Phenylalanine
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Phenylalanine: From Parenteral Nutrition Amino Acid to Sclerosing Cholangitis
One-Sentence Summary
Phenylalanine is an essential amino acid used as a component of parenteral nutrition and amino acid infusion products. The TxGNN model predicts it may be effective for sclerosing cholangitis, but there are no registered clinical trials and only 3 publications, none of which show a therapeutic effect. The prediction currently rests on the model alone.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not stated in the Singapore licence records (marketed in amino acid and parenteral nutrition infusion products) |
| Predicted New Indication | Sclerosing cholangitis |
| TxGNN Prediction Score | 99.43% |
| Evidence Level | L5 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 19 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Based on known information, phenylalanine is an essential amino acid supplied as part of multi-component amino acid infusions for parenteral nutrition. Its role as a nutrient is well established, but a mechanistic link to sclerosing cholangitis has not been identified.
The only relevant literature is an observational study of plasma tyrosine and fatigue in primary biliary cirrhosis and primary sclerosing cholangitis. It suggests aromatic amino acid metabolism is altered in cholestatic liver disease. This describes a disease-associated metabolic marker, not a therapeutic rationale. The other two papers (a cholangiocarcinoma serum metabolic signature and a bacterial peptide radioimmunoassay) do not address phenylalanine therapy.
Other predicted indications are also weakly supported. These include congenital prothrombin deficiency, epiglottitis, hypophosphatemic rickets, laryngitis, cholecystolithiasis and diabetic nephropathy. For diabetic nephropathy, which has the most literature, elevated phenylalanine and altered phenylalanine/tyrosine metabolism are associated with worse outcomes. That signal points toward risk rather than benefit.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 15790420 | 2005 | Cohort | BMC Gastroenterology | Examined the relation between plasma tyrosine and fatigue in primary biliary cirrhosis and primary sclerosing cholangitis; abnormal amino acid patterns were investigated as a marker of fatigue |
| 32025163 | 2020 | Cohort (metabolomic) | J Clin Exp Hepatol | Serum metabolic signature of cholangiocarcinoma versus benign hepatobiliary disease; a biomarker study, not a treatment study |
| 2103382 | 1990 | Basic research | J Gastroenterol Hepatol | Radioimmunoassay for a bacterial chemotactic peptide (fMLP) and its enterohepatic circulation; not about phenylalanine therapy |
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN16337P | AMINOVEN Solution for Infusion 15% | Infusion, solution | Not stated |
| SIN11682P | AMINOVEN Solution for Infusion 5% | Injection | Not stated |
| SIN11829P | AMINOVEN Solution for Infusion 10% | Injection | Not stated |
| SIN06299P | NEPHROSTERIL for Intravenous Infusion | Injection | Not stated |
| SIN08352P | AMINOPLASMAL-15% Infusion | Injection | Not stated |
All 19 registrations are valid single-ingredient licences, mainly amino acid infusions and parenteral nutrition emulsions. Only the first five are listed here.
Safety Considerations
Package insert warnings and contraindications were not available for this report. Please refer to the package insert for safety information.
- Knowledge-graph contraindication signals (not label text): The TxGNN knowledge graph links phenylalanine to contraindications in several disease areas:
- Phenylketonuria and other disorders of phenylalanine metabolism
- Kidney disease, including chronic kidney disease, end-stage renal failure, nephrolithiasis and nephrocalcinosis
- Heart and cardiovascular disease, digitalis poisoning and ventricular fibrillation
- Hypercalcaemia (including humoral hypercalcaemia of malignancy), sarcoidosis and phosphorus metabolism disease
These signals need to be confirmed against official labelling.
- Drug interactions: No interaction records were found.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction has no clinical trials and no literature showing a therapeutic effect, so the evidence level is L5 (model prediction only). In diabetic nephropathy, the indication with the most literature, phenylalanine is associated with worse outcomes. Phenylalanine is also flagged in the knowledge graph as contraindicated in kidney disease, which may overlap with some of the predicted indications.
To proceed, the following is needed:
- Package insert warnings and contraindications from the HSA website, required before any safety screening
- Mechanism of action data (for example from DrugBank)
- A plausible biological rationale linking phenylalanine to sclerosing cholangitis, supported by preclinical or mechanistic studies
- Review of the knowledge-graph contraindications (especially renal and cardiac) against official labelling
- Confirmation of the approved indications for the Singapore products, as the licence records contain none
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.