ENDOTHELION Study Group: Effect of Bosentan in NAION Patients

Inclusion Criteria:

• Non arteritic ischemic optic neuropathy (NAION) with onset < 21 days
• Age ≥ 50 years old
• Signed informed consent form
• Patients affiliated with a national health insurance scheme or beneficiaries of such ascheme

Exclusion Criteria:

• Pregnant women, women in labour or breast-feeding mother
• Patients with other acute or chronic intercurrent ocular pathology interfering withvisual acuity or visual field (diabetes, drug-induced or other retinopathy, otheroptic neuropathy including uni- or contralateral glaucoma and/or intraocular pressure > 30 mmHg, advanced cataract, corneal opacities, amblyopia < 5/10, severe myopia > -6diopters, retinal disease)
• Simultaneous bilateral NAAION, 1 month apart or less
• Signs that may raise suspicion of other inflammatory neuropathy: arterial NAAION (Horton's disease), pain on eye movement or any signs suggestive of optic neuritis,known diagnosis of multiple sclerosis, history of inflammatory optic neuropathy (homo-or ipsi-lateral). A temporal artery biopsy should be performed if there are symptomssuggestive of Horton's disease, or if there is pale and/or diffuse edema, orobliteration of the associated central retinal artery.
• Patients with systolic blood pressure below 100 mmHg
• Patient with orthostatic hypotension (20 mmHg drop in SBP and/or 10 mmHg drop in DBPwhen moving to a standing position)
• Neurological history of vascular or tumour-related changes to the visual field orother optic neuropathy
• Systemic inflammatory disease
• Known allergy to bosentan
• Patients with moderate to severe hepatic impairment (Child-Pugh class B or C), biliarycirrhosis (serum levels of liver aminotransferases, aspartate aminotransferases (ASAT)and/or alanine aminotransferases (ALAT), greater than three times the upper limit ofnormal, bilirubin greater than twice normal)
• Estimated glomerular filtration rate (GFR) < 30 ml/min/1.73 m2
• Patients treated with drugs whose efficacy may be reduced by activation of cytochromeP450, 2C9, 3A4 and 2C19 isoenzymes
• Patients treated with amiodarone
• Patient treated with systemic corticosteroids (background treatment or treatmentinitiated at the time of NAAION diagnosis)
• Person deprived of liberty by judicial or administrative decision, adult protected bylaw, hospitalized person
• Ongoing participation in another clinical research study or in the exclusion period ofanother clinical study