The FDA has just approved esketamine for adults with treatment-resistant depression, in a landmark announcement marking the first new major depression treatment introduced for clinical use in over 30 years. The nasal spray is a close chemical relative to the controversial anesthetic ketamine.

Called Spravato, this final FDA approval was predicted last month after an advisory panel voted overwhelmingly in favor of allowing the new treatment for clinical use.

Ketamine has had a checkered history since originally being developed in the 1960s as a new anesthetic. It then quickly slipped into counter-cultural use due its curious hallucinogenic qualities. More recently, it has been rediscovered for its rapid anti-depressant effects with ketamine clinics popping up across the United States delivering off-label doses to customers for thousands of dollars.

Esketamine is an enantiomer of ketamine, molecularly similar but not exactly the same. It is thought to be more potent than ketamine with slightly less unpleasant dissociative effects. The more skeptical observer would argue the only reason it has been developed into a clinical medicine over ketamine is that ketamine is a decades-old drug past its patent, so there is no money to be made in large-scale drug development for that particular compound.

The approval of Spravato is not without controversy. Only one of three short-term clinical trials investigating the drug reported results more effective than a placebo. It is unusual that a drug has reached approval with such limited proof of efficacy, however, in a statement from the FDA accompanying the approval Tiffany Farchione, acting director of the Division of Psychiatry Products in the FDA's Center for Drug Evaluation and Research, notes the pressing need for new anti-depressant agents.

"There has been a long-standing need for additional effective treatments for treatment-resistant depression, a serious and life-threatening condition," says Farchione. "Controlled clinical trials that studied the safety and efficacy of this drug, along with careful review through the FDA's drug approval process including a robust discussion with our external advisory committees, were important to our decision to approve this treatment."

Despite its easy nasal spray delivery, Spravato has been approved through a restricted delivery system. This means the spray will only be delivered in a certified doctor's office or clinic, followed by two hours of monitoring after each treatment. The spray will remain with health care providers and is not a take-home medicine. Spravato has also been approved only to be used in conjunction with an oral antidepressant, and only for patients who have not responded to at least two other antidepressant treatments.

It is unclear exactly how much Spravato will cost at this stage, but investigations from Stat News suggest an individual session could run close to a thousand US dollars, and patients could be administered at least eight sessions in a single month of general treatment.

Further studies from the company behind Spravato will explore broader uses for the newly approved drug over the coming years, however as it stands this landmark approval is the first new antidepressant agent with a novel mechanism of action to be approved for clinical use by the FDA since the 1980s.

Source: FDA/Janssen Pharmaceutical Companies of Johnson & Johnson