Gas-Filled Balloon Device Is Safe, Effective for Weight Loss

NASHVILLE, Tenn — In its first year of commercial use, the swallowable, gas-filled, three-balloon weight loss device (Obalon, Obalon Therapeutics) demonstrated a good safety record and resulted in greater weight loss than seen in the pivotal randomized trial leading to its US approval, new data show.

Safety and efficacy results from more than 1300 patients at over 100 sites in Obalon's voluntary registry were presented November 14 here at Obesity Week 2018 by Rachel L. Moore, MD, a metabolic surgeon in New Orleans, Louisiana.

Approved by the US Food and Drug Administration (FDA) in 2016, the Obalon Balloon System consists of three balloons that are delivered to the stomach via a capsule that the patient swallows. Once in place, the balloons are inflated with attached microcatheters and left in for 6 months, after which they are retrieved endoscopically. The system is indicated for patients with a body mass index (BMI) of 30 to 40 kg/m² with or without obesity-related comorbidities.

The registry, in which prescribing physicians enter weight loss and safety data, was launched when the Obalon Balloon System became available in January 2017.

In February 2017, the FDA issued a health alert about two liquid-filled intragastric balloon weight-loss devices but specifically noted that the alert did not extend to the Obalon device, as there had been no safety concerns reported.

Important Registry Data

Moore, who formerly trained physicians in the use of one of the liquid-filled balloon devices, has mostly switched over to the gas-filled system, except in cases where patients are unable to swallow the capsule or other unusual circumstances, she said.

With the gas-filled balloons, she noted, "Patients aren't sick. The tremendous acclimation period of nausea and vomiting with the saline-filled balloons was the reason for me changing my preference to this device."

Asked to comment, session moderator Corrigan "Cori" McBride, MD, of the Minimally Invasive and Computer Assisted Surgery Center at the University of Nebraska Medical Center, Omaha, told Medscape Medical News that the balloon device approach to obesity treatment is "clearly a technology that is developing. The safety profile is the most important thing that we as surgeons or procedurists are looking for in a device."

This particular study is important, McBride said, because "it's the single largest registry of patients who have had this particular device. It continues to validate the safety profile that was in the initial pivotal trial that led to FDA approval."

And, she said, the fact that patients in the real world actually lost about 30% more total body weight than those in the company's clinical trial is "exciting" and "speaks to how this is really a tool, and the patients who are now seeking it out in the commercial environment are looking for a tool. They are highly motivated. They're going to use it as one piece of their weight loss journey."

Real-World Experience: Swallowing the Balloons

The registry included a total of 1343 patients who swallowed one or more of the gas-filled balloons over a years' time at 108 US centers. Patients were a mean age of 46 years, 79% were women, and 67% were white.

Mean BMI was 35.4 kg/m², but 17% had BMIs above the indicated range (> 40 kg/m²), and 12.5% had BMIs below the range (25.1 to 29.9 kg/m²).

Most of the patients (88%) had swallowed all three balloons, with median administration times of second and third balloons at 2.6 and 7.4 weeks after the first one.

Another 9% received just two balloons, and 3% had only one. A majority (82%) kept the balloons in for the entire recommended 6 months.

Moore pointed out that the gas-filled balloons are administered without sedation and patients are typically able to drive themselves home or back to work afterword. However, swallowing the capsule is a psychological challenge for some patients.

Moore shared her techniques for facilitating the procedure. She first has patients swallow a practice capsule. She tells them to think about the "ooey, gooey point of the pizza slice, and how big that bite is...as you're eating throughout the day, you're swallowing much bigger bites than the size of this capsule and you really can do it."

She also keeps her office quiet and the lights low, and forbids staff from barging in. Sometimes she'll place the capsule at the back of the patient's throat with her hand.

But if the patient still can't swallow the device, they can't use the treatment.

No Major Safety Concerns

Out of a total of 3818 balloons administered in the registry, deflations occurred in just 0.18% and failure to inflate in 0.13%.

The latter is typically the result of the patient biting the catheter, she noted. In such cases, the device is endoscopically removed and another one swallowed.

There were no deaths or unanticipated adverse device effects. Two (0.14%) serious adverse device effects were reported — a gastric perforation and dehydration requiring hospitalization and balloon removal — neither had permanent sequelae.

The most common adverse events were abdominal pain and nausea, both each in about 5% of patients, vomiting in 2%, and abdominal distension in 1%.

In fact, Moore noted that if vomiting occurs in patients with the device it's a reason for concern, "because it's not a common scenario at all."

Greater Weight Loss Than Seen in Clinical Trial

Overall weight loss was 9.6 kg for the 1177 patients who had three balloons, compared with 6.6 kg and 3.1 kg, respectively, for those with two and one balloons. Total body weight loss was 9.6%, 6.9%, and 3.4%, respectively.

Comparing results at 22 weeks for 787 registry patients with those of the pivotal trial involving 174 participants, weight loss was 9.7 kg versus 7.1 kg, and total percent body weight loss was 10.0% vs 7.1%.

The reason for the better weight loss in real life, Moore speculated, is because the device isn't covered by insurance, and patients who pay $8,000 to $10,000 out-of-pocket for the system may be more likely to stick to lifestyle modification programs.

Indeed, she noted, "the intragastric balloon is definitely intended to be paired with lifestyle treatment."

At Moore's facility patients pay for a year of treatment, which includes the 6 months the device is in and 6 months more afterward to continue with maintenance of or continued weight loss after the device is retrieved.

She enrolls all her balloon patients in an online aftercare platform that provides extensive one-on-one and group coaching and exercise classes, in addition to interdisciplinary services. She sees patients monthly for a year.

McBride said it was also her experience that the more motivated patients did better.

"As a bariatric professional, one of the things I find is that the patients who are looking for a tool to help them will always do better than the ones who are looking for a device or a surgery to do everything for them. You really have to embrace the concept that this is a tool to be added to lifestyle modification."

McBride also said that balloons and other minimally invasive devices are best suited to patients with moderate but not severe obesity and who have fewer comorbidities compared with those who might be better candidates for surgery.

"In general, I think we're coming to realize that obesity is a lifetime disease, and there is a great demand for less invasive options that may be repeatable over time and that don't burn any bridges in case 10 or 20 years down the line you need something else. I think that's part of what is appealing about this for patients."

The registry is supported by Obalon. Moore has reported receiving research grants from Obalon, Apollo Endosurgery, Allurion Technologies, and Elira, and consulting fees from Apollo, Medtronic, and Olympus. McBride has reported no relevant financial relationships.

Presented November 14, 2018 at Obesity Week 2018.

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