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SEP-363856 Extension Trial Shows Continued Improvement in Schizophrenia Symptoms

September 11, 2020

A 6-month extension of a short-term trial published earlier this year in The New England Journal of Medicine showed continued improvement with SEP-363856 in patients with schizophrenia, without adverse effects reported with typical and atypical antipsychotic drugs. Researchers presented the findings in a poster at Psych Congress 2020.

“SEP-363856 is a novel non-D2 receptor antagonist, and preclinical data suggest that agonism at trace amine associated receptor 1 (TAAR1) and the serotonin 5-H1A receptor contributes to its efficacy,” researchers wrote. “In a previous double-blind, placebo-controlled study, SEP-363856 demonstrated significant efficacy in the treatment of an acute exacerbation of schizophrenia.”

The 6-month open-label extension phase that followed the 4-week double-blind trial investigated the safety and effectiveness of longer-term treatment with SEP-363856.

Among 156 patients who started in the extension phase, 66.9% completed the 6 months of treatment. Reasons for discontinuation included adverse events (11.5%), withdrawal of consent (10.2%), and lack of efficacy (5.1%), according to the poster abstract. Adverse events affecting 5% or more of participants included headache (11.5%), insomnia (8.3%), and anxiety (5.1%).

Researchers observed no clinically meaningful changes on movement scales, metabolic laboratory parameters, or prolactin levels in participants. From double-blind baseline through the end of the 6-month extension phase, the average change in weight was -0.3 kilograms, researchers reported.

Throughout the open-label extension phase, participants showed continued improvement on the Positive and Negative Syndrome Scale (PANSS), with a mean total score decrease of 19.8 points.

“Up to 26 weeks of treatment with SEP-363856 had minimal effects on weight, metabolic parameters, prolactin, or extrapyramidal symptoms,” researchers concluded. “SEP-363856 was associated with continued improvement from open-label baseline in the PANSS total score.” 

Sunovion Pharmaceuticals Inc. sponsored the study.

—Jolynn Tumolo


Koblan KS, Hopkins S, Kent J, Cheng H, Goldman R, Loebel A. Safety and effectiveness of SEP-363856 in schizophrenia: results of a 6-month, open-label extension study. Poster presented at Psych Congress 2020 Virtual Experience; September 10-13, 2020.

Koblan KS, Kent J, Hopkins SC, et al. A non–D2-receptor-binding drug for the treatment of schizophrenia.The New England Journal of Medicine. 2020;82:1497-1506.

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