Is this the answer to cutting obesity? New method blocking key hormone under trial
Science Editor Deborah Cohen on the new treatment that could one day help tackle our growing obesity crisis
Tom Keech and his mum, Catherine, have been struggling with their weight for years.
It’s come to dominate so much of both of their lives.
“It makes you feel on show,” Tom says. “I've had bad experiences flying where people would physically have made it very clear that they don't want to sit next to me.”
For Tom it’s something he’s been conscious of since childhood, having to get special school trousers. “I've always been a bigger kid, it was always a struggle finding clothes,” he says.
Tom finds it difficult to control his weight with diet and exercise. “I've just tried so much, but I've never got results I was happy with,” he says.
Catherine has gone to more extreme lengths and says she has tried “every single thing on the market”.
“I went to my first slimming club at 20 and lost five or six stones. And from then on it's just gone on and off and on and off,” she says. She’s even tried water injections and prescription drugs that were like speed.
Both he and his mum have enrolled in a clinical trial run by Imperial College London, Imperial College Healthcare NHS Trust and University College London Hospital NHS Trust. And it is funded by the public body, the National Institute for Health and Care Research, to test a new procedure for treating obesity that’s much less invasive than current weight loss surgery.
Obesity is a leading cause of preventable death worldwide and associated with a range of health problems including type 2 diabetes, cardiovascular disease and cancer.
Diets and exercise don’t work for everyone and the amount of weight people may lose long term might be limited. And obesity drugs have a really checkered history. Several of them have been taken off the market because of side effects.
Surgery is the most effective treatment, but it’s not suitable for all patients, is not wanted by all, and is expensive. Plus, there are lengthy NHS waits for treatment - 6,000 bariatric procedures are done a year yet over two million people are eligible.
This is something experts call a treatment gap.
“There's a real need to find other techniques which are going to be able to give people long-term effective weight loss without needing surgery,” Mr Ahmed Ahmed, a bariatric surgeon at Imperial College NHS Trust, who is leading the trial.
And this is where the procedure comes in.
For decades doctors have been treating stomach bleeds from an ulcer by something called left gastric artery embolization. This procedure reduces the blood supply to the top of the stomach to stop the bleed.
What they noticed was that people who had this done started losing weight afterwards. Researchers started to do very small studies to see if people who didn’t have an ulcer would lose weight with this procedure.
“When we feel hungry, that's actually driven by a number of hormones. One of these hormones is called ghrelin,” Mr Ahmed says.
When your blood levels of ghrelin go up, you feel hunger, he says. Ghrelin is produced at the top of the stomach. Doctors think that if the blood supply is blocked to that area, the ghrelin levels will drop and this, in turn, will reduce the appetite.
"We also think that this treatment may have an impact on stomach emptying. So we know that if you have a reduced rate of stomach emptying, you'll feel full for longer,” he adds.
Dr Robert Thomas is an interventional radiologist also at Imperial College. He’s one of the people who does the procedure and he calls it “pinhole surgery”.
“Our plan is to get into the pulse in the wrist, put a little tube in, and that's our access point,” he says.
He says they navigate through the arteries - “the natural motorways of the body” - and into a tiny artery at the top of the stomach just 3mm wide.
“We can then use a blocking agent - little beads in this case - that then flow with blood and they stagnate the blood. They don't block the blood supply completely,” he adds. And it’s hoped that this will stop ghrelin release from that part of the stomach.
But before the treatment is rolled out any further, doctors set up what’s called a randomised controlled trial to find out just how well it works.
“When it comes to new treatments, it is really important for us to evaluate them in a scientifically rigorous manner,” Mr Ahmed says.
We watch while Tom has his procedure. He’s awake while the doctors get to work - there’s no general anaesthetic. And it only takes about 40 minutes.
But here’s the rub - he may not be having the actual blocking agent in his body to stop the hormone. He may just be getting a placebo procedure. He won’t know what he’s had.
And only certain members of the research team will know. Those analyzing any data from the trial won’t.
Mr Ahmed is one of them. He doesn’t want his interpretation of the results to be biased by knowing what treatment people like Tom and Catherine have had. And they need to know if any weight loss they see is down to the actual procedure or if it's a placebo effect.
It may be that it doesn’t produce the clinical benefits they’re hoping for - but this is also the point of doing a trial, Mr Ahmed says.
“We need to really show whether the active treatment is superior to the placebo treatment. Because if we cannot show that difference, there's no point in millions of people receiving this treatment,” he adds.
But if they do show a clinically meaningful benefit, this could be a “game-changer” he says.
“A lot more people could benefit from this than, for example, from surgery, which takes much longer. It requires anaesthesia and it requires a stay in hospital,” he adds.
But some argue that while developing new treatments is important, with 60% of UK men and 50% of women estimated to be living with obesity by 2050, it’s only part of the solution.
They are critical of rumoured government plans to roll back on other measures to tackle obesity such as sugar tax. We need to try to prevent people from gaining too much weight and it’s not as simple as it’s down to the individual.
Prof Jim McManus, president of the Association of Directors of Public Health says that while new cost effective treatments are important we “can't treat your way out of this”.
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“Individual treatments are more costly per head and per outcome than public health treatments,” he says.
Official reports on obesity suggest that society has radically altered over the past five decades, with major changes in work patterns, transport, food production and food sales.
We’re surrounded by fatty and high calories foods. Healthy foods may be more expensive. And it’s not always easy to go out for a walk or cycle, for example. It’s these kinds of issues that also need tackling, some experts say.
“There’s about 65 different public health measures and counting on reducing obesity and it’s a case of you need a number of them to add up,” Prof McManus says adding: “We know the sugar tax has reduced the amount of sugar consumption by 10% in some populations. That actually will have an impact.”
Tom agrees it’ll take more than the procedure to keep his weight off. He’ll get further support as part of the trial.
“There [needs to be a] change in the mindset, making sure what you think is healthy is actually healthy. You know, what you're putting in your body is what you body needs,” he says.
In 12 months, Tom will know whether he was given the treatment or a placebo. And only then will we know if this is the much-needed breakthrough treatment.