Figure 6

Schematic of the use and interpretation of biochemical markers. (a) Rheumatoid arthritis (RA) may consist of many different subphenotypes, with similarities and dissimilarities, as illustrated by the overlap and non-overlap of the different colored circles. If this population is left unsegmented, and the population treated as a whole, a relatively low number of responders may be identified. (b) A biomarker combination may identify a subset of patients representing a given phenotype that will respond to treatment, or respond preferentially to a particular therapeutic intervention, increasing overall response rates. (c,d) Different questions can be addressed by the use of biochemical markers. Each may require a different biomarker subset. (c) Prognostic markers are those able to predict which patients will progress most rapidly. This is important for identifying those patients most in need of treatment. (d) A marker of efficacy will allow interpretation of potential efficacy far earlier than traditional radiological-based changes.