London — It will probably be at least 10 years before any new generation of antidepressants comes to market, despite evidence that depression and anxiety rates are rising worldwide, say specialists.
The depression drug pipeline has run dry due to "failure of science" and big pharma groups pulling investment out of research and development in the neuroscience field because of uncertainty on profit potential, they say.
"I’d be very surprised if we were to see any new drugs for depression in the next decade. The pharmaceutical industry is simply not investing in the research because it can’t make money from these drugs," Guy Goodwin, a professor of psychiatry at the University of Oxford, told reporters in London.
Andrea Cipriani, a consultant psychiatrist at Oxford, said risk aversion was understandable, given uncertain returns and the cost of developing and bringing a new drug to market at about $1bn.
"It’s a lot of money to spend, and there’s a high rate of failure," Cipriani said.
Treatment for depression usually involves medication, psychotherapy or a combination. But up to half the people treated fail to get better with first-line antidepressants, and about a third are resistant to medication.
Depression rates rising
The experts said that since the current generation of SSRI (selective serotonin reuptake inhibitors) antidepressants — including Eli Lilly’s blockbuster Prozac — are widely available as cheap generics, there is reluctance among health services to fund expensive new drugs that may not be much better.
The specialists said this was partly because existing medications were, though by no means perfect, quite effective in more than half of patients, and partly because in this condition placebos can have a massive impact.
That made it difficult, they said, to show that a new drug was working above and beyond a positive placebo response and an already effective generation of available drugs.
Depression is already one of the commonest mental illness, affecting more than 350-million people worldwide and ranking as the leading cause of disability globally, according to the World Health Organization.
And rates are rising. Glyn Lewis, a professor of psychiatric epidemiology at University College London, cited data for England showing a doubling in prescriptions for antidepressants in a decade, to 61-million in 2015 from 31-million in 2005.
In the US too, more people than ever take antidepressants. A study in the Journal of the American Medical Association in 2015 found incidence almost doubled from 1999 to 2012, rising to 13% from 6.9%. Yet several big drug groups, including GlaxoSmithKline and AstraZeneca, scaled back on neuroscience R&D in recent years, citing unfavourable risk-reward prospects.
Goodwin said the absence of a drug development pipeline was also due to lagging scientific research into what is really happening in the brains of those who do and do not respond to antidepressants.
"It’s partly a failure of science, to be frank," said Goodwin. "Scientists have to … get more of an understanding about how these things actually work before we can then propose ways to improve them."
Reuters
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