High Baseline Levels Of C-Reactive Protein Predict Better Response To Lurasidone in Bipolar Depression
In a study presented at the 2017 meeting of the International Society for Affective Disorders, Charlies L. Raison and colleagues examined whether baseline levels of the inflammatory marker C-reactive protein (CRP) affected antidepressant response to the antipsychotic drug lurasidone in bipolar depression. The participants were divided into three double-blind groups: one received 20–60mg/day of lurasidone, another received 80–120 mg/day of lurasidone, and the third received placebo over a period of six weeks. The effect was dramatic—in people with CRP levels above 5 mg/L at the beginning of the study, lurasidone (at either dosage level) had a very large effect size (d=0.85), while in people with baseline CRP levels below 5 mg/L the effect size was smaller (d=0.35).
Interestingly, 118 of the participants (24.5%) had CRP levels above 5mg/L at baseline, indicating a substantial amount of inflammation was present in a quarter of the bipolar depressed patients. Higher levels of CRP at baseline were correlated with better improvement on specific items on the Montgomery–Åsberg Depression Rating Scale (MADRS): “lassitude” (or lack of energy), “apparent sadness,” “reported sadness,” and “pessimistic thoughts.” Raison and colleagues concluded: “These findings suggest that the efficacy of lurasidone in patients with bipolar depression may in part be linked to the inflammatory status of patients prior to treatment. If confirmed in prospective investigations, [the results of a wide-range CRP assay] may prove useful as a predictive biomarker that could help optimize the use of lurasidone for the treatment of patients with bipolar depression.”
Editor’s Note: In many instances, high levels of CRP predict a poor response to treatment (such as to selective serotonin reuptake inhibitor antidepressants (SSRIs) in unipolar depression), so these findings are of considerable interest. They also suggest the untested possibility that lurasidone has anti-inflammatory effects, as those with high levels of inflammation at baseline often respond better to drugs with direct anti-inflammatory effects such as celecoxib (Celebrex) or the antioxidant N-acetylcysteine (NAC).
