Efficacy of a Bevacizumab Nasal Spray as a Treatment for Epistaxis in Hereditary Hemorrhagic Telangiectasia (HHT)

Inclusion Criteria: * Age ≥ 18 years. * Patients who have given their free informed and signed consent. * Patients affiliated to a social security scheme or similar. * Patients monitored for clinically confirmed HHT (presence of at least 3 Curaçao criteria) and/or confirmed by molecular biology. * Patients who have not undergone nasal surgery in the 3 months prior to inclusion. * Patient with nosebleeds of a monthly duration of more than 20 minutes and justified by follow-up grids completed for at least the 3 months prior to the time of inclusion. Exclusion Criteria: * Women who are pregnant or likely to become so in the course of the study. * Patients not affiliated to a social security scheme. * Patients who are protected adults under the terms of the law (French Public Health Code). * Refusal to consent. * Patients for whom the diagnosis of HHT has not been confirmed clinically and/or by molecular biology. * Patients with an on-going infectious condition. * Participation in another clinical trial within the 28 days prior to inclusion. * Known hypersensitivity to the active ingredient or one of the excipients. * Known hypersensitivity to products of Chinese hamster ovary cells (CHO) or other human or humanized recombinant antibodies. * Patients who have incompletely filled in the nosebleed grids in the 3 months preceding the treatment. * Patients who do not present with nosebleeds with a monthly average duration over the 3 months preceding the treatment of more than 20 minutes ((duration M1 + duration M2 + duration M3) / 3). Remark: only the 3 months strictly preceding the treatment will be taken into account, even if the grids have been completed over a longer period. * Patients who have received Avastin® intravenously in the 6 months prior to inclusion.