Vasculitis occur when the body's immune system, rather than protecting the body, attacks blood vessels, causing injury to the vessel and the part of the body it supplies with blood. Vasculitis is rare, and there are a number of different types, which can affect both adults and children. We treat vasculitis with steroids and drugs aiming to damp down the activity of the immune system, but they often cause side effects. Some patients do not improve with this treatment, or cannot tolerate it and their vasculitis worsens; this is known as refractory vasculitis. Patients with refractory vasculitis are at high risk of health complications from the disease and its therapy and are in need of newer more effective treatments with fewer side effects.||Biologics are drugs which are designed to precisely target parts of the immune system and may have fewer side effects. Biologics have been used for several years to treat vasculitis, particularly anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis or AAV. However, for many of the rarer types of vasculitis, and especially those vasculitis disease types that are not ANCA-associated, there is little information to support use of biologic therapies as effective treatments.||The purpose of this trial is to find out whether biologics are effective and represent value for money for participants with refractory vasculitis. The trial will include patients with Non-ANCA-associated vasculitis (NAAV)