Researchers at the Yale School of Medicine and Janssen Research and Development have developed a fast-acting nasal spray formulation of ketamine to treat symptoms of depression, with trial results published in The American Journal of Psychiatry (AJP).

The Phase II study compared the standard treatment combined with an intranasal formulation of esketamine, with the standard treatment combined with placebo as treatments for symptoms of depression, including suicidal thoughts.

A total of 68 participants were enrolled, all of whom were categorised as being at imminent suicide risk. Subjects were randomly assigned to either the esketamine or placebo arms, receiving their combination treatment—in addition to antidepressants—twice a week for four weeks.

The treatments’ effects were examined at three points: four hours, 24 hours and 25 days following dosing.

Results showed the esketamine group experienced a significant improvement in depression scores and a decline in suicidal ideation at both four hours and 24 hours following treatment. However, at 25 days the effects of the esketamine group were not greater than placebo. Suicide risk was measured according to both patient and clinician opinions.

As such, findings showed that a nasal spray formulation of esketamine could provide a potential fast-acting treatment for depressive symptoms. As the majority of existing antidepressants take between four and six weeks to take full effect, the discovery of a rapid treatment would provide much needed relief for those at imminent risk of suicide.

The research team is looking to take the nasal spray through a Phase III study, at which point they will also examine the potential abuse of ketamine, such as patients’ craving.

The potentially harmful effects of the drug are a point of concern in the treatment’s progression.

An AJP editor’s note voices the necessity for research into the development of effective controls on the use and distribution of ketamine, saying: “Protection of the public’s health is part of our responsibility as well, and as physicians, we are responsible for preventing new drug epidemics.”

The study team have in turn stressed that such control should not hinder ketamine use for medical or beneficial purposes, saying the drug should be “available to those with need, while the population that is at-risk for abuse is protected from an epidemic of misuse”.