iWAIST Trial: ERCG (Endoscopic Radial Compression Gastroplasty) vs Optimized Lifestyle Intervention for Weight Loss (iWAIST-RCT)

iWAIST Trial: A Multicenter, Single-Blind, Randomized, Sham-Controlled Trial of Endoscopic Radial Compression Gastroplasty (ERCG) Plus Optimized Lifestyle Intervention for Weight Management in Chinese Adults With Overweight or Mild-to-Moderate Obesity

Obesity and overweight are rising in Chinese populations, where metabolic risks begin at lower BMI thresholds than in Western cohorts. Many individuals with overweight or mild-to-moderate obesity are ineligible or unwilling to undergo bariatric surgery due to invasiveness and risk. Endoscopic bariatric and metabolic therapies offer minimally invasive alternatives but vary in complexity, cost, and safety profiles. Investigators developed a sutureless endoscopic procedure, Endoscopic Radial Compression Gastroplasty (ERCG), which reduces gastric volume by apposing gastric walls using a clip-and-loop system. This randomized controlled trial evaluates the efficacy and safety of ERCG versus an optimized lifestyle intervention in Asian adults with BMI 24.0-37.4 kg/m² who have not succeeded with conservative measures. Preliminary studies suggest ERCG can achieve approximately 12% total body weight loss (TBWL) at 3 months. The primary endpoint is percent TBWL at 3 months; secondary outcomes include changes in BMI, metabolic parameters, quality of life, and adverse events. Results are expected to inform the role of ERCG as a safe, effective, and scalable option between conservative care and bariatric surgery.

Study Overview

• Status: Recruiting
• Conditions: Metabolic Syndrome; Nonalcoholic Fatty Liver Disease; Overweight and/or Obesity; Chinese
• Intervention / Treatment: Procedure: Endoscopic Radial Compression Gastroplasty; Behavioral: Optimized Lifestyle Intervention (OLI)

Detailed Description

The prevalence of obesity and overweight continues to increase worldwide, and Chinese populations are particularly vulnerable due to lower thresholds for metabolic risk compared with Western populations. Individuals with overweight or mild-to-moderate obesity (BMI 24.0-37.4 kg/m²) often fail conservative measures but are ineligible or unwilling to undergo bariatric surgery because of its invasiveness, risk, and costs. This creates an unmet need for minimally invasive, effective, and scalable interventions.

Endoscopic bariatric and metabolic therapies (EBMTs) have emerged as alternatives, but many existing procedures involve technically complex endoscopic suturing, high costs, or device-related risks. Investigators developed ERCG, a novel endoscopic procedure that reduces gastric volume by apposing the gastric walls using a newly designed clip-and-loop system. Preliminary studies demonstrated that ERCG can induce rapid weight loss, with mean percent total body weight loss (TBWL) of approximately 12% at 3 months, while maintaining a favorable safety profile.

This randomized controlled trial aims to evaluate the efficacy and safety of ERCG compared with an optimized lifestyle intervention (OLI) in Chinese adults with overweight and mild-to-moderate obesity who have failed conservative weight reduction efforts. Eligible participants will be randomized 1:1 into two groups. The experimental group will undergo ERCG under general anesthesia or deep sedation, following a standardized perioperative protocol, then receive structured OLI. The control group will receive structured OLI consisting of individualized dietary counseling, caloric restriction, exercise prescription, and behavioral support. Follow-up visits are scheduled at 1 month, 2 month, 3 month and 6 month after enrollment.

The primary endpoint is percent TBWL at 3 months, assessed using standardized weight measurement protocols. Secondary endpoints include %EBWL at 3 and 6 months, changes in BMI, metabolic parameters (fasting plasma glucose, HbA1c, insulin resistance indices, lipid profile), quality of life assessed by validated questionnaires (IWQOL-Lite), and the incidence of adverse events classified according to international standards.

Randomization will be computer-generated with concealed allocation, and outcome assessors will be blinded to treatment assignment. Analyses will follow the intention-to-treat principle with appropriate methods for handling missing data.

The study is expected to generate high-quality evidence regarding the short-term and medium-term efficacy of ERCG, to clarify its safety profile, and to determine whether ERCG can serve as a safe and scalable option bridging the therapeutic gap between conservative lifestyle approaches and bariatric surgery for overweight and mildly to moderately obese Chinese populations.

• Study Type: Interventional
• Enrollment (Estimated): 216
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Yan Liu, M.D. PH.D.; Phone Number: +8601066947300; Email: 13911798288@163.com
• Study Contact Backup: Name: Yiyu Qiao, M.D. PH.D.; Phone Number: +8601066947300; Email: qyy96@126.com

Study Locations

• China
  • Beijing Municipality
    • Beijing, Beijing Municipality, China, 100073
      • Not yet recruiting
      • The fifth Medical Center of Chinese PLA General Hospital, Beijing
      • Principal Investigator: Yan Liu
      • Contact: Yan Liu, M.D. PH.D.; Phone Number: +8601066947300; Email: 13911798288@163.com
      • Sub-Investigator: Yiyu Qiao
    • Beijing, Beijing Municipality, China, 100073
      • Recruiting
      • The fifth Medical Center of Chinese PLA General Hospital, Beijing

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Asian adults aged 18-65 years.
• BMI 24.0-37.4kg/m²(Chinese standard)。
• Failed prior conservative weight loss attempts ≥2 months。
• Willingness to comply with follow-up.
• Provided written informed consent.

Exclusion Criteria:

• Prior gastrointestinal surgery with clinically relevant sequelae.
• Active or clinically significant gastrointestinal disease, including inflammatory conditions (e.g., esophagitis, Barrett's esophagus, Crohn's disease), peptic ulcer disease (gastric/duodenal ulcer), or neoplastic lesions.
• Any condition associated with an increased risk of upper gastrointestinal bleeding.
• Hiatal hernia >2 cm or severe/refractory gastroesophageal reflux disease (GERD); acid reflux requiring ≥2 medications for symptom control.
• Esophageal/pharyngeal structural abnormalities that may impede endoscope passage (e.g., stricture, diverticulum).
• Achalasia or other severe esophageal motility disorder.
• Severe coagulopathy.
• Insulin-dependent diabetes mellitus.
• Chronic abdominal pain.
• Gastrointestinal motility disorder (e.g., gastroparesis).
• Hepatic impairment or cirrhosis.
• Severe or uncontrolled psychiatric illness.
• Alcohol abuse or substance dependence.
• Unwilling to participate in a physician-supervised diet/behavior modification program and/or unwilling to comply with routine follow-up.
• Daily regular use of NSAIDs, anticoagulants, or other gastric-irritating medications.
• Unable or unwilling to take proton pump inhibitor (PPI) therapy as prescribed during the treatment period.
• Known or suspected hypersensitivity to any material/component of the study system.
• Pregnant or breastfeeding.
• Severe cardiopulmonary disease or other serious systemic/organic disease.
• Positive Helicobacter pylori (H. pylori) test.
• Use of time-critical medications potentially affected by altered gastric emptying (e.g., antiepileptics, antiarrhythmics).
• Current systemic corticosteroids, immunosuppressants, or opioid analgesics.
• Use of any weight-loss medication within the past 3 months or current use.
• Prior use of any intragastric device.
• Participation in a weight-affecting clinical trial within the past 6 months.
• Symptomatic congestive heart failure, clinically significant arrhythmia, or unstable coronary artery disease.
• Clinically significant respiratory disease.
• Autoimmune connective tissue disease.
• Life expectancy <1 year or severe renal/hepatic/pulmonary or other serious medical illness.
• Known genetic or endocrine cause of obesity (e.g., hypothyroidism, Prader-Willi syndrome) or other endocrine disease known to affect body weight.
• Eating disorder (e.g., night eating syndrome, bulimia nervosa, binge eating disorder, compulsive eating).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: ERCG + OLI; Sutureless endoscopic gastric volume reduction using a clip-and-loop apposition system under general anesthesia or deep sedation, plus standardized OLI (dietary counseling, calorie deficit, physical activity prescription, and behavioral support) with visit frequency matched to the comparator.	Procedure: Endoscopic Radial Compression Gastroplasty; Sutureless endoscopic gastric volume reduction using a novel clip-and-endoloop apposition system; performed under general anesthesia or deep sedation; standard perioperative care.; Behavioral: Optimized Lifestyle Intervention (OLI); Structured nutrition counseling, calorie deficit plan, physical activity prescription per regional guidelines, and behavioral support; visit frequency matched to the ERCG arm.
Active Comparator: OLI; Structured lifestyle program including individualized nutrition counseling targeting a 【~500-750 kcal/day】 deficit, physical activity prescription (≥150 min/week moderate-intensity plus resistance training twice weekly), and behavioral support delivered at the same schedule as the experimental arm.	Behavioral: Optimized Lifestyle Intervention (OLI); Structured nutrition counseling, calorie deficit plan, physical activity prescription per regional guidelines, and behavioral support; visit frequency matched to the ERCG arm.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percent Total Body Weight Loss (%TBWL)	%TBWL = [(Baseline weight - Follow-up weight) / Baseline weight] × 100. Measured using calibrated scale under standardized conditions.	1-6 months post-intervention
Clinical Responder Rate (CRR)	Percentage of participants with %TBWL > 5% at 3/6 months, where %TBWL = [(baseline weight - month 3/6 weight) / baseline weight] × 100.	3 month, 6 month

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body Height (m)	Standing height measured with a wall-mounted stadiometer, no shoes, heels together, Frankfurt plane horizontal.	Baseline
Adverse Events (AEs/SAEs) Related to Procedure	Number and proportion of participants with device-/procedure-related AEs/SAEs, graded by Clavien-Dindo and per FDA/ISO definitions.	3, 6, 12 months
Postoperative Pain (VAS/NRS)	Patient-reported pain intensity using a 0-10 scale (0=no pain, 10=worst imaginable pain). Assessed at rest.	6 hours, 24 hours, and 7 days
Postoperative Nausea Score	Patient-reported nausea severity using a 0-10 numeric rating scale (0=no nausea, 10=worst nausea).	6 hours, 24 hours, and 7 days
Body Weight (kg)	Weight measured on a calibrated scale under standardized conditions (light clothing, no shoes, preferably morning after ≥8h fasting).	Baseline, 1 month, 2 month, 3 month, 6month
Percent Excess Body Weight Loss (%EBWL)	%EBWL is calculated as [(Baseline weight - Follow-up weight) / (Baseline weight - Ideal weight)] × 100. Ideal weight is defined as the weight corresponding to a BMI of 23.9 kg/m². Weight is measured using a calibrated scale under standardized fasting conditions at each visit.	1-6 months post-intervention
Change in BMI (kg/m²)	BMI will be calculated as weight (kg) divided by height squared (m²).	Baseling, 1 month, 2 months, 3 months and 6 months
Glycated Hemoglobin (HbA1c)	HbA1c will be measured using standard laboratory methods. Values at each visit and changes from baseline will be summarized.	Baseline, 3 months
GERD-Q Total Score	Gastroesophageal Reflux Disease Questionnaire (GERD-Q) total score, validated 6-item instrument. Higher scores indicate more severe reflux symptoms.	Baseline, 3, and 6 months
Total Cholesterol	Total cholesterol will be measured after an overnight fast using standard laboratory methods. Values at each visit and changes from baseline will be summarized.	Baseline, 3 months
Low-Density Lipoprotein Cholesterol (LDL-C)	LDL-C will be measured directly or calculated using standard methods. Values at each visit and changes from baseline will be summarized.	Baseline, 3 months

Collaborators and Investigators

• Sponsor: Liu Yan
• Collaborators: The First Affiliated Hospital of Soochow University; Wuhan TongJi Hospital; First Affiliated Hospital of Lanzhou University; Ankang City Central Hospital; The Second Affiliated Hospital of Zhejiang Chinese Medical University

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2026
• Primary Completion (Estimated): December 30, 2026
• Study Completion (Estimated): May 31, 2027

Study Registration Dates

• First Submitted: September 16, 2025
• First Submitted That Met QC Criteria: November 18, 2025
• First Posted (Actual): November 20, 2025

Study Record Updates

• Last Update Posted (Actual): March 13, 2026
• Last Update Submitted That Met QC Criteria: March 11, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Obesity; Overweight; Chinese; Weight loss; Endoscopic bariatric therapy; Endoscopic gastroplasty; Gastric volume reduction
• Additional Relevant MeSH Terms: Nutrition Disorders; Metabolic Diseases; Overnutrition; Body Weight; Body Weight Changes; Digestive System Diseases; Glucose Metabolism Disorders; Liver Diseases; Insulin Resistance; Hyperinsulinism; Fatty Liver; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Overweight; Obesity; Weight Loss; Metabolic Syndrome; Non-alcoholic Fatty Liver Disease
• Other Study ID Numbers: 307-2026-iWAIST-RCT

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No