Cidofovir

Evidence Level: L5 Predicted Indications: 4

Table of Contents

  1. Cidofovir
    1. Pharmacist Assessment Report
    2. Cidofovir: From Antiviral Therapy to Sclerosing Cholangitis
    3. One-Sentence Summary
    4. Quick Overview
    5. Why is This Prediction Reasonable?
    6. Clinical Trial Evidence
    7. Literature Evidence
    8. Canada Market Information
    9. Cytotoxicity
    10. Safety Considerations
    11. Conclusion and Next Steps
    12. Disclaimer

Pharmacist Assessment Report

Cidofovir: From Antiviral Therapy to Sclerosing Cholangitis

One-Sentence Summary

Cidofovir is a nucleotide-analog antiviral that inhibits viral DNA polymerase and has a single marketed product in Canada. The TxGNN model predicts it may be effective for sclerosing cholangitis, with a very high score. However, no clinical trials and no publications currently support this prediction, so it is a computational signal only.

Quick Overview

Item Content
Original Indication Not specified in the Canadian licence data compiled for this report
Predicted New Indication Sclerosing cholangitis
TxGNN Prediction Score 0.9994
Evidence Level L5
Canada Market Status Marketed (marketed DINs: 1 of 1)
Number of DINs 1 (marketed: 1)
Recommended Decision Hold

Why is This Prediction Reasonable?

Detailed mechanism-of-action data for cidofovir is not available in the data compiled for this report. Based on general knowledge, cidofovir is a nucleotide analog that inhibits DNA polymerase in cytomegalovirus (CMV) and other DNA viruses.

A possible indirect link is AIDS-related or CMV-associated cholangiopathy, which can present as secondary sclerosing cholangitis. This is speculative and is not supported by the supplied data. Primary sclerosing cholangitis is largely immune-mediated, so an antiviral mechanism is not an obvious fit. The high score comes from the TxGNN model (deep learning) and may reflect similarities the model learned between related diseases, not biological evidence. It should not be read as evidence of efficacy.

Other predictions in the candidate list have even weaker support:

  • Rheumatoid arthritis (score 0.9982): None of the 5 retrieved publications tests cidofovir in this disease. They cover CMV in transplant recipients, drug-related retinal toxicity and wart treatment. The association appears to come from leflunomide, an RA drug used as an anti-CMV agent, which is the reverse direction of repurposing.
  • Colobomatous microphthalmia-rhizomelic dysplasia syndrome (0.9962) and brachydactyly-syndactyly syndrome (0.9949): These are rare developmental genetic disorders with no plausible link to an antiviral mechanism. The scores likely reflect network artifacts.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

Currently no related literature available for the lead prediction, sclerosing cholangitis.

Canada Market Information

DIN Product Name Dosage Form Approved Indication
02473925 MAR-CIDOFOVIR Not specified Not specified

Cytotoxicity

Cidofovir is an antiviral, not an antineoplastic agent, so this section does not apply.

Safety Considerations

  • Contraindications suggested by the knowledge graph (derived from PrimeKG drug-disease edges, not from label text): kidney disease, pyoureter, acidosis disorder, acquired lactic acidosis.
  • Nephrotoxicity: Cidofovir is known to be nephrotoxic and is generally given with probenecid and hydration. This is a significant concern for any new use.
  • Drug interactions: The interaction check found 55 interacting drugs. Examples of Major interactions include:
    • Amphotericin B (including lipid complex, cholesteryl sulfate and liposomal forms)
    • Aminoglycosides: kanamycin, neomycin, streptomycin
    • Polymyxin B and vancomycin
    • Aminosalicylates: mesalazine, balsalazide, olsalazine, sulfasalazine
    • Deferasirox and deferoxamine
    • Iodinated contrast agents: diatrizoate, iodipamide
    • Iobenguane (I-131)

    Moderate interactions include exenatide and trospium. Many of these are nephrotoxic agents, which adds to the renal risk.

Please refer to the package insert for the full warnings and contraindications.

Conclusion and Next Steps

Decision: Hold

Rationale:

  • The only support for sclerosing cholangitis is a model prediction (evidence level L5), with no clinical trials or literature. The mechanistic fit is weak, and cidofovir’s nephrotoxicity and extensive interaction profile raise the bar for any new use.

To proceed, the following is needed:

  • Health Canada package insert warnings and contraindications, which are currently missing and block safety screening
  • Mechanism-of-action data from DrugBank
  • The approved indication, dosage form and manufacturer for the Canadian licence
  • A targeted literature search on cidofovir or antivirals in CMV-associated or secondary cholangiopathy
  • Preclinical or mechanistic evidence for a role in sclerosing cholangitis
  • Route-of-administration compatibility assessment and a renal safety plan

    Disclaimer

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

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