The Sunday Times Published: 18 December 2011. Lois Rogers.
Scientists are close to producing a drug that helps the obese lose weight by removing the pleasure of eating without bad side effects
The pharmaceutical firm Pfizer is conducting clinical trials on a compound which, it hopes, will stop the obese from feeling hungry by mimicking the effect of a hormone that switches off appetite and the pleasure of eating.
The time between successful clinical trials and a product being available on prescription or sold in shops can be as little as three years, although it can take considerably longer.
The compound, which has the codename OAP-189, is a synthetic version of a hormone called oxyntomodulin, whose effect was discovered by researchers at Imperial College London.
The drug has the potential to bring Pfizer the same kind of financial success it enjoyed with Viagra, the libido enhancer, which it launched in 1998. Viagra is no longer protected by patents and so is more cheaply available, reducing its profitability to the drug company.
While a drug that suppresses appetite is on the market in the form of Xenical or Alli, its use is limited because of unpleasant side effects that can include diarrhoea, wind and even incontinence.
Pfizer is engaged in a race with other pharmaceutical groups to develop a drug that stops people feeling hungry. The discovery of the function of oxyntomodulin and the licensing of that work to Pfizer will, they hope, allow it to win the race.
Scientists at Imperial College found that patients who had undergone stomach bypass operations, generally the only group of previously obese adults to achieve permanent weight reduction, produced higher levels of appetite suppressing hormones, including oxyntomodulin. Those hormones are able to fool the brain by telling it the body does not want or need food.
Stephen Bloom, professor of investigative medicine at Imperial College and head of the team that made the oxcyntomodulin discovery, said: “I think we could mimic the dramatic weight loss achieved with stomach bypass surgery by giving people gut-hormone derived therapies. If you take away hunger, food is not attractive. If you take away pleasure, people stop eating.”
With well over half of adults overweight in some western countries, such as Britain, and almost one in four obese, the savings to health services and profits to drug firms are enormous.
More than 130 drugs have already been tested as anti-obesity agents. Most have been ineffective when used long term or have had unacceptable side effects.
As well as Xenical, two more drugs, Rimonabant and Reductil, have gone on sale only to be withdrawn amid safety fears. Doctors and other experts in the field of obesity broadly welcomed the development of a weight loss drug.
Tam Fry, a spokesman for the National Obesity Forum, said: “Using these hormones to try to treat the overweight has to be the way forward because they are having an effect on the brain. We think this approach offers the prospect of the breakthrough we need. We just have to hope it doesn´t take too long to get one of them on the market.”
Matthew Capehorn, a doctor who runs the Rotherham Obesity Institute in South Yorkshire, Britain´s largest National Health Service specialist weight loss service, said: “Anything that produces even small levels of weight loss makes people feel better and encourages them to try to change their lifestyle.”
As well as their work on oxyntomodulin, the team at Imperial College has found that artificially boosting three other appetite-suppressing hormones that are produced in the digestive system may also be effective in weight loss.
Unlike the vast number of other compounds that have been seized upon as possible treatments, the hormones – GLP-1, PYY and cholecystokinin – are produced naturally, lessening the likelihood of serious side effects.
GLP-1 is already licensed for the treatment of diabetes and is also undergoing trials by the drug company Novo Nordisk to see if it can be used as a weight loss agent. Studies of the compounds are also underway in China.
Asked about its work on OAP-189, a spokesman for Pfizer said: “We are not able to confirm the extent of our involvement or work in this area.”