MERIT: Endoscopic sleeve gastroplasty study meets primary endpoints

Study investigators of the Multi-Center Endoscopic Sleeve Gastroplasty (ESG) Randomized Interventional Trial (MERIT) have announced that the study has met its primary endpoints for safety and efficacy. Patients undergoing the ESG procedure achieved excess body weight loss (EWL) of 49.2% at 12 months and a serious adverse event rate of 2%. In addition, they also reported clinically significant reductions in diabetes, hypertension and metabolic syndrome at 12 months.

The MERIT study is a multi-centre, prospective randomised clinical trial evaluating the safety and effectiveness of the ESG procedure, compared to a medically monitored regimen of diet and healthy lifestyle. The co-principal investigators are Dr Erik Wilson, University of Texas at Houston (Houston, TX), and Dr Barham Abu Dayyeh, Professor of Medicine and Director of Advanced Endoscopy at the Mayo Clinic, Rochester, MN, under a collaborative research agreement sponsored by Apollo Endosurgery.


ESG is a minimally-invasive (nonsurgical) weight loss procedure that uses Apollo Endosurgery's OverStitch Endoscopic Suturing System to reduce the volume of a person's stomach. According to the company, the MERIT data adds to a larger body of evidence for ESG of more than 200 publications and abstracts reporting positive outcomes in over 6,500 patients.


Dayyeh presented the data at the Virtual International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) meeting, during the ‘Top 10 Papers at IFSO’ session. Key highlights from the trial include:

  • Study Methods: The trial enrolled 208 patients across nine US centres. Patients were randomised between ESG and moderate lifestyle modification controls. Average BMI at enrolment was 35.7±2.6 kg/m2. The primary efficacy endpoint was %EWL and responders were defined as those achieving at least 25% EWL at 12 months. The study targeted a serious adverse event rate of <5%, which was the primary safety endpoint. Patients were followed for 24 months, with control subjects given the option to cross over at 12 months.

  • Efficacy: Patients undergoing ESG demonstrated an EWL of 49.2% (+32%) at 12 months, which was a 45% difference in %EWL compared to patients undergoing moderate intensity lifestyle modification. Furthermore, 77% of subjects undergoing ESG achieved at least 25% EWL, and percent total body weight loss (%TBWL) for this responder group was 16.3% (+7%).

  • Impact on Co-Morbidities: Patients undergoing ESG demonstrated improvements in diabetes, hypertension, and metabolic syndrome compared to controls, as well as improvement in, and no onset of, gastroesophageal reflux disease (GERD).

  • Safety: ESG met the primary safety endpoint with a rate of serious adverse events of 2.0% (3/150), all of which resolved and did not require intensive care or surgical intervention.

  • Durability: Despite the Global Pandemic during year-two, cross-over patients achieved similar results to the initial treatment group and those that had undergone treatment maintained the vast majority of their weight loss at 24 months.

"The MERIT outcomes are compelling, and the medical community is eager to embrace new treatment options to address the global obesity problem," said Dayyeh. "Endoscopic Sleeve Gastroplasty offers a scalable, safe, effective, organ-sparing solution that can be performed in an outpatient facility by either a gastroenterologist or a bariatric surgeon. In addition, the ESG procedure can be combined with other therapeutic options to further enhance patient outcomes."

"This is a significant milestone for Apollo in our mission to dramatically impact chronic obesity and obesity-related health conditions that continue unabated around the world," said Chas McKhann, President and CEO of Apollo Endosurgery. "The results of MERIT support that the ESG procedure offers a compelling value proposition of clinically significant weight loss from a safe, convenient, outpatient procedure. We look forward to our continued work with the FDA, following our recent De Novo 510(k) submission, as we seek regulatory clearance to recognize ESG as a potential treatment option for those living with obesity."