What’s so special about Apollo Endosurgery’s stomach-shrinking weight loss tech?

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.

“We [have] the only intralumenal suture system that does full-thickness running and interrupted stitching,” Neudeck said. “There’s nothing else out there.”

“There is no competition” that provides consistent, full-thickness suture placement, Gostout added.

This conversation has been lightly edited for space and clarity.

How and why was Apollo Endosurgery founded?

Gostout: Apollo Endosurgery was formed in 2005. It was the culmination of multiple projects from an endoscopy working group called the Apollo Group organized in 1998 with the concept that we wanted to drive therapeutic endoscopy beyond what was being done at that time. We wanted to create some out-of-the-box projects that would really open the world of interventional endoscopy. 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 — but we initiated several projects. One 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 full-thickness sutures, but it was clumsy to use, with variability in suture depth. It provided stitch placement deeper than anything else that was yet on the market at that time. Around 2004, I had initiated upon the request of the Mayo Clinic the development of an endoscopic weight loss procedure that would reduce the volume of the stomach. I was trying to mimic what was called the Magenstrasse and Mill procedure. I was trying to do that with the suturing systems available, the Bard EndoCinch system and then the Eagle Claw. In 2005  the suturing effort was sidelined by withdrawal of support from Olympus. 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 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, NOTES (natural orifice translumenal endoscopic surgery) hit the scene. … One of the Apollo group projects other than a suturing device was to establish transgastric cholecystectomy procedures. The Apollo group had completed several 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. A group from India did a transgastric appendectomy and that launched NOTES. There was a meeting with representatives from 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. NOTES fell by the wayside despite physician enthusiasm. Insurance companies received it as highly experimental. The medical device companies were not interested in creating any ancillary devices to facilitate NOTES procedures. Consequently, with a dependable suturing device in hand, the gastric reduction project was resurrected at Mayo.

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 identified a suture pattern that would effectively reduce the gastric volume by about 75–80% and looked like a sleeve, mimicking a sleeve gastrectomy. Encouraged by the results, we initiated a clinical pilot study at Mayo.

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.” Our first patient was a success, losing weight and becoming a distance runner. The patient subsequently developed symptomatic gallstones and had to have a gallbladder removal. During the gall bladder removal, the surgeon commented that the stomach was impressively reduced with the full-thickness sutures present, seen from the outside. I thought, “Wow, we did it. We hit the home run.” …  We completed the other cases for the study, and we were getting the same results. And I thought, “Well, this procedure’s here to stay.” And then it caught on. The technique became modified to add efficiency to the procedure and ensure long-term suture retention.

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. It fills the gap between standard weight loss efforts with diet and exercise, pharmacotherapy and traditional surgery. Our ESG system can be used within the BMI range of 30-50.

How does the ESG procedure work?

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 called plications that concentrically reduce the volume of the stomach. The procedure avoids two areas of the stomach: the very top of the stomach (the fundus) and the very bottom of the stomach (the antrum). The plications are stacked along the length of the stomach, foreshortening it while forming 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 plications 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 effect 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 experience total body weight loss ranging from 15% to 18% or more. There will be significant improvement in associated comorbidities such as type 2 diabetes, hypertension, and metabolic syndrome. A patient can get the benefits of a surgical procedure — not as much dramatic weight loss, but significant weight loss — and have improvement in some comorbidities with a safer, lower-risk procedure.

How did Apollo Endosurgery develop the OverStitch device?

Neudeck: Apollo started as a NOTES company. NOTES was a novel concept and was the big carrot for people who invested in Apollo. For a NOTES procedure, you needed a series of tools, you needed safe endoscopic access to the peritoneal cavity. Apollo developed a port that was inserted into the stomach endoscopically. You then made an incision somewhere in the stomach in a favorable area depending on the procedure you want to perform. You then placed the sterile port through the opening and inflated two balloons on either side of the stomach wall. This secured the port and created a water-tight seal to have access to the abdominal cavity without any external incisions. You then needed different endoscopic tools to perform a surgical procedure, an examination or a biopsy. At the end of a NOTES procedure you always have to close the access hole left in the stomach. The intent of the OverStitch suturing device was to be able to perform this closure procedure safely and effectively by applying full-thickness suturing. We started off with a Gen 0 device, a pretty clunky device, mostly machined components with some 3D-printed parts that we tested in explant tissue and animal labs. After more design iterations, this morphed into what we called our Gen 1 device. which did full-thickness suturing. We knew we couldn’t commercialize that Gen 1 device. It had too many machined components and was too expensive to manufacture. At that point, all manufacturing was done in-house. Commercially, it wouldn’t have been a viable solution. However, because endolumenal suturing did not exist at the time — we were the first ones in the world to accomplish this — the Gen 1 device enabled us to get some initial clinical data. We built a small amount of devices — I think we built a total of 300 for a small group of advanced gastroenterologists, the people at the top of their profession. They had access to that Gen 1 device. Being an endoscopic suturing tool, you can do a lot more with it than just closing holes. It was a very advanced technology in the toolbox for endoscopists who always had the desire to use endoscopic access not just for diagnostics but for therapeutic treatments. You want to help the patient after you diagnose the issue, you want to treat rather than writing a report and sending the patient to somebody else for further treatment. People then very quickly developed a number of procedures: fistula closures, oversewing defects and stent fixation. When endolumenal stents get placed in the GI tract — for example, the esophagus — they all have one thing in common. They all have a tendency to migrate, because your GI tract is designed to pass things in one direction. Now GIs had access to a suture tool and were able to stitch stents in place, which greatly reduced the likelihood of dislodgement and migration. Once physicians had access to this novel technology, new therapeutic procedures were developed pretty quickly.

How did you make the turn toward commercialization?

Neudeck: We received additional funding at that point and split our resources. One part of the business supported our clinical work with our Gen 1 device. And the majority of the R&D people focused on developing our Gen 2 platform, taking into consideration the learnings and user feedback from the field. The second generation of Overstitch is the device which is commercially available today. We launched it just over 10 years ago. And the first ESG procedure was done with the Gen 2 device by Dr. Gostout in 2012.

And that’s when you outsourced your supply chain?

Neudeck: Yes, we switched from doing everything in-house to a fully outsourced supply chain. We collaborated with some good component suppliers, and worked with a contract manufacturer to develop a robust assembly process and component inspections and launched Overstitch Gen2. As volumes increased, we made a number of iterations on the manufacturing process to improve scalability. But in essence, the device we are selling today remained unchanged. About four years ago, we launched a new endoscopic suture platform called Sx. This device is scope agnostic — Gen 2 only works with specific endoscopes — and is compatible with most single-channel endoscopes that GIs and surgeons have access to and enables intralumenal full-thickness suturing.

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

Gostout: Traditional suturing employs a curved needle. Every attempted suturing device functions as a sewing machine using straight needles. The Apollo Group wanted a curved needle to add the versatility of being able to place a stitch wherever you want as opposed to having to align tissue into a sewing machine. The OverStitch device needle tip has a T-tag design to the needle which fits into a curved driver arm. That curved arm simulates the ergonomics of hand suturing. That’s the beauty of our device, the curved needle arm.

Neudeck: In the stomach, one risk when placing a full-thickness suture is to inadvertently stitch through a sensitive organ on the outside. There are two ways the Overstitch procedure mitigates this risk.  We use a tissue approximation tool called Tissue Helix with our suture system to pull the tissue into the suture aperture of the device before you place your stitch. It’s a corkscrew-type device that gets drilled into the tissue where you want to place your stitch. By pulling tissue towards the device instead of pushing the system against the stomach, you effectively mitigating the risk of accidentally suturing into an outside structure. Once you have the tissue pulled into the device, the curved needle ensures that your needle trajection is away from outside organs as opposite from a straight needle. With the combination of curved needle and Tissue Helix, we have never had any issues with stitching into the spleen or 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 one of the toughest environments for developing implantable med devices. The constant movement of the stomach, and the gastric fluid’s acidity make it a very harsh environment.  And pH and diet is different from patient to patient. Blood in comparison is a very well-characterized fluid and very similar across patients, which makes it easier to develop benchtop models and test methods to do a lot of the early engineering working in the lab. Trying to simulate the gastric environment is really difficult. The stomach is a big muscle. If you do something to it, it responds over time to space-filling or -restricting implants. And the physiology of the gastric tract, with it being a strong peristaltic pump, we have seen a lot of other companies trying to develop obesity devices over the years but often failed because of the unique environment, because everything starts to migrate in the stomach.

Gostout: One thing that’s an absolute is durability provided by the ability to place full-thickness sutures. I had conducted research centered around creating new working spaces inside the GI tract wall beneath the lining, which has become referred to as third-space endoscopy. A variety of applications were studied and included trying to secure magnets in the wall of the esophagus and stomach, placement of drug-eluting materials to treat localized diseases and even access the surface of the heart. These research efforts demonstrated if any foreign material is not placed full thickness, the body extrudes it over several days. It’s impressive how your body deals with foreign materials, and it’s this full-thickness aspect that’s absolutely a must for durability of a suture-based weight loss procedure.

This post was updated with additional information and commentary from Neudeck and Gostout in January and February 2023.