Approval of the first and only treatment in the United States specifically targeting postpartum depression offers hope for millions of women each year who suffer from the debilitating mental health disorder after giving birth.
The new drug brexanolone — marketed under the name Zulresso and approved on March 19 by the U.S. Food and Drug Administration — is expected to become available to the public in late June. Developed by Sage Therapeutics, based in Cambridge, Mass., the drug is costly and treatment is intensive: Its administered in the hospital as a 60-hour intravenous drip, and a treatment runs between $20,000 and $35,000. But researchers say that it could help many of the estimated 11.5 percent of U.S. new moms each year who experience postpartum depression, which can interfere with normal bonding between mothers and infants and lead to feeling hopeless, sad or overly anxious.
Heres a closer look at the drug, its benefits and some potential drawbacks.
How does the new drug work?
How exactly brexanolone works is not known. But because the drugs chemical structure is nearly identical to the natural hormone allopregnanolone, its thought that brexanolone operates in a similar way.
Allopregnanolone enhances the effects of a neurochemical called gamma-aminobutyric acid, or GABA, which stops nerve cells in the brain from firing. Ultimately this action helps quell a persons anxiety or stress.
During pregnancy, the concentration of allopregnanolone in a womans brain spikes. This leads some neurons to compensate by temporarily tuning out GABA so that the nerve cells dont become too inactive. Levels of the steroid typically return to normal quickly after a baby is born, and the neurons once again responding to GABA shortly thereafter. But for some women, this process can take longer, possibly resulting in postpartum depression.
Brexanolone temporarily elevates the brains allopregnanolone levels again, which results in a patients mood improving. But its still not clear exactly why the drug has this effect, says Samantha Meltzer-Brody, a reproductive psychiatrist at the University of North Carolina School of Medicine in Chapel Hill and the lead scientist of the drugs clinical trials. Nor is it clear whether allopregnanolones, and thus possible brexanolones, influence on GABA is affecting only postpartum depression. But the drug clearly “has this incredibly robust response,” she says, “unlike anything currently available.”
How effective was the drug in clinical trials?
Brexanolone went through three separate clinical trials in which patients were randomly given either the drug or a placebo: one Phase II trial, which tests the drugs effectiveness and proper dosage, and two Phase III trials, which tested the drugs effects on moderate or severe postpartum depression and were necessary to gain approval for the drugs commercial use in people.
Of 234 people who completed the trials, 94 received the suggested dosage of brexanolone. About 70 of those patients, or 75 percent, had what Meltzer-Brody described as a “robust response” to just one course of treatment. And of those patients with positive responses, 94 percent continued to feel well 30 days after the treatment. The results suggest that the drug may be most effective for those with severe postpartum depression; among those with moderate symptoms, the drug and the placebo had a fairly similar impact.
Can people take the drug again?
“Theres nothing prohibiting” a second course of brexanolone, but the effects of a repeat course have not been studied, Meltzer-Brody says. The drug was designed to be taken in tandem with the start of antidepressants, which take effect after about two to four weeks. So by the time the brexanolone wears off, the antidepressants would have kicked in.
Its not clear yet if some patients could need a second dose. The clinical trials compared a group of women taking both antidepressants and brexanolone with another group taking only brexanolone and found no difference in the two groups response 30 days after tests ended, Meltzer-Brody says. Because the study ended at 30 days, its unclear if the effects of brexanolone on its own last longer.