Treat-to-target in vasculitis: is this a sensible approach?
It is possible to achieve substantial initial control of systemic vasculitis in the majority of patients. However, the 'target' has shifted considerably over the last 20-30 years from keeping patients alive to maintaining good quality disease control, avoiding the development of comorbidities - either as a result of disease or treatment, and also preventing relapses. This expansion of potential targets that can be achieved in systemic vasculitis has arisen because we have more effective therapies, but more importantly we have developed a framework within which targets can be created reproducibly. In other words we have much clearer definitions of what constitutes clinical disease activity, relapse, remission and morbidity. These targets are based on simple clinical evaluation, limited laboratory assessments of patients that can be undertaken by any secondary care facility. As a result of this they remain at a clinical level and may not address the most important targets, which are curing disease and that would be the aspiration to move towards. The first step towards that is to move from clinically-based targets towards mechanistic targets based primarily around the pathophysiological drivers of disease. That in turn may lead to identification of specific targets that can turn off disease. The systemic vasculitides are heterogeneous and although for ANCA-associated vasculitis in the short term treatments are similar, the development of clear understanding of mechanisms and new targets may bring with it the promise of much more focused therapies that will address only individual targets and therefore personalize therapy for each individual condition and patient.