The U.S. Food and Drug Administration approved Johnson & Johnson's ketamine-based nasal spray Spravato to treat adults with major depressive disorder (MDD), the company said on Tuesday.

The approval paves the way for use of Spravato in patients whose disease has stopped responding to at least two oral anti-depressants.

"Treatment-resistant depression can be very complicated, especially for patients who do not respond to oral antidepressants or cannot tolerate them," said J&J's Bill Martin, who leads the company's neuroscience therapy development.

MDD is one of the most common psychiatric disorders, with an estimated 21 million adults in the U.S. living with the disease, according to J&J's estimates.