Phenylalanine
| Evidence Level: L5 | Predicted Indications: 2 |
Table of Contents
Phenylalanine: From Amino Acid Supplement to Sclerosing Cholangitis
One-Sentence Summary
Phenylalanine (DB00120) is an essential amino acid with no approved therapeutic indication on record and is currently not marketed in Taiwan. TxGNN assigns a high embedding score (99.43%) linking it to Sclerosing Cholangitis, but none of the 4 supporting publications actually studies phenylalanine’s effect on this disease — the strongest matches concern a different substance (the bacterial peptide fMLP, whose name happens to contain “phenylalanine”). This candidate should be treated as an unverified model artifact, not a validated repurposing signal.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not established — Phenylalanine is an essential amino acid/nutritional component with no recorded disease indication (original_moa: Data Gap) |
| Predicted New Indication | Sclerosing Cholangitis |
| TxGNN Prediction Score | 99.43% |
| Evidence Level | L5 (model prediction only) |
| Taiwan Market Status | ✗ Not marketed (Not marketed) |
| Number of Registrations | 0 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Mechanism-of-action data for phenylalanine is not available ([Data Gap]), and unlike typical repurposing candidates, there is no established original indication to anchor a mechanistic bridge to sclerosing cholangitis.
More importantly, the supporting literature does not actually corroborate the link. Of the 4 publications returned, one (PMID 15790420) studies tyrosine, not phenylalanine, in relation to fatigue in PBC/PSC; one (PMID 32025163) is an unrelated cholangiocarcinoma metabolomics study; and two (PMID 8000512, PMID 2103382) study N-formyl-methionyl-leucyl-phenylalanine (fMLP), a bacterial chemotactic peptide used as an immunology reagent — a distinct pharmacological entity that merely shares the substring “phenylalanine” in its name with DB00120.
Taken together, this strongly suggests the TxGNN score reflects a knowledge-graph embedding artifact (likely driven by textual/entity overlap) rather than a genuine pharmacological relationship. No mechanistic rationale currently supports this prediction.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 15790420 | 2005 | Cohort | BMC Gastroenterology | Examines plasma tyrosine (not phenylalanine) and fatigue in PBC/PSC — does not study phenylalanine treatment |
| 32025163 | 2020 | Cohort/Metabolomics | J Clin Exp Hepatol | Serum metabolomic profiling in cholangiocarcinoma; unrelated to phenylalanine as an intervention |
| 8000512 | 1994 | Animal study | J Gastroenterol | Rectal fMLP (a bacterial peptide, distinct from the amino acid) induced small duct cholangitis in rats with colitis |
| 2103382 | 1990 | Basic research | J Gastroenterol Hepatol | Characterizes enterohepatic circulation of bacterial F-met chemotactic peptides, not free phenylalanine |
Note: none of the above studies evaluates phenylalanine itself as a therapeutic agent for sclerosing cholangitis; matches appear driven by name/text overlap with the unrelated peptide fMLP.
Safety Considerations
Please refer to the package insert for safety information. Note: TFDA label warnings/contraindications are marked as a Blocking data gap (DG001) — this must be resolved before any safety pre-assessment (S1) can proceed.
Conclusion and Next Steps
Decision: Hold
Rationale: The evidence level is L5 (model prediction only), with no clinical trials and no literature that genuinely supports phenylalanine’s activity in sclerosing cholangitis. The available publications appear to reflect a name-collision artifact with the unrelated peptide fMLP rather than a real pharmacological signal, and the drug is not currently marketed in Taiwan.
To proceed, the following is needed:
- Resolve blocking data gap DG001 (TFDA label warnings/contraindications) before any safety pre-assessment
- Obtain verified mechanism-of-action data (DG002) for phenylalanine
- Independent literature/database re-query specifically excluding fMLP and other name-collision entities, to confirm whether any genuine phenylalanine–cholangitis evidence exists
- Note: the secondary candidate (congenital prothrombin deficiency, score 99.26%) was also assessed and is equally unsupported — its only associated trial (NCT06227429, studying Nitisinone, not phenylalanine) was withdrawn with zero enrollment; it carries the same Hold recommendation
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.