Biomarkers in Systemic Autoimmune Diseases

In an ideal scenario, a biomarker would both reveal the driver of disease and identify an effective treatment. In oncology, genetic biomarkers that molecularly or clinically classify patient populations for targeted therapies, e.g., BRAF [1] and HER-2 [2], have been clinically validated and are reaching this ideal. However, biomarkers are necessarily based on the pathobiology of the underlying disease and therefore for most diseases must be used to advance drug development and patient care in a more sequential fashion. Systemic autoimmune diseases, such as rheumatoid arthritis [3] (RA), are complex disorders that may be influenced by a variety of factors including immunological mechanisms, genetics and the environment. Biomarkers in use and under evaluation offer an important opportunity to advance clinical trial design and to change clinical practice. The biomarkers ultimately selected will reflect the complexity of these diseases.