The U.S. Food and Drug Administration (FDA) in January approved Viibryd tablets (vilazodone hydrochloride) to treat major depressive disorder in adults.

The medication, manufactured by Clinical Data Inc., is a combined serotonin reuptake inhibitor and 5HT1a agonist. The drug will be available in 10 mg, 20 mg, and 40 mg tablets.

In a statement released after the drug was granted FDA approval, the company said that the efficacy of Viibryd as a treatment for major depression was established in two eight-week, multicenter, randomized, double-blind, placebo-controlled studies in adults who met DSM-IV criteria for the disorder. In these studies, patients were titrated over two weeks to a dose of 40 mg of Viibryd once daily.

Viibryd proved to be superior to placebo in improving depressive symptoms as measured by the mean change from baseline to week 8 in the Montgomery-Asberg Depression Rating Scale (MADRS) total score.

The most commonly observed adverse reactions in Viibryd-treated patients were diarrhea, nausea, vomiting, and insomnia; no single adverse event led to discontinuation of treatment in more than 1 percent of patients. Overall, 7.1 percent of the patients who received Viibryd discontinued treatment due to an adverse reaction, compared with 3.2 percent of placebo-treated patients.

"It's not going to change the nature of the treatment of depression, but it will be an additional player in the market," said psychopharmacology expert Charles Nemeroff, M.D. "The theoretical basis for the development of the drug was that by combining the action of an SSRI and a 5HT1a agonist, you would have a really good antidepressant."

He added, however, that what remains to be answered "is where this new drug will fall in the algorithm of treating depression—which patients will benefit from it and how should it be used. And so far there are no data on how patients who failed to benefit from other treatments will do with this drug."

Nemeroff, who has no association with Clinical Data Inc., is professor and chair of the Department of Psychiatry and Behavioral Sciences at the University of Miami's Leonard M. Miller School of Medicine.

He said the drug was originally developed by a German company and later acquired by Clinical Data Inc.

"Is it an incremental advance in the treatment of depression? Not really. But it will be prescribed, and the FDA did the right thing to approve the drug on the basis of the clinical data," Nemeroff said.

In a statement announcing the drug's approval, Thomas Laughren, M.D., director of the Division of Psychiatry Products in the FDA's Center for Drug Evaluation and Research, stressed, "Medications affect everyone differently, so it is important to have a variety of treatment options available to patients who suffer from depression."