For some people, depression is very difficult to treat, but a new biomarker and a new treatment approach may bring hope. Researchers at Emory University and the University of Arizona have followed up the link between inflammation and depression that has been discussed since the 1980s and found that a simple and easily available blood test that measures the levels of C-reactive protein (CRP) marks the patients whose depression is most likely to respond to Janssen's Remicade (infliximab). This is a monoclonal antibody drug usually used to treat inflammatory disease such as inflammatory bowel disease or rheumatoid arthritis.
Generally, people with depression and high levels of inflammation do not respond well to standard antidepressants or psychotherapy. A group of outpatients at Emory University who had depression that was moderately resistant to treatment was given infliximab or placebo as three infusions over 12 weeks. Infliximab blocks tumor necrosis factor (TNF), which is involved in inflammation. Not all the patients treated with infliximab found that their depression lifted, but those with higher levels of CRP (and therefore higher levels of inflammation) were more likely to respond to infliximab than to placebo. In contrast, some of the patients with low CRP levels did less well on infliximab than on placebo, suggesting that CRP levels could select both those patients who could benefit from infliximab, and those who should avoid it. The study was published online in Archives of General Psychiatry.
"The prediction of an antidepressant response using a simple blood test is one of the holy grails in psychiatry," says Andrew H. Miller of they Emory University School of Medicine. "This is especially important because the blood test not only measured what we think is at the root cause of depression in these patients, but also is the target of the drug."
As the first time that a biological therapy has been successful in depression, this could lead to new approaches and new biomarkers to tailor and personalize treatment for this common disease that has such a huge impact on people, their families, and society as a whole.