IV Bevacizumab Treatment of Patients With Hereditary Hemorrhagic Telangiectasia (HHT) or Rendu-Osler (RO) Disease: A Retrospective Analysis of French Cohort Data From 2009 to 2024

Rendu-Osler disease (RO), also known as Hereditary Haemorrhagic Telangiectasia (HHT), is an autosomal dominant genetic disorder. Its pathophysiology is associated with an imbalance in angiogenic balance. The resulting epistaxis and digestive bleeding can be severe, requiring repeated transfusions in 5% of patients. In addition, some patients with HHT may present with liver damage, leading to high-flow heart failure. Vascular Endothelial Growth Factor (VEGF) plays a role in the pathophysiology of Rendu-Osler disease, leading to the use of a recombinant anti-VEGF monoclonal antibody, bevacizumab. Studies conducted and promoted by HCL have demonstrated the efficacy and safety of bevacizumab in patients with HHT. In 2014, bevacizumab was granted orphan drug designation for this disease. The 2020 international guidelines for the diagnosis and management of HHT suggest the use of systemic antiangiogenic agents in cases of epistaxis resistant to other treatments. The use of bevacizumab has been widely published in uncontrolled studies, demonstrating its efficacy in reducing epistaxis, improving anaemia, reducing transfusion dependence and improving quality of life. In France, bevacizumab is currently prescribed outside the scope of its marketing authorization. Treatment indications are validated within the French network of expert centres and the FAVAmulti rare disease network. In other countries, access to this treatment varies widely according to local regulations, and is currently being evaluated in the European VASCERN network. The aim of this study is to describe the use of bevacizumab in patients treated for HHT in France.

Inclusion Criteria: * \- Adult over 18 years of age * Rendu-Osler disease treated with bevacizumab prescribed for this condition * Treated and followed in France Exclusion Criteria: * \- Patient opposition to data use