in volume when it comes into contact with water. So this “hydrogel” can be packed tight into a capsule that’s small enough for people to swallow. When you drink a water to down the capsule, it releases all those superabsorbent and expanding hydrogel particles in the stomach to at least partly fill you up so you have less room for food.
Once the hydrogel particles are released and filling up with liquid, they put pressure on the walls of the stomach, sending a signal to the brain that says the person is full, and it’s time to stop eating. The particles mix with the food, which keeps the food in the stomach longer. Eventually, stomach acids then shrink the particles during digestion, so they release the water, and they can travel with the food to the small intestine. The particle can re-swell to an extent at that part of the journey, and 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. It gets excreted in the feces.
The technical challenges to navigate this biological journey sound immense. One big trick was to find a combination of food-grade natural polymers that could cross-link together in a 3-D form to expand properly, Sannino says. Then there was the need to make it absorbent enough. The next big challenge was making the particles sensitive to ever-changing pH conditions they encounter from the stomach through the intestines. And the latest task has been to set up an efficient production system.
Gelesis isn’t saying where the material comes from for the hydrogel particle, or how much the raw material costs. But it does provide “nice commercial margins,” based on the models Gelesis is using for what such a drug might cost in the marketplace, Elenko says.
Interestingly, even though this product is taken in a capsule, Gelesis believes it could technically be considered a medical device, not a drug, by the FDA. That’s an important distinction to make, since the material works mechanically to treat obesity, rather than being absorbed into the blood like a drug. If the capsules are considered a device, that would change the regulatory pathway Gelesis would need to clear before reaching the U.S. market.
So what did the clinical trial show in detail? The study enrolled 95 people at Gemelli Hospital in Rome, Italy. The average person had a body-mass index of 31, the equivalent of someone who’s 5-foot-6 and weighs 190 pounds. They took a placebo, or
