Efficacy and tolerability of the novel triple reuptake inhibitor amitifadine in the treatment of patients with major depressive disorder: A randomized, double-blind, placebo-controlled trial

Amitifadine (EB-1010, formerly DOV 21,947) is a serotonin-preferring triple reuptake inhibitor with a relative potency to inhibit serotonin, norepinephrine, and dopamine uptake of ∼1:2:8, respectively. This 6-week, multicenter, randomized, double-blind, parallel, placebo-controlled study evaluated the efficacy and tolerability of amitifadine in 63 patients with major depressive disorder. Eligible patients (17-item Hamilton Depression Rating Scale [HAMD-17] ≥ 22 at baseline) were randomized to amitifadine 25 mg twice daily (BID) for 2 weeks, then 50 mg BID for 4 weeks or placebo. Mean baseline scores in the modified intent-to-treat population (n = 56) were 31.4 for the Montgomery-Åsberg Depression Rating Scale (MADRS), 29.6 for the HAMD-17, and 25.4 for the Derogatis Interview for Sexual Functioning - Self Report (DISF-SR). At the end of the 6-week double-blind treatment, estimated least squares mean change from baseline (mixed-model repeated measures [MMRM]) in MADRS total score was statistically significantly superior for amitifadine compared to placebo (18.2 vs. 22.0; p = 0.028), with an overall statistical effect size of -0.601 (Cohen's d). Amitifadine also was statistically significantly superior to placebo (p = 0.03) for the Clinical Global Impression of Change - Improvement. An anhedonia factor score grouping of MADRS Items 1 (apparent sadness), 2 (reported sadness), 6 (concentration difficulties), 7 (lassitude), and 8 (inability to feel) demonstrated a statistically significant difference in favor of amitifadine compared to placebo (p = 0.049). No differences were observed between treatments in DISF-SR scores. Amitifadine was well-tolerated. Two patients on each treatment discontinued the study early due to adverse events; however, no serious adverse events were reported. This initial clinical trial in patients with severe major depression demonstrated significant antidepressant activity with amitifadine, including attenuating symptoms of anhedonia, and a tolerability profile that was comparable to placebo. The efficacy and tolerability of amitifadine for major depressive disorder are being investigated in additional clinical trials.