To directly compare placebo responses in objective biomarkers and subjective patient-reported outcomes, rheumatoid arthritis RCTs are ideal, as they usually collect data for assessment of patient-reported pain levels as well as changes in objective biomarkers (C-reactive protein [CRP] levels or erythrocyte sedimentation rate [ESR]),8 enabling insights into the magnitude of placebo effects within the placebo response in a homogeneous patient population. This evidence concerns the gene CRP and rheumatoid arthritis.