no registered license in this evidence pack (total_licenses: 0, market status: Not Marketed). No authorization records are available to summarize.
Safety Considerations
Drug Interactions (DDI): The database records 235 total documented interactions. Notable examples from the returned set:
- Moderate-level: Amphotericin B (all formulations), Betamethasone, Budesonide, Dexamethasone, Hydrocortisone, Prednisolone, Prednisone, Triamcinolone, Naltrexone, Orlistat, Rosuvastatin, Simvastatin
- Minor-level: Cimetidine, Clarithromycin
- Level not classified: Pantoprazole, Morphine, Metformin, Omeprazole
Key warnings and contraindications are not available in this evidence pack (flagged as Blocking data gap DG001 — TFDA/India label warnings and contraindications). Please refer to the official package insert once available.
Conclusion and Next Steps
Decision: Hold
Rationale: The top-ranked TxGNN prediction (SIV infection) and the second-ranked prediction (feline AIDS) are non-human animal diseases and therefore not viable human repurposing targets, despite very high TxGNN similarity scores (~99.96%). Two other high-scoring predictions in this pack (an ultra-rare neurodevelopmental disorder and an “obsolete” metabolic disease concept) have zero supporting trials or literature and are best treated as knowledge-graph noise (L5). Two lower-ranked entries in this set — “AIDS related complex” and “congenital HIV” — are not new indications at all; they are zidovudine’s own original, already-approved uses (including the landmark ACTG 076 perinatal-transmission trials), and their L1/”Proceed with Guardrails” status reflects mature standard-of-care evidence rather than a repurposing opportunity.
To proceed, the following is needed:
- TFDA/India label warnings, contraindications, and boxed-warning text (DG001, Blocking)
- Formal mechanism-of-action documentation from DrugBank (DG002)
- A re-run of the TxGNN candidate list filtered to exclude non-human disease nodes and the drug’s own original indications, to surface genuinely novel human repurposing candidates
- If India market entry is being considered even for the existing HIV/AIDS indication, a full regulatory dossier and local licensing pathway assessment
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.