Sunovion Pharmaceuticals has announced positive findings from the SEP361-202 open-label extension study of SEP-363856 in patients with schizophrenia.

Discovered in alliance with PsychoGenics, SEP-363856 is an agonist of trace amine-associated receptor 1 (TAAR1) and serotonin 1A (5-HT1A) receptors. The drug is being developed to treat schizophrenia and psychosis associated with Parkinson’s disease.

In May this year, the Food and Drug Administration (FDA) awarded breakthrough therapy designation for SEP-363856 to treat schizophrenia.

The open-label extension study assessed the long-term safety and effectiveness of the drug over 26 weeks in 157 patients who completed the four-week, double-blind treatment phase of SEP361-201 study.

About 66% of participants completed the open-label study and 11.5% discontinued because of an adverse event.

Results showed that SEP-363856 was generally safe and well-tolerated, without any clinically meaningful changes in metabolic parameters or prolactin levels.

In addition, the drug led to clinically meaningful improvements on the efficacy measures of Positive and Negative Syndrome Scale (PANSS) total score, the Clinical Global Impression Scale – Severity (CGI-S) score and the Brief Negative Symptom Scale (BNSS) total score.

Disease exacerbation, headache, insomnia and anxiety occurred in at least 5% of patients.

Sunovion Pharmaceuticals Psychiatry global clinical research head Justine Kent said: “The results of our six-month, open-label extension study in patients living with schizophrenia demonstrate that SEP-363856 has an excellent long-term safety profile, with continued, clinically meaningful improvement seen in the PANSS total score.

“We look forward to swiftly progressing our global Phase III clinical studies of SEP-363856 in both adult and adolescent patients with schizophrenia.”

Schizophrenia is a chronic and severely disabling brain disorder that causes hallucinations, delusions, disorganised thinking, social withdrawal and cognitive impairment, among other symptoms.