(Adds details on postpartum depression drug, background, share price)
Dec 7 (Reuters) - Sage Therapeutics Inc said on Thursday its drug to treat patients with moderate to severe depression met the main goal of reducing symptoms in a mid-stage study, sending its shares soaring 52.3 percent in premarket trading.
The 89-patient study testing the drug, SAGE-217, showed statistically significant reduction of depression symptoms, when compared to a placebo.
Depression is a common mental illness characterized by persistent sadness and a loss of interest and lack of ability to do everyday activities and work.
The drug was granted fast-track designation by the U.S. Food and Drug Administration in May, the company said.
Patients were assessed on a scale that rated the severity of their depression symptoms such as mood, feelings of guilt, suicidal thoughts and insomnia.
Sage's postpartum depression drug succeeded in two late-stage studies in November, paving the way for it to bring to market the first FDA-approved treatment for the disorder.
The company's shares jumped 52.3 percent to $140 in premarket trading. (Reporting by Akankshita Mukhopadhyay in Bengaluru; Editing by Shounak Dasgupta)