Tolcapone
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Tolcapone: From Parkinson Disease to Rasmussen Subacute Encephalitis
One-Sentence Summary
Tolcapone is an oral COMT inhibitor, originally used for Parkinson disease and related parkinsonian syndromes. The TxGNN model predicts it may be effective for Rasmussen subacute encephalitis, but there are currently 0 clinical trials and 0 publications supporting this specific prediction. It is a model prediction only.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Parkinson disease (and related parkinsonian syndromes) |
| Predicted New Indication | Rasmussen subacute encephalitis |
| TxGNN Prediction Score | 99.93% |
| Evidence Level | L5 |
| US Market Status | Cancelled only (no currently valid licenses) |
| Number of NDAs | 2 (both cancelled) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Tolcapone is known as a catechol-O-methyltransferase (COMT) inhibitor. It is used as an add-on to levodopa in Parkinson disease, where it prolongs the action of dopamine-related therapy. Detailed mechanism of action data is not available in the data compiled for this report, so this description relies on general knowledge of the drug class.
Rasmussen encephalitis is a chronic, inflammatory and probably autoimmune brain disease. Based on the data compiled, no plausible link between COMT inhibition and this pathology can be established. The high TxGNN score (99.93%) reflects a pattern found by the model in its knowledge graph, not biological or clinical validation. The prediction should be regarded as a hypothesis only.
For context, the other top predictions also lack trial or literature support. Two are worth noting:
- Lewy body dementia (score 99.64%): shares dopaminergic and alpha-synuclein pathology with Parkinson disease, so there is a plausible indirect rationale. The only publication is a preclinical organoid study, which did not test tolcapone.
- Paralysis agitans, juvenile, of Hunt (score 99.52%): a juvenile parkinsonian syndrome that may largely overlap with existing labeled indications rather than representing true repurposing.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
Currently no related literature available for Rasmussen subacute encephalitis.
US Market Information
| Authorization Number | Product Name | Dosage Form | Status |
|---|---|---|---|
| NDA020697 | Tolcapone (Oceanside Pharmaceuticals) | Tablet, film coated | Cancelled |
| ANDA208937 | Tolcapone (Ingenus Pharmaceuticals, LLC) | Tablet | Cancelled |
Approved indication text was not available for either authorization. Neither is currently valid.
Safety Considerations
- Contraindication signals from the knowledge graph (not label text): liver disease, gallbladder disease, melanoma, hypotensive disorder, rhabdomyolysis, nodular fasciitis, tardive dyskinesia, lingual-facial-buccal dyskinesia.
- Drug Interactions: 65 interactions were identified. The most notable:
- Major: methylene blue
- Moderate: epinephrine (including ophthalmic and topical forms), morphine (including liposomal), opium, codeine, dronabinol, nabilone, naltrexone, metoclopramide, promethazine, chlorpheniramine, cetirizine, dextromethorphan, ethanol
- Minor: warfarin, dicoumarol
- Unknown severity: omeprazole
Please refer to the package insert for official warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction rests on model output alone (evidence level L5), with no trials or publications, no established mechanistic link to Rasmussen encephalitis, and no currently valid US marketing authorization. Safety signals (liver disease, among others) further argue against advancing without supporting data.
To proceed, the following is needed:
- FDA package insert warnings and contraindications (a blocking gap for safety screening)
- Mechanism of action data (e.g., from DrugBank)
- Preclinical or mechanistic evidence linking COMT inhibition to Rasmussen encephalitis pathology
- Consideration of a better-supported candidate, such as Lewy body dementia, as a research question
- Review of the cancelled US licensing status and its reasons
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.