How Apollo Endosurgery’s OverStitch helps patients lose weight

The Apollo Endosurgery OverStitch Sx endoscopic suturing system [Image courtesy of Apollo Endosurgery]

Apollo Endosurgery — set to be purchased by Boston Scientific for $615 million — develops new devices and minimally invasive procedures for weight loss.

The procedure is called endoscopic sleeve gastroplasty (ESG) and the device that made it possible is the OverStitch endoscopic suturing system.

Austin, Texas-based Apollo Endosurgery first won 510(k) clearance for OverStitch in 2008, with successive clearances for improved designs over the years. Most recently, in July the FDA granted de novo clearance for Apollo Endosurgery’s Apollo ESG, Apollo ESG Sx, Apollo REVISE and Apollo REVISE Sx systems. They’re the first FDA-authorized devices for ESG and endoscopic bariatric revision procedures.

Medical Design & Outsourcing spoke with Apollo Endosurgery Chief Medical Officer Dr. Christopher “CJ” Gostout and R&D VP Tom Neudeck earlier this year — before the Boston Scientific deal was announced — to learn more about the new devices and procedures. This conversation has been lightly edited for space and clarity.

How and why was Apollo Endosurgery founded?

A portrait of Apollo Endosurgery CMO Dr. Christopher "CJ" Gostout

Apollo Endosurgery CMO Dr. Christopher “CJ” Gostout [Photo courtesy of Apollo Endosurgery]

Gostout: Apollo Endosurgery was formed in 2005. It was kind of the culmination of multiple projects from an endoscopy working group called the Apollo Group. A handful of us organized ourselves in 1998 with the concept that we wanted to drive therapeutic endoscopy beyond what was being done at that time. We wanted to think of some out-of-the-box projects that would really open the world of interventional endoscopy. And in our discussions at that time was an intent to somehow reduce the volume of the stomach. We never launched that project — I did individually in my own research lab at the Mayo clinic subsequent to that — but we initiated several projects. Our dominant project was to create a flexible endoscopic suturing system. We were working with the Olympus Corp. in that development project. They had initially worked with us and developed a suturing device called the Eagle Claw. That device had the best prospects for providing deep sutures. We were looking for what we call transmural full-thickness sutures, and the Eagle Claw had that potential. But it was an extremely clumsy device to use. And it was variably predictable as to how deep the sutures would go. It was certainly deeper than anything else that was yet on the market at that time. And it was basically the C.R. Bard EndoCinch device that provided very superficial sutures. So around 2004-ish, I had initiated upon the request of the Mayo Clinic to develop an endoscopic weight loss procedure and I had in mind a procedure that would reduce the volume of the stomach. I was trying to mimic what was called the Magenstrasse and Mill procedure, which basically along the length of the stomach created a series of plications to reduce the volume. I was trying to do that with the suturing systems available, the Bard system and then the Eagle Claw, which turned out to be too clumsy. And then lo and behold around the same time — 2005 now — Olympus said, “You know what, we’re done funding the Apollo Group and we’re pulling out.” We got together in a panic because we had these projects that were maturing and we thought, “Oh man, what are we going to do?” And, um, and then one of our team members, Jay Pasricha, said, “Why don’t we form a company? We have the IP. Why don’t we just build a company around our IP?”

Your initial focus differed from today’s devices, is that right?

Gostout: In 2005, that’s when NOTES (natural orifice translumenal endoscopic surgery) hit the scene. … With the Apollo Group, one of our projects other than a suturing device was to figure out how to do transgastric cholecystectomies. We had done a bunch of animal labs that demonstrated it was certainly feasible to do transgastric operations of some kind, whether it’s an appendectomy, a cholecystectomy, or even a fallopian tube ligation. Then a group from India did a transgastric appendectomy and that launched NOTES. There was a meeting, kind of a convocation of the two endoscopy societies, the ASGE (American Society for Gastrointestinal Endoscopy) and SAGES (Society of American Gastrointestinal and Endoscopic Surgeons). We convened in New York City, formed a working group called NOSCAR (Natural Orifice Surgery Consortium for Assessment and Research) to push forward NOTES. So Apollo was formed thinking that we were going to create medical devices that would enable NOTES procedures and at the top of the pyramid of our devices would be our suturing device that we would focus our attention on. And Apollo did create several devices that could facilitate NOTES procedures, but NOTES fell by the wayside. It got no traction. Insurance companies thought it was highly experimental. They weren’t the least bit interested in reimbursement. The medical device companies were not interested in creating any ancillary devices to facilitate the opportunities to do NOTES procedures. And so in my own lab at Mayo, I said, “You know what, I’m moving ahead.” I’ve got a suturing device in my hand here that does give me full-thickness sutures, and I’m going to re-explore and pick up the momentum on our gastric reduction procedure. And that’s what we did.

Where did you go from there?

Gostout: Through a series of animal models — starting out with a pig stomach, then a dog stomach and then a baboon stomach — I figured out a pattern that would effectively reduce the gastric volume by about 75–80%. It looked very, very impressive. When it was all done, it literally looked like a sleeve, like we had done a sleeve gastrectomy, but not so. We actually preserved the stomach, but there was an effective sleeve that ran the length of the stomach. Then we set up a clinical pilot study at Mayo and I started doing the procedure in humans.

You had your doubts?

Gostout: To be honest with you, my thoughts were, “I don’t know if this is going to last. Maybe a couple of weeks, maybe not.” And our first patient, it was just unbelievable. She was losing weight like crazy. She became a marathon runner, subsequently developed gallstones and had to have a gallbladder removal. During the gall bladder removal, the surgeon commented, “That stomach is impressive. You really reduced the stomach, and all the sutures were visible and in place.” And I thought, “Wow, we did it. We hit the home run.” …  I was just amazed, and of course, we completed the other cases for the study, and we were getting the same kinds of results. And I thought, “Well, this procedure’s here to stay.” And then it caught on. People started modifying our technique, and we had different groups trying to develop the technique. And it just kept growing.

What sort of patients is this ESG procedure meant for?

Gostout: It’s a very viable, scalable procedure for weight loss that fits very nicely in the spectrum of opportunities to help guide obese patients throughout their life of weight loss, beginning with dietary modifications, lifestyle modifications, drug therapy and then there’s a big gap before they’re eligible for surgical therapies. They have to reach a BMI of at least 35 with a comorbidity, or 40 and above. And we fit very nicely in that gap area where we can do this procedure and create the opportunity for the obese patient to get something done before they really hit those high BMI levels.

How does the ESG procedure work?

An illustration of a stomach that's been folded up to shrink its capacity

Endoscopic sleeve gastroplasty (ESG) shrinks the stomach with intraluminal suturing. [Image courtesy of Apollo Endosurgery]

Gostout: It’s basically looking at the stomach as a relatively flaccid organ and then creating a series of folds, very similar to when you open the drapes in your living room. … We’re creating a series of folds in the stomach that concentrically reduce the volume of the stomach. We don’t enter into two areas of the stomach; the very top of the stomach (the fundus) and the very bottom of the stomach (the antrum). We do everything in between and create these folds and then they’re all sewn together, bunched together … so that you’re left with a channel that’s about the size of your thumb running down the length of the stomach with the exception of the fundus and the antrum. The antrum is avoided because it’s tremendously muscular. In the process of digesting your food, it’s responsible for grinding and emptying food from the stomach. To try to have sutures hold up in that region is really challenging. The fundus of the stomach is avoided because it’s extremely thin. … The procedure works in two ways. The pleats reduce the volume of the stomach, which means you can’t eat the same volume per meal that you had prior to the procedure. The other thing that happens is that the exclusion of the fundus causes a delay in gastric emptying. So now, not only can you not eat that much, but what you do eat takes a long time to eventually exit the stomach. That gives you this prolonged sense of fullness. … It takes
an hour-and-a-half to two hours longer to empty the stomach.

How much weight do patients lose after ESG?

Gostout: It doesn’t compare to the sleeve gastrectomy by any means. Patients will not lose the same amount of weight. They should be expected to be losing around 15% to 18% of total body weight loss from the ESG procedure. If they have comorbidities, you can pretty much guarantee them that there’s going to be significant improvement in comorbidities, similar to the sleeve gastrectomy. … If you have joint symptoms, you’re going to get that weight off those joints. So you can get the benefits of the surgical procedure — not as much dramatic weight loss, but significant weight loss — and have improvement in some of the medical conditions that you are also having to deal with. And it’s a safer procedure. It’s incredibly safe. It’s a low-risk procedure.

How did Apollo Endosurgery develop the OverStitch device?

A portrait of Apollo Endosurgery VP of R&D Tom Neudeck

Apollo Endosurgery VP of R&D Tom Neudeck [Photo courtesy of Apollo Endosurgery]

Neudeck: When Apollo started out, NOTES was the big carrot for people who invested in Apollo. To do a NOTES procedure, you need a series of tools, you’ve got to get access. In this case, the idea was that we create a port, a portal that would be inserted endoscopically. You’ll then make an incision somewhere in the stomach in a favorable area depending on what sort of procedure you want to perform. You then place that sterile port, you inflate two balloons to create a gas- or water-tight seal, and then you have an access portal to the outside of the stomach without any external incisions. Then you obviously need a bunch of different tools to then go into places and do a resection, for example, maybe take a biopsy sample or whatever the NOTES procedure would be. In the end, though, when you’re done with your NOTES procedure, and you come back, you have to close that hole in the stomach. OverStitch, really the intent of that suture device was to be able to perform that procedure and do it safely. We started off with a sort of gen zero device, a pretty clunky, 3D-printed device that we tested in explant tissue and animals. Then that morphed just through design iterations into what we called our gen one device, and that was the device that did the full-thickness suturing. At that point, we knew we couldn’t commercialize that gen one device. They had too many machined components on it. Commercially, it wouldn’t have been a viable solution. However, we thought because endoluminal suturing wasn’t really a thing — we were the first ones in the world to do that — we did a limited launch with that gen one device. We built a small amount of devices — I think we built a total of 300 [for] the mavericks of the GIs, the KOLs (key opinion leaders), the people at the top of the pyramid from a therapeutic endoscopy standpoint. They had access to that gen one device. And it being a suture tool, you can do a lot more things with it than just closing holes. It was a brand new tool in the toolbox for the folks who always had this desire to do more than just look and see with the endoscope, but actually to do therapy. You want to help the patient, you want to treat rather than writing a report and then sending the patient on to somebody else. People then very quickly did a number of procedures: fistula closures, overflowing defects … stent fixation. Endoluminal stents that get placed in the esophagus or somewhere else, they all have one thing in common. They all start migrating, because your GI tract is designed to pass things in one direction. All of a sudden, now you have a suture tool. … We learned as people had access to this technology what else could be done with it and what sort of therapeutic procedures could be developed.

How did you make the turn toward commercialization?

Neudeck: We got additional funding at that point, and we knew that we couldn’t commercialize gen one, so we basically bifurcated the resources that we had. One side of the business supported our first demand study, our gen one device. That was all built in-house. And then a majority of the R&D people we focused on developing based on our learnings and the learnings from the field the gen two device. That is the device that today is commercially available. We launched that just over 10 years ago. That first ESG was with the gen two device.

And that’s when you outsourced your supply chain?

Apollo Endosurgery’s OverStitch Sx for single-channel scopes (left) and OverStitch for dual-channel scopes (right) [Image courtesy of Apollo Endosurgery]

Neudeck: At that point, we went away from trying to do it all in-house. We selected some good partners, contract manufacturers, and that was the device that we really launched with. As volumes increased, there were a number of iterations around the manufacturing process where we scaled things up. But in essence, that is still the device that we are selling today. … The platform is now scope agnostic. Pretty much any single-channel scope that any GI has access to in the world can attach our suture mechanism to it and perform intraluminal suturing.

How important is the OverStich device’s curved needle arm?

Gostout: When you suture, you use a curved needle, and every attempted suturing device up to that point were more sewing machines, just straight needles. There’s only so much you can do with a straight needle. We wanted a curved needle to add the versatility of being able to place a stitch wherever you want as opposed to having to align something into the sewing machine. The OverStitch device needle tip is a T-tag, but that fits into a curved arm. That curved arm simulates the ergonomics of hand suturing. That’s the beauty of our device, the curved needle arm.

An illustration showing Apollo Endosurgery's OverStitch device pulling stomach tissue toward the needle

Apollo Endosurgery’s OverStitch device pulls stomach tissue toward it to avoid puncturing other organs. [Image courtesy of Apollo Endosurgery]

Neudeck: In the stomach, obviously, one of the risks is you don’t want to place a full-thickness suture where the suture leaves the stomach, goes out of the serosa and comes back in. You don’t want to stitch through the stomach to a sensitive organ on the outside. There are two ways to do that. One is the tissue approximation tool that we use in our suture system to pull the tissue where you want to place your stitch. We pull that into our suture aperture with our tissue helix, a corkscrew-type device that gets drilled — kind of like point-and-shoot — where you want to place the stitch. You then pull the stomach toward the device instead of pushing the system against the stomach. so that effectively mitigates the risk that you accidentally suture into an outside structure. Once you have the suture pulled into the device, the curved needle ensures that your needle trajection is away from outside organs rather than a straight needle. With the curved needle plus our tissue helix, we have never had any issues with stitching into the spleen or any other sensitive organ.

What did Apollo Endosurgery learn about the stomach that you’d like to share with our readers?

Neudeck: The stomach is probably the toughest environment to develop implantable med devices. The makeup of the stomach, the exact shape and also the pH acid footprint of every stomach is different from patient to patient. For example, blood is very, very well characterized and every patient’s blood is very similar. And so you can develop bench setups to really do a lot of the hardcore engineering work in your lab. Trying to simulate the gastric environment is really, really difficult. … The stomach is a big muscle. If you do something to it, as a response over time it tries to almost find ways around implants. And the whole nature of the gastric tract, it being a big muscle that contracts like a peristaltic pump, we’ve seen a lot of other companies trying to develop obesity devices over the years where something had to be placed … in nets and nitinol baskets [but] they really all failed because of the unique environment, because everything starts to migrate in the stomach. Nothing wants to stay where it’s at.

Gostout: One thing that’s an absolute is for durability, we’ve been saying full thickness all along. Throughout my career, in my developmental endoscopy unit, part of my activities were centered around creating working spaces inside the GI tract underneath the lining. It’s now called third-space endoscopy. In that program, we were looking at trying to secure magnets in the wall of the esophagus and stomach. We were trying to secure drug-eluting materials that maybe could treat localized diseases. And if anything is placed and it’s not full thickness, it’s gone. Your body just extrudes it. It’s just gone typically within a couple of days. It’s very dramatic how your body deals with foreign materials and it’s this full-thickness capture that’s absolutely a must for durability of basically any weight loss procedure that you want to attempt in a similar fashion.


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