Ketoconazole
| Evidence Level: L5 | Predicted Indications: 1 |
Table of Contents
Ketoconazole: From Fungal Infection to Acne
One-Sentence Summary
Ketoconazole is a broad-spectrum imidazole antifungal, traditionally used to treat fungal skin and systemic infections. The TxGNN model predicts it may also be effective for Acne, with 1 clinical trial and 15 publications currently identified as supporting evidence — though most of this literature is mechanistic or observational rather than confirmatory.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not specified in this evidence pack (ketoconazole is an imidazole antifungal, conventionally indicated for fungal infections) |
| Predicted New Indication | Acne (disease) |
| TxGNN Prediction Score | 99.80% |
| Evidence Level | L4 (preclinical / mechanistic evidence) |
| UK Market Status | Not currently marketed |
| Number of Marketing Authorisations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed original-indication data is not available in this evidence pack, but the underlying mechanistic rationale for repurposing has been captured. Ketoconazole is an imidazole antifungal that primarily works by inhibiting fungal CYP450 14α-demethylase, disrupting ergosterol synthesis in the fungal cell membrane. When given systemically, it also non-selectively inhibits human adrenal and gonadal steroidogenic enzymes (notably 17,20-lyase), producing an anti-androgenic effect.
This dual mechanism offers two distinct — and largely indirect — routes by which ketoconazole could theoretically benefit acne. First, the anti-androgenic effect of systemic ketoconazole could plausibly improve acne driven by hyperandrogenism, such as that seen in polycystic ovary syndrome (PCOS). Second, topical ketoconazole’s activity against Malassezia (Pityrosporum) yeasts may be useful in cases of fungal folliculitis that are frequently misdiagnosed as acne vulgaris, and in vitro data also suggest some inhibitory activity against Propionibacterium acnes lipase.
Importantly, neither mechanism directly targets the pathways conventionally implicated in acne vulgaris (P. acnes colonisation, sebum overproduction, follicular inflammation). The mechanistic link is therefore best characterised as indirect/bypass rather than a primary, on-target effect, which is consistent with the L4 (preclinical/mechanistic) evidence level assigned.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrolment | Key Findings |
|---|---|---|---|---|
| NCT07237763 | Not Applicable | Active, not recruiting | 52 | Randomised comparison of topical ketoconazole 2% cream vs. topical adapalene 2% cream in mild comedonal and papulopustular acne, assessing whether ketoconazole is a viable, better-tolerated alternative to topical retinoids. Results not yet reported. |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 28111792 | 2017 | In vitro study | Microbiology and Immunology | Ketoconazole inhibits Propionibacterium acnes lipase activity, suggesting a possible antifungal-independent mechanism relevant to acne. |
| 20045949 | 2010 | In vitro study | Biological & Pharmaceutical Bulletin | Azole antifungals, including ketoconazole, show in vitro activity against P. acnes isolates from acne patients. |
| 8593718 | 1995 | Case series | Clinical and Experimental Dermatology | Pityrosporum (Malassezia) folliculitis is frequently misdiagnosed as acne vulgaris; antifungal therapy is discussed as treatment. |
| 8255067 | 1993 | Review | The Keio Journal of Medicine | Reviews Pityrosporum ovale pathogenicity in skin disease, including folliculitis presenting as acne-like eruptions. |
| 8629828 | 1996 | Case report | Archives of Dermatology | Describes neonatal Malassezia furfur pustulosis, an entity often labelled “neonatal acne,” linked to fungal aetiology. |
| 12566804 | 2003 | Review | Dermatology (Basel) | Reviews systemic acne treatment options, providing general context for evaluating novel systemic agents. |
| 33216275 | 2021 | RCT (different indication: Cushing’s syndrome) | Pituitary | Levoketoconazole (ketoconazole enantiomer) improves clinical signs/symptoms in Cushing’s syndrome via steroidogenesis inhibition — informs anti-androgenic mechanism, not direct acne evidence. |
| 19445767 | 2009 | Review | BMJ Clinical Evidence | Reviews PCOS management; notes association between hyperandrogenism and acne. |
| 8090657 | 1993 | Review | Polski Tygodnik Lekarski | Discusses treatment of hyperandrogenic manifestations (including acne) in PCOS. |
| 32872149 | 2020 | Review | Pharmaceuticals (Basel) | Reviews adapalene, the comparator agent used in the ongoing ketoconazole acne trial (NCT07237763). |
UK Market Information
Ketoconazole currently holds no marketing authorisations recorded in this evidence pack (0 licences, market status: not marketed). No MHRA-approved product information or approved indication text was available for review.
Safety Considerations
Please refer to the SmPC and BNF for safety information. Report suspected adverse reactions via the Yellow Card Scheme.
Note: Detailed warnings, contraindications and drug interaction data for ketoconazole were not available in this evidence pack. Given ketoconazole’s known hepatotoxicity risk (boxed warning in some jurisdictions for oral formulations) and CYP3A4 interaction potential, a full SmPC-based safety review is a prerequisite before any further evaluation.
Conclusion and Next Steps
Decision: Hold
Rationale: The evidence base for ketoconazole in acne consists of a single, small, unreported (Active, not recruiting) topical trial, together with in vitro, case-report, and mechanistically indirect literature (L4). The proposed mechanism does not act on the primary pathways implicated in acne vulgaris, and a blocking data gap exists around core safety information (warnings/contraindications), which must be resolved before any safety screening can proceed.
To proceed, the following is needed:
- Full SmPC/product safety data (warnings, contraindications, drug interactions) — currently a blocking gap
- Confirmed original indication and regulatory history for ketoconazole
- Results from NCT07237763 upon completion
- Additional controlled trials directly comparing ketoconazole to standard acne therapies, ideally in the specific acne phenotype (e.g., Malassezia folliculitis vs. classic P. acnes-driven acne) where the mechanism is most plausible
- Route/formulation-specific evaluation (topical vs. systemic), given differing risk-benefit profiles
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.