A ketamine-like drug that could be licensed in the UK as early as November could transform the treatment of severe depression, said one of the country's leading psychiatrists.
The drug, called esketamine, administered by means of a nasal spray, would be one of the first "fast-acting" drugs for the treatment of depression and the first drug in decades to target a new brain pathway .
Unlike conventional antidepressants, which take weeks or months to take effect, ketamine has shown persistent effects in some patients within hours.
Professor Allan Young, director of the Center for Affective Disorders at King's College London, said that for the vast majority of patients who do not respond to conventional medications, ketamine treatments could offer new hope.
"We have not been really new in 50 or 60 years. What is particularly interesting is the arrival of a new type of treatment and ketamine, "he said. "Pharmacology is different. It's not just the same old steam engine, it seems to work differently and faster. "
However, other experts questioned the overall effectiveness of the drug and said that taking ketamine for long periods of time could pose serious safety risks.
The European Medicines Agency and the UK Health Regulatory Authority will make a decision in November on licensing this drug, which Johnson & Johnson sells. in the United States under the brand Spravato. If approved, esketamine would be available in private clinics. Nice must make a decision on the approval of the drug for use of the NHS in March next year.
Young believes the drug could be an important alternative for the 2.7 million Britons who suffer from chronic depression and have not responded to conventional medicines.
The most commonly used drugs, called selective serotonin reuptake inhibitors (SSRIs), work by preventing the brain from cleaning serotonin, a chemical. They usually take six to eight weeks to have an impact on the symptoms.
Ketamine appears to act on a different brain chemical, glutamate, and studies in animals have helped to restore links between brain cells, which are thought to shrink for long periods of time. depression.
Carlos Zarate, Head of Experimental Therapies and Pathophysiology at the US National Institute of Mental Health, who led the first clinical trial of ketamine for depression in 2006, said: "Ketamine is now the prototype of the next generation of antidepressants that effects robust in a few hours and last a long time. "
In the form of a nasal spray, it is administered at doses well below those of the street drug, ketamine.
However, side effects experienced by patients, including hallucinations, vertigo and feelings of anxiety, mean that they must be monitored in a clinic for two hours after each weekly dose of the drug. The huge amounts of clinical supervision involved could be an obstacle to its wide dissemination.
Earlier this year, the US Food and Drug Administration (FDA) cleared the drug against treatment-resistant depression. The decision was controversial because the FDA had relaxed its usual rules of drug approval based on clinical need. The test results have been mixed and mostly short-term, and some say the drug is not worth the $ 32,400 (£ 25,808) per patient per year billed for the drug in the United States.
Questions also arise about the long-term safety of taking ketamine-like substances, especially if patients can develop tolerance to this substance and if, for some, this can serve as a gateway to illegal drug use, as in the opioid crisis.
Rupert McShane, consultant psychiatrist and associate professor at the University of Oxford, who has treated hundreds of patients with chronic depression with intravenous ketamine, is asking for the establishment of a registry to control the effectiveness and possible side effects if the drug is made more widely available. .
Some also fear that the hype around the potential of ketamine to treat depression may lead some people to seek the drug illegally and treat themselves.
"The potential for harm with long-term use is simply unknown," McShane said. "It's a drug, not a miracle," he added. "Ketamine, according to my experience, and esketamine, according to the data, are potent and potentially transformational antidepressants."
Wes Boyd, associate professor of psychiatry at Harvard, said it was worrisome that some clinical trials had shown no significant benefit over placebo and that another trial had suggested that only some patients benefited from it.
"The cost of esketamine is extremely high and has a very important and frightening side effect profile," he said. "It's so potentially dangerous that clinicians are forced to stay with patients for two hours after the drug is administered. I do not know of any other antidepressant that requires one hundredth of this type of observation after the administration. The result is that the drug is an oversized scam. "