Nitric Oxide

證據等級: L5

預測適應症: 10 個

Nitric Oxide (Inhaled): From Neonatal Persistent Pulmonary Hypertension to Pulmonary Arterial Hypertension

Note on indication selection: This Evidence Pack ranked 10 TxGNN-predicted indications by raw similarity score. The top 6 ranked candidates (e.g., "malformation syndrome with odontal/periodontal component," "hypertrichosis," "Dandy-Walker malformation") were explicitly flagged in the pack's own repurposing_rationale as likely knowledge-graph embedding artifacts with no supporting mechanism, trials, or literature (evidence_level L5, decision_stage S0, recommendation Hold) — the pack itself recommends excluding them from screening. This report therefore focuses on rank 7 — Pulmonary Arterial Hypertension (PAH) — the highest-quality, most actionable candidate in the set (Evidence Level L1, decision_stage S3, "Proceed with Guardrails"). Ranks 8–10 (related PAH subtypes) are summarized briefly at the end for completeness.

One-Sentence Summary

Inhaled Nitric Oxide is an established gas therapy for hypoxic respiratory failure with pulmonary hypertension in neonates. Evidence in this pack strongly supports expanding its pharmacological rationale to Pulmonary Arterial Hypertension more broadly (adult/general WHO Group 1 disease), backed by 50 clinical trials (including completed Phase 3/4 studies) and 20 supporting publications describing the NO–sGC–cGMP pathway as a core, already-druggable mechanism in PAH.

Quick Overview

Item	Content
Original Indication	Not formally recorded in the supplied regulatory dataset (data gap); per the trial/literature evidence in this pack, inhaled NO's established clinical use is hypoxic respiratory failure with pulmonary hypertension in neonates (PPHN)
Predicted New Indication	Pulmonary Arterial Hypertension
TxGNN Prediction Score	99.41% (rank 6252 of candidate set)
Evidence Level	L1
Norway Market Status	✗ Not marketed
Number of Authorizations	0
Recommended Decision	Proceed with Guardrails

Why is This Prediction Reasonable?

Currently, detailed mechanism of action data for this DrugBank entry is not available (data gap). However, based on the pharmacology consistently described across the supplied trial and literature evidence, Nitric Oxide (NO) is an endogenous vascular endothelial relaxing factor. Inhaled NO diffuses selectively into pulmonary vascular smooth muscle, activates soluble guanylate cyclase (sGC), and raises intracellular cGMP, producing selective pulmonary vasodilation without significant systemic hypotension — the same mechanism exploited by approved oral PAH therapies (PDE-5 inhibitors, sGC stimulators) that act on this identical pathway downstream.

The established original use of inhaled NO — reversing hypoxic respiratory failure caused by elevated pulmonary vascular resistance in neonates — and the predicted new indication, general pulmonary arterial hypertension, are mechanistically the same disease process (elevated pulmonary artery pressure driven by pulmonary vascular tone/remodeling), differing mainly in patient population (neonatal vs. adult/broader PAH etiologies) and route of chronic administration.

Multiple reviews in the evidence set (e.g., PMID 32442078, 23822809, 20051913) directly document that NO pathway deficiency and endothelial dysfunction are central to PAH pathogenesis, and that restoring NO signaling (via inhaled NO or downstream pathway drugs) is one of only three validated therapeutic pathways in PAH (alongside endothelin and prostacyclin pathways). This gives the TxGNN prediction strong, literature-confirmed mechanistic plausibility rather than a purely statistical association.

Clinical Trial Evidence

Trial Number	Phase	Status	Enrollment	Key Findings
NCT01142219	Phase 3	Completed	40	RCT of L-arginine (NO precursor) as adjuvant therapy for sickle cell disease-associated PAH; direct evidence of NO-pathway modulation
NCT04231084	Phase 4	Completed	115	Head-to-head acute hemodynamic comparison of inhaled NO vs. inhaled epoprostenol across PH phenotypes
NCT00139217	N/A	Completed	400	Large completed trial of non-invasive inhaled NO in persistent pulmonary hypertension of the newborn
NCT05213676	Phase 4	Recruiting	600	Multi-center "NoNO Trial" evaluating de-implementation of iNO in congenital diaphragmatic hernia with PH
NCT01959828	Phase 3	Completed	18	Safety/efficacy of inhaled NO (IK-3001) in Japanese patients with PH associated with cardiac surgery
NCT07099144	Phase 4	Recruiting	120	Ongoing safety study of INOmax combined with ventilatory support for neonatal hypoxic respiratory failure with PH
NCT00955487	Phase 2	Completed	124	Low-dose iNO to reduce bronchopulmonary dysplasia and associated pulmonary hypertension in premature newborns
NCT01265888	Phase 2	Completed	31	Dose-escalation study of inhaled GeNOsyl NO in PAH (WHO Group 1) and PH secondary to idiopathic pulmonary fibrosis
NCT06249633	Early Phase 1	Unknown	20	Pilot study of early iNO for ARDS-related pulmonary hypertension (small sample, status unknown)
NCT01275339	Phase 4	Terminated	10	PDE5 inhibition pilot in aortic stenosis-related pulmonary venous hypertension (terminated, non-direct NO test)

Literature Evidence

PMID	Year	Type	Journal	Key Findings
32442078	2020	Review	Current Medicinal Chemistry	Details the NO pathway as a core pathomechanism, biomarker source, and drug target in PAH
33836637	2021	Review	J Cardiovasc Pharmacol Ther	Combination PAH therapy targeting NO and prostacyclin pathways together
38054614	2024	Review	Small	Reviews inhalable NO delivery technologies developed specifically for PAH treatment
23822809	2013	Review	Am J Respir Crit Care Med	Landmark review on NO deficiency and endothelial dysfunction as central PAH mechanism
20051913	2010	Review	Journal of Hypertension	NO, oxidative stress and inflammation as drivers of PAH pathophysiology
35412560	2022	Review	JAMA	Contemporary diagnosis and treatment review of PAH
39209476	2024	Review	European Respiratory Journal	Current PAH treatment algorithm across endothelin/NO/prostacyclin/BMP pathways
37516248	2023	Review	Presse Médicale	General PAH review covering diagnosis, pathophysiology and management
38416633	2024	Network meta-analysis	European Heart Journal	Individual participant data network meta-analysis comparing PAH treatment pathways
33773120	2021	RCT	Lancet Respiratory Medicine	REPLACE trial: switching to riociguat (same NO-cGMP pathway) vs. continued PDE5 inhibitor therapy in PAH

Norway Market Information

Nitric Oxide currently holds no marketing authorizations in Norway (market status: Not marketed; total authorizations: 0). No product-level dosage form or approved-indication data is available for this jurisdiction at this time.

Safety Considerations

Please refer to the package insert for safety information. No structured warnings, contraindications, or drug-interaction data were retrievable for this compound in the current evidence pack; this is flagged as a Blocking data gap (DG001: TFDA/label warnings and contraindications) that must be resolved before any formal safety pre-assessment (S1) can proceed.

For completeness, two additional high-quality candidates were identified among the 10 TxGNN predictions and may warrant parallel tracking:

Pulmonary arterial hypertension associated with congenital heart disease (rank 8, score 99.41%, Evidence Level L1, decision_stage S3, "Proceed with Guardrails") — iNO is already the clinical standard for acute post-operative PH crises after congenital heart surgery; strong mechanistic and trial overlap with the primary candidate above.
PAH associated with connective tissue disease and PAH associated with chronic hemolytic anemia (ranks 9–10, Evidence Level L3, decision_stage S1, "Research Question") — mechanistically plausible (endothelial NO deficiency / NO scavenging by free hemoglobin) but currently supported only by observational/mechanistic literature, with no dedicated interventional trials of NO/iNO in these subgroups yet.

Conclusion and Next Steps

Decision: Proceed with Guardrails

Rationale: Inhaled Nitric Oxide's proposed expansion to Pulmonary Arterial Hypertension is supported by the strongest evidence tier in this pack (L1) — including completed Phase 3/4 trials directly testing NO or NO-pathway agents in relevant PAH populations — and by a well-established, literature-confirmed mechanism (NO–sGC–cGMP selective pulmonary vasodilation) that is already the basis of approved PAH drug classes (PDE5 inhibitors, sGC stimulators). However, the drug is currently unmarketed in Norway and lacks any formal safety labeling data in this dataset, so guardrails are warranted before advancing further.

To proceed, the following is needed:

Official TFDA/manufacturer package insert data (warnings, contraindications) — currently a Blocking data gap
Confirmed detailed mechanism of action (MOA) documentation from DrugBank or equivalent source — currently a High-severity data gap
Formal drug-drug interaction (DDI) profile, currently unretrieved ("not_found")
Regulatory pathway assessment for Norway market entry, given zero current authorizations
Clarification of the original approved indication record, since this field was empty in the source data despite iNO's well-documented use in neonatal PPHN
Disclaimer

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