Bariatric Surgery vs. Semaglutide vs. Tirzepatide

The recent introduction of the new generation of anti-obesity medications (AOMs) will change the future of obesity treatment. These highly effective medications, such as high-dose semaglutide and tirzepatide, are hormone analogues that augment the incretin function and exert multiple physiological effects by activating glucagon-like peptide-1 (GLP-1) and/or glucose-dependent insulinotropic polypeptide (GIP) distributed in various organs. These medications provide an average of 15-22% weight reduction in one-year trials, which had not been seen in the past with medical therapy. While the literature suggests that bariatric surgery is superior to these new highly effective medications, there is no head-to-head comparison between the most common bariatric operations (Roux-en-Y gastric bypass \[RYGB\] and sleeve gastrectomy \[SG\]) with semaglutide (once weekly) and tirzepatide (once weekly). The goal of this Randomized Clinical Trial (RCT) is to compare these effective therapies in patients with severe obesity to provide the best evidence to inform clinical decisions in treating patients with obesity.

This is a randomized, non-blinded, controlled efficacy/safety study with 3 parallel groups who will either receive bariatric surgery (RYGB or SG), semaglutide, or tirzepatide. The study has 2 phases: the first 12 months for the assessment of the primary endpoint ( mean percentage weight loss) and the second 12 months as the extension phase of the study to mimic the real-life setting. Findings at the end of each phase will be separately reported.

A randomized trial of 125 patients with a BMI of 35-65 kg/m2 who sought treatment for obesity at Cleveland Clinic will be performed. Patients who meet the ASMBS/IFSO 2022 guidelines for bariatric surgery will be invited for possible enrollment. Interested and eligible patients will be randomized to receive their already chosen bariatric surgery (RYGB or SG), tirzepatide. or semaglutide in 2:2:1 ratio.

The study is not intended to compare RYGB vs SG head-to-head. RYGB and SG constitute one group as a bariatric surgery group. The assignment of RYGB or SG is not based on a randomized design. Each patient and surgical team will make a shared decision about the most appropriate surgical procedure. The study is also not intended to compare semaglutide vs tirzepatide head-to-head.

In the second or extension phase of the study, participants are followed from month 12 to month 24, regardless of the treatment that they receive. In this phase, the study medications (semaglutide and tirzepatide) will not be provided by the study. The goal of this phase is to provide valuable insights into A) access to AOMs and the durability of effects in the real-life setting, B) cross-over from AOMs to bariatric surgery, and C) adjuvant pharmacotherapy after bariatric surgery.

Eligibility Criteria:
Inclusion Criteria:

Entry into the study would require that the patient:

1. Is a candidate for general anesthesia
2. Is eligible for bariatric surgery (RYGB or SG) based on ASMBS/IFSO 2022 guidelines
3. Is ≥18 and ≤70 years old (both inclusive)
4. has a BMI ≥35 and ≤65 kg/m2 (both inclusive)
5. Patients with and without T2DM are eligible for the study. Patients with T2DM should have been on a stable dose of anti-diabetic medication (including insulin but not semaglutide or tirzepatide) for at least 3 months prior to entry, with HbA1c ≤12%.
6. No weight loss \> 20 lbs. in 3 months before screening (self-reported)
7. Has the ability and willingness to participate in the study, provide informed consent, and agree to any of the arms involved in the study.
8. Is able to understand the options and to comply with the requirements of each arm.
9. Has a negative urine pregnancy test at randomization visit for women of childbearing potential.
10. Women of childbearing age must agree to use reliable method of contraception for 2 years.

Exclusion Criteria:

1. Significant cardiac or atherosclerotic disease (planned to undergo cardiac, coronary, carotid, or peripheral artery revascularization procedures in the next 12 months)
2. Severe uncompensated cardiopulmonary disease leading to American Society of Anesthesiologists Class IV or V
3. Classified as New York Heart Association Class IV
4. Left ventricular ejection fraction \<25% at the time of screening (if already known)
5. Myocardial infarction, unstable angina, stroke, transient ischemic attack, heart surgery, coronary stent placement in the past 6 months
6. Prior bariatric surgery of any kind

   • Intragastric balloon that has been removed at least 6 months prior to the first study visit is allowed.
7. History of solid organ transplant
8. Type 1 diabetes or autoimmune diabetes
9. eGFR \< 30 mL/min/1.73 m2 or being on dialysis
10. History of deep vein thrombosis, pulmonary embolism, or venous thromboembolism
11. On therapeutic dose of anticoagulants such as warfarin or direct oral anticoagulants (DOACs)
12. Decompensated cirrhosis characterized by presence of ascites, hepatic encephalopathy, portal hypertension, or esophageal varices.
13. History of severe anemia defined as hemoglobin less than 8 g/dL
14. Use of investigational therapy
15. Liver transaminase level or alkaline phosphatase \>200 U/L
16. Significant alcohol use (average \>2 drinks/day)
17. Presence of active malignancy (except non-melanoma skin cancer)
18. Life expectancy less than 3 years due to concomitant diseases
19. Major mental health, psychological disorders, or substance abuse disorders that in the opinion of the investigators could disqualify the patient from bariatric surgery
20. Any condition or major illness that, in the investigator's judgment, places the subject at undue risk by participating in the study
21. Unable to understand the risks, benefits and compliance requirements of study
22. Lack capacity to give informed consent
23. Plans to move outside the primary location of study (northeast Ohio) within the next 12 months
24. Pregnant, breast-feeding or the intention of becoming pregnant or not using adequate contraceptive measures
25. Hypothalamic obesity
26. Continuous treatment with semaglutide (once weekly) or tirzepatide (once weekly) \<60 days before screening
27. History of semaglutide (once weekly) or tirzepatide (once weekly) use in the past for obesity with lack of clinical response
28. Chronic use of systemic steroids
29. Uncontrolled thyroid disease: thyroid stimulating hormone (TSH) \> 6.0 mIU/L or \< 0.1 mIU/L

    • Note: Patients receiving treatment for hypothyroidism can be included if their thyroid hormone replacement dose has been stable for at least 3 months.
30. Acute pancreatitis \< 180 days before screening
31. History or presence of chronic pancreatitis
32. History of Crohn's disease
33. Known or suspected allergy to semaglutide, tirzepatide, excipients, or related products
34. A personal or family history of medullary thyroid carcinoma (MTC) or in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
35. Previous participation in this trial and got randomized to one of the study groups but did not proceed.