Dive Brief:

• An experimental drug developed by Sage Therapeutics Inc. significantly eased symptoms of postpartum depression (PPD) in two Phase 3 studies of women with either moderate or severe forms of the disorder, sending shares in the biotech soaring by more than 50% Wednesday. 
• Sage Therapeutics said it plans to file for approval of the drug, known as brexanolone, sometime next year. Results from the trials validated findings from a small study that had sparked excitement about the drug's prospects last summer. 
• Treatment with brexanolone led to mean reductions of between 14 to 20 points from baseline scores on a rating scale known as HAM-D. In both studies, a statistically significant effect was measured at 60 hours, and among patients with moderate PPD that benefit extended out through 30 days. 

Correction: There were no patient deaths in either of the studies of brexanolone in postpartum depression, although deaths were reported in a prior trial of the drug in super-refractory status epilepticus. A previous version of this article had incorrectly reported one patient death in each of the postpartum depression studies. BioPharma Dive regrets the error. 

Dive Insight:

Sage's success with brexanolone in PPD helps erase the sting of the drug's recent failure to show a benefit in patients with a severe type of epilepsy. 

That setback had trimmed Sage's share price by a fifth, but the surge Wednesday morning more than offset that earlier decline.

There are currently no treatments for PPD, a condition which affects as many as one of out 10 women. Women who suffer from the condition can experience intense depressive symptoms that can disrupt daily life. Unlike general stress and anxiety experienced around childbirth, PPD doesn't dissipate as readily, according to the American Psychological Association. 

"We believe the data represent an unprecedented opportunity in the development of treatments for PPD, and may serve as the catalyst for a paradigm shift in how the disease is approached and, if approved, may change how PPD is treated," said Sage CEO Jeff Jonas in a Nov. 9 statement. 

In the first study, called 202B, Sage tested two doses of brexanolone in 122 women with severe PPD, splitting trial participants evenly into two treatment arms and a placebo group. Treatment with 90 mcg/kg/hour of the drug led to a lowering in mean HAM-D scores of 17.7 points from baseline. Those on the 60 mcg/kg/hour dosing saw an even greater 19.9 reduction in HAM-D scores. Both results were a statistically significant improvement over the 14 point drop seen in the placebo arm. 

Benefit from brexanolone was first observed two days after treatment began and was sustained through 30 days of follow-up.

The HAM-D scale is used to measure the severity of depression, rating symptoms like feelings of guilt, suicidal ideation, insomnia, weight loss and other characteristics of depressive disorders. 

In study 202C, which tested the 90 mcg dosing of brexanolone in 104 women with moderate PPD, Sage also reported a statistically significant reduction in mean HAM-D scores. A significant treatment effect was observed through Day 7 but not at Day 30 — as improvement in the placebo group during the month meant the difference between groups was no longer statistically significant at Day 30. 

Adverse event rates were similar across both treatment and placebo groups. Sage reported one serious adverse event from each study, although neither required hospitalization and one was judged not to be related to treatment.

Editor's note: This post has been updated to clarify the treatment effect of brexanolone at Day 30 in study 202C.