https://goo.gl/3ytAVQ
An intranasal formulation of ketamine quickly diminished depressive symptoms in patients with treatment-resistant depression, researchers found.
In a phase II study, those taking one of three doses of esketamine (28 mg, 56 mg, or 84 mg) had significantly greater improvement in Montgomery-Asberg Depression Rating Scale (MADRS) scores compared with placebo over 8 days, Ella Daly, MD, of Janssen, and colleagues reported online in JAMA Psychiatry.
Those improvements persisted despite reduced dosing frequency in a subsequent open-label phase that lasted about two months, the researchers said.
Several studies have shown ketamine to have antidepressant effects, and there's been growing interest in this and other NMDA receptor antagonists, in the class of glutamate receptor modulators, to treat depression and suicidality -- especially since about a third of patients don't respond to current treatment options.
A limitation of ketamine, however, is that it needs to be delivered intravenously. So researchers at Janssen developed an intranasal formulation called esketamine, which is the S-enantiomer of ketamine. This version has a higher affinity for the NMDA receptor than the ketamine R-enantiomer, the researchers explained, adding that nasal delivery will also boost bioavailability of the compound. (The chirally pure molecule can also be patented separately from the racemic form.)