Idursulfase
| Evidence Level: L5 | Predicted Indications: 10 |
Table of Contents
Idursulfase: From Mucopolysaccharidosis to Ptosis-Strabismus-Ectopic Pupils Syndrome
One-Sentence Summary
Idursulfase is an enzyme replacement therapy originally used to treat mucopolysaccharidosis (Hunter syndrome, MPS II). The TxGNN model predicts it may be effective for ptosis-strabismus-ectopic pupils syndrome with a very high score, but no clinical trials and no publications support this prediction, so it rests on model output alone. The only prediction with any supporting literature is the closely related lysosomal disorder, Scheie syndrome, and that evidence is indirect.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Mucopolysaccharidosis (the approved indication text is not listed in the Singapore licence record; this is taken from the knowledge-graph indication) |
| Predicted New Indication | Ptosis-strabismus-ectopic pupils syndrome |
| TxGNN Prediction Score | 97.89% |
| Evidence Level | L5 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 1 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. Based on known information, idursulfase is a recombinant iduronate-2-sulfatase. It breaks down glycosaminoglycans (dermatan sulfate and heparan sulfate) inside lysosomes, and this is why it is used in MPS II.
For the top-ranked prediction, no mechanistic link could be identified. Ptosis-strabismus-ectopic pupils syndrome is a congenital ocular and neurodevelopmental malformation with no known glycosaminoglycan accumulation. The high score is most likely a knowledge-graph artifact caused by shared ocular phenotype nodes, not a biological rationale.
The other top-ranked predictions show the same pattern. These include camptodactyly-myopia-medial rectus fibrosis, congenital Horner syndrome, ptosis-vocal cord paralysis syndrome, jaw-winking syndrome, congenital entropion, epiblepharon and congenital ectropion. All are structural or neural developmental conditions unrelated to lysosomal storage, and idursulfase is not expected to correct them. The drug also does not cross the blood-brain barrier appreciably, which further weakens any neurological rationale.
The one exception is Scheie syndrome (rank 10, score 94.79%), the attenuated form of MPS I. It involves the same GAG degradation pathway, but the missing enzyme is alpha-L-iduronidase, which idursulfase does not replace. The appropriate therapy there is laronidase, so direct benefit from idursulfase is not expected.
Clinical Trial Evidence
Currently no related clinical trials registered, for the top prediction or for any of the other predicted indications.
Literature Evidence
No literature is available for the top prediction. The five publications below were found for Scheie syndrome (rank 10). They cover shared MPS management and do not test idursulfase in Scheie syndrome.
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 22210671 | 2011 | Review | Rheumatology (Oxford) | Overview of MPS therapy; ERT is available for MPS I (laronidase) and MPS II (idursulfase) within multidisciplinary care |
| 21211680 | 2010 | Review | La Revue de Médecine Interne | Review of enzyme replacement therapy across lysosomal storage diseases |
| 36329518 | 2022 | Case series | Orphanet J Rare Dis | Desensitization protocol for idursulfase (MPS II) and laronidase (MPS I S) |
| 39731157 | 2024 | Cohort (follow-up) | Orphanet J Rare Dis | Two-year follow-up after drug desensitization in MPS types I S and II |
| 21732093 | 2012 | Cohort | J Inherit Metab Dis | Serum heparin cofactor II-thrombin complex as a biomarker in treated MPS I and II patients |
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN13902P | Elaprase (TM) Solution for Intravenous Infusion 2 mg/ml | Infusion, solution concentrate | Not listed in the licence record |
The product is an intravenous injectable, manufactured by Shire HGT, Inc with fill-finish by Vetter Pharma-Fertigung GmbH & Co. KG.
Safety Considerations
Please refer to the package insert for safety information.
The data compiled for this report found no recorded drug interactions. The literature does note that infusion-related hypersensitivity reactions can lead to interruption of enzyme replacement therapy, and desensitization protocols have been used to restore treatment in MPS patients.
Conclusion and Next Steps
Decision: Hold
Rationale: The top predictions have no clinical trials, no literature and no plausible mechanism. They are most likely knowledge-graph artifacts based on shared ocular phenotypes. Scheie syndrome is the only biologically adjacent candidate, but the missing enzyme there is not the one idursulfase replaces, so it is better treated as a research question than a development candidate.
To proceed, the following is needed:
- The package insert from the Singapore Health Sciences Authority (HSA), covering the approved indication, warnings and contraindications
- Mechanism of action data (for example from DrugBank) to support any mechanistic analysis
- A biological rationale and preclinical evidence for any ocular or neurodevelopmental target before further consideration
- For Scheie syndrome, a comparison against laronidase to show whether idursulfase adds any value
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.