Clinical Trials in Vasculitis

Abstract

The systemic vasculitides include a heterogenous group of diseases characterised by inflammation of blood vessels. Evidence for treatment in this group of patients is limited due to rarity of the diseases, incomplete understanding of the pathogenesis and lack of appropriate biomarkers. In the last 20 years, international collaboration and networking led to clinical trials in a select subgroup of patients with systemic vasculitis. Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is the most studied subgroup. This article discusses the treatment options of AAV in light of evidence from clinical trials. Treatment of AAV, which includes an induction and a maintenance phase, is dependent on the severity of the disease. Oral or intravenous cyclophosphamide and high-dose glucocorticoids are considered to be standard of care for induction of remission in AAV patients with generalised disease. Latest evidence supports rituximab as an alternative to cyclophosphamide especially in relapsing patients and is increasingly being used in patients who cannot have cyclophosphamide. Plasma exchange and intravenous immunoglobulins (IVIGs) are used as adjunctive therapies for induction. Azathioprine or methotrexate (in non-renal patients) is considered to be the choice for remission maintenance, whilst mycophenolate mofetil is reserved for patients who cannot tolerate either of them. Rituximab is also being increasingly used for remission maintenance in relapsing patients. Even though an enormous progress has been made in the outlook of patients with AAV, a number of questions remain unanswered with regard to the optimal treatment strategy.

Keywords: ANCA; ANCA-associated vasculitis; Azathioprine; Clinical trials; Cyclophosphamide; Glucocorticoids; Mycophenolate mofetil; Plasma exchange; Rituximab; Treatment; Vasculitis.

Fig. 1

Mechanism of the onset of antineutrophil cytoplasm antibody (ANCA)-associated vasculitis. LAMP-2 lysome-associated membrane protein-2, MPO myeloperoxidase, NETs neutrophil extracellular traps, PR3 proteinase 3, ROS reactive oxygen species. Reprinted from [11], by permission of Nature Publishing Group and Macmillan Publishers Ltd.