A Randomized, Double-blind, Placebo-controlled Proof-of-Concept Trial to Evaluate the Efficacy and Safety of Non-racemic Amisulpride (SEP-4199) for the Treatment of Bipolar I Depression

•Atypical antipsychotics with antagonist activity at the 5-HT7 receptor have been found to have antidepressant efficacy.•Amisulpride is a racemic (50:50) mixture whose enantiomers exhibit stereoselective binding affinity: one has high 5-HT7 binding; the other has high D2 binding.•We engineered a non-racemic amisulpride (SEP-4199; 85:15 ratio) with higher 5-HT7 and lower D2 receptor binding activity optimized for the treatment of bipolar depression.•We report here results of a study that provides preliminary proof of concept for the efficacy of SEP-4199 in bipolar depression.