Phenylalanine

證據等級: L5

預測適應症: 2 個

Phenylalanine: From No Approved Indication to Sclerosing Cholangitis

One-Sentence Summary

Phenylalanine is an essential amino acid with no approved therapeutic indication and no marketing authorization on file. The TxGNN model predicts it may be effective for Sclerosing Cholangitis, but a review of the supporting evidence — 0 clinical trials and 4 publications — finds no data that actually support this claim.

Quick Overview

Item	Content
Original Indication	Not applicable — phenylalanine is an essential amino acid; no marketed drug license or approved indication text exists in the record
Predicted New Indication	Sclerosing Cholangitis
TxGNN Prediction Score	99.43%
Evidence Level	L5
Market Status	Not marketed
Number of NDAs	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism of action data is not available for phenylalanine in this context. Based on known information, phenylalanine is a naturally occurring essential amino acid rather than a drug with an approved indication, so there is no established pharmacological rationale connecting it to sclerosing cholangitis.

A review of the four literature citations returned for this prediction finds none of them actually support a treatment relationship. One study (PMID 15790420) examines plasma tyrosine — not phenylalanine — as a fatigue biomarker in primary biliary cirrhosis/PSC patients; another (PMID 32025163) is a metabolomics study of cholangiocarcinoma unrelated to treatment; and the remaining two (PMID 8000512, PMID 2103382) concern fMLP (N-formyl-methionyl-leucyl-phenylalanine), a bacterial chemotactic peptide that is a distinct compound from free phenylalanine, and describe it as inducing bile duct inflammation in animal models — i.e., a disease-causing mechanism, not a therapeutic one.

Given the very low TxGNN rank (13,234th out of the model’s candidate list, despite a superficially high score), the absence of any supportive mechanism, and the fact that cited literature describes an unrelated compound or the opposite biological effect, this prediction is most plausibly a knowledge-graph false positive driven by node co-occurrence (phenylalanine/tyrosine appearing alongside hepatobiliary disease terms) rather than a genuine repurposing signal.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
15790420	2005	Observational	BMC Gastroenterology	Examines plasma tyrosine (not phenylalanine) as a fatigue biomarker in PBC/PSC patients; not a treatment study
32025163	2020	Metabolomics	J Clin Exp Hepatol	Serum metabolomic profiling of cholangiocarcinoma vs. benign hepatobiliary disease; not related to phenylalanine treatment
8000512	1994	Animal model	J Gastroenterol	fMLT (a chemotactic peptide, not free phenylalanine) induces small duct cholangitis in rats — describes disease pathogenesis, not treatment
2103382	1990	Basic research	J Gastroenterol Hepatol	Studies enterohepatic circulation of the bacterial peptide fMLP, not phenylalanine itself

Safety Considerations

Please refer to the package insert for safety information.

Conclusion and Next Steps

Decision: Hold

Rationale: No clinical trials and no supportive literature exist for phenylalanine in sclerosing cholangitis; the cited publications either study a different compound (the peptide fMLP/fMLT) or unrelated biomarkers, and the TxGNN score is undermined by the extremely low candidate rank (13,234). This prediction should be treated as an unconfirmed model artifact rather than a repurposing lead.

A second, lower-priority candidate — congenital prothrombin deficiency (TxGNN score 99.26%, rank 16,307) — was also reviewed and shows the same pattern: the only associated trial (NCT06227429) is a withdrawn, zero-enrollment study of an unrelated drug (Nitisinone), in which phenylalanine appears only as a monitored lab value, not as treatment. No plausible mechanism links phenylalanine to prothrombin synthesis. This candidate is also recommended for Hold.

To proceed, the following is needed:

Mechanism of action (MOA) data for phenylalanine confirming any plausible hepatobiliary or coagulation-related pathway
Regulatory/label data (currently no marketing authorization exists to review)
Independent confirmation that the TxGNN association is not an artifact of node co-occurrence (e.g., phenylalanine/tyrosine/fMLP entity conflation in the knowledge graph)
If pursued further, preclinical mechanistic studies specific to free phenylalanine (not fMLP) in cholestatic liver disease models
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.