Efficacy of Duloxetine and Selective Serotonin Reuptake Inhibitors

Abstract

It has been proposed that serotonin and norepinephrine reuptake inhibitors (SNRIs) may result in higher remission rates of major depressive disorder than therapy with selective serotonin reuptake inhibitors (SSRIs). To test this hypothesis, a meta-analysis of individual patient data (N = 1833) was performed for the complete set of 6 phase II/III studies that compared duloxetine (fixed doses; range, 40-120 mg/d) with 2 SSRIs (paroxetine or fluoxetine; 20 mg/d) in outpatients with major depressive disorder. Remission was defined as an end point score of less than or equal to 7 on the 17-item Hamilton Rating Scale for Depression (HAMD17); alternate outcome criteria were also examined, as were remission rates among the 1044 patients with moderate-to-severe depression (HAMD17 total score greater than or equal to 19). The HAMD17 remission rates were 40.3% (351/871), 38.3% (162/423), and 28.4% (144/507) for duloxetine, the 2 SSRIs, and placebo, respectively. Both active treatments were superior to placebo; the difference between duloxetine and SSRIs was not statistically significant. Similar findings were observed for alternate outcomes. Duloxetine therapy was significantly more effective than therapy with the 2 SSRIs for patients with more severe depression, with remission rates of 35.9% (183/510) versus 28.6% (70/245) (P = 0.046). A secondary analysis of dose-response relationships indicated that this advantage was not attributable to the studies using higher doses of duloxetine. Thus, whereas duloxetine and the 2 SSRIs were comparably efficacious overall, therapy with the serotonin and norepinephrine reuptake inhibitor resulted in a significantly higher remission rate among patients with moderate-to-severe depression.