Methotrexate
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Methotrexate: From Established Chemotherapy/Immunomodulatory Use to Pulmonary Blastoma
One-Sentence Summary
Methotrexate is a long-established antifolate (DHFR inhibitor) used across oncology, rheumatology and dermatology, but this evidence pack contains no UK licensing or original-indication data for the drug. The TxGNN model predicts a possible new application in Pulmonary Blastoma, a rare lung malignancy, but this prediction is currently supported by 0 clinical trials and 0 publications — it is a model-only signal.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not available in this evidence pack — no UK licence or original-indication data recorded |
| Predicted New Indication | Pulmonary Blastoma |
| TxGNN Prediction Score | 99.45% |
| Evidence Level | L5 |
| UK Market Status | Not marketed |
| Number of Marketing Authorisations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in this evidence pack. Based on the repurposing rationale provided, methotrexate is a dihydrofolate reductase (DHFR) inhibitor that blocks folate metabolism and thymidylate synthesis — a mechanism common to many antimetabolite chemotherapy regimens used against rapidly proliferating malignant cells.
The predicted link to pulmonary blastoma rests solely on this generic antiproliferative mechanism. There is no disease-specific mechanistic data, preclinical model, or clinical experience connecting methotrexate to pulmonary blastoma in the evidence pack — the rationale text itself notes the absence of any tumour-specific supporting evidence.
Because pulmonary blastoma is an extremely rare biphasic lung tumour and no trials or literature have been identified for this specific drug-disease pairing, the mechanistic plausibility alone (broad antimetabolite activity against dividing cells) is insufficient to support clinical extrapolation at this stage.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available.
UK Market Information
No UK marketing authorisation data is available in this evidence pack (market status: Not marketed; 0 licences recorded). This may reflect a gap in the source dataset rather than the drug’s true regulatory status, given methotrexate’s well-established global use — this should be verified directly against the MHRA/BNF before any decision is finalised.
Cytotoxicity
Methotrexate is a conventional cytotoxic antimetabolite (folate antagonist / DHFR inhibitor) and is treated here as an antineoplastic agent.
| Item | Content |
|---|---|
| Cytotoxicity Classification | Conventional cytotoxic (Antimetabolite class, folate antagonist) |
| Myelosuppression Risk | High — antimetabolite-class agents typically carry significant bone marrow suppression risk, dose- and schedule-dependent |
| Emetogenicity Classification | Low to moderate (dose-dependent; higher with high-dose intravenous regimens) |
| Monitoring Items | FBC with differential, liver function tests, renal function, folate status |
| Handling Protection | Must follow cytotoxic drug handling regulations (COSHH-compliant preparation, administration and waste disposal) |
Note: This evidence pack contains no drug-specific toxicity dataset; the above reflects the recognised pharmacological class profile and should be confirmed against the current SmPC.
Safety Considerations
Please refer to the SmPC and BNF for safety information. Report suspected adverse reactions via the Yellow Card Scheme.
Conclusion and Next Steps
Decision: Hold
Rationale:
- The top-ranked predicted indication (pulmonary blastoma) is supported only by a TxGNN model score, with zero clinical trials and zero publications — this is Evidence Level L5 (model prediction only). In addition, blocking data gaps exist (UK/TFDA-equivalent warnings and contraindications, and detailed MOA), meaning safety cannot yet be assessed.
To proceed, the following is needed:
- MHRA/BNF-sourced warnings, contraindications and drug interaction data for methotrexate
- Confirmed UK marketing authorisation status (the “Not marketed” flag in this pack should be verified, as methotrexate is widely used in UK clinical practice)
- Detailed mechanism of action documentation to support or refute mechanistic relevance to pulmonary blastoma
- Any preclinical or case-level evidence specific to pulmonary blastoma before considering further evaluation
Additional note: This evidence pack also contains other predicted indications for methotrexate with substantially stronger evidence — notably Hodgkin lymphoma (Evidence Level L2, “Proceed with Guardrails”, supported by an RCT and multiple Phase 2/3 trials of MTX-containing regimens such as VBM) and rhabdomyosarcoma (Evidence Level L2, “Proceed with Guardrails”, supported by a completed Phase 2 trial and disease-specific literature). These candidates warrant separate, dedicated evaluation reports rather than being assessed under the top-ranked but poorly evidenced pulmonary blastoma prediction.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.