One of the more offbeat ideas in the obesity drug development business has gathered some new evidence to suggest it might someday help people lose weight.
Boston-based Gelesis, the developer of a superabsorbent capsule designed to swell up in the stomach and make people feel full, said its treatment was able to help rats reduce their food intake over an 18-hour period when compared to a placebo. The findings were presented over the weekend at The Obesity Society’s annual meeting in San Diego.
It’s way too early to say the Gelesis treatment will work in people, particularly since many other weight loss drugs have been tripped up by safety concerns. But the news of the long-lasting effect in rats is interesting in part because it comes about six months after Gelesis reported on a more rigorous clinical trial of 95 patients. This other study showed the capsules helped people feel full after meals and less hungry in between. The company is betting that, taken together, these early signs—controlling hunger in people, and reducing food intake in rats—will prove to be important leading indicators that the drug will ultimately help people lose a meaningful amount of weight. If proven in future trials, the Gelesis capsule could someday become a new option for the estimated two-thirds of people in the U.S. who are overweight or obese.
“We are definitely looking at further clinical trials that will build on this data,” said Eric Elenko, a partner at Puretech Ventures, and a co-founder and a director of Gelesis. “The rat data is particularly promising.”
Part of what has Gelesis’ scientists excited about the rat study is the 18-hour effect on food intake. It wasn’t a given that the Gelesis capsule, called Attiva, would last that long. The treatment, a superabsorbent polymer about the size of a grain of sugar, is made to work unlike any other treatment available today.
As I described in a feature story back in April, the Gelesis capsule is taken with a drink of water. It is then supposed to swell up more than 100-fold in volume when in contact with the water. When all those superabsorbent particles get released in the stomach, people naturally have less room for food.
Besides that, the particles put pressure on the walls of the stomach, which is thought to send a signal to the brain that says the person is full, and it’s time to stop eating. Eventually, stomach acids then shrink the particles during digestion, so they release the water, and they can travel with any food to the small intestine. The particle can re-swell to an extent at that part of the journey, Gelesis says, which increase the viscosity in the small intestine so that sugars and fatty acids get absorbed more slowly there. The hydrogels then proceed to the large intestine, release their water, and disintegrate. The Gelesis product is designed so it never gets absorbed into the bloodstream like a drug.
That’s the idea, and the rat study offers some incremental support for the concept. It’s important to note that the Gelesis capsules don’t last in the stomach for a full 18 hours. So if the drug was only working there, it would likely have a much more temporary effect. The longer-lasting effect in rats suggests that the Gelesis capsule is having an effect during the digestive process, as food passes through the small intestine, says Hassan Heshmati, Gelesis’ chief medical officer, and the lead author of the study.
Not every rat responded exactly the same way to the Gelesis treatment, the scientists noted in their poster presentation. That’s probably because some rats were young and actively growing, and doses of the capsule weren’t adjusted accordingly, Heshmati says.
The idea behind Gelesis has been around in academia for more than 15 years, but it got a big commercial push back in January 2008 when the company raised $16 million from OrbiMed Advisors, Queensland BioCapital Funds, Puretech Ventures, and others.
A number of other drugs that work through central nervous system pathways have failed in the past because they were linked to damaged heart valves, or suicidal thinking. That has created plenty of regulatory risk in the field, as expert advisors to the FDA have in the past couple of months in public meetings to review new drug applications from Mountain View, CA-based Vivus (NASDAQ: VVUS) and San Diego-based Arena Pharmaceuticals (NASDAQ: ARNA).
While Gelesis notes that its treatment is designed to work in a different way, the FDA is on high alert about any safety concerns with weight loss drugs that could potentially be taken by millions of people with a non-life threatening condition. Plus, there’s still a lot of basic research being done to identify multiple genetic factors that might contribute to obesity, meaning scientists don’t really know what causes some people to become more overweight or obese than others.
All of that makes obesity one of the toughest markets to crack for drug developers. The clinical trials will be long, expensive, and risky, but there’s no question that if Gelesis can prove its concept in later trials, it will have a big commercial opportunity.
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