MERIT RCT: Endoscopic Sleeve Gastroplasty is safe and results in significant weight loss

Updated: Aug 9

Outcomes from the Multi-center ESG Randomized Interventional Trial (MERIT) have demonstrated that Endoscopic Sleeve Gastroplasty (ESG) is a safe intervention that results in significant weight loss, maintained at 104 weeks, with important improvements in metabolic comorbidities. The results were featured in the paper, 'Endoscopic sleeve gastroplasty for treatment of class 1 and 2 obesity (MERIT): a prospective, multicentre, randomised trial', published in The Lancet.

OverStitch Endoscopic Suturing System

The MERIT study is a multi-centre, prospective randomised clinical trial evaluating the safety and effectiveness of ESG, a minimally invasive, endoscopic weight loss procedure performed with Apollo's Endosurgery's OverStitch Endoscopic Suturing System.


"After decades of research in the field of bariatric endoscopy, we finally have an endoscopic procedure that has proven to be safe, effective, and durable out to at least two years in a randomized controlled trial," stated Dr Erik Wilson, Professor and Vice Chair of Surgery at The University of Texas Health Science Center at Houston and a co-principal investigator. "The ESG procedure will be an important tool for both surgeons and gastroenterologists to help address the global obesity epidemic."


In the study, patients with Body Mass Index (BMI) ≥30 and ≤40 kg/m² were randomised to treatment with ESG and lifestyle modification or to a control group which involved lifestyle modification alone. At the conclusion of the primary end point (52 weeks), qualifying patients in the control group were allowed to cross-over to ESG if they met certain conditions.

Nine US centres participated in the study, representing both gastroenterology and bariatric surgery practices from academic and community settings. One hundred and fifty-seven subjects completed the study through 52 weeks of follow-up (68 treatment and 89 control subjects). Seventy-two control patients crossed over to treatment at 52 weeks, and both groups were followed an additional 52 weeks.


The primary endpoint at 52 weeks was the percentage of excess weight loss (EWL), with excess weight being that over the ideal weight for a BMI of 25kg/m2. Secondary endpoints included change in metabolic comorbidities between the groups.


At 52 weeks, the primary endpoint of mean percentage of EWL was 49.2% (SD 32.0) for the ESG group and 3.2% (18.6) for the control group (p<0·0001). Mean percentage of total bodyweight loss was 13.6% (8.0) for the ESG group and 0.8% (5.0) for the control group (p<0·0001), and 59 (77%) of 77 participants in the ESG group reached 25% or more of EWL at 52 weeks vs 13 (12%) of 110 in the control group (p<0·0001).


At 52 weeks, 41 (80%) of 51 participants in the ESG group had an improvement in one or more metabolic comorbidities, whereas six (12%) worsened, compared with the control group in which 28 (45%) of 62 participants had similar improvement, whereas 31 (50%) worsened. At 104 weeks, 41 (68%) of 60 participants in the ESG group maintained 25% or more of EWL. ESG-related serious adverse events occurred in three (2%) of 131 participants, without mortality or need for intensive care or surgery.

Barham Abu Dayyeh

Three ESG patients (2.0%) experienced a device or procedure related serious adverse event, all of which resolved and did not require intensive care or surgical intervention.


"In addition to weight loss, the MERIT study demonstrated clinically meaningful improvements in obesity related comorbidities," stated Dr Barham Abu Dayyeh, Professor of Medicine and Director of Advanced Endoscopy at Mayo Clinic and one of the co-principal investigators. "This procedure is a global advancement in the fields of bariatrics and endoscopy."


In July 2022, following a De Novo Classification review, the FDA authorised the marketing of the Apollo ESG and Apollo REVISE Systems, the first and only FDA-authorised systems for ESG and endoscopic bariatric revision.


"The publication of this randomised trial in such a high impact and influential journal as The Lancet speaks to the significance of its findings and implications for patients who suffer from obesity," commented Chas McKhann, President and CEO of Apollo. "The results of the study are a strong testament to the opportunity that we have at Apollo to expand the therapeutic spectrum of obesity and metabolic care to affect real change in the obesity epidemic."


The MERIT study was funded by Apollo Endosurgery and the Mayo Clinic.


To access The Lancet paper, please click here


This trial is registered with ClinicalTrials.gov, NCT03406975.