Sunovion Pharmaceuticals said that a phase 2 study evaluating SEP-4199 as the treatment of major depressive episodes associated with bipolar I disorder (bipolar I depression) failed to meet its primary endpoint.
The primary endpoint of the SEP380-201 trial was the variation from baseline in Montgomery-Åsberg Depression Rating Scale (MADRS) total score after six weeks of treatment with SEP-4199.
According to Sunovion Pharmaceuticals, SEP-4199 is a non-racemic ratio of amisulpride enantiomers. The investigational oral medicine is said to have increased potency for serotonin 5-HT7 receptors relative to dopamine D2 receptors.
The drug candidate was assessed for its efficacy, safety, and tolerability in the SEP380-201 trial in 344 patients in the 18-65 years age group across 91 clinical trial sites in the US, Japan, and Europe.
The patients were grouped randomly in a 1:1:1 ratio to be subjected to SEP-4199 200mg/day or 400mg/day or placebo.
Sunovion Pharmaceuticals said that the drug candidate did show numerical improvement in the MADRS total score, in comparison to placebo after six weeks of treatment. However, the company said that a relatively large improvement in MADRS total score was noted in the placebo arm, which could have contributed to the trend level findings of the primary analysis.
The mean MADRS of the patients at baseline in Europe and the US was 34.0 and in Japan was 32.8.
Sunovion Pharmaceuticals said that the results from the SEP380-201 trial indicate that patients having bipolar I depression treated with SEP-4199 in the two dose groups had clinically meaningful improvements over the study period.
The company said that its drug candidate was well-tolerated by the participants of the mid-stage study, with relatively low rates of adverse events.
Sunovion Pharmaceuticals chief scientific officer Kenneth Koblan said: “SEP-4199 is a prime example of how Sunovion’s deep expertise and understanding of unmet medical needs leads our scientists to create novel solutions for people with serious neuropsychiatric conditions like bipolar depression.
“The topline efficacy results of this study, coupled with the tolerability profile, provides us with confidence in the potential of SEP-4199 as a novel treatment option for people living with bipolar depression. The results of this study will guide us as we consider our plans to start Phase 3 studies.”