Posaconazole
| Evidence Level: L5 | Predicted Indications: 1 |
Table of Contents
Posaconazole: From Invasive Fungal Infections to Pneumocystosis
One-Sentence Summary
Posaconazole is a triazole antifungal originally used for fungal infections such as aspergillosis, candidiasis (including oral candidiasis), and histoplasmosis. The TxGNN model predicts it may be effective for Pneumocystosis, but only 1 loosely related clinical trial (which tests a different drug) and 5 general publications (none directly testing posaconazole for this condition) are available, so the supporting evidence is very weak.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Chromomycosis, coccidioidomycosis, aspergillosis, candidiasis, histoplasmosis, sporotrichosis, fusariosis, mycetoma and other fungal infections |
| Predicted New Indication | Pneumocystosis |
| TxGNN Prediction Score | 99.77% |
| Evidence Level | L5 |
| US Market Status | Cancelled only (all licenses cancelled) |
| Number of NDAs | 14 (2 NDAs and 12 ANDAs, all cancelled) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. Based on general pharmacology, posaconazole is a triazole antifungal that inhibits fungal lanosterol 14-alpha-demethylase (CYP51), which blocks ergosterol synthesis. Its efficacy against several fungal infections is established.
The prediction is weak mechanistically. Pneumocystis jirovecii has cholesterol rather than ergosterol in its membranes, so azoles are generally considered ineffective against it. First-line therapy is trimethoprim-sulfamethoxazole. The very high TxGNN score likely reflects the drug’s broad antifungal class association in the knowledge graph rather than a true mechanistic link.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT04368559 | Phase 3 | Completed | 602 | Rezafungin (an echinocandin, not posaconazole) vs standard antimicrobial regimen for preventing invasive fungal disease in adults undergoing allogeneic blood and marrow transplantation. It provides no direct evidence for posaconazole. |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 26901377 | 2016 | Review | Swiss Medical Weekly | Overview of invasive candidiasis, aspergillosis, cryptococcosis and Pneumocystis pneumonia. Notes that mould-active posaconazole prophylaxis reduced invasive fungal infections in high-risk haemato-oncological patients. |
| 21973267 | 2011 | Review | Clinical Pharmacokinetics | Penetration of antifungal and other anti-infective agents into pulmonary epithelial lining fluid. |
| 41232547 | 2026 | Guideline | The Lancet Infectious Diseases | British Society for Medical Mycology 2025 update on diagnosing serious fungal diseases. |
| 41362140 | 2025 | Guideline | Chinese Journal of Tuberculosis and Respiratory Diseases | 2025 Chinese guidelines for diagnosing and managing invasive pulmonary fungal diseases. |
| 35596686 | 2022 | Cohort | Transplant Infectious Disease | Retrospective study of infectious complications in acute graft-versus-host disease after liver transplantation. |
None of these publications tests posaconazole for pneumocystosis.
US Market Information
All 14 US authorizations are listed as cancelled. The data compiled for this report contains no approved indication text. The main authorizations are:
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| NDA205596 | NOXAFIL (Merck Sharp & Dohme LLC) | Solution | Not available (cancelled) |
| NDA205053 | Posaconazole (Bryant Ranch Prepack) | Tablet, coated | Not available (cancelled) |
| ANDA214842 | Posaconazole (Eugia US LLC) | Injection | Not available (cancelled) |
| ANDA212226 | Posaconazole (Golden State Medical Supply) | Tablet, delayed release | Not available (cancelled) |
| ANDA219057 | Posaconazole (Camber Pharmaceuticals) | Solution | Not available (cancelled) |
Available dosage forms include injectable, oral (delayed-release and coated tablets) and solution.
Safety Considerations
- Drug Interactions: 100 interactions were identified. The examples below are from the 20 that were itemized.
- Major: loperamide, triamcinolone, budesonide
- Moderate (examples): famotidine, ranitidine, cimetidine, omeprazole, rabeprazole, hydrocortisone, dexamethasone, betamethasone, aprepitant, clarithromycin, saxagliptin, bisacodyl
Please refer to the package insert for warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The high TxGNN score is not backed by a plausible mechanism, because Pneumocystis lacks ergosterol and azoles are generally ineffective against it. No trial or publication directly tests posaconazole for pneumocystosis, and the only trial found studies a different drug. The evidence level is L5 (model prediction only).
To proceed, the following is needed:
- Mechanism of action data, plus evidence that posaconazole has activity against Pneumocystis
- Preclinical or clinical studies of posaconazole in pneumocystosis, or a review of any posaconazole-containing prophylaxis trials that report Pneumocystis outcomes
- FDA package insert warnings and contraindications (a blocking gap for safety screening)
- Clarification of the regulatory status, since all US licenses are listed as cancelled
- Comparison against trimethoprim-sulfamethoxazole, the standard of care
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.