As we wrote back in 2008, the EndoBarrier is a very clever way to simulate the effect of a gastric bypass without the unpleasant scalpel part. It looks like a long clear plastic stocking, and it’s simply threaded through the patient’s mouth and stomach, down to the small intestine, where it lines the intestine’s upper section (the same part that is bypassed in traditional surgery). Food slips right through it, but digestive enzymes are trapped on its other side. The two don’t get to join forces until a couple of feet further downstream, so the effect on diabetes is a lot like that of a bypass: It resolves the symptoms of type 2 diabetes.
Stuart Randall, the CEO of GI Dynamics, says “The idea for the EndoBarrier was thought up by our founder, a gentleman named Andy Levine. He was one of three individuals who founded a medical device incubator in Boston in about 2000. They started seeing the effectiveness of gastric bypass surgery, particularly its effects on diabetes, and they said, ‘Gee, maybe we could figure out a way to do this endoscopically, without surgery.’ It’s a real simple idea, but in the 90s and the early 2000s, bariatric surgery was still a small field, and it wasn’t getting a lot of attention. That’s obviously changed in the last ten years as the obesity epidemic has become more well known. So yes, it’s a simple idea, During one of our first meetings at the FDA, they said that the EndoBarrier was ‘elegant in its simplicity,’ which, as a technical person, you take as quite a compliment.”
The tube, which is made of a proprietary fluoropolymer, has a little wire cage at the front end that lodges in the duodenal bulb to hold the tube in place. The cage is made of nitinol, a material that is used in a number of medical device implants, particularly stents. Randall says, “Nitinol is a shape memory alloy. The beauty of it is, you can set to one shape, and then you can compress it down to a very, very small size and fit it in a capsule. When you push it out, it just springs open.”
Last year, the EndoBarrier received CE Mark approval, meaning that the product is approved for sale in the European Union. Randall says, “That was the result primarily of two studies that we completed. One of those studies was a 12-month diabetes study, which showed a 2.3% reduction in A1C at one year. We also showed a statistically significant reduction in LDL, triglycerides, glucose levels, and insulin levels. And then we also had results from a 12-month weight loss study, which showed a 20 percent absolute weight loss at one year, as well as a statistically significant reduction in blood pressure and LDL and triglycerides again.”
“These were 12 month studies by design, and so therefore our CE Mark approval is for a 12-month implant. We have some studies ongoing to evaluate the opportunity to put it back in at some time post-explant.” As to how long the A1C effects last after the EndoBarrier is removed, Randall says,”We’ve got some data, limited data at six months post-explant, where in this particular study, A1C originally went down 2.3 points. In those patients for whom we have data, after six months it’s up about 0.3%.”
The EndoBarrier is not yet approved for use in the US. Randall says, “We’re working with the FDA on designing a trial, but it’s fair to say that it will be a number of years.”
Randall adds, “No one knows exactly why, when one bypasses the proximal intestine, that diabetes seems to go away rather rapidly. What we do know is that there are a very large number of hormones that are triggered by food contacting the wall of the intestine. When you restrict that from happening, which is what the EndoBarrier does, some of these hormones are upregulated and some are downregulated. That triggers effects on satiety, caloric intake, energy levels, and a number of other things. What the mechanisms are by which these effects happen is still a great mystery. Whoever figures out why diabetes goes away when you bypass the first part of the intestine, that person is likely to win a Nobel Prize one day.”