Bevacizumab In Hereditary Hemorrhagic Telangiectasia

In this research study, the investigators are studying the study drug, bevacizumab. Researchers would like to see whether bevacizumab effectively treats Hereditary Hemorrhagic Telangiectasia (HHT) and what side effects occur. \- The research study procedures include: screening for eligibility, pretreatment period, study treatment, end-of-study visit, and follow-up visit. * Participants will be observed for 12 weeks and then receive study treatment for 24 weeks and will be followed for 30 days after ending study treatment. * This research study involves the following study drug: Bevacizumab * It is expected that about 33 people will take part in this research study. This research study is a Phase II clinical trial. Phase II clinical trials test the safety and effectiveness of an investigational drug to learn whether the drug works in treating Hereditary Hemorrhagic Telangiectasia (HHT). "Investigational" means that the drug is being studied. The U.S. Food and Drug Administration (FDA) has not approved bevacizumab for Hereditary Hemorrhagic Telangiectasia (HHT), but it has been approved for other uses.