However, it is noteworthy that an ongoing phase 2 clinical trial is testing the efficacy of augmentation with sirukumab, a monoclonal antibody against IL-6, in depressed patients with CRP levels ≥ 3 mg/L (NCT02473289) and in TRD patients who have failed to respond to at least one but no more than three adequate antidepressant treatments during their current episode of depression. Here, CRP is linked to depressive disorder.