Omega Gastric Bypass (150cm) Compared to the Roux-en-Y Gastric Bypass (YOMEGA-2 Multicentric Trial) (YOMEGA-2)

Randomized Controlled Non-inferiority Trial Evaluating the Safety and Efficacy of the Omega Gastric Bypass With 150 cm Biliopancreatic Loop Length Compared to the Roux-en-Y Gastric Bypass

Obesity with its consequences such as type 2 diabetes, high blood pressure, dyslipidemia, fatty liver disease, sleep apnea and cancers, remains a major healthcare problem worldwide. Bariatric surgery, combined with nutritional education and close monitoring, has been shown to be the most effective treatment for patients with morbid obesity resulting in significant and lasting weight loss and improvements in co-morbidities . With nearly 50000 procedures per year France ranks third in the world in terms of care for patients suffering from morbid (BMI ≥ 40 kg/m²) and severe (BMI 35-40 kg/m²) obesity.

In parallel with the significant increase in the number of patients operated on for obesity in the world, over the past two decades, significant development has been observed in the field of bariatric surgery with a decrease or even disappearance of some procedures and the appearance of others.

Performed for more than 40 years, the Roux-en-Y Gastric Bypass (RYGB) is a restrictive and malabsorptive procedure and currently is considered as gold standard procedure for the treatment of morbid obesity and its comorbidities. However, despite the good effectiveness (with an average Excess Weight Loss % (EWL%) of approximatively 70% at 2 years), RYGB is technically demanding procedure with learning curve requiring more than 100 cases and an overall complication rate ranging from 10% to 20% Introduced in 2001, one anastomosis gastric bypass (OAGB) is a modified gastric bypass that consists of a single gastrojejunal anastomosis between a long gastric pouch and a jejunal (biliopancreatic) omega loop. In Sept. 2019, taking into account the results from YOMEGA trial, the French High Authority for Health (Haute Autorité de Santé (HAS)) recommended to ban OAGB with 200 cm or longer BPL and urged to assess the efficacy and safety of OAGB with 150 cm BPL in a randomized controlled trial. Indeed, YOMEGA-2 trial is logical continuity of the YOMEGA trial.

The aim of this study is to assess weight loss efficiency and the nutritional safety of the OAGB-150 in comparison to a standard (RYGB).

The hypothesis of this study is that the OAGB with a 150 cm BPL could have the same efficacy on weight loss and nutritional complication rate in comparison to the RYGB at 2 years.

Study Overview

• Status: Recruiting
• Conditions: Obesity; Morbid
• Intervention / Treatment: Procedure: Laparoscopic OAGB; Procedure: Laparoscopic RYGB

Detailed Description

Obesity with its consequences such as type 2 diabetes, high blood pressure, dyslipidemia, fatty liver disease, sleep apnea and cancers, remains a major healthcare problem worldwide. Bariatric surgery, combined with nutritional education and close monitoring, has been shown to be the most effective treatment for patients with morbide obesity resulting in significant and lasting weight loss and improvements in co-morbidities . With nearly 50000 procedures per year France ranks third in the world in terms of care for patients suffering from morbid (BMI ≥ 40 kg/m²) and severe (BMI 35-40 kg/m²) obesity.

In parallel with the significant increase in the number of patients operated on for obesity in the world, over the past two decades, significant development has been observed in the field of bariatric surgery with a decrease or even disappearance of some procedures and the appearance of others.

Performed for more than 40 years, the Roux-en-Y Gastric Bypass (RYGB) is a restrictive and malabsorptive procedure and currently is considered as gold standard procedure for the treatment of morbid obesity and its comorbidities. However, despite the good effectiveness (with an average Excess Weight Loss % (EWL%) of approximatively 70% at 2 years), RYGB is technically demanding procedure with learning curve requiring more than 100 cases and an overall complication rate ranging from 10% to 20% Introduced in 2001, one anastomosis gastric bypass (OAGB) is a modified gastric bypass that consists of a single gastrojejunal anastomosis between a long gastric pouch and a jejunal (biliopancreatic) omega loop. In Sept. 2019, taking into account the results from YOMEGA trial, the French High Authority for Health (Haute Autorité de Santé (HAS)) recommended to ban OAGB with 200 cm or longer BPL and urged to assess the efficacy and safety of OAGB with 150 cm BPL in a randomized controlled trial. Indeed, YOMEGA-2 trial is logical continuity of the YOMEGA trial.

The aim of this study is to assess weight loss efficiency and the nutritional safety of the OAGB-150 in comparison to a standard (RYGB).

The hypothesis of this study is that the OAGB with a 150 cm BPL could have the same efficacy on weight loss and nutritional complication rate in comparison to the RYGB at 2 years.

• Study Type: Interventional
• Enrollment (Estimated): 368
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Tigran POGHOSYAN, MD-PhD; Phone Number: 33 1 40 25 82 39; Email: tigran.poghosyan@aphp.fr

Study Locations

• France
  • Paris, France
    • Recruiting
    • Hopital Bichat Claude-Bernard

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Patient aged from 18 to 65 years old
• Type III obesity (BMI ≥ 40 kg/m²), or Type II obesity BMI 35-40 kg/m2 associated with at least one co-morbidity which will be improved by surgery (high blood pressure, type 2 diabetes mellitus, obstructive sleep apnea, dyslipidemia, arthrosis)
• Patient who had benefited from an Upper GI Endoscopy with biopsies to look for Helicobacter pylori within 12 months before surgery
• Patient who has benefited from a multidisciplinary evaluation at least 6 months, with a favorable opinion for a gastric bypass
• Patient who understood and accepted the need for a long-term follow-up
• Patient who agreed to be included in the study and who signed the informed consent form
• Patient affiliated to a social security scheme
• For child-bearing aged women, efficient contraception

Exclusion Criteria:

• History of previous bariatric surgery
• History of chronic inflammatory bowel disease
• Presence of chronic diarrhea
• Presence of a severe and evolutive life threatening pathology
• Presence of dysplastic modifications of the gastric mucosa, chronic atrophic gastritis or history of gastric cancer
• Presence of an unhealed gastro-duodenal ulcer
• Presence of Helicobacter pylori resistant to medical treatment
• Presence of esophagitis
• Pregnancy or desire to be pregnant during the study
• Mentally unbalanced patients, under supervision or guardianship
• Patients who don't understand French and not able to give consent
• Patient included and followed in another interventional trial
• Unable to consent, under tutelage or curatorship, or judiciary safeguard
• Presence of type 1 diabetes

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental group; This corresponds to patients with type 2 obesity (BMI 35-40) with comorbidities (high blood pressure, type 2 diabetes mellitus, obstructive sleep apnea, dyslipidemia, arthrosis) and type 3 obesity (BMI ≥ 40 kg/m²) and candidates for bariatric surgery. Laparoscopic OAGB will be performed with long and narrow gastric pouch (30cc) and 150 cm biliopancreatic limb	Procedure: Laparoscopic OAGB; It is a gastric bypass surgery with a unique gastro-jejunal anastomosis, a long (11-14cm) and narrow (3-4cm) gastric pouch will be created by applying one horizontal 45-mm stapler at the angle of lesser curvature, just above the left branch of the crow's foot, and then four to five vertical 60-mm staple cartridges will be placed upwards to the angle of His, and calibrated along a 32-Fr bougie. Sectioning of the greater omentum into a bivalve will be performed. The jejunum will be measured using pre-measured strip and amounted antecolically at 150 cm from the ligament of Treitz. An end-to-side anastomosis will be performed with the gastric pouch, using a 45-mm linear stapler and an anterior running suture to close gastro-enterotomy.; Other Names: One Anastomosis Gastric Bypass / Mini Gastric Bypass
Active Comparator: Control Groupe; This corresponds to patients with type 2 obesity (BMI 35-40) with comorbidities (high blood pressure, type 2 diabetes mellitus, obstructive sleep apnea, dyslipidemia, arthrosis) and type 3 obesity (BMI ≥ 40 kg/m²) and candidates for bariatric surgery. Standard laparoscopic RYGB will be performed with a gastric pouch (30cc) and 150 cm antecolic Roux limb and a 50 cm biliopancreatic limb.	Procedure: Laparoscopic RYGB; A small gastric pouch (30cc) will be created using a linear stapler. The alimentary limb will be moved up into an antecolic position after an epiploic transection so as to perform the gastro-jujunal anastomosis. The gastro-jejunostomy will be performed manually or using a linear or circular stapler. An alimentary limb of 150 cm and a biliary limb of 50cm will be measured (using premeasured strip) in order to perform the latero-lateral jejuno-jejunal anastomosis using a linear stapler. All mesenteric defects (Petersen's space and mesenteric defect) will be closed with a non-absorbable running suture; Other Names: Roux-en-Y Gastric Bypass

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To demonstrate that OAGB with 150 cm biliopancreatic limb is not inferior to RYGB on nutritional complication rate (safety)	For each patient co-primary endpoints will be assessed at 2 years after surgery composed by: Safety: Nutritional complications defined by at least one vitamin deficiency (vit. B1 < 66nmol/l or B12 < 145pmol/l), malnutrition (albumin < 30g/l), anemia (hemoglobin < 10g/dl) or a combination of these. The assessment of the primary co-endpoint will be standardized between the sites.	2 years after the surgery
To demonstrate that OAGB with 150 cm biliopancreatic limb is not inferior to RYGB on weight loss (efficacy).	For each patient co-primary endpoints will be assessed at 2 years after surgery composed by: Efficacy: Weight loss according to Excess Weight Loss % (EWL%) calculated using the following formula: ((weight 2 years after surgery - initial weight) / (initial weight - ideal weight)) x 100. Ideal weight defined as the weight corresponding to a BMI = 25 kg/m². The assessment of the primary co-endpoint will be standardized between the sites.	2 years after the surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Absolute weight loss assessment	Weight loss at 1, 3, 6, 12, 18 and 24 months after surgery, according to absolute weight loss (aWL) in kg.	1, 3, 6, 12, 18 and 24 months after surgery
Excess Weight Loss percentage assessment	Weight loss at 1, 3, 6, 12, 18 and 24 months after surgery, according to Excess Weight Loss percentage (EWL%), calculated using the following formula: ((weight at visit X - initial weight) / (initial weight - ideal weight)) X 100	1, 3, 6, 12, 18 and 24 months after surgery
Excess BMI Loss percentage assessment	Weight loss at 1, 3, 6, 12, 18 and 24 months after surgery, according Excess BMI Loss percentage (EBL%), according to the formula : ((BMI at visit X - initial BMI) / (initial BMI - ideal BMI)) X 100 with Ideal BMI = 25 kg/m²	1, 3, 6, 12, 18 and 24 months after surgery
Measurement of albumin	Measurement of albumin will explore the nutritional status of patients. Results will be expressed in g/l	Before and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of pre-albumin	Measurement of pre-albumin will explore the nutritional status of patients. Results will be expressed in g/l	Before and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of hemoglobin	Measurement of hemoglobin will explore the nutritional status of patients. Results will be expressed in g/l	Before and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of calcium	Measurement of calcium will explore the nutritional status of patients. Results will be expressed in mmol/l	Before and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of ferritin	Measurement of ferritin will explore the nutritional status of patients. Results will be expressed in μg/l	Before and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of iron	Measurement of iron will explore the nutritional status of patients. Results will be expressed in mmol/l	Before surgery and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of % of transferrin saturation	Measurement of % of transferrin saturation will explore the nutritional status of patients. Results will be expressed in %	Before surgery and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of zinc	Measurement of zinc will explore the nutritional status of patients. Results will be expressed in mmol/L	Before surgery and 6, 12 months and 24 months after surgery
Measurement of vitamin A	Measurement of vitamin A will explore the nutritional status of patients. Results will be expressed in mmol/l	Before surgery and 6, 12 and 24 months after surgery
Measurement of vitamin B1	Measurement of vitamin B1 will explore the nutritional status of patients. Results will be expressed in nmol/l	Before surgery and 6, 12 and 24 months after surgery
Measurement of vitamin B9	Measurement of vitamin B9 will explore the nutritional status of patients. Results will be expressed in nmol/l	Before surgery and 6, 12 and 24 months after surgery
Measurement of vitamin B12	Measurement of vitamin B12 will explore the nutritional status of patients. Results will be expressed in pmol/l	Before surgery and 6, 12 and 24 months after surgery
Measurement of vitamin E	Measurement of vitamin E will explore the nutritional status of patients. Results will be expressed in mmol/l	Before surgery and 6, 12 and 24 months after surgery
Measurement of vitamin D	Measurement of vitamin D will explore the nutritional status of patients. Results will be expressed in nmol/l	Before surgery and 6, 12 and 24 months after surgery
Measurement of prothrombin rate	Measurement of prothrombin rate will explore the nutritional status of patients. Results will be expressed in %	Before surgery and 6, 12 and 24 months after surgery
Measurement of the 24-hour steatorrhea rate	Measurement of the average number of stool will explore the nutritional status of patients. Results will be expressed in number of stool/day	6 month after surgery
Measurement of HbA1c	Measurement of HbA1c will explore the Metabolic efficiency of surgery. Results will be expressed in %	Before surgery and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of fasting glycemia	Measurement of fasting glycemia will explore the Metabolic efficiency of surgery. Results will be expressed in mmol/l	Before surgery and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of HDL	Measurement of HDL will explore the Metabolic efficiency of surgery. Results will be expressed in mmol/l	Before surgery and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of LDL	Measurement of LDL will explore the Metabolic efficiency of surgery. Results will be expressed in mmol/l	Before surgery and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of cholesterol	Measurement of cholesterol will explore the Metabolic efficiency of surgery. Results will be expressed in mmol/l	Before surgery and 1, 3, 6, 12, 18 and 24 months after surgery
Measurement of triglycerides	Measurement of triglycerides will explore the Metabolic of surgery. Results will be expressed in mmol/l	Before surgery and 1, 3, 6, 12, 18 and 24 months after surgery
Evaluation of antidiabetic drugs	Assessment of number of antidiabetic medications will explore the Metabolic efficiency of surgery. This outcome will be expressed in terms of increase, decrease, discontinuation or restart of treatment.	Before surgery and 6, 12 and 24 months after surgery
Evaluation of antilipidemic drugs	Assessment of the number of antilipidemic medications will explore the Metabolic efficiency of surgery. This outcome will be expressed in terms of increase, decrease, discontinuation or restart of treatment	Before surgery and 6, 12 and 24 months after surgery
Evaluation of antihypertensive drugs	Assessment of the number of antihypertensive medications will explore the Metabolic efficiency of surgery. This outcome will be expressed in terms of increase, decrease, discontinuation or restart of treatment.	Before surgery and 6, 12 and 24 months after surgery
Evaluation of the use of Continuous Positive Airway Pressure for Obstructive Sleep Apnea	Evolution of the use of Continuous Positive Airway Pressure for Obstructive Sleep Apnea will explore the Metabolic efficiency of surgery. This outcome will be expressed in terms of the use or discontinuation of the use of Continuous Positive Airway Pressure machine	Before surgery and 6, 12 and 24 months after surgery
Hospitalization length	The Length of stay (in days) is based on the number of days of hospitalization from surgery (day of surgery = D0) until the end of hospitalization.	The last day of hospitalization
Number of patients readmitted	Number of patients readmitted within 30 days after surgery.	30 days after surgery
Occurrence of kidney stone	For each visit after the surgery, the presence or not of kidney stones will be documented and if applicable the treatment will be noted	Within 2 years after surgery
Overall complications rate	Rate of medical and surgical (> or = grade III) complications within 24 months after surgery using the Dindo-Clavien classification, described as : Grade I = Any deviation from the normal postoperative course. Grade II = Requiring pharmacological treatment with drugs other than such allowed for grade I complications. Grade III = Requiring surgical, endoscopic or radiological intervention, not under (Grade IIIa) or under general anesthesia (Grade IIIb) Grade IV = Life-threatening complication with single organ (Grade IVa) or Multiorgan dysfunction (Grade IVb) Grade V = Death of a patient.	Within 24 months after surgery
Type of early complications	Type (medical or surgical) of early complications (within 30 days) for each procedure.	Within 30 days after surgery
Severity of early complications	Severity of early complications (within 30 days) for each procedure according to the Dindo-Clavien classification	Within 30 days after surgery
Type of late complications	Type (medical or surgical) of late complications (after 30 days) for each procedure.	Within 2 years after surgery
Severity of late complications	Severity of late complications (after 30 days) for each procedure according to the Dindo-Clavien classification	Within 2 years after surgery
Gastroesophageal reflux assessment	Evolution of gastroesophageal reflux will be assessed at each study visit, before and after surgery. This outcome will be expressed in terms of improvement, aggravation or onset.	Before surgery and 1, 3, 6, 12, 18 and 24 months after surgery
Quality of life assessed with GIQLI questionnaire	This questionnaire consists of 36 items exploring 5 dimensions or subscales: symptoms, physical condition, emotions, social integration and the effect of any medical treatment. For each item, 5 responses will be proposed to the patients and for each answer, a score ranging from 0 to 4 (highest score = 144) will be assigned. A high score defines a more favorable health state	Before surgery and at 6, 12 and 24 months after surgery
Quality of life assessed with SF36 questionnaire	This questionnaire taps eight health concepts: physical functioning, bodily pain, role limitations due to physical health problems, role limitations due to personal or emotional problems, emotional well-being, social functioning, energy/tiredness, and general health perceptions. It also includes a single item that provides an indication of a perceived change in health	Before surgery and at 6, 12 and 24 months after surgery
Quality of life assessed with Sigstad questionnaire	The Sigstad questionnaire allows the identification and diagnosis of postoperative dumping syndrome and early hypoglycaemia: a score >7 suggests a dumping syndrome	Before surgery and at 1, 3, 6, 12, 18 and 24 months after surgery
Body composition	Body composition level on a subsample of the total population: By impedancemetry : Muscle mass index in kg/m2; Non-fat mass index in kg/m2; Fat mass index in kg/m2	Before and 24 months after surgery.
Sarcopenia level	Sarcopenia level on a subsample of the total population will be assessed by Handgrip Strength	Before and 24 months after surgery.

Collaborators and Investigators

• Sponsor: Assistance Publique - Hôpitaux de Paris
• Investigators: Principal Investigator: Tigran POGHOSYAN, MD-PhD, Bichat (APHP)

Study record dates

Study Major Dates

• Study Start (Actual): November 13, 2023
• Primary Completion (Estimated): October 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: April 3, 2023
• First Submitted That Met QC Criteria: September 21, 2023
• First Posted (Actual): September 28, 2023

Study Record Updates

• Last Update Posted (Actual): February 27, 2026
• Last Update Submitted That Met QC Criteria: February 24, 2026
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Bariatric surgery; RYGB; MGB/OAGB
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity; Therapeutics; Surgical Procedures, Operative; Digestive System Surgical Procedures; Anastomosis, Surgical; Bariatric Surgery; Bariatrics; Obesity Management; Gastroenterostomy; Gastric Bypass
• Other Study ID Numbers: APHP211050

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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