Ambrisentan

Evidence Level: L5

Predicted Indications: 5

Ambrisentan

Pharmacist Assessment Report

Ambrisentan: From Pulmonary Arterial Hypertension to Pulmonary Arteriovenous Malformation

One-Sentence Summary

Ambrisentan is an endothelin receptor antagonist originally used to treat pulmonary arterial hypertension (PAH). The TxGNN model predicts it may be effective for pulmonary arteriovenous malformation, but the evidence is very thin: 0 clinical trials and 1 publication (a case report) are currently available. This prediction is best viewed as a hypothesis, not a validated new use.

Quick Overview

Item	Content
Original Indication	Pulmonary arterial hypertension
Predicted New Indication	Pulmonary arteriovenous malformation
TxGNN Prediction Score	0.9941
Evidence Level	L5
Canada Market Status	Marketed (marketed DINs: 4 of 4)
Number of DINs	4 (marketed: 4)
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism-of-action data are not available in the data compiled for this report. Ambrisentan is known to be an endothelin receptor antagonist. It blocks endothelin signalling, which reduces pulmonary vasoconstriction and vascular remodelling. This is the basis of its proven benefit in PAH.

The link to pulmonary arteriovenous malformations (AVMs) is indirect. Pulmonary AVMs often occur in hereditary hemorrhagic telangiectasia (HHT), and HHT patients can also develop PAH. The one supporting publication is a case report of a patient with HHT and PAH. It shows that the two conditions can coexist, but it does not show that ambrisentan treats the AVM itself.

The high TxGNN score is a computational prediction and has not been clinically validated.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
33969094	2021	Case report	World Journal of Clinical Cases	Reports PAH in a patient with HHT, with a review of treatment and family gene analysis, to raise awareness of this rare multimorbidity. It does not show ambrisentan efficacy for the AVM.

Canada Market Information

DIN	Product Name
02307065	VOLIBRIS
02307073	VOLIBRIS
02475375	APO-AMBRISENTAN
02475383	APO-AMBRISENTAN

All four authorizations are single-ingredient products with valid status.

Safety Considerations

Conditions flagged in the knowledge graph (derived from drug-disease contraindication links, not from package insert text): congestive heart failure, anemia, macrocytic anemia, pulmonary veno-occlusive disease.
Drug Interactions: 100 interactions were recorded in total. The main ones with a known severity are:
- Moderate: canagliflozin, dapagliflozin, empagliflozin, ertugliflozin, eliglustat, naltrexone
- Minor: clarithromycin, miconazole, omeprazole

Please refer to the package insert for official warnings and contraindications.

Conclusion and Next Steps

Decision: Hold

Rationale: The only support is a single case report describing coexisting PAH and HHT, and there are no registered trials. The prediction score is high, but there is no clinical evidence that ambrisentan treats pulmonary AVMs.

To proceed, the following is needed:

Clinical or observational data on ambrisentan specifically for pulmonary AVM, not only for coexisting PAH
Detailed mechanism-of-action data linking endothelin blockade to AVM biology
Package insert warnings and contraindications, to assess safety in HHT and AVM patients, including the anemia-related concerns

Other predicted indications for ambrisentan have stronger support. In particular, PAH associated with connective tissue disease has two registered trials (NCT02290613 and NCT01042158) and several ambrisentan-specific studies. It is a more promising candidate for further evaluation.

Disclaimer

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